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Instructions to give any Windows system a clean install.


The following instructions were written to FDISK and FORMAT a 12 GB hard drive.
You can of course use these same instructions for any size hard drive.
Your hard drive size, the number and size of the partitions you want will be different of course.
Just by changing the % numbers you can adjust the partition sizes.
You can also change the number of partitions by adjusting the numbers.


I strongly suggest you backup your important files
before using the instructions on this page.

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You will need a 'Floppy Boot Disk' that contains drivers for your CD ROM.
Windows 98 or later will make one for you
OR Get
A Better Boot Disk - fdisk download

If you have a hard drive in excess of 64GB you will need the new fdisk file from Here Download and unpack the file. Copy the contents of the folder created onto your floppy boot disk. Allow the files to overwrite your current fdisk.exe file.





I'm going to give a disclaimer here:
( Even though it doesn't really apply, since you're trying to lose all your data :-)
      FDISK is a powerful tool. It can do severe damage to your data if you tell it to do the wrong thing. So make sure, at each step along the way, that you read the information it gives you. If it prompts you for information, make sure that you understand what it's asking for before responding. Depending on how your system is configured, FDISK may give you additional prompts that will not show up in the steps I'm describing. So, before you type in something that I've told you to type, make sure that it's really asking you what I'm describing that it should be asking you at that point.


With that out of the way, here's the best attempt I can give at instructions:

      The first thing you're going to need is a boot floppy disk. A floppy disk is a disk that you can successfully start your computer into DOS from, and that has the necessary drivers to let you access your CD-ROM drive. Make sure that it works, and lets you successfully read CDs before proceeding. If it turns out that there's a problem with this disk, you'll be in deep trouble later on.

      In the COMMAND directory of your Windows directory at C:\WINDOWS\COMMAND,( unless you've rearranged things ), you will find the files FDISK.EXE and FORMAT.COM. If these two files are not on your startup disk copy them from the command directory onto your boot floppy disk.


      You are about to erase your entire hard disk. Make sure that you have backups of your files, and that you have all the CDs that you will need to reinstall things once you're done.

Place your boot floppy into the drive and reboot your computer.
( choose: Start Computer with CD-ROM support if prompted )

      You should wind up at the A:\> MS-DOS prompt. Again, make absolutely, positively sure that you can access your CD-ROM at this point by typing DIR E: ( or whatever drive letter your CD-ROM drive has ), and and pressing ENTER. If you can now see a list of files on the CD you know it works.

At the A:\> prompt, type FDISK and press ENTER.
      You will see a very long message, telling you that "Your computer has a disk larger than 512 MB", and asking if you wish to enable large disk support. ( "Large disk support" means "FAT32" ) Answer Y to enable large disk support.

You will see the main FDISK Options menu, and the Enter choice: prompt.
      It will tell you Current fixed disk drive: 1 in other words, unless you tell it otherwise, it's going to operate on disk 1, the first disk it's found on the system. Since there's only one hard drive on your system ( Make sure this is true ), this is what you want to do.

You want to start out by deleting the existing partition from the disk.
      To do that, type in 3 the Delete partition or Logical DOS drive option and press ENTER.
A menu will appear, asking you what sort of partition to delete. Enter 1 Delete Primary DOS partition and press ENTER.
      A list of partitions will appear; there will probably only be one partition there. It will ask you what primary partition to delete; choose 1 the only one listed, and press ENTER.
      To make absolutely sure that you know what you're doing, it may prompt you to type in the volume label for the partition, which will be listed in the partition list. If the Volume Label column is blank, then the volume label is blank too, so just press ENTER.
It will tell you Partition deleted, or words to that effect, and send you back to the main menu.

Now you want to create a new partition.
To do that, choose option 1 Create DOS partition or logical DOS drive and press ENTER.
It will prompt you for what sort of partition to create; choose option 1 Create Primary DOS partition and press ENTER.
It will prompt you Do you wish to use the maximum available size for a Primary DOS partition and make the partition active (Y/N)?
No, you don't;
that would put you right back where you started with one partition the size of the whole hard drive. So choose N and press ENTER.
      It will show you the total space on the drive, and prompt you Enter size in MBytes or percent of drive space (%): You want this first partition to take up one quarter of the drive space, so type in 25% ( make sure to include the percent sign ), and press ENTER.
( If you would like a different partition size, just adjust the % number )
It should tell you Partition created; drive letters changed or added, or words to that effect. If it sends you back to the main FDISK Options menu, great; if it doesn't, just press the Esc key until you're back there.



      Before we go any farther, let's make this partition the active partition. That is the one that the system will try to boot from.
Choose option 2, Set active partition, and press ENTER.
It will show you a list of partitions which should only include one partition, the one you just created and ask you what partition to set as the active one. Choose 1 ( the number of the partition you just created ), and press ENTER. It will tell you that it's made that partition active, and prompt you to press Escape to go back to the main menu. Do that.

