Weak knowledge of computer: March 2011

Sunday, March 27, 2011

【 Weak current College 】 how to use the virtual memory paging file is set to a non-system partition

Optimization of the masters in performance enhancing recommendations: the virtual memory paging file settings to use to non-system partition

You can improve system performance 【 follows 】:

Right-click my computer, select "Properties" and click "Advanced" tab, and in "performance" click "settings" inside, button, select "Advanced" tab at the bottom there is "virtual memory", click "change" button in the virtual memory dialog box, select the c disk, select the "custom size", then the minimum value box, enter "0", and the maximum value, enter "0", click "settings". Then select drive d, you need to set the minimum and maximum values. When you are finished, click "settings" button, and finally, click "OK" button, your system might require a restart, press the "OK" after system restart, virtual memory is on the "D" of the disc.

First, the size of
1. General conditions
In General, it is recommended that you allow Windows to automatically assigned the manage virtual memory, it can based on the actual memory usage, to dynamically adjust the size of virtual memory.
2. with regard to the minimum value
Windows recommended page file should be the minimum value for the current system physical memory size plus 12MB for physical memory size less than 256MB users, it is recommended that you set the page file, the minimum value set more bigger:
① use 128MB or less memory for the user, it is recommended that the current physical memory capacity of 1.75 times is set to the page file.
② memory size in 128MB to the user, between 256MB proposes the current physical memory capacity of 1.5 times is set to the page file.
3. with regard to the maximum value
In General, the pagefile maximum value, the larger the better, it is recommended that you set to the minimum value of 2 to 3 times.
4. for extreme conditions
If the hard disk space more nervousness, set the page file, you only need to ensure that it is not less than the physical memory of 3/4. If the physical memory is large (greater than 512MB), you can set the virtual memory is disabled.
5. depending on the task environment settings
① to 3D game-based environment
3D games on the CPU, video card, and memory requirements are very high, if the physical memory is less than 256MB, recommended virtual memory presets so little, it improves the stability of the game and fluency.
② to play the video-based environment
Video applications on hard disk space "appetite" is very big, but never like 3D gaming environment like the virtual memory set up very large, especially users of WindowsXP. Because WindowsXP will not automatically put unneeded space freed up, that is to say that the increasing Pagefiles.sys file. If you have virtual memory and WindowsXP is placed in the same partition, play RM, ASF and so video streaming file, the system always prompts you to set the virtual memory too low or insufficient disk space. To view a page file at this time, there are already enough 1GB size. It is recommended that often enjoy video file WindowsXP, initial values the user based small point, or virtual memory to the system disk other than the partition.
Second, the setting method
The following spoke in the transfer of virtual memory under WindowsXP is letter, for example about virtual memory settings: enter "open → Control Panel → System", select "Advanced" tab, click on "performance" bar "setting" button, select "Advanced" tab, click on the "virtual memory" and "change in column" button to enter the "virtual memory" window;

1. in the drive list, select the system drive letter, and then tick the "no paging file" option, and then click the "settings" button;

2. then click on another partition, select the "custom size" option in the "initial size" and "Max" settings.

【 Weak current College 】 describes IDE interface hard drive jumper jumper settings method---Power By 【 China power house network 】

To recommend a good use of hard drive jumper, like everyone on the hard drive jumper, and then on the hard drive jumper comprehensive explanation describes, in the hope that is useful to everybody. Jumper while type variety, but it is mainly present in the motherboard, hard drive jumper, optical drives these three hardware, video cards, sound cards and other accessories in the relatively rare. Here we follow learning jumper.

Motherboards jumper

Jumper up to the most complex is the motherboard jumper. In General, the motherboard jumper mainly include CPU setting jumpers, BIOS clear jumper, jumper BIOS prohibition. These jumpers, set the jumper CPU is the most complicated, it mainly has the CPU multiplier and FSB, voltage, three jumper.

On board the corresponding CPU multiplier jumper is a set of jumpers, each jumper corresponds with a multiplier that you want to find the appropriate multiplier value (or jumper combo), and then unplug the keycap shorted it (or pull to ON), this multiplier is set.

By the same token, when setting the CPU FSB jumper and voltage jumper is too, but it is important to note that the CPU FSB, double frequency and voltage setting is the most complex and each motherboard settings may not be the same, it is recommended that you set before you must carefully read the motherboard manual, follow the instructions in the specific instructions for hands-on, safer.

Motherboard manufacturers in order to reduce the user's workload, but also to attract user attention, has above the CPU FSB, multiplier and voltage jumpers are moved to the motherboard BIOS Setup, so now the motherboard has been harder to see than jumper, sometimes see also three of one or two.

In the motherboard jumper has existed in the BIOS to clear jumper. When we forget the BIOS password, the most direct way is to open the case, find the BIOS clear jumper (it usually next to the motherboard battery) to clear. Typically, clear information, as long as BOIS will be key cap from 1, 2-pin unplug and then plug in 2, 3-pin (expressed clear BIOS content) is cleared, then Reseat keycap 1, 2-pin.

Just now we introduce the main on the Board, in fact, the jumper on the motherboard with some small jumper. Like the keyboard on the jumper, etc., of the specific situation depends on you own to see your motherboard documentation. For the convenience of everyone, some manufacturers also on board set the jumpers on hard and soft jumper between the jumper function. Like Asus P4T motherboard, if we put 10 DIP switch all set to "OFF", then we can use the BIOS soft jumper, otherwise, only hard-jumper.

Hard drive jumper

Hard drive jumper on the system with master and slave. These two States are usually in a set of jumpers in the control. Most of the hard drive jumper jumper settings on the hard drive jumper power socket and cable outlet, and of course there is also a small part is set in the circuit board (such as: Samsung WN312021A hard drive jumper). Due to the hard drive jumper by interface is mainly divided into IDE and SCSI interface, so the hard drive jumper's jumper has two situations, where we introduce the IDE interface hard drive jumper jumper settings.

Current personal computer hard drive jumper mostly IDE interface, because the manufacturers are different, their settings there are significant differences. However, they are divided into three jumper settings, that is, Master, Slave and CableSelect three. Which Master indicates primary disk (normally the factory preset values), the Slave is a slave, but CableSelect refers to data line answered the IDE device, from the "identity" is received by them in the location on the data line.

ATA only use CableSelect/66 and ATA/100 dedicated cable can be achieved, and ATA/66 and ATA/100 dedicated cable blue connector must be connected to the motherboard IDE connector, connect the cable between the plug devices must be connected from disk, the data line end plugs on the device or the primary disk.

As vendors, standards are not standard and determine hard drive jumper's jumper is varied. However generally hard drive jumper spare body reverse text we can find the detailed setup instructions. Hard drive jumper jumper is actually a set of key Cap-jumper, we just follow the instructions in the keycap corresponding PIN.

In General, if our IDE interface (channel) on only by one hard drive jumper (no other IDE devices), we do not require a jumper. Only when IDE connector on the two devices only need to be set, otherwise it will cause a conflict. In general the IDE1 connector on the hard drive jumper settings for master and the other IDE device (such as another hard drive jumper or optical drive) is set to slave, this can improve overall system performance.

Optical jumper

Optical drive (including burner, DVD-ROM) and hard drive jumper, mostly IDE interface, they are also called IDE device. Jumper settings and hard drive jumper almost, in General, the jumper in the optical drive data cable from the left, it consists of three sets of pins. Represent the three States, namely, the Master, Slave and CableSelect. The motherboard is different is the optical drive of jumper description is generally printed on the CD-ROM jumpers over metal case above, we just follow the above instructions to set it.

In General, people will drive IDE2 connector installed on the motherboard, and set the master (actually drive the factory default values is the master, so do not set up to use). But if the IDE2 connector on the existence of the second IDE settings (such as a second hard drive jumper, the recorder or DVD, etc.)We are the main settings, from disk, or system does not recognize. At the same time we should note that due to the hard drive jumper jumper with CD key cap are embedded in the jumper inside plug by hand, generally difficult, it is recommended that you use tweezers.

