File Server

A file server is a combination of a computer, internal hardware and software that allows network users to share computer programs and data. A file server usually has a significantly faster processor, faster interface card, more memory and more data storage than most PCs. It may also have a tape back-up unit, modems, and several printers attached.

A file server is a computer which is used for storing files. Any user on the network can store or retrieve files on the server with some request.

All services are controlled by the File server. Network requires a high-end Server with redundancy. It requires special equipment and software to diagnose network problems. It requires Certified Network Specialist to identify problems.

File server is single and critical machine. Suppose the File server got crashed all the operations will collapse. There are chances to get the files deleted. The following section explains how those deleted files would be recovered.

Some of the Computer Virus Infections

• BOBBIT VIRUS - Removes a vital part of a hard disk then re-attaches it. (But that part will never work properly again.)

• OPRAH WINFREY VIRUS - 200MB hard drive suddenly shrinks to 80MB, and then slowly expands back to 200MB.

• MCI VIRUS - Every three minutes it reminds that a person pays too much for the AT&T virus.

• PAUL REVERE VIRUS - This revolutionary virus does not horse around. It warns that of an impending hard disk attack -- once if by LAN and twice if by floppy.

• POLITICALLY CORRECT VIRUS - Never calls itself a "virus", but instead refers to itself as an "electronic micro-organism."

• RIGHT TO LIFE VIRUS - Will not allow the user to delete a file, regardless of how old it is.

• ROSS PEROT VIRUS - Activates every component in a system, before quitting.

• MARIO CUOMO VIRUS - It would be a great virus, but it refuses to run.

• TED TURNER VIRUS - Colorizes the monochrome monitor.

• ARNOLD SCHWARZENEGGER VIRUS - Terminates and stays.

Reduce the chance of getting computer viruses from E-mail

What are the possibilities to reduce the chance of getting viruses from E-mail?

Save the attachment to disk and then check it with an up-to-date virus scanner before opening the file.

If an executable file shows up unexpectedly attached to an E-mail, delete it unless it should be positively verified what it is, where it came from and why it was sent. The recent outbreakof the Melissa virus was a vivid demonstration of the need to be extremely careful when a E-mail is received with attached files or documents. Just because an E-mail appears to come from known person, this does NOT mean file is safe or that the supposed sender had anything to do with it.

What's the story on viruses and E-mail?

No computer can get a virus just by reading a plain-text E-mail message or Usenet post. What one has to watch out for are encoded messages containing embeded executable code (i.e., JavaScript in an HTML message) or messages that include an executable file attachment (i.e., an incoded program file or a Word document containing macros).

In order to activate a virus or Trojan horse program, the computer has to execute some type of code. This could be a program attached to an E-mail, a Word document that is downloaded from the Internet or something received on a floppy disk. There is no special hazard in files attached to Usenet posts or E-mail messages, they are no more dangerous than any other file.

How computer can be protected from viruses?

There are several things that should be followed to protect the computer from virus infections. They are:

• High-quality anti-virus program is to be used and updated regularly. It is used to scan and files, programs, software, diskettes (even new software from a commercial company) before using them on computer.

• Back-up copies of important documents or files is to be made and stored on separate diskettes. Making backups will also protect the information against accidental file deletion, diskette failure and other damage.

• Whenever using a computer in a campus lab, be sure to reboot or run "cleanup" before starting the session and to log out when ending the session.

• Do not share commercial software with anyone. It is a violation of the author's copyright to distribute such material and it is a way to spread viruses.

• Always scan the diskettes and files after using them on another computer.

• Always scan all files downloaded from the Internet.

• Always scan Word or Excel file email attachments before reading them.

How do computer viruses spread?

When executing program code that is infected by a virus, the virus code will also run and try to infect other programs, either on the same computer or on other computers connected to it over a network. And the newly infected programs will try to infect yet more programs. When sharing a copy of an infected file with other computer users, running the file will infect the computer and files from that computer may spread the infection to yet more computers.