      Now it's time to create the extended partition, the partition that will contain the remaining three partitions. Choose option 1 Create DOS partition or Logical DOS drive again.
When it prompts you for what type of partition to create, choose option 2 Create Extended DOS partition and press ENTER.
If it prompts you Do you wish to use the maximum available size?, then press Y you do. Otherwise, if it prompts you to enter a size, enter the maximum value it allows. For example, if it tells you that the maximum possible size is 12843 MBytes, enter 12843 with no percent sign and press ENTER.
FDISK should tell you that it's created the partition. Press Esc to return to the FDISK Options menu, if it doesn't send you there on its own.

      Now it's time to fill up that extended partition you just created, by making three logical partitions to fill it. Again, choose option 1 Create DOS partition or logical DOS drive and press ENTER.
This time, when it asks you what type of partition to create, choose option 3 Create Logical DOS drive(s) in the Extended DOS Partition and press ENTER.
It will prompt you to Enter logical drive size in MBytes or percent of disk space once again. Type in 33% with the percent sign and press ENTER.
( Remember; if your want a different size, the % number you enter is the percent of the "extended" partition )
It will create the first logical partition, and immediately prompt you to Enter logical drive size... again. This time, type in 50% with the percent sign, and press ENTER. It's 50% this time because half of the remaining is one third of what you started with.
( Again, if changing the numbers from what I list the % number is the percent of the "extended" partition )
It will create the second logical partition, and prompt you once again to "Enter logical drive size..." This time, look above the prompt, to where it says "Maximum space available for logical drives is (some number) MBytes". Type in the number of MBytes shown there, without a percent sign, and press ENTER.
It will create the third logical partition, and tell you that All available space in the Extended DOS partition is assigned to logical drives in other words, you've filled the entire space, just as you wanted to do. Press Escape to continue.


      Believe it or not, you have now successfully partitioned your drive.
Press Escape once more to exit FDISK. It will give you one last warning, telling you that you must restart the computer for the changes to take effect. Press Escape one more time.
You should now be back at the A:\> prompt. Press Ctrl-Alt-Delete to restart the computer. Again, let it boot from the boot floppy.
When it gets back to the A:\> prompt, type FORMAT C: to format the primary partition. When that finishes, type FORMAT D:, then FORMAT E:, then FORMAT F:, to format the remaining partitions.
( If you varied the number partitions from what I list, remember to format "every" partition )

You should now have a nice clean hard drive, with four 3GB partitions, ready to install your operating system of choice. Celebrate with your beverage of choice.

I hope this helps you Guys / Gals.
+ نوشته شده در  شنبه بیست و ششم خرداد 1386ساعت 1:50  توسط  beta  | 

Wikipedia, the free encyclopedia
Jump to: navigation, search
Norton Utilities 6.0 for DOS.
Norton Utilities 6.0 for DOS.

The Norton Utilities releases were collections of software utilities. Peter Norton published the first version for DOS, The Norton Utilities, Release 1, ca 1981. Release 2 came out several years later, subsequent to the first hard drives for the IBM PC line. Peter Norton's company was sold to Symantec in 1990. However his name remains as a "brand" for Symantec's range of utility and security software for home users.

Contents

[

[edit] Norton Utilities Releases

Norton Utilities 4.0 for DOS.
Norton Utilities 4.0 for DOS.

[edit] Release 1.0

The initial release featured the UNERASE utility. This allowed files to be undeleted by restoring the first letter of the directory entry (a feature of the FAT file system used in MS-DOS, albeit one that was not originally documented). The UNERASE utility was what launched NU on its path to success.

Other utilities included the following:

  • ASK, used for batch file programming
  • BEEP, causes the PC speaker to beep
  • VERIFY

Following this release Peter Norton was made Utilities Editor of PC Magazine.

[edit] Release 2.0

The main feature of this version was FILEFIND, used for searching for files.

[edit] Release 4.0

Release 4.0 included a number of features including Norton Disk Doctor, a disk defragmenter (SPEEDISK), a sector level disk editor, a system information diagnostic utility, and a disk caching program (NCACHE), which was between 10 - 50% faster than Microsoft's SMARTDrive when properly configured. This version also included a menu system to tie the utilities together called the Norton Integrator (NI). Previously the utilities were accessed by typing the command name (usually a cryptic 2 character name such as FF) at the DOS prompt.

[edit] Release 5.0

Release 5.0 included more features, including a utility to perform low level formatting on hard disks, and changes such as password protection on the more "dangerous" utilities. It also included a licensed version of the 4DOS replacement for COMMAND.COM called NDOS. This version also allowed the choice of "classic" names (such as FF.EXE) or longer names (such as FINDFAST.EXE); these were configurable in the updated version of the Norton Integrator menu system.