【 Weak current College 】 optimal wireless router settings for optimal wireless network speed-Power By 【 China power house network 】

Wireless router settings is a wireless network quality decision makers, many of my friends are reflected in the wireless network speed will not do, in fact, the wireless router's configuration issue, how is the right configuration? what are the optimal choice? please see below. Wireless technology is good, then easy but if you cannot download BT, cannot smoothly games it has no value. While the focus of this article is to introduce you to how to proceed in WLAN environment reasonable BT download settings to get the best results. Maybe a lot of friends all have this feeling that their own wired router into a wireless router, BT download the stability and the connection speed is a significant decrease, even not for BT download.　　In fact, whether wired or wireless routing their works are basically the same: intranet outward network messages are not blocked, but want to have access to from outside the internal network's information will be identified and filtered before they are forwarded to the internal network computer that is only based on this principle, causing many intranet BT users download a stop and slow. Of course, for the wireless router, we also require some additional wireless router settings to obtain the same download cable network. Turn off SSID SSID (Service Set Identifier) is normally provided by the access point or wireless router broadcasts out of local area network name, its purpose is to let only the wireless router is set to the value of the same name as the SSID of the computer to communicate with each other. For BT download, we recommend that you turn off SSID to better use your effect.　　Because, after you turn off SSID can save bandwidth usage and relieve many network redundant information, improve the download speed BT. On the other hand, turn off SSID can also play a role on network protection. Turn off SSID broadcasting, other users will not be able to search the SSID of your wireless device, unless he can manually fill out you the correct SSID in order to connect. Enabling encryption, control the number of users compared with traditional cable routing, wireless router more susceptible to intrusion by others, in particular not to use any encryption measures of wireless routing, your neighbor will be effortless to use your network for download, and other operations, thereby affecting the quality of your network.　　In addition to the above mentioned off SSID, we also can through the wireless WEP and WPA encryption tools to protect the network. Here we suggest to you, in other wireless router is set properly, the exclusion of ISPs and software problems, you may wish to see if someone secretly infiltrate your network. Use UPnP function UPnP (Universal Plugand Play, Universal Plug and play) is the Internet and LAN using the TCP/IP protocol-based technology.　　Internet access through wireless network users are in an intranet, in order to ensure such as BT P2P software to work correctly, open UPnP is essential, but the majority of current wireless router has this feature set. (Most of the wireless router's UPnP set to off by default, users can manually turn on this feature, you can reset the router back into force) of the extranet is not necessary to use UPnP port mapping "automatically" feature, but still need to use the UPnP support UPnP network firewall software (such as WindowsXP with ICF, Norton Internet Security 2003/2004) to automatically open ports. For using WinXP OS users, UPnP support module is not installed by default, therefore, we need to be manually installed. Open the "Add/Remove Programs", go to the "Windows form. 2. in the "Windows Components Wizard", click on the "network service"-the "detailed", and then select the "Universal Plug and play" check box.　　After rebooting, WinXP tips found new hardware, after entering my network places you will find the router on the UPnP feature is turned on. In addition, BT download the UPnP feature in the software will also need to turn on. Bit Comet support UPnP port mapping automatically, you can locally to automate gateway port mapping configuration. (By default this feature is turned on) this software may not make any configuration automatically at the gateway to open external port, the speed will be a degree of upgrading. Open the DMZ feature we should use UPnP functionality to address of extranet and intranet, you will also need a DMZ (demilitarized zone) to install a firewall after external network cannot access the internal network server. In order to ensure that BT such P2P tools not be limited to the greatest degree of fluency of the download, we need to open the DMZ feature to the establishment of a non-secure system and security system buffer, the buffer is located on the internal network and external networks of small network within the region.

【 Weak current College 】 backup important data disaster recovery five issues

Historically, lift the data security, people think of network security, how to prevent hacker attacks. For data integrity, availability, lack of attention. The so-called data security, it is with these simple to do in the enterprise, the data backup that data security is very good that the enterprise's systems are fully guaranteed. In fact, these are the simplest ideas, data backup and disaster recovery are not equal to the data, the backups are not equal to boil the ocean. Because the backup data can also be other factors lead to data corruption, such as earthquake, fire, etc., for these enterprises should enhance capacity data disaster, to further address data against potentially unsafe.
In this way, will someone asked what is the "disaster recovery"? actually simply is to minimize and avoid the disaster caused by the loss of data. Backup and recovery is the "disaster recovery" in the most important part, provide data recovery and storage capacity. Also, have the ability to improve data availability, as well as the prevention of natural disasters caused by the system stored data and loss.

Refer to disaster recovery, data backup, so think first data backup and disaster recovery are relationships? for enterprises, this relationship is reflected in what respects is the most concerned about. Business critical data loss will significantly impact business development, at the same time, causing severe economic losses. But many companies still do not understand the disaster that the simple creation of backup systems after that peace of mind, in fact, the disaster recovery system is indispensable to their mutual relations can explain the importance of disaster recovery system.

Backup is a disaster recovery Foundation

Data backup can be businesses data availability in the last line of Defense, to a system crash is able to quickly restore data. Although this is a form of disaster recovery, but with limited capacity. Because nowadays traditional backup or use of data and external tape drive for cold backup, backup mechanism also consolidated in room management, once the engine room into a disaster, data on the backup tape will also be destroyed, no effective protection for data security.

Disaster recovery non-simple data backup
Data backup or the most basic form, no data backup any disaster without practical significance. But it is not enough light back up, the real data disaster recovery is able to compensate for the lack of traditional backup, disaster recovery of the entire system can be timely. Therefore, for the purposes of disaster recovery for IT is to provide a variety of disaster prevention information system of the computer. Visible, to understand the real purpose of disaster recovery, for enterprises, how to back up data on disaster recovery and avoid the problem, you will need enterprise clear data disaster real meaning, and related tools.

For an enterprise, data backup is just the start of the entire disaster recovery, backup purpose is to be able to system failure for effective recovery. But for many enterprises, especially small and medium-sized enterprises, data backup is a simple task, for disaster recovery plan without knowing the true meaning, not the data disaster in the first place, it will result in a disaster-recovery problems.

1, the meaning is not clear to disaster recovery

Enterprise for disaster recovery is not effect assessment that spend significant effort and financial resources in the data connection, end the problem occurs when simple cover recovery, no real feeling the effects of practical significance. Even the lack of complete documentation of recovery plans and measures.

2. disaster recovery plan for feasibility

Many companies understand the significance of disaster recovery, and is not a valid plan, resulting in many disaster recovery plan is taken for granted for writing, not any lack of simulation exercises, real feasibility. Finally once the disaster, there is no adequate disaster recovery, data recovery is not effective.

3. disaster recovery configuration document not available

For large enterprises, disaster recovery and backup has a professional IT talent, not lack of relevant experience and means. However, for some businesses, especially small and medium-sized enterprises is not for the current system configuration and related files necessary for archiving. In a disaster recovery, cannot find the corresponding original system configuration document, leads to the disaster recovery unnecessary difficulties.

4. save the data document incorrectly

Many enterprise IT staff typically for a data storage medium and configuration system document simple storage, such as cabinets, shelves, ignore these data to the desired storage conditions and the required security safeguards, the direct consequences of the data document will vary depending on the moisture metamorphism, the configuration document is missing, let enterprises in data loss.

5. no more backup tools

For disaster recovery and backup, many enterprises are just some of the needs of the long-term preservation of data simple quarter annual backup, backup, especially some documentation. Due to the long, hard data document due to moisture metamorphism can not be used, but this time the enterprise has no such document is valid in more than one alternative strategies, resulting in a loss of data caused similar problems. Therefore, this class requires the long-term preservation of critical backup, you can save at least 2 different places more backup application.

It disaster recovery recovery of very critical, for effective to avoid problems, it may in the future of enterprise data security be guaranteed that the further with core data to market competition.

College】【weak computer hardware failure Raiders 4 --- Power By 【China】 weak home network.