If a computer is infected with a boot sector virus, the virus tries to write copies of itself to the system areas of floppy disks and hard disk. Then the infected floppy disks may infect other computers that boot from them and the virus copy on the hard disk will try to infect still more floppies. Some viruses, known as 'multipartite' viruses, can spread both by infecting files and by infecting the boot areas of floppy disks.

What kind of files can spread computer viruses?

Viruses have the potential to infect any type of executable code. not just the files that are commonly called 'program files'. For example, some viruses infect executable code in the boot sector of floppy disks or in system areas of hard drives. Another type of virus, known as a 'macro' virus, can infect word processing and spreadsheet documents that use macros. And it's possible for HTML documents containing JavaScript or other types of executable code to spread viruses or other malicious code.

Since virus code must be executed to have any effect, files that the computer treats as pure data are safe. This includes graphics and sound files such as .gif, .jpg, .mp3, .wav, etc., as well as plain text in .txt files. For example, just viewing picture files will not infect computer with a virus. The virus code has to be in a form, such as an .exe program file or a Word .doc file, that the computer will actually try to excute.

Types of Computer Viruses

There are currently different types of computer viruses are available, each spread in a different ways. They are:

• Macro Viruses - Word processing documents can serve as sources of transmission for viruses that take advantage of the auto-execution macro capabilities in products such as Microsoft Word. Simply by opening an infected document, the virus, written in a product's macro language, can spread.

• Boot Sector Viruses - These viruses are spread by sharing diskettes between different computers. Any diskette can spread a boot sector virus, even if it is not a bootable system diskette. If the files are shared using sharing diskettes, boot sector viruses are spread to other computers, which then can infect other diskettes.

• Program - These viruses are spread by sharing program files. Because most users share programs less frequently than they share data or document files, this type of virus is less common than others. A program virus can infect other programs and damage data files on computer.

• Email or Hoax - These viruses are not really virus programs at all. They are email messages sent by well-meaning people to warn others about a new virus they read of. These false warning messages usually say "be sure to send this to everyone you know" and warn of major damage to computer or files. Hoax virus warnings can cause huge amounts of Internet traffic and unnecessary worry to others.

• File Infectors - These viruses attach themselves to regular programs, such as .COM or .EXE files under DOS. Thus, they are invoked each time the infected program is run.

• Cluster Infectors - They modify the file system so that they are run prior to other programs. Unlike file infectors, they do not actually attach themselves to programs.

• System Infectors - Computer operating systems typically set aside a portion of each disk for code to boot the computer. Under DOS, this section is called a boot sector on floppies or a master boot record (MBR) for hard disks. System infectors store themselves in this area and hence are invoked whenever the disk is used to boot the system.

Computer Virus

Computer Virus is a program designed to spread itself by first infecting executable files or the system areas of hard and floppy disks and then making copies of itself. Viruses usually operate without the knowledge or desire of the computer user. Closely related to computer viruses are Trojan Horses and Worms.

• Trojan Horse is a program that performs some undesired yet intended action while, or in addition to, pretending to do something else. One common class of trojans are fake login programs-collecting accounts and passwords by prompting for this information just like a normal login program does. Another is a disk defraggre that erases files rather than reorganizing them. A Trojan Horse differs from a virus in that the former does not attempt to reproduce itself.

• A Worm is just a self - propagating virus.

Computer Network Workstation Requirements

Computers connected to a LAN differ slightly from computers that are stand-alone. They have additional hardware installed in them and they run additional network software.

Computer Network Workstation Software

Network workstations also need networking software to work with the network. This software consists of several components: a driver for the NIC, driver software for the protocols being used and a network requester. Workstations acting in a peer-to-peer fashion also have peer software that provides network services to other workstations. Addtionally, network service software may be needed, such as that required to use  particular network directory service such as Novell's Novell Directory Service (NDS).

For Windows-based computers, Client for Windows Network is used to connect to Windows NT/2000 based Networks. Novell's network software Client for Netware Networks can be used for novell-based networks. Both sets of network software work well, although differences exist.