[edit] Release 7.0

Release 7.0 had revised user interfaces for the utilities that feature a menu-driven user interface. Also some of these tools now did not need to run in full-screen-mode but just displayed a window in the center of the screen, like the disk formatter or the disk duplicator utility.

[edit] Release 8.0

Release 8.0 was nearly the same as 7.0, but added a few Windows 3.1 utilities, like Norton Disk Doctor, Speed Disk, SystemWatch, FileCompare and some INI tools called INI-Tracker, INI-Tuner and INI-Adviser.

[edit] Norton Utilities/SystemWorks for Windows

The Windows version of Norton Utilities was originally released for Microsoft Windows 95. Norton was in need of a major update as the VFAT system used by Windows 95 to provide long file names was incompatible with utilities such as Norton Utilities' 'SPEEDISK.EXE'. However, the Windows version, called 'Speed Disk' works with much greater speed than Microsoft's supplied defrag program, as it moved groups of clusters, not single clusters as Microsoft's Windows Disk Defragmenter. Changes in the way Windows operates meant that many of the old utilities were either dropped completely or replaced with GUI based versions. However, with the advent of Windows XP onwards, Norton's 'Speed Disk' reverted back to single-cluster defragmentation.

Norton Systemworks started off as a collection of tools which also included Norton AntiVirus, Norton Utilities, and a number of other utilities that expanded as Symantec purchased more utilities companies. SystemWorks continues to be a suite of utilities, but Norton Utilities is no longer available as a separate package.

[edit] Norton Utilities for the Macintosh

Norton Utilities for Macintosh was a separate utility suite for the Mac OS, providing much of the same features as the equivalent Windows version. Version 1.0 for the Macintosh was released in 1990. When Apple released System 7, Norton Utilities for the Macintosh needed to be updated in order to run safely. This proved to be a recurring story in the history of this utility; version 4 was highly regarded for a while, but proved to be specifically hazardous to use with newer disk structures and operating systems.

Recent versions were known as simply Symantec Utilities for Macintosh, after Symantec bought the product in the late 1990s. After Mac OS X v10.3 (Panther) was released Norton Utilities was eventually listed as being incompatible, and some time later it was quietly discontinued.

There was also a SystemWorks suite for the Mac OS, encompassing Allume Systems' Spring Cleaning and Retrospect in addition to Symantec's own Norton Utilities. It too was eventually discontinued some time after the release of Mac OS X Panther, although with such little publicity that it remained listed on some Symantec web sites for more than a year afterwards. Spring Cleaning and Retrospect continue to be sold separately.

[edit] Unix

A Unix version of Norton Utilities was developed and marketed by INTERACTIVE Systems Corp.

[edit] Incorporation of Norton Utilities into MS-DOS

A number of the Norton Utilities were licensed by Microsoft over the years. The most famous one was SPEEDISK licensed as DEFRAG in MS-DOS 6 onward.

[edit] List of included applications

  • Batch Enhancer
  • Norton Cache
  • Calibrate
  • NCD (Norton Change Directory)
  • Norton Companion
  • Norton Connection Doctor
  • Norton Diagnostics
  • Directory Sort
  • Norton Disk Doctor
  • Norton Disk Editor
  • Disk Monitor
  • Disk Tools
  • Diskreet
  • NDOS (Norton DOS)
  • DupDisk
  • Fast Find
  • File Attributes
  • Norton File Compare
  • File Date
  • File Find
  • File Fix
  • File Locate
  • FileSaver
  • File Size
  • Norton Image
  • INI Advisor
  • INI Editor
  • INI Tracker
  • INI Tuner
  • Norton Integrator
  • Line Printer
  • LiveAdvisor
  • LiveUpdate
  • Norton Optimization Wizard
  • Norton Protection
  • Norton Registry Editor
  • Norton Registry Tracker
  • Norton Rescue and Norton ZIP Rescue
  • Safe Format
  • SmartCan
  • Space Wizard
  • Speed Disk
  • Norton SpeedStart
  • Norton System Check
  • Norton System Doctor
  • Norton System Genie
  • System Information
  • System Watch
  • Text Search
  • Norton UnErase
  • Unformat
  • Volume Recover
  • Norton WinDoctor
  • Wipe Info
  • Norton AntiFreeze
  • Norton CrashGuard

[edit] Competitors

[edit] Old times (1980s and 1990s)

[edit] Modern times (2000s)

[edit] Modern times (2000s) Macintosh utilities

+ نوشته شده در  شنبه بیست و ششم خرداد 1386ساعت 1:41  توسط  beta  | 

1837 - Samuel Morse Invents The Telegraph


In 1837, Samuel Morse invented the original telegraph transmitter and receiver. This invention was the foundation which led to the information age as we know it today.