computer failure of the sound card ★ ★ Troubleshooting chapter one: sound mute. .There are common causes of this failure: 1. Default output driver is "mute." .Click the sound icon bottom right corner of the screen (small loudspeaker), appear to adjust the volume slider below the "mute" option, click the check box in front to clear the check mark box, then the normal pronunciation. . 2. Sound card and other cards have. .PnP card solution is used to adjust system resources so that all cards without disturbing each other. .Sometimes, open the "Device Manager", although no yellow exclamation point (mark), but the sound is not audible, it is still there but the system did not check out. . 3. After installing the DirectX sound card is not audible. .DirectX compatible sound card and that this is not good, need to update the driver. . 4. One channel silent. .Check the sound card to the audio speaker cable is disconnected. . Two common faults: excessive noise from the sound card. .There are common causes of this failure: 1. Card is not correct. .Manufacturing precision is not high enough because the chassis, sound card manufacturer or installed outside the damper caused by bad sound card can not be closely integrated with the motherboard expansion slots, can be seen visually on the card "Goldfinger" and the expansion slot reeds are misplaced. .This phenomenon in the ISA card or PCI card has, are common problems. .Pliers generally available correction. . 2. Active Speaker Speaker input connected to the sound card output. .For the active speakers, sound cards Lineout should be connected to the terminal, it outputs a signal amplifier on the card without the noise is much smaller. .Some of the sound card is only one output, or the Speaker is Lineout jumpers onthe card depends on the decision, the factory default is often Speaker, so the jumper to disconnect the sound card. . 3.Windows driver that comes with bad. .Sound card driver is installed, you should select the "drivers provided by the manufacturer" and not to vote for "Windows default driver," If you use "add new hardware" install, choose "Have Disk" .not from the list box. .If you have installed the Windows driver that comes with the optional "Control Panel → System → Device Manager → voice, video and game controllers", points in the sub-device, choose "Properties → Driver → Change → from the disk driver .Installation. " .Then insert the disk or CD-ROM with sound card, load the driver provided by the manufacturer. . Fault Three: Sound can not "recognize" 1. To make use of a new driver or alternative procedures. .I once had a sound card, under Windows98 with the original driver disk to install the driver install does not matter how, and had to use CreativeSB16 driver instead, everything is normal. .Later upgrade to WindowsMe, not normal and back with Windows2000 (full version) comes with just the normal sound card drivers. . 2. The biggest headache than Plug and Play devices detected under Windows9X has chosen to given a free hand to help you install the driver, the driver side is not used, then, every time you delete .Reload this problem will repeat, and can not use the "add new hardware" solutions. .Here I reveal a secret detached trick: Go to Win9xinfother directory, the *. inf file on the sound card, delete all and restart manually after installation, this was one hundred percent efficacious, have saved countless lives ... ... of course, sound card, change up .table can achieve the same purpose. . 3. Does not support the PnP sound card installed (also applies to not use the PnP install the PnP sound card): Go to "Control Panel" / "Add new hardware" / "Next", when prompted to "need .Windows search for new hardware? ", select" No ", then select from the list," Sound, video and game controllers "with a driver disk or directly select the sound card type to install. . Troubleshooting four: Play CD silent 1. Completely silent. .Use Windows98's "CD player" put CD silent, but the "CD player" and work at the normal, indicating that a CD-ROM audio cable is not connected. .Using a 4-pin CD-ROM audio cable to connect the analog audio output and CD-in on the card can be, this line will purchase CD-ROM included. . 2. There is only one channel sound. .Optical output signal generally about two lines, the middle two lines to ground. .Because the audio signal line 4 line color is generally different, the color can be found from the line correspond to the interface. .If only one interface or sound card and audio cable for each interface does not match the wiring had to change the order of the audio line, usually only one of two lines of the change can be. . Five common faults: PCI sound card sonic boom occurs because the PCI card is usually caused by BusMaster technology PCI bus hung on the hard disk read and write, mouse movements and other operations to enlarge the sake of background noise .. .Solution: Turn off the BusMaster PCI graphics capabilities into AGP graphics card, sound card for the PCI slot. . Six common faults: not the normal recording first check if there is nothing wrong with the microphone jack into the other, and second, double-click the little speaker, select menu "Properties → Recording" .see if the settings are correct. .Then in the "Control Panel → Multimedia → equipment" adjustment "mixer device" and "Line equipment", set them to "use" status. .If the "Multimedia → Audio" in the "Record" option is grayed It would be bad, of course, is not without room for saving, you can try the "Add New Hardware → Systems and Equipment" in addition "ISAPlugandPlaybus", simply put .sound card with the card to restart after the installation tool. . Seven common faults: Can not Play Wav's, Midi Wav Music can not play music phenomenon is rare, often due to "Multimedia" → "equipment" under the "audio device" is more than one .One can disable; can not play MIDI files may have the following 3 possible: 1. Early ISA sound card 16-bit mode may be due to 32-bit mode is not compatible with the MIDI playback is not caused by the normal, by installing .the way the software wave table should be able to resolve 2. Today, most of the popular PCI sound card with wavetable synthesis technology, if the MIDI playback is not part of it is likely because you do not load the appropriate wavetable sound library. . 3.Windows volume control in the MIDI channel is set to silent mode. . Eight common faults: PCI sound card does not properly use the WIN98 some users complained that the sound card driver installation process everything is normal, no device, but the following is not a WIN98 .sound, or have other problems. .This phenomenon usually occurs in the PCI sound card, please check the installation process your PCI sound card inserted in the article which PCI slot. .Thermal considerations for some friends, like to stay away from the sound card plugged into the AGP slot, near the ISA slot that several PCI slots. .The problem often arises here, because there is a Windows98 Bug: sometimes only correctly identified andinserted in the PCI-1 PCI-2 sound card two slots. .ATX motherboard in the two next to AGP is the PCI-1 PCI and PCI-2 (the opposite in some ATX motherboard, close to the ISA is the PCI-1), so if you do not have the PCI sound card installed in the correct .the slot, the problem will have a .

【 Weak current College 】 teach you prohibit others use USB interface

Companies, schools, Internet cafés, etc. often need to disable USB disk and removable hard drive, and other devices, the reasons are varied, such as preventing employees take the confidential information to prevent the students go to school with game room and play, and so on ... ....

Many of my friends might use USB management experts what kind of special restrictions on the use of USB disk software, but many of them is to charge wow ...

Today, it provides a less specialized software will be able to disable the USB disk's tips for everyone:

Method a, BIOS settings method (quick method)

Enter the BIOS Setup, select the option "IntegratedPeripherals" that will "USB1.1Controller" and "USB2.0Contr01ler" option set to "on", you can disable Disableed USB interface. Finally don't forget to set a password on BIOS so that others will not be able to modify the registry for the "lock" the above equipment.

Note: this method is a complete ban on a USB interface, which means that the various USB devices are not used, which of course includes the u disk and move up. Because this method too overbearing, used with caution.

Method two, suppress Flash disk or removable hard drive's boot (for WindowsXP/2000/2003)

Open the registry editor, expand the following Branch [HKEY_LOCAL_MACHINE\SYSTEM\CurrentCntrolSet\Services\USBSTOR], in the right pane, locate the name of "Start" DWORD value, double-click the Edit dialog box to modify its value data as 16-bit hexadecimal value "4". Point "OK" button and close the registry editor and restart the computer for the settings to take effect. After reboot, when someone is a USB storage device connected to your computer, while the led on the USB device in the normal blinking, but among the resource manager is unable to find the letter, and therefore there is no way to use a USB device.

Method 3, hidden letter and prohibited see (for Windows systems)

Open the registry editor, expand the following Branch [HKEY_CURRENT_USER\software\Microsoft\Windows\CurrentVersion\Ploicies\Explorer], create a new binary value "NoDrives" and their default values are not hidden, 00000000 any drive. Key value consists of four bytes, each byte of each bit (bit): from A corresponding to a spare Z:, if the corresponding bit is 1, the "my computer" in the drive to be hidden. The first byte represents a to h 8 disc, i.e. 01-A, b, 04/02 to C. .. And so on, the second byte on behalf of the I-to-P and the third byte represents Q to X, the 4th byte represents the Y and Z. For example, to close the C disk, change the key values; to close D 04000000, is re-routed 08000000, to close the disc tray and D C, then changed to 0C000000 (C conversion to hexadecimal, decimal is 12).

Understanding the principles below to my computer, for example shows how to: my computer with a floppy drive, a hard drive (5 partition), an optical drive, letter distribution is this: A: (3.5 floppy disk), C: D: E,,:, F:, G: H:, (CD-ROM), so my "NoDrives" value is "02ffffff", hides the B, I to z disk.

Restart your computer, then insert the USB drive in my computer is invisible, but in the address bar, enter the I: (my computer after power is a letter H) or you can access mobile disk. Here we see that the "NoDrives" just camouflage, so we need to do one more step, is to create a binary "NoViewOnDrive" value to "02ffffff", which means that its value is the same as the "NoDrives". In this way, we don't see U letter also access not to the USB disk.

Method 4, install the USB driver

In Windows Explorer, go to the "system tray: \WINDOWS\inf" directory, locate the name of "Usbstor.pnf" file, right-click the file, in the pop-up menu, select "Properties", and then switch to the "security" tab, in the "group or user names" box select the banned user group, user group permissions box, select the "full control" later "refused" check box, and finally click "OK" button.

Then use theabove method, find the "usbstor.inf" file and in the Security tab page is set to deny the user access to the group, its operating procedure ibid. After completing the above setup, this group of users will be unable to install USB device drivers, and thus achieve the purpose of the disabled.

Note: If you want to use the access control list (ACL) that you want to use the NTFS file system.

【 Weak current College 】 L1 cache and L2 cache differences

In order to distinguish between these two concepts, let's first look at the RAM. RAM and ROM, RAM is the blackout, the information which the vanishing, the ROM in power-down after the information is not lost.

RAM is divided into two types of static RAM, SRAM, and the other is the dynamic RAM, DRAM. The former storage faster than the latter, we now use memory generally dynamic RAM.

Some rookie said, in order to increase the speed of the system, the cache is not expanded, extended, the larger the cache of data, the more system not faster? cache are usually static RAM, speed is very fast, but static RAM integrated low (store the same data, static RAM size is 6 times the dynamic RAM), the price is high (with capacity of static RAM is four times the dynamic RAM), thus expanding the static RAM as the cache is a very stupid behavior, but in order to improve system performance and speed, we need to expand the cache so that you have a middle way, does not extend the original static RAM cache, but the increase in the number of high speed dynamic RAM for caching, these high speed dynamic RAM speed than conventional dynamic RAM, but more than the original static RAM caching slow, we put the original static ram cache called the L1 cache, and the subsequent increase of dynamic RAM called L2 cache.

L1 cache and L2 cache is an in-memory data access frequency high copy (map), their existence is to reduce high speed CPU on slow memory access. Usually find data or CPU instruction sequence is: first-level cache, find, find again to be found in the level 2 cache, if you still can't find it, only to find out in memory.

Weak current College】【CAD skills summary (4).

56. the old users multiple replication in CAD is always required to enter M, streamlining?
You can add in acad.lsp files without having to enter the program realization: M
(defunC:CVV()
(setvar"cmdecho"0)
(setqcss(ssget)) (command"copy"css"""m")
(setqcssnil) (setvar"cmdecho"1)
(prin1))
That is, enter the CVV return, multiple replication can be implemented.

57. How do I replace a missing original fonts?
Replication of the fonts you want to replace, as will be replaced by the character set names, such as: open a picture, tips not found font jd, you want to replace it with hztxt.shx, then you can go to AutoCAD font folders (font) inside a copy of hztxt.shx, renamed, and then in turn jd.shx XX.shx into font inside, when you reopen the diagram. Later, if you open the map containing the jd you camera, there is no font, you'll never go to you to find a font substitution.
58. how to remove stubborn layer?
Method 1: turn off unwanted layers, select all, COPY paste to a new file, those useless layer won't stick around. If you do not have in this layer defined block, and another layer to insert the block, so this not layers are not able to use this method to delete.
Method 2: select the graphics need to leave behind, and then select the file menu-& gt; gt; & output-block file, this file is to select a block of some of the graphics, if the graphic is not in the specified layer, the layer will not be saved in the new tile graphics.
Method 3: open a CAD file, to delete the layer off, in leaving you need visible graphic, point to file-save as, and determine the file name, file type .DXF format column, select * from the dialogue window, point to tools-options-DXF options, and then select the object, call hook, click OK, and then points to save, you can choose to save the object, the visible or graphic you want to use the chosen can be determined after the completion of the save, and exit the file you just saved, and then open a look, you'll find that you don't want the layer to disappear.
Method 4: use laytrans command, you can delete the shadow layer to layer 0, this method removes the object with the entity or by any other block nested defined layers.

59.AutoCAD in XP operating system the following fatal error when printing?
This version uses AutoCAD2002 and above print meter. In 2000, additional print meter features a lot of BUG, this feature in the 2002 version directly as AutoCAD functionality. This feature is at 98 operating system completely without problems, but in some XP system, an error occurs. So XP systems it is best not to turn on this feature. If you have unfortunately this feature is turned on, the AutoCAD in a fatal error occurs while printing, the solution is this: the root of the AutoCAD AcPltStamp.arx file is found, change it to another name or deleted so that print will not be wrong, but also less print meter feature, the method for version 2002 and 2004 editions are valid.

60. in multiline text (mtext) command in the edit text with Word97.
Mtext multiline text editor is a new feature in AutoCADR14, it provides Windows word processing software of the interface and work methods, it can even take advantage of the powerful features of Word97 to edit text, this feature can be used as follows: open the "Tools" menu select "Preferences" command, "Preferences" dialog box pops up, open "Files/TextEditor, Dictionary, andFontFileName/TextEditorApplication/Internal", double-click on the "Internal", "dialog box appears" Selectafile, he went on to found the "Winword.exe" application file, click "open" button, then click "OK" to return. After completing the above setup, users like to use mtext command system will automatically call our familiar Word97 application, text for AutoCAD.

61.AutoCAD Map import photoshop.
This is a very old problem, the solution is the "virtual printing" to a step below. (for the convenience of everyone, in English, the parentheses is the English version):
A, open the "file (file)" menu under "printer Manager (plottermanager)".
B, running the "Add Printer Wizard (Add-A-PlotterWizard).
C, click on the "next (next)", on the right of option, select "my computer (MyComputer)", continue to the "next" and enter "printer model (PlotterModel)" select the page.
D, on the left of the "vendors (Manufacturers)" select the "raster file formats (RasterFileFormats)" this is what we can see in the right "model (Model)," lists the many familiar graphics format, I used to use JPG cellType, select the "Independent JPEG Group (IndependentJPEGGroupJFIF)", click on the "next (next)", until complete. So we can add CAD graphics output bit JPG format. Next we look at how to use it.
E, CAD and do a plan, we open the "file (file)" menu under "print (plotter ...)". In the print dialog box, select the type of printer we just installed "IndependentJPEGGroupJFIF", in the following "print to file (plottofile)" was added to the generated file name and path, the file is one you can then edit graphics in photoshop. In page setup, select a dimension that we need to rest and to use the real printer method is the same. Click Print, and so after a few seconds, the graphic is generated.
Note: the default page size is only 1280 * 1600, this size will not be able to satisfy our needs. We can in the printer's properties to customize the size we want.
Enjoy! added: If the CAD is 2004 or later, you do not have their own loading printer, the print device has a "PublishToWebJPG.pc3" printer, directly on the line
F: Supplement to the point were the teacher if you want to export a solid black line recall to plot of all colors of the pen, are changed to 7 colors, so that you can export pure black figure, remember to put in PS to RGB mode, so that the image is clearer.

62. After you finish modifying the ACAD.PGP file, you do not have to restart immediately loaded AUTOCAD just modified ACAD.PGP file.
Type a REINIT command, hooks, and then determine the PGP

63. resolve AutoCAD2005 method cannot be registered.
Remove the hidden files and folders. Delete C:\DocumentsandSettings\AllUsers\ApplicationData\Autodesk\SoftwareLicenses\B2260000.dat

64. how to adjust the AUTOCAD drawing area to the left shows the coordinates of the box?
Press F6 to switch. Or will modify the COORDS system variable to 1 or 2. System variable to 0, use the pointing device update coordinates display the specified point. System variable to 1, is continually updated to display the coordinates. System variable to 2, continuously updated coordinate display, distances and angles when needed, to the point of distance and angle.

65. How do I switch the use in English menu?
At the same time saved in AutoCAD and English set menu system, it is possible to switch back and forth. Specific approach is to integrate the finished menu file was renamed Pacad.mnu, placed in AutoCAD installation directory in a subdirectory of \\SUPPORT, of course, also don't forget to copy into Pacad.mnl acad.mnl, drop? *** acad.mnu in the same directory. In the Chinese menu, use the menu command to load Pacad; in exchange for English menu when you load the menu command again to use acad menu file.

66. how to draw a curve?
----At the plotted drawing, often experiencing art intersection line, intersecting lines and curves. Hand-drawn very troublesome, special points and a number of General points, and even the errors of the curve. Draw with AutoCAD2000 Planar curve or space curve is very easy.
-Method 1: use the command draw 2D graphics Pline adopted special points of a polyline in the Pedit command or Spline curve Fit, can become a smooth surface curve. By 3Dpoly command draw 3D graphics through special points of a polyline, the Pedit command Spline curve fit, can become a smooth space curve.
----Method 2: use basic commands to create a three-dimensional Solids entities (rectangular, cylindrical, tapered, spherical, etc.), then by a combination of Boolean (Boolean): AC, and operations, and complex interference from obtaining, and then use the drop-down menu the entity View (view) (3D perspective)/3DViewpoint, select different viewpoints to create standard views, get a different view of the projection of the curve.

67. in the AutoCAD drawing in what proportion?
It is best to use the 1: 1 ratio, the ratio can freely adjust the output. Drawing scale and output ratio is two concepts, the output is "output 1 unit = drawing 500 units" is to press the 1/500 proportional output, if the "output 10 units = drawing 1 unit" is magnified 10 times the output. With 1: 1 scale drawing many advantages. First, easy to find mistakes, because according to the actual size of the drawing, it is easy to discover the size settings are not reasonable. Second, the dimension is very convenient, size number is, the software itself, should draw the wrong measurement, a look at the size digital discovered (of course, the software will also be able to set the dimension ratios, but always more work). Thirdly, in various local graphics between replication or use the block, the result is 1: 1 ratio adjustment block size and convenience. Fourth, by parts diagram spell Assembly or by the Assembly to remove picture parts diagram is very convenient. Fifth, there's no need for cumbersome downscaling and enlarge, improve work efficiency, prevent conversion process error may occur.

Weak current College】【EXCEL tips, life is enough for you to enjoy (1) --- Power By】【China power house network.