Samuel Morse
 
Telegraph

 

 


 


In 1858, the Atlantic cable was established to carry instantaneous communications across the ocean for the first time. Although the laying of this first cable was seen as a landmark event, it only remained in service a few days.

Atlantic Cable Sample
 
 
The History of the Internet
1866 - The Next Trans-Atlantic Cable Is A Success


On the next attempt, cables which were laid in 1866 were a complete success. This event, in its time, would compare to events like the moon landing of a century later. The cable of 1866 remained in service for the next 100 years.

Atlantic Cable Buoys


Cable buoys were used to mark the location of cables. The largest of the buoys used on the Atlantic telegraph cable of 1865-66 could carry a cable weight of 20 tons.

http://historyoftheinternet.org/wowacademy/timeline03.cfm

+ نوشته شده در  شنبه نوزدهم خرداد 1386ساعت 4:23  توسط  beta  | 

From Wikipedia, the free encyclopedia

Jump to: navigation, search
Total Commander
Image:Total Commander logo.gif

Total Commander 6.03a running on Windows 2000
Developer: Christian Ghisler
Latest release: 7.00 / 7 June 2007
OS: Windows, Windows CE
Genre: File manager
License: Shareware
Website: www.ghisler.com

Total Commander is a shareware Orthodox File Manager (OFM) for Windows. Some features include a built-in FTP client, file compare, archive file navigation, and a multi-rename tool.

At one point, Total Commander was called Windows Commander; the name was changed in 2002 after the developers received a letter from Microsoft alleging "Windows" was a registered trademark.[1]

This application is written by Christian Ghisler in Delphi 2 (32-bit version) and Delphi 1 (16-bit version). The program is extensible by programmers via an open plugin-API and it has the ability to bind external programs for viewing or editing files. Many plugins are freely available for e.g. different packer formats or file viewer for special file formats.

A freeware version of Total Commander also exists for Windows Mobile.

The main version is shareware – the user should register or delete it within 30 days. The unregistered version nags for registration every time it starts, but it retains full functionality, even after the 30-day trial period.

One notable feature of Total Commander is that in addition to allowing access to Windows partitions, there is a plugin that allows users to access both EXT2/EXT3 and Reiser partitions on the same machine. Hence, for dual-boot machines with Windows and Linux, Total Commander allows access to files stored on the Linux partition while running Windows.

The download is about 2MB; available in both 16- and 32-bit versions, for the various versions of Windows, and works just as well on Linux using Wine. Linux users may also want to consider using similar open source software Krusader or GNOME Commander.

Total Commander is more similar to Dos Navigator than to Norton Commander.

[edit] References

  1. ^ http://www.ghisler.com/name.htm

[edit] See also

[edit] External links

+ نوشته شده در  شنبه نوزدهم خرداد 1386ساعت 3:14  توسط  beta  | 

Blue RJ-45 (8P8C) patchcord of the type commonly used to connect network devices.
Blue RJ-45 (8P8C) patchcord of the type commonly used to connect network devices.

A computer network is multiple computers connected together using a telecommunication system for the purpose of communicating and sharing resources.

Experts in the field of networking debate whether two computers that are connected together using some form of communications medium constitute a network. Therefore, some works state that a network requires three connected computers. For example, "Telecommunications: Glossary of Telecommunication Terms" [1]

states that a computer network is "A network of data processing

nodes that are interconnected for the purpose of data communication", the term "network" being defined in the same document as "An interconnection of three or more communicating entities". A computer connected to a non-computing device (e.g., networked to a printer via an Ethernet link) may also represent a computer network, although this article does not address this configuration.

This article uses the definition which requires two or more computers to be connected together to form a network. Therefore, this does not

include intranets, due to their not needing to be connected via two or

more computers.[2] The same basic functions are generally present in

 this case as with larger numbers of connected computers.

 

 

Contents

[edit] Basics

A computer network may be described as the interconnection of two or more computers that may share files and folders, applications, or resources like printers, scanners, web-cams etc. The internet is also a type of computer network which connects millions of computers around the world.

[edit] Protocols

Main article: Protocols

A protocol is a set of rules and conventions about the communication in the network. A protocol mainly defines the following:

  1. Syntax: Defines the structure or format of data.
  2. Semantics: Defines the interpretation of data being sent.
  3. Timing: Refers to an agreement between a sender and a receiver about the transmission.