Convert columns to rows or rows into columns Suppose you have a text column: Dim sum Meat Beverage Special products You want .to change it to a line, as follows: Dim sum meat beverage-products Or you might want to change the row of data in each column. Once a to move the data manually can be very tedious .. To save time, you can use the "Paste" command to quickly add a column of data transfer for row data, and vice versa. In the rows and columns to move data between 1. in a column / .row or columns / rows in the replication data. 2. Paste the copied data, right-click the first destination cell (want to paste the data into rows or columns of the first cells), and then click the "Paste" .. 3. in the "Paste Special" dialog box, select the "transpose", and then click OK. "Transpose" check box located at the corner of the dialog box: From .your choice of the first cell, Excel pastes the data into a row or column. Comments Columns and rows can overlap. For example, if you select values in column c, and try to paste it into the c columns .overlap line, Excel displays an error message. You want to paste the rows or columns, the target area must be in original value area. If more columns in the copy and paste data to Excel from top leftmost column begins to drop data .. For example, suppose you from worksheet columns a and b to copy data from another table row 1 began to paste the data into it. Excel adds A column of data in row 1, column b of the data in row 2, and so on .. If you do not see the "Paste" command, make sure that you right-click the first destination cell. You can also edit "menu," find the order. If you still don't see the command, make .sure that you are using Excel2000 or later Conditional Sum. 1. single conditional sum: statistical C1 company construction projects with a total construction area, and place the result in the E18 cell, as long as we enter the E18 .cell formula "= SUMIF (D2: D17," C1 ", E2: E17)" that is, complete this survey. Note: If the Excel function is not too familiar with, in the cells directly into the formula, we .can use the "insert function" command (or press the toolbar's "paste function" command button), select the function you need, according to the instructions to complete the formula input. 2. multiple conditional sum: statistical C2 company construction .quality rating to "qualified" project with a total construction area, and place the result in the E19 cell, we use the "conditional sum" feature to implement: ① "Tools → Options → Conditional Sum Wizard" command (without this .command option, you can use the "add" to add this command option), in the pop-up dialog box, press the lower band "-" button (the dialog box into a similar tool of Windows Forms floating on the desktop), .using the mouse to select D1: I17 area, and press on the right side of the window with a red arrow button (the recovery status dialog box). ② Press "next" in the pop-up dialog box, press the ."add columns" to the right of the drop-down button to highlight the "building area" item, and then press the "conditions for columns, operators, and comparison values" to the right of the drop-down button, then select " .construction units, "" = "(default), the" C2 company "option, then press the" Add condition "button. Repeat the above operation, the column will be" conditions, the operator, a comparison value "set to" quality .grade, "" = "," qualified ", and press the" Add condition "button. ③ twice to click" next "in the pop-up dialog box, press the lower band" - "button, use the mouse .to select the E19 cell, and press the right side of the window with a red arrow buttons. ④ Press "Finish" button, at this point eligible summary results automatically and accurately displays the cell at the E19. Note .: this is actually an array formula has been entered, we can also direct the E19 cells enter the formula: = SUM (IF (D2: D17 = "C2", IF (I2: I17 = "qualified", E2: E17)) .), and then hold down Ctrl + Shift keys (key!!!) and press the Enter key, you can achieve the above objective of multiple conditional sum. Excel2003 function complete Handbook First, the function .application Foundation 1. functions and formulas (1) what is the function Excel functions that is predefined, perform a calculation, analysis and processing data task special formula. To add the sum function are .commonly used as an example, it's syntax is "SUM (number1, number2, ...)". The" SUM "as the name of the function, a function only a name, it determines the function and purpose. The function name followed .immediately by an opening parenthesis followed by a comma-separated list of content, called parameters with a closing parenthesis to end represents the function ends. Parameter is a function of most complex components, it regulates the function of objects, order, or .structure. Allows the user to a cell or range for processing, such as analysis of deposit interest, determine performance ranking, calculations, trigonometric, etc. The source of the function, Excel functions can be divided into the built-in functions .and extension functions. The former just start Excel, users will be able to use them; whereas the latter must be by clicking on the "Tools" menu → add-ins command to load before you can use as a built-in function. < .br> (2) what is the formula Functions and formulas are differentiated and contact each other. If the formerAre Excel predefined special formula, which was designed by the user on the worksheet for calculating and processing of the formula. With the formula ."= SUM (E1: H1) * A1 + 26", for example, it should equal sign "=" start, its internal can include functions, references, operators, and constants. On the type of "SUM (E1: H1) ."is a function," A1 "is in cell a1 reference (use the stored data)," 26 "is a constant, the" * "and" + "is the arithmetic operators (addition, comparison operators, text, and reference operators .). If the function you want to appear in the formula, it must have two components, one for the function name preceded by an equal sign and the other is the function itself. 2. the function .of parameters Function right part in brackets is called a parameter, if a function you can use multiple parameters, parameters and arguments between half-width comma. Parameter can be a constant (numeric and text), logical values (such as TRUE .or FALSE), array, error values (such as # N / A), or cell references (eg E1: H1), or even another one or several functions, etc. Parameter of the type and location must meet the requirements of function syntax ., otherwise an error message is returned. (1) constant Constants are entered directly into the cell or the formula for the number or text, or by the name representations of numbers or text values, such as digital "2890.56 .", date" 2003-8-19 "and the text" Dawn "are constants. But the formula or calculated by the formula result is not a constant, because as long as the formula parameter is changed, it itself, or the results will .change. (2) logical values Logical value is rather special kind of parameter, which only TRUE (true) or FALSE (false) in two types. For example, in the formula "= IF (A3 = 0 ., "", A2/A3) "," A3 = 0 "is a can return true (true) or FALSE (false) argument of the two results. When the" A3 = 0 "to true (true) when the cell in .the formula with "0", fill in the cells A2/A3 "result". (3) of the array The array used to produce more than one result, or you can store in a row and column in .a group of arguments that are calculated by the formula. Excel has a constant and regional class array. The former is placed in the "" (press Ctrl + Shift + Enter key combination auto-generated), and internal numerical columns with a comma- .separated by ",", the numeric value you want to use semicolon ";" Separated. If you would like to express the 1 line of 56, 78, 89 and line 2, 76, 80, 90, should establish a 2 rows of .3 columns of constant array "{56, 78, 90, 89; 76, 80}. Area array is a rectangular range of cells, the cells in a region with a formula. For example, the formula" = TREND ( .B1: B3, A1: A3) "when used as an array formula, it refers to a rectangular range of cells B1: B3", A1: A3 "is a regional array. (4) error value Use .the error value as parameters are primarily information functions, such as "ERROR.TYPE" function is the error value as a parameter. Its syntax is "ERROR.TYPE (error_val)", if the parameter is the # NUM!, the return value .of the "6". (5) a cell reference Cell reference is the function of the most common parameters, the reference is intended to identify the worksheet cell or range of cells, formula, or function and specifying the .location of the data makes it easy for them to use the data worksheet, or multiple functions use the same cell data. You can also refer to the same workbook to a different worksheet cell, or references to other workbooks. According to the .formula in the cell's location is changed, the cell reference changes, we can reference consists of a relative reference, absolute, and mixed references three types. To be stored in the formula in cell F2 "= SUM (A2: E2)", for .example, when a formula from the cell to F2 F3 cell, the formula references will change to "= SUM (A3: E3)". If formula since F column down to continue replication, "row" per row, the row or the formula .1 automatically. If the above formula to "= SUM ($ A $ 3: $ E $ 3)", regardless of where to copy the formula, the reference location is always the "A3: E3" area. Mixed references are "absolute column and relative row", or "absolute row and relative column" two forms. The former as "= SUM ($ A3: $ E3)", the latter as "= SUM (A $ 3: E .$ 3). " The above referenced several instances of the same data in a worksheet, if you want to analyze the same workbook more data on the worksheet, use a 3-d reference. If the formula is placed in the Sheet1 .C6 cells, to refer to a worksheet Sheet2 "A1: A6" and "Sheet3 B2: B9," areas of summations, the references in the formula in the form "= SUM (Sheet2! A1: A6, B2: B9 Sheet3!) .". That is not only in a 3-d reference that contains the cell or range reference, but also added with"! "The name of the worksheet. If you want to refer to data from another workbook, such as the .workbook Book1 in the sum function to absolute references Book2 workbook, the data in the formula "= SUM ([Book2] Sheet1! SAS1: SAS8, [Book2] Sheet2! SBS1: SBS9)" in the original cell references with "[Book2] .Sheet1! ". Placed in square brackets inside the workbook name with"! "Is the name of the worksheet. That is cross referenced workbook cell or range, the references object must be preceded by"! "The separator as a work table, and .then use the brackets as delimiters for the workbook. However a 3-d reference to be more restricted, for example, you cannot use array formulas, and so on. Tip: described above is a reference to the Excel default, known .as "a1 reference style". If you want to calculate at the "macro" rows and columns, you must use the "R1C1 reference style". In this reference style, Excel uses the "R" and "row" and "C" .and the "column labels" method indicates that the cell location. Enable or disable the R1C1 reference style must click "Tools → Options" menu command that opens a dialog box in the "General" tab, select or clear the "settings" under " .R1C1 reference style "option. Because of this reference style is rarely used, limited to the length of this article does not make further introduction. (6) nested functions In addition to the above, the function can also be .nested, that is, a function is a function of parameters, such as "= IF (OR (RIGHTB (E2, 1) =" 1 ", RIGHTB (E2, 1) =" 3 ", RIGHTB (E2, 1) = ."5", RIGHTB (E2, 1) = "7", RIGHTB (E2, 1) = "9"), "male", "female") ". Which of the if function in the formula uses a nested RIGHTB function ., which returns the results as IF logical judgement. (7) the name and logo In order to more visually identifies the cell or range of cells, we can give them a name, resulting in a formula or function in .a direct reference. For example "B2: B46" area located at the student's physics, the formula for the average score is "= AVERAGE (B2: B46)". In B2: B46 area named after the "physical score", the formula .can become "= AVERAGE (physical score)," so that the formula becomes more intuitive. To a cell or range name: select a named cell or range of cells, mouse click the formula bar at the top of the "name ."box, enter the name of a carriage return. Or you can select a named cell or range of cells, click the name of the" insert → → define "menu command in the open" definition name "dialog box, enter the name to .determine. If you want to delete has named ranges, you can follow the same method to open the "define name" dialog box, select the name you want to delete to delete it. Since most of the Excel worksheet with the " .column labels ". For example, a result table of the first row usually with the" serial number "," name "and" math "and" physical "and the" column labels "(also called fields), if you click the" .Tools → Options "menu command in the open dialog box, click the" recalculate "tab, select the option" workbook "option group logo" to accept the formula, the formula is "option can be a direct reference to the" column labels " .. For example "B2: B46" area housed students' physical, B1 cell have entered the "physical", the average score for physical formulas that can be written as "= AVERAGE (physical)". To note is that creating .a good name can be any sheet references, and references do not need to be added in front of the name of the sheet name (and this is the main advantage of using the name), so the name reference is an absolute reference. But the .formula refers to the "column labels" time limit, it can only be used in the current data column below the reference, cannot span worksheet references, but refer to the "column labels" formula under certain conditions, can be replicated. In essence, .the name and logo are all cell references. Because they are not the text, use the name and logo will not be able to add a quotation mark. 3. the function input method On the Excel formula ., the function is one of the main components, so the formula input can be attributed to the function input. (1) the "insert function" dialog box The "insert function" dialog enter a formula in Excel is .an important tool for the formula "= SUM (Sheet2! A1: A6, B2: B9 Sheet3!)", for example, Excel input process of the formula is: First select the hold calculation result (ie the need to apply .a formula) of cells, click the formula bar (or toolbar) in the "fx" button, the formula "=" appears in the cell and the formula bar, and then open the "insert function" dialog box, select the "find ."function" list "function SUM. If you do not need to be inside of a function, you can open" or select a category "drop-down list to select it. Finally click" OK "button to open" function parameters "dialog .box. The SUM function, it can be used from the beginning until the number1 number30 total 30 parameters. On the above formulas, the first should put the cursor in the dialog box "number1" box, click workbook "Sheet2!" .The worksheet tab, "Sheet2!" You can automatically enter it, then drag the mouse to select the area you want to reference. Then use the mouse to click the dialog box "number2" box, click workbook "Sheet3!" The worksheet tab ., the name "Sheet3!" You can automatically enter it, and then press the same method to select the cell range reference. The above method of the biggest advantage is the reference area is very accurate, especially 3-d references not .prone to worksheet or workbook name entry error. (2) Edit bar input If you want to borrow a ready-made formulas, or enter some nested relations complex formula, using the formula bar, enter moreShortcut. First select the store the results of a; the Edit Bar mouse click Excel, according to the formula of the parts in the order entry, enter a formula, click the Edit Bar "input" (ie "√") button (or return .). You can also manually enter the take method reference described above, with the formula "= SUM (Sheet2! A1: A6, B2: B9 Sheet3!)", for example, you can be the first in the formula bar ., enter "= SUM ()," and then move the cursor to the insert brackets, then by the method described above to enter the formula references. But the comma between the separate references must be entered manually, but cannot "insert function" dialog .box that automatically added. .