[edit] Standards Organizations

Various standards organizations for data communication exist today. They are broadly classified into three categories:

  1. Standards Creation Committees.
  2. Forums
  3. Regulatory Agencies

[edit] Standards Creation Committees

Some important organizations in this category are:

A multinational standards body
Previously, CCITT. Developed under United Nations for national standards.
An affiliate of ITU-T
Largest professional engineering body in the world. Oversees the development and adoption of international electrical and electronic standards.
Aligned with ANSI. Focuses public awareness and lobbying for standards.

[edit] Forums

University students, user groups, industry representatives and experts come together and set up forums to address various issues and concerns of data communication technology and come up with standards for the day's need. Some of the well-known forums are:

  • The Internet Society(ISOC)
  • Internet Engineering Task Force (IETF)
  • Frame Relay Forum
  • ATM Forum
  • ATM Consortium

[edit] Regulatory Agencies

These are government appointed agencies like Federal Communications Commission (FCC).

[edit] Communication Techniques

Data is transmitted in the form of electrical signals. The electrical signals are of two types viz., analog and digital. Similarly, data can also be either analog or digital. Based on them, data communication may be of following types:

  • Analog data, analog transmission
e.g.: transmission of voice signals over telephone line
  • Analog data, digital transmission
e.g.: transmission of voice signal after digitization using PCM, delta modulation or adaptive delta modulation
  • Digital data, analog transmission
e.g.: communication using modem
  • Digital data, digital transmission
e.g.: most of present day communication

[edit] Modes Of Data Transmission

Digital data can be transmitted in a number of ways:

  • Parallel and serial communication
  • Synchronous, iso-synchronous and asynchronous communication
  • Simplex, half-duplex and full-duplex communication'

[edit] Transmission Errors

It is virtually impossible to send any signal, analog or digital, over a distance without any distortion even in the most perfect conditions due to:

  • Delay Distortion
Signals of varying frequencies travel at different speeds along the medium. The speed of travel of a signal is highest at the center of the bandwidth of the medium and lower at both the ends. Therefore, at the receiving end, signals with different frequencies in the given medium will arrive at different times causing delay error.
  • Attenuation
As a signal travels through a medium, its signal strength decreases.
  • Noise
A signal travels as an electromagnetic signal through any medium. Electromagnetic energy that gets inserted somewhere during transmission is called noise.

Many attempts have been made to detect and rectify the transmission errors. Error detection schemes:

  • Vertical Redundancy Check (VRC) or Parity Check
  • Longitudinal Redundancy Check (LRC)
  • Cyclic Redundancy Check (CRC)

Error correction schemes:

  • stop-and-wait
  • go-back-n
  • sliding-window


[edit] Building a computer network

A simple computer network may be constructed from two computers by adding a network adapter (Network Interface Controller (NIC)) to each computer and then connecting them together with a special cable called a crossover cable. This type of network is useful for transferring information between two computers that are not normally connected to each other by a permanent network connection or for basic home networking applications. Alternatively, a network between two computers can be established without dedicated extra hardware by using a standard connection such as the RS-232 serial port on both computers, connecting them to each other via a special crosslinked null modem cable.
Practical networks generally consist of more than two interconnected computers and generally require special devices in addition to the Network Interface Controller that each computer needs to be equipped with. Examples of some of these special devices are listed above under Basic Computer Network Building Blocks / networking devices.

[edit] Types of networks:

Below is a list of the most common types of computer networks.

[edit] A personal area network (PAN) :

A personal area network (PAN) is a computer network used for communication among computer devices (including telephones and personal digital assistants) close to one person. The devices may or may not belong to the person in question. The reach of a PAN is typically a few meters. PANs can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink).
Personal area networks may be wired with computer buses such as USB and FireWire. A wireless personal area network (WPAN) can also be made possible with network technologies such as IrDA and Bluetooth.

[edit] Campus Area Network (CAN):

A network that connects two or more LANs but that is limited to a specific (possibly private) geographical area such as a college campus, industrial complex, or a military base
Note: A CAN is generally limited to an area that is smaller than a Metropolitan Area Network.

[edit] Metropolitan Area Network (MAN):

A network that connects two or more Local Area Networks or CANs together but does not extend beyond the boundaries of the immediate town, city, or metropolitan area. Multiple routers, switches & hubs are connected to create a MAN

[edit] Wide Area Networks (WAN):

A WAN is a data communications network that covers a relatively broad geographic area and that often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.

Types of WANs:

Centralized:
A centralized WAN consists of a central computer that is connected to dumb terminals and / or other types of terminal devices.
Distributed:
A distributed WAN consists of two or more computers in different locations and may also include connections to dumb terminals and other types of terminal devices.

[edit] Internetwork:

Two or more networks or network segments connected using devices that operate at layer 3 (the 'network' layer) of the OSI Basic Reference Model, such as a router.
Note: Any interconnection among or between public, private, commercial, industrial, or governmental networks may also be defined as an internetwork.
Internet, The:
A specific internetwork, consisting of a worldwide interconnection of governmental, academic, public, and private networks based upon the Advanced Research Projects Agency Network (ARPANET) developed by ARPA of the U.S. Department of Defense – also home to the World Wide Web (WWW) and referred to as the 'Internet' with a capital 'I' to distinguish it from other generic internetworks.

[edit] Extranet:

A network or internetwork that is limited in scope to a single organization or entity but which also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities (e.g., a company's customers may be provided access to some part of its intranet thusly creating an extranet while at the same time the customers may not be considered 'trusted' from a security standpoint).
Note: Technically, an extranet may also be categorized as a CAN, MAN, WAN, or other type of network, although, by definition, an extranet cannot consist of a single LAN, because an extranet must have at least one connection with an outside network.
Intranets and extranets may or may not have connections to the Internet. If connected to the Internet, the intranet or extranet is normally protected from being accessed from the Internet without proper authorization. The Internet itself is not considered to be a part of the intranet or extranet, although the Internet may serve as a portal for access to portions of an extranet.

[edit] Classification of computer networks

[edit] By network layer

Computer networks may be classified according to the network layer at which they operate according to some basic reference models that are considered to be standards in the industry such as the seven layer OSI reference model and the five layer TCP/IP model.

[edit] By scale

Computer networks may be classified according to the scale or extent of reach of the network, for example as a Personal area network (PAN), Local area network (LAN), Campus area network (CAN), Metropolitan area network (MAN), or Wide area network (WAN).

[edit] By connection method

Computer networks may be classified according to the technology that is used to connect the individual devices in the network such as HomePNA, Power line communication, Ethernet, or Wireless LAN.

[edit] By functional relationship

Computer networks may be classified according to the functional relationships which exist between the elements of the network, for example Active Networking, Client-server and Peer-to-peer (workgroup) architectures. Also, computer networks are used to send data from one to another by the hardrive

[edit] By network topology

Computer networks may be classified according to the network topology upon which the network is based, such as Bus network, Star network, Ring network, Mesh network, Star-bus network, Tree or Hierarchical topology network, etc.

Topology can be arranged in a Geometric Arrangement

Network Topologies are logical layouts of the network. The term "logical" used here marks a great significant. That means network topologies depends not on the "physical" layout of the network. No matter that computer on a network are placed in a linear format, but if they connected via a hub they are forming a Star topology, not the Bus Topology. And here is the important factor where networks differ, visually and operationally.

[edit] By services provided

Computer networks may be classified according to the services which they provide, such as Storage area networks, Server farms, Process control networks, Value-added network, Wireless community network, etc.

[edit] By protocol

Computer networks may be classified according to the communications protocol that is being used on the network. See the articles on List of network protocol stacks and List of network protocols for more information.

[edit] See also

[edit] References

  1. ^ Error on call to Template:cite web: Parameters url and title must be specified. Institute for telecommunication sciences (1996-08-07). Retrieved on 2007-01-14.
  2. ^ Groth, David; Toby Skandier (2005). 'Network+ Study Guide, Fourth Edition'. Sybex, Inc.. ISBN 0-7821-4406-3. “the term network describes two or more connected computers” 

This article contains material from the Federal Standard 1037C, which, as a work of the United States Government, is in the public domain.

[edit] External links


http://www.networkingboards

+ نوشته شده در  جمعه هجدهم خرداد 1386ساعت 0:45  توسط  beta  | 

 

You can just format your computer before putting it on Ebay or donating it to your local school or church. But everyone has probably heard by now that merely erasing data isn’t good enough. Forensics can uncover a startling amount of data from freshly-formatted hard drives. Your bank information, credit card numbers and other personal information can be retrieved quite easily by someone who knows what they’re doing.

Because this is an article about security, we want to make sure computer users are aware that data is not gone until it is shredded using Department of Defense standards. There are programs available that shred the data by writing ones and zeros over the drive repeatedly until the data is no longer recognizable. While this can be a long process, depending on the size of the hard drive, it’s necessary to do this to avoid identity theft.

There are many programs out there to shred files. You can choose a program like Zilla Data Nuker 2 or any of the others that employ the same type of DoD standards.

Most of these programs work the same way. You will need to go into the BIOS to make sure your PC is set to boot to the CD drive. Then you’ll insert the disk you made from the program. The program will run and make numerous passes over the boot record and the data on the hard drive until nothing is left. It could take all night to complete, so start the program before bed or leaving for work.