【 Weak current College 】 Web application firewall the depth perception

Web application firewall (WAF) aims to protect Web applications from common attacks (such as cross site scripting and SQL injection attacks, etc.). Traditional firewalls are protected network perimeter, and WAF is deployed in a Web client and Web server. Experts said that the Web application firewall for the greatest benefit is that help analyze application layer flow for any breach of the security policy of the security issues.
　　
Although some traditional firewall can provide some degree of protection, but from the aim and scope, like WAF. For example, the WAF you can detect whether the application to its provisions in the running, and able to help you write more specific security policies to prevent the same thing happening again.
　　
WAF and intrusion prevention system (IPS) vary, Gartner analyst GregYoung said, "this is a very different technologies, it is not based on signatures, but from the Act, it can help reduce your own inadvertently may manufacture of vulnerability,"
　　
Foreign markets with a WEB application firewall feature of the product name that have different dozens, not to mention is the product of forms and describes. It is difficult to define because the name includes the things too much. Lower network layer (Web application firewall is placed in the seventh floor) is covered by many devices, each of these devices have their unique features, such as routers, switches, firewalls, intrusion detection systems, intrusion prevention system and so on. However, in the HTTP world, all of these features are integrated in one device: Web application firewall.
　　
Because Web application firewall is multifaceted, with different knowledge, backgrounds are often concerned about its different features. For example, a network intrusion detection backgrounds tend to think of it as is to run in HTTP layer IDs device; with the firewall itself backgrounds more and see it as a firewall function modules. There is also a kind of understanding comes from "depth detection firewall" this terminology. They think that deep inspection firewall is a Web application firewall and functional equivalent of a device. However, despite the two devices are some similarities, but the difference is very big. Deep inspection firewall usually work in the network of the third level and higher level, and the Web application firewall the seventh layer handles HTTP service and it is a great way to support it.
　　
Enhanced input validation
　　
The frequent Web security issues, some of its Web design model of misunderstanding, others come from the program that the browser is authentic. Many Web programmers use JavaScript in the browser for input validation. While the browser is only a simple tool for the user control, so an attacker can easily bypass input validation, a malicious code input directly to the Web application server.
　　
There is a solution to these problems the right way is in the service-side input validation. If this method cannot be implemented by the client and application server to increase agent, the agent to perform Web pages embedded in JavaScript, for input validation.
　　
Negative security model VS positive security model
　　
Used to set firewall rules, you may encounter such a suggestion: allow known safe flow, deny all other access. This is a very good positive security model. On the contrary, the negative security model is the default allow all access, only to reject some of the known dangerous traffic patterns.
　　
Each security model are there different issues:
　　
Negative security model: what is dangerous?
　　
Positive security model: what is safe?
　　
Negative security model of the more commonly used. Identify a dangerous mode and configure their systems against it. This simple and interesting, but not very secure. It relies on people's awareness of the risk, if the problem persists, it is not being aware of (this is usually the case), youwill leave for an attacker to take advantage of the machine.
　　
Positive security model (also known as the white list model) looks a better formulation of policy, is well suited to configure firewall policy. In the field of Web application security, positive security model is usually summarized pairwise application every script enumeration. On the enumeration of every script that needs to establish an appropriate list, the table content is as follows:
　　
* Allow request form (for example, GET/POST or POST)
　　
* Allow Content-Type
　　
* Allow Content-Length
　　
* Allow parameters
　　
* Specify parameters and optional parameters
　　
* The parameter type (for example, text or integer) * additional parameter limits
　　
The above list is only an example, the actual positive security model typically include more elements. It tries to complete the programmer from the outside would have from within: to submit information to the Web application to verify every bits. If you are willing to spend time, use a positive security model is a better choice. One of the difficulties of this model lies in the application mode as the application's development. Whenever you add a new script in the application or change the old script, you need to update mode. However, it applies to protect those who are stable, no one the maintenance of the old application.
　　
Automatic development strategy can solve the above problem:
　　
* Some WAF can monitor traffic, and in accordance with these traffic data automatically configure policies, some products can carry out such work in real time.
　　
* Through whitelist, you can identify the specific IP addresses are trusted, and then, based on the observation of traffic, configure the WAF, update security policies.
　　
* If you pass a comprehensive test of attenuation (simulation of correct behavior) to create an application, and monitoring the WAF in State, then the WAF you canautomatically generate policy.
　　
Visible, no mode is perfectly satisfactory. Negative security model applied to deal with known issues, and the positive security model is applied to the stability of the Web application. Ideally, in real life, will use a combination of both, learn from each other.

Timely patch
　　
Positive security model theoretically better because the browser and WEB applications for communication protocols through HTML specification had a very good definition. Now Web development language can deal with multiple parameters in a HTTP request. Because these parameters in the Web application firewall are visible and therefore WEB application firewall can analyze these parameters determine the existence of allow the request. ，
　　
When an application vulnerability is found in most cases we will try to patch it in code. Affected by many factors (such as the size of the application, whether developers, legal issues, and so on), the patch process may take several minutes, or until an infinite time. The time is the attacker to launch an attack.
　　
If developers in a very short time fix vulnerabilities in your code, then you need not worry. But if the patches this vulnerability could take several days or even weeks to repair? Web application firewall is the ideal tool for: just give a security expert, good WAF and sufficient vulnerability information, he can in under an hour off this loophole shielding. Of course, this kind of shielding off vulnerability approach is not very perfect, and you have not installed the corresponding patch is a security threat, but we have no choice, no protective measures are better than no protection measures better.
　　
Timely patch of principle can be better applied to XML-based application, because communication protocols are normative.
　　
Based on the rules of protection and protection based on exception
　　
Now the majority of products on the market is based on the rulesof the WAF. The principle is that each session will have to undergo a series of tests, each test consists of a multiple detection rules, if the test failed, the request will be considered illegal and rejected.
　　
Rule-based WAFs is very easy to build and can effectively protect against known security problems. When we want to make custom defense strategy using it will be more convenient. But since they must first confirm that the characteristics of each threat, to the rules by a powerful database support. Producers maintain that database WAF, and to provide automatic update tool.
　　
This method cannot effectively protect their Web applications exploitation or zero-day vulnerability (an attacker use the vulnerability is not public), the threat of anomaly-based WAF more effective.
　　
The basic concept of abnormal protection is to establish a protective layer, protective layer to the application under test legitimate data statistical model, this model is based on identifying the actual communication is the data. In theory, but build is successful, this anomaly-based system should be able to detect any anomalies. With it, we no longer need a rules database and zero-day attacks will no longer be a problem. But a system based on exception protection are difficult to build, so it is not common. Because users do not understand how it works do not believe it, so it is not as a rule-based application the varied WAF.
　　
State management
　　
The stateless nature of HTTP for Web application security has many negative effects. Sessions can only be implemented on the application tier, but for many applications this added functionality can only meet the business needs to consider the safety factors. Web application firewall the focus session protection, it's features include:
　　
Force login page. In most sites, you can choose from any of you know the URL to access the site, this usually facilitates the attacker to defense increased difficulties. WAF can judge whether the user is the first visit and you will be redirected to the default login page and log events.
　　
Respectively detect each user session. If you are able to distinguish between different sessions, and this has brought the unlimited potential. For example, we can monitor the landing request send frequency and users go to page. By detecting the user's entire operation behaviors we can more easily identify attacks.
　　
On the violent attack of recognition and response. The usual Web application network is not detecting a brute force attack. The State management mode, WAF can detect abnormal events (such as login failed), and in the limit values for processing. At this point it can increase the number of authentication requests, this slight change users feel, but enough to deal with auto attack script. If an authentication script needs 50 milliseconds, that it can emit approximately 20 times per second. If you increase a little delay, for example, a second delay, that request is reduced to less than once per second. At the same time, the issue of further detection of warning, this will constitute a good defense.
　　
Implementation of session timeout. Beyond the default time session will fail and the user will be required to recertify.Users in the long time request will be automatically logged out.
　　
Session hijacking of detection and defense. In many cases, session hijacking will change the IP address and request data (http request header will be different). Status monitoring tool can detect these exceptions and to prevent the occurrence of illegal applications. In this case should terminate sessions, the requirements of the user authentication and logging a warning log information.
　　
Only in the previous request response. Some of the WAF is very strict, and only allows the user to access a previous request to return a link in the page. This seems an interesting features but it is difficult to be implemented. One problem is that it does not allow the user to use multiple browser Windows, another problem is that it makes use of JavaScript to automatically establish a connection failure of application.
　　
Other protection technology
　　
Other security WAF enhancements to solve WEB programmers too trusting input data. For example:
　　
Hidden form fields. Sometimes, the internal application data through a hidden form variable, but they are not really hidden. Programmers usually use a hidden form variable ways to save the execution status, send data to the user, to ensure that these data return has not been modified. This is a complicated process, WAF often use password signature technology.
　　
Cookies. And hidden form similar is that cookies are often used to pass the user's personal data for the application, some cookies may contain sensitive data. WAFs usually add the entire content encryption, or will the cookies mechanism of virtualization. With this setting, the end user can only see the cookies tokens (like the session token), thus ensuring cookies in safely storing WAF
　　
Anti intrusion circumvention technologies. Network-based IDS against WEB attacks are attacks against circumvention technologies. Rewriting HTTP input request data (attack data) way too many and various rewrite request IDS can evade detection. In this regard if you have a complete understanding of HTTP is significantly improved. For example, the WAF you can see the whole of each HTTP request, you can avoid all the types of HTTP requests to the partitioning of the attack. Because a good understanding of the HTTP protocol, so the ability to dynamically request and static request separately, there is no need to spend a lot of time protection is not an attack of static data. This way you can have enough WAF capable to deal with a variety of attack evasion technique, which is completed by NIDSs is time-consuming.
　　
Response monitoring and disclosure of information protection. Information leak prevention is to monitor HTTP output data of a name. From the principle, it and request monitor is the same, aims to monitor suspicious of output, and prevent suspicious http output data to the user. Most likely the application mode is monitoring your credit card number and social security number. In addition, this technology is another application is found signs of a successful intrusion. As experienced attacker always give information coding to prevent monitoring, preventing such determined and skilled attacker gets information is very difficult. However, the attacker does not have full control over the server but only try to Web application security vulnerabilities, this technology can play a protective effect.