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Troubleshooting a PC Power Supply isn't that difficult. Various PC parts will use either 3.3 volt, 5 volt, or 12 volt. The 3.3 and 5 volt leads usually power digital circuits, while the 12 volt leads provide power to fans and drives. The common form factor used in computers today is the ATX. This power supply has a single, twenty-pin connector.Some typical symptoms of a bad power supply include:  Dead system, partially dead system, and random rebooting. If the PSU's fan quits working, replace it immediately

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When first setting up a hard drive, you need to consider how many partitions that disk will contain. For example, some people like to partition their single drive into two partitions and keep their data on one partition and Windows on another. This makes reinstalling Windows easier and helps to protect your data. Below are the steps for creating and removing partition using the fdisk utility

 

Before you can FORMAT your hard drive, you must partition it. Most drives only have a Primary partition, but that partition can be split into an Extended partition which can be further divided into Logical Drives. The C: drive is normally the Primary partition. The logical drives after that can be labeled D: E: F: etc. To partition the drive you’ll need a boot disk. This disk (sometimes called a Startup Disk) will contain the FDISK utility. We recommend downloading one from bootdisk.com to match your Operating System, or you can make one in the Add / Remove Programs area of the control panel. You’ll need a formatted, blank floppy for this.

Once the boot disk has been created, insert the disk and reboot. You will eventually wind up at the A:/ prompt. Type fdisk and hit enter. you will be taken to a screen with the following options:

  1. Create DOS partition or Logical DOS Drive

  2. Set active partition

  3. Delete Partitions or Logical DOS Drive

  4. Display partition information

  5. Change current fixed drive

You will choose option one first, then when asked if you want to use the entire amount of space for this you will say Y if you have no intention of partitioning further, or N if you want to create an Extended partition (recommended). Your Extended partition must take up the remaining space on the disk. You will then be able to create Logical drives.

Your Primary partition should automatically be set as the Active partition. If not, you may need to go to the option 2 to designate it as such.

Keep in mind that there are some restrictions on partition sizes. You may need to partition huge drives into 64 gigs or smaller.

Deleting Partitions

Before creating partitions on older drives, you will have to delete the current partitions. Backup any important data because all data will be lost after deleting a partition. To avoid losing data, you can use non-destructive partitioning software such as Partition Magic--but it’s wise to backup just in case.

If you have an NTFS partition on a drive FDISK will not be able to remove it. You’ll probably see an error like this NTLDR is missing. Press any key to restart. You can use a utility called delpart.exe to remove the NTFS partition. This is also available at bootdisk.com.

Hard Drive Utilities

Most hard drive manufacturers include partitioning and copying software with the new drives. This will be a disk similar to a boot disk that will provide a graphical interface that walks you through the process of transferring files from one drive to another and partitioning the new disk into the FAT 32 or NTFS format. This is by far the easiest way to go. However, it is still recommended that you know the differences between a Primary, Extended and Logical drive.

+ نوشته شده در  جمعه هجدهم خرداد 1386ساعت 0:19  توسط  beta  | 

The BIOS (Basic Input Output System) is a program installed on a ROM chip physically connected to the motherboard.  Modern PC's use a technique called "flashing the BIOS" which means rewriting the data that is on this chip.  This chip is considered "firmware" because it is a combination of hardware and software. Under normal conditions the BIOS makes the PC aware of itself by initiating the hardware and software installed on the computer.  However, when there is a critical problem, the BIOS uses a series of BEEP CODES to alert the user of the problem.  Usually you can tell what BIOS your system is using by either watching the startup screen or by looking for the name stamped on the BIOS chip on the motherboard.  
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Whether you're a novice or an expert PC technician, we've all had an experience when a new PC would not boot. There's no worse feeling than pushing the power button on the front of a new machine an hearing absolutely nothing. This article will focus on some of the common problems with new builds and help to reduce the computer troubleshooting time when diagnosing problems with your new computer.

Take A Quick Visual Of The Computer

You should have already done this before trying to power up the PC, but a lot of novice PC builders will skip this step in anticipation of powering up their new machine. This step may save you time and money. First, triple check to make sure the CPU is sitting flat on the motherboard socket. It's probably hard to tell because of the heat sink, but if the entire CPU and heat sink combo looks skewed, then chances are it's not installed properly. Next, go over the IDE cables and the thin wires running from the power and reset switches to the motherboard. While the IDE cables are keyed, it's quite possible to get those case wires backwards or completely. Lastly give the PC a little shake. Make sure an errant screw didn't fall behind the motherboard during the install. This could blow the motherboard or cause the system to go to ground.

Computer Hardware Troubleshooting

When a new PC will not boot, a good place to start is the power supply. Is the machine getting power? If there is no fan activity at the rear of the power supply, then the power supply isn't working. First, check the wall socket and power strip to make sure power is actually being supplied to the computer. If there is power to the outlet, confirm that the | / O lever in the back is set to |. Then confirm that the voltage is set to 110V in the USA or 220V in countries that require that setting. If you have a voltmeter, you might want to consider testing the power supply. Refer to the pin out chart for the correct power supply voltages .