Friday, March 18, 2011

【 Weak current College 】 wireless LAN technology on two---Power By 【 China power house network 】

12. What is a bridge (AccessPoint)?

AccessPoint, generally known as a network bridge, as the name implies, is deemed to be traditional wired LAN and wireless local area network of bridges, so any computer equipped with a wireless network card of the PC can share via the AP to even wired local area network, wide area network resources. In addition, the AP itself also has a network of capabilities for wireless network cards with the PC mutatis mutandis, of the control.

13.AccessPoint use how many workstations simultaneously support?

Theoretically you can support a CLASSC, but in order to enable the workstation itself have sufficient bandwidth available to the general recommendations supported one AP about 20 ~ 30 meters of the station for the best.

14. What is the roaming (Roaming)?

As mobile phone, you can roam in different base stations, wireless network workstation can roam between different AP, AP group defines the same ESSID, natural wireless network workstation free roaming in radio waves can cover the area.

15. If the wireless network equipment set up on the outdoor, how to protect against lightning?

Basically, the wireless network you can configure the arrester equipment, this device you can choose to install a wireless network device in order to facilitate foreign of surge caused damage to the system.

16. What is the AccessControl?

Basically every wireless network card has a unique hardware address, the so-called MACaddress, you can define certain card AccessControltable can login to the AP, some card is denied access, so they can achieve control mechanism that prevents non-associated persons feel free to log into the network, the theft of resources.

17. What is ASBF?

ASBF (AutomaticScaleBackFunctionality), this feature is specific to the function, GemplexAP guarantee WLAN is always the best quality online, and provide support for multiple manufacturers of wireless network card, but its network card must be compatible with the specification and design of the IEEE802.11.

18. What is a PowerManagement?

Because the Notebook uses about 2 hours or so after they must charge, if and while using the other peripheral device, you must have more power, so this feature is to effectively manage a wireless network card's power consumption, in other words, its timely control when DATAsendingorreceiving, is in the "Wakeupstatus", while in powerdownmode.

19. antenna using the length of the feeder are influential transmission quality?

In General, the use of antenna-feeder length, material quality, impedance matching, will have some of the signals, but the most obvious is to gain attenuation. Usually in terms of length 20feet or signal attenuation about 1.2dBi about average attenuation 8dBi will let the original transmission distance of approximately halved, so the length of the feeder and quality in wireless products application cannot be ignored.

20. What is Ad-hoc?

Constitute a special wireless network application mode, a group of computers connected to the wireless network card to connect, share, through the AccessPoint.

21. What is Infrastructure?

An integrated wired and wireless local area network infrastructure, and through this kind of schema mode, you can reach the shared network resource, the application needs through the AccessPoint.

22. What is the BSS?

A special application called Ad-hocLAN BasicServiceSet (BSS), a group of computers to set the same BSS name, you can become a group name, and this BSS, the so-called BSSID.

23. What is ESS?

An Infrastructure applications, one or more of the above, the BSS is defined as a ExtendedServiceSet (ESS), users can access on roaming and the ESS BSSs any information in which you must set the same AccessPoints ESSID and channel to allow roaming.

24. What is SNMP?

"SimpleNetworkManagementProtocol", a network of communication protocols through SNMP software can be connected to an SNMP-enabled devices and gathers all the information of the device and do other integrated applications, there are support GemplexWirelessLANproduct.

25. What is a WEP?

"WiredEquivalentProtection" shorthand, a data encryption, the encryption is WEP40bits IEEE802.11 standard specification. Processing through WEP can make our information more secure in the transmission.

【 Weak current College 】 common underlying hackers technology related terms term explanation

Describes some of the more common terms. basis of hackers dedicated

1. chicken: the so-called "broiler" is an image of the metaphor, analogy that can be controlled, they can be a WINDOWS system, or UNIX/LINUX system, may be an ordinary personal computer, or it can be a large server, we can operate their own computer to manipulate them like that, not being found by each other.

2. the Trojan horse: who on the surface, disguised as a normal procedure, but when the program is running, you will get the entire control system. Many hackers are hot in and use the Trojan to control someone's computer, such as the gray pigeon, black hole, PcShare etc.

3. Web Trojans: disguised as an ordinary Web page file or just code directly into a normal Web page file, when someone visits the page Trojans will use each other's system or browser vulnerabilities automatically configured on the server side to download Trojan horse to a visitor's computer up executed automatically.

4. hang horse: is in someone else's Web site files into Web pages is a Trojan or dive into the code to each other normal Web page file, so that visitors to the Maldives.

5. the back door: this is an image of the parables, intruders in the use of certain methods of successful control of the target host, you can in each other's system in the implantation of a specific program or modify certain settings. These changes on the surface, it is very difficult to be detected, but the intruder can use the appropriate procedure or a way to easily and establish connections with this computer, to regain control of the computer, as if intruders secretly with a master room, you can access at any time if without being the owner found. Usually most of the Trojan horse (TrojanHorse) program can be an intruder language system, a backdoor (BackDoor)

6.rootkit: rootkit is the attacker used to hide their whereabouts and retain root (root permissions, can be understood as the WINDOWS system or administrator rights) access tools. Typically, an attacker remotely exploitable manner obtain root access, or use the password guess solution (solution) to gain access to the system of common access rights, access to the system after it is passed, the other system memory in security vulnerability to obtain system root permissions. Then, the attacker will in each other's rootkit, installed in the system to achieve their long-term control each other's purpose, rootkit and we mentioned the Trojans and the front door is similar, but much lower than they are subtle, hackers defenders is very typical of the rootkit, domestic ntroorkit etc are good rootkit tools.

7.IPC $: is shared "named pipes" of resources, it is to enable inter-process communication and open hungry named pipes, you can verify the user name and password for the appropriate permissions, in the remote management computer and view the computer's shared resources.

8. the weak password: refers to those who have enough strength, easy to guess solution, similar to 123, abc such password (password).

9. default share: default share is WINDOWS2000/XP/2003 systems open shared services automatically when you open a shared hard disk, because a "$" symbol, so don't see share hand chart, also become hidden shares.

10.shell: refers to a command line environment means, such as our press the keyboard's "start key + R" run "when", inside the dialog box, enter "cmd" a black used to execute the command window, this is the Windows Shell execution environment. Usually we use remote overflow overflow remote computer program successfully from the command used to execute the system environment is the other side of the shell

11.WebShell: WebShell is to asp, php, jsp or cgi, a Web page file in the form of a command execution environment, it can also be called a Web back door. Hacker in the invasion of a site, usually the asp or php backdoor file and Web servers WEB Directory normal Web page file, after you use a browser to access the asp or php backdoor, get a command execution environment to achieve the purpose of controlling the Web server. You can upload and download files, view the database, to execute arbitrary programs command, etc. There are domestic common WebShell, Haiyang ASP Trojan, c99shell Phpspy etc

12. overflow: exact, should be "buffer overflow". The simple explanation is the procedure to accept input data does not implement effective detection and result in an error, the consequences may be caused program crash or execute the attacker's command. Can roughly be divided into two categories: (1) heap overflow; (2) stack overflow.