Troubleshooting Video Cards

If the system powers up, but you get nothing on the screen, the video card may be the culprit. First, confirm the video cable is secured to the video card's output. If the motherboard has built in video, and you're using a PCI-E or AGP card, make sure the cable is secured to the correct port. Also, check for bent pins on the connector and confirm the monitor works and the brightness controls are set correctly. Do you hear any beeps? If so, refer to our BIOS beep code chart . It's always a good idea to reseat the RAM and video card when you get the "No Signal Displayed" message on the monitor.

Dead Motherboard or CPU

Improper installation of the motherboard and CPU can cause instant failure. We like to install the CPU and RAM modules on the motherboard before installing the motherboard in the case this is because it sometimes requires some effort to get the heat sink seated properly on the CPU. The CPU itself should slide effortlessly into place and lock without any problems with the lever. If you require resistance when installing the CPU, make sure the CPU's pins are properly aligned to the socket on the motherboard. Apply the correct amount of thermal grease or tape as recommended by the manufacturer, then install the heat sink. The heat sink should rest flatly on top of the CPU.

As for the motherboard, refer to the manual about each of the connections to the case. A common problem area are the standoffs between the case and motherboard, and the connection of the thin wires from the power and reset switches to the motherboard.

BIOS BEEP Codes

You will often receive a BIOS beep code when there is a hardware issue with the PC. You should determine the BIOS residing on the motherboard by physically looking for the BIOS chip on the motherboard. Look for something like AMI-BIOS, AWARD BIOS or PHOENIX. Refer to our BIOS Beep Code Chart when diagnosing beep code errors. This will often lead you quickly to the source of the hardware problem.

In Conclusion

While these new computer installations can be frustrating, it's important to take a step back and think before you do more damage. Take a nap or a walk and then look at the problem with fresh eyes. If you need further assistance, please consult our techs on our message boards .

Authored by: David .
Click Here to View all the questions in PC Troubleshooting category.
 
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+ نوشته شده در  جمعه هجدهم خرداد 1386ساعت 0:7  توسط  beta  | 

 

When first setting up a hard drive, you need to consider how many partitions that disk will contain. For example, some people like to partition their single drive into two partitions and keep their data on one partition and Windows on another. This makes reinstalling Windows easier and helps to protect your data. Below are the steps for creating and removing partition using the fdisk utility.

Creating Partitions

Before you can FORMAT your hard drive, you must partition it. Most drives only have a Primary partition, but that partition can be split into an Extended partition which can be further divided into Logical Drives. The C: drive is normally the Primary partition. The logical drives after that can be labeled D: E: F: etc. To partition the drive you’ll need a boot disk. This disk (sometimes called a Startup Disk) will contain the FDISK utility. We recommend downloading one from bootdisk.com to match your Operating System, or you can make one in the Add / Remove Programs area of the control panel. You’ll need a formatted, blank floppy for this.

Once the boot disk has been created, insert the disk and reboot. You will eventually wind up at the A:/ prompt. Type fdisk and hit enter. you will be taken to a screen with the following options:

  1. Create DOS partition or Logical DOS Drive

  2. Set active partition

  3. Delete Partitions or Logical DOS Drive

  4. Display partition information

  5. Change current fixed drive

You will choose option one first, then when asked if you want to use the entire amount of space for this you will say Y if you have no intention of partitioning further, or N if you want to create an Extended partition (recommended). Your Extended partition must take up the remaining space on the disk. You will then be able to create Logical drives.

Your Primary partition should automatically be set as the Active partition. If not, you may need to go to the option 2 to designate it as such.

Keep in mind that there are some restrictions on partition sizes. You may need to partition huge drives into 64 gigs or smaller.

Deleting Partitions

Before creating partitions on older drives, you will have to delete the current partitions. Backup any important data because all data will be lost after deleting a partition. To avoid losing data, you can use non-destructive partitioning software such as Partition Magic--but it’s wise to backup just in case.

If you have an NTFS partition on a drive FDISK will not be able to remove it. You’ll probably see an error like this NTLDR is missing. Press any key to restart. You can use a utility called delpart.exe to remove the NTFS partition. This is also available at bootdisk.com.

Hard Drive Utilities

Most hard drive manufacturers include partitioning and copying software with the new drives. This will be a disk similar to a boot disk that will provide a graphical interface that walks you through the process of transferring files from one drive to another and partitioning the new disk into the FAT 32 or NTFS format. This is by far the easiest way to go. However, it is still recommended that you know the differences between a Primary, Extended and Logical drive.

Authored by: David This question has been viewed 6318 times so far.
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