13. injection: with B/S mode application development development, use this mode to write the program more and more programmers to more, but as a programmer of DMV a considerable part of the application for security breaches. Users can submit a database query code, according to the procedure returns results for certain he'd known data, this is the so-called SQLinjection, namely: SQL note.

14. the injection point: can the injection place, usually a Access database. According to the injection point database running account permissions, you receive permissions differently.

15. intranet: popular is the LAN, such as Internet, intranet, corporate intranet, etc. belong to this class. View the IP address if it is in the following three scope, descriptionWe are in the intranet of: 10.0.0.0-10.255.255.255, 172.16.0.0-172.31.255.255 192.168.0.0-192.168.255.255,

16. external network: direct to the INTERNET (Internet), and the Internet as a computer with access, the IP address is not a reserved IP (gateway) IP address.

17. port (Port) corresponds to a data transmission channel. To accept some data, and then transmitted to the appropriate services, and computer processing of these data, and then apply the appropriate recovery through open ports to each other. Generally each port open pairs corresponding to the service, to close the ports need only turn off the corresponding service.

18.3389, 4899 broiler: 3389 is the Windows Terminal Services (TerminalServices) by default uses port number, the service is Microsoft in order to facilitate network administrators to remotely manage and maintain the server and launch, network administrators can use remote desktop to connect to any server on your network to open the Terminal Services computer, after a successful login will be like the operation of their computer as operations master. It and the remote control software or even a Trojan program implementation functions very similar to the Terminal Services connection is stable and will not be any antivirus software, so it is killing the hacker's favorite. Hacker in the invasion of a host, usually try to first add in a own backdoor account, and then turn on the other side of the Terminal Services, so that, at any time you can use Terminal Services to control each other, the host, usually is called 3389 broiler. Radmin is an excellent remote control software, 4899 is Radmin default to often be hackers as a Trojan to use (it is for this reason, the current anti-virus software also on Radmin killing). Some people in the use of the service port number. Since Radmin control is powerful, the transmission speed is faster than most Trojans, but without being the killing virus software, Radmin remote administration computers using a blank password or weak passwords that hackers could use some software to scan the network exists Radmin blank password or weak password for host, then you should be able to login on the remote control up, this is controlled by the host usually was to do 4899 broiler.
China Red League network security services expert http://www.runet.cn xiaocao QQ1191924009021-51872351 Server security services
19. free: through a shell, encryption, modifying the signature, and take instructions, and so on technology to modify the program, to escape the killing virus software.

20. shell: is the use of special acid, EXE executable or DLL dynamic link library file to change the encoding (such as compression, encryption) to reduce the file size or encryption program code, or even escape the purpose of killing the virus. At present there are more commonly used shell UPX, ASPack, PePack, PECompact, UPack, immune 007, Trojans sparingly, and so on.

21. the flower directive: it is a few compilation instructions for compiling statement some jump, anti-virus software can not be normal judge virus file structure. Said popular point is "antivirus software is from head to foot in order to find the virus. If we put a virus on the head and foot upside-down position, the anti-virus software will not find viruses ".

【 Weak current College 】 users how to find your own computer intruders

How timely discovery hacker intrusion, find the intruder and take effective measures. This chapter 1, section 2, you will be mainly describes network is attacked by anomalies as well as the measures to be taken; in the third section on intrusion detection principle, purpose and related products are described in section 4 provides for you in a number of recommendations on network security.

How to find the intruder

The system is not known intrusion is the worst thing, here's the UNIX system as example show you how to analyze network anomalies identified on the basis of your network system for intruders.

Exception of access log

Intruder in intrusion and control system, often used scan tool or manual scanning method for detecting system for more information. The scanning behavior is a system service logging off. Example: one IP times appear in the system's various services logs, and attempt the more vulnerability; and if a IP times in the same system for multiple service established a null connection, this is most likely that the intruder in gathering information about the version of a service.

Note in UNIX operating systems if someone visited system unnecessary services or have a serious security risk services such as finger, rpc; or Telnet, FTP, POP3, and other service logs a large number of consecutive failed login record of continuity, it is most likely that the intruder tries to guess the password of the system. These are precursory attack!

Network traffic increase

If you find that the server's access traffic increases the many suddenly, this indicates that your system may have been an intruder control, and intrusion is used to scan and attacks on other servers. As it turns out, many intruders are intermediary host on remote hosts for scanning and identifying security vulnerabilities, and attacks. But these actions will result in a sudden increase in network traffic.

Illegal access

If you find that a user attempted to access control and modify/etc/shadow, system logs and system configuration file, then it is likely that the user is already an intruder control and try to win a higher permission.

Normal termination of service

For example, System log services suddenly strange to quit, or your IDS program terminated abruptly, it is implied that an intruder attempting to quit these threats to avoid in the system log on the "mark".

Suspicious process or the emergence of illegal services

System of any suspicious process should be carefully checked, for example, to start the HTTP service root or system had shut down the service is started again. These suspicious processes and services are likely to be an intruder launch attack process, backdoor process or Sniffer process.

System files or user

Intruders often changes the system configuration files to avoid tracing, or load the backdoor, attacks such as software programs to facilitate the next time you enter. For example, for UNIX, the intruder or modify the syslog.conf file to remove the entries to avoid secure login backdoor audit, or modify the hosts.deny, hosts.allow to unlock the tcpwrapper on intruders IP filtering; even an additional entry in the rc.d inside, so that the system starts at the same time start the backdoor. It is illegal to modify the system or baffling and added a user and some phenomenon means that your system may well be the intruder control.

Suspicious data

System if found named such as spaces, dots and spaces, ".. ^ M "(content ctrl + M), the" ... "(blah) and other suspicious directory, you need to pay attention, because intruders often in this directory using and hidden files, such as some directory may (especially the/tmp directory) is a temporary file generated by the scanner.

【 Weak current College 】 Windows7 the basic skills of 70 (2)

16. activate the speed launch bar

When you use Win7, you will miss that in XP and Vista looks very useful high speed launch bar. Fortunately, you can be resolved more quickly steps give it to get to. Right-click the title bar--toolbar--a new toolbar in the space provided enter "%UserProfile%\AppData\Roaming\Microsoft\InternetExplorer\QuickLaunch", and then choose folder. Make him look like in Vista, right-click the toolbar--rescission "lock the toolbars", then right click on the "display respectively and revocation of the title" and "display text". Start by right-clicking the toolbar and select "display small icons" you're done.

17. in the resources to maintain in the show preview

In the maintenance window by pressing ALT + P to preview window on the right side should be out today.

18. desktop expansion lens

Press WIN + plus sign or minus sign to expand or reduce. You can zoom to any place on your desktop, you can also configure your expansion. You can select invert colors that follow the mouse pointer, follow keyboard focus maybe text input.
19. minimize all Windows except for now

Press win + Home

20. power maintenance fault elimination

Win7 can inform you of how much power the system may provide you with the application on power, and for each order and equipped with the doubts about the meticulous information. Network Institute (http://www.hackhome.com) prompted the masses can use this method to optimize your battery, extend its use of life. Press WIN + R input POWERCFG-ENERGY-OUTPUTPATH\FILENAME a minute it will generate a file in your energy-report.html set folder. (For example POWERCFG-ENERGY-outputc: \ one will be in the root directory of drive c to generate detailed energy-report.html internal power supply configurations. ) 21. in your desktop Web search

Win7 permit you resolved to an additional free download interface to search for online resources. For example, logon http://www.bizzntech.com/flickrsearch flicker interface. After that, you should see in your search FlickerSearch folder and you will be able to perform a search on your desktop without opening a Web page.

22. in the start menu, add video

Suppose that you have been looking for a faster way to find your video, now Win7 gave you an answer. Right-click the start--property--start menu--custom and then configure the video for "link show" is complete.

23. in the monitor window to switch between

Suppose you use two or more monitors, you'll want to move from one window to another. Here is a very easy way to do it. Everything you want to do is press the WIN + SHIFT + left or right, depending on whether you want to move to the monitor.

24. power button

Suppose that you seldom turn off your computer, but you can always restart it may let it sleep, so here you have a choice is to use a different behavior to replace your shutdown button. Right-click the start--property--power button action then you can in the given option was chosen in random.

25. quietly songsong add new fonts

Now add a new font to more easily than before. Only need to download the fonts you need, double-click it, you will see the device button.

26. the vertical stretch window

You can use the WIN + SHIFT + up to maximize vertical stretch your window right now. WIN + shift + down to recover it.

27. open Windows Explorer

Press WIN + E opened new Windows Explorer

28. setting up a new title bar of the first icon of the process

Press WIN + 1 can be used to turn over a new title bar on the first icon. This function in some cases really useful.

29. the Act Center

Windows move delivers to you in your computer's primary information, for example anti-virus pattern, promotions, perceived problems and provide a programme for the backup function. Control Panel-system and security--a move Center
30. the trouble with aware platform
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This platform can help you address many you can encounter questions, such as network interface hardware equipped with the system slow down, and so on. You can pick your diagnosis of doubt, he will also give you some of these questions indicate that real assistance to you, which provides many viable options, advice and information, so try to press the win after entering the "troubleshoot" maybe "fix". 31. shut down the system notifications

System notification will usually be bothering you and they often are not used, so you will want to close some of them. You can double-click the Win7 Control Panel notification area icon to complete it. Here you can alter behavior Center networkLuo, sound, Windows Explorer, Media Center small order pallets and Windows automatically qualify for notification, and icons.

Weak knowledge of computer