For Novell-based networks, Microsoft's networking software consumes less memory than Novell's, but it doesn't offer as many features and doesn't integrate with the Novell servers quite as well. Still, its reliable and performs well. Novell's client software (called Client 32) works well and makes good use of the Novell server's features. 

Computer Network Workstation Hardware

All network computers need an installed network interface to connect to the network. Such an interface usually takes the form of a Network Interface Card (NIC), but some computers have the NIC integrated onto the system's motherboard. Each NIC is specific to the type of network it supports. NICs are available for Ethernet networks, Token Ring networks, and even other networks. NICs are also usually specific to the cable media that is installed. For example, Ethernet NICs are available for 10Base-2 media, 10Base-T media, or 100Base-T media, with 1000Base-T NICs now beginning to appear. Some NICs also support multiple media types, which can be a blessing while migrating from one media type to another. For example, some Ethernet NICs support 10Base-2, 10Base-T and 100Base-T on a single NIC.

Computer Network Workstation

Any computer on a network that is used by people is usually referred as a Network Workstation. Sometimes such workstations are also called network clients. Network workstastions can also be any type of computer that includes the necessary network hardware and software, such as an Apple Macintosh or some form of UNIX -based computer.

Do not confuse a network workstation with workstation-class computers. Workstation-class computers are high-end  computers used for computer-aided design, engineering and graphics work.


Network Workstation Requirements

Computers connected to a LAN differ slightly from computers that are stand-alone. They have additional hardware installed in them and they run additional network software.

Disaster Preparedness

Disaster preparedness means being prepared for anything. Good planning and preparedness activities an significantly reduce the impact of a disaster and may prevent business failure. While a disaster plan is a key component of preparedness, its is not enough to protect. Take all of the steps necessary to mitigate and to preare for disasters. This includes procuring the necessary emergency equipment and services.

Appendices

Appendices to the plan generally include notification lists and other items that must be routinely updated. Some examples are:

• Notification Lists: Names and numbers of employees and vendors that will need to be contacted, including office and home numbers.
• Recovery team members: List of recovery/salvage team members (including work and home phone numbers) with description of their responsibilities, scope of authority, and reporting lines.
• Detailed building plans: May be incorporated by reference.
• Resource lists: Locations and inventory of emergency supplies, sources of commercial supplies/equipment that may be purchased, names of consultants and other specialists, sources of auxiliary/volunteer personnel, etc.

Disaster Recovery Plan

A typical disaster plan would include the following elements:

• Emergency Sheet: Simple summary of steps to be taken and individuals to be contacted in an emergency.
• Table of Contents: Should be generated based on headings.
• Introduction of the Plan: Its purpose, process, and orgranization.
• Structure of the Planning Organization: Includes the plan maintenance process and the roles and responsibilities of team members.
• Departmental Responsibilities: Addresses the responsibilities of various departments such as human resources, administration, facilities, and information technology.
• Pre-disaster Actions: Outline of procedures to be followed in advance of emergency for which there is advance warning (e.g. hurricane, flooding), including assignment of responsibilities for those actions.
• Specific Response and Recovery Plans: These plans provide, at the functional level, the steps to be taken to maintain services and to recover normal operations. These plans summarize the procedures to be followed in the plan scenarios as well as other emergency incidents.

Disaster Planning Process

First step in the disaster recovery process is to perform a business impact analysis that considers all the potential impacts from each type of disaster. Disaster Recovery Plans should consider how to deal with these possible events:

• Natural Disasters (Earthquake, Fire, Flood, Storms)
• Terrorist Acts (Weapons of Mass Destruction)
• Power Disruptions, Power Failure
• Computer Software or Hardware Failures
• Computer Shutdowns due to Hackers, Viruses etc.
• Processing Shutdowns
• Labor Strike (Walkouts, Shutdowns).

Having determined the potential events, the management must next look at the impacts of each event and the magnitude of the resulting disruptions. This critical activity will determine which scenarios are most likely to occur and what recovery processes are needed.

The key components of a disaster plan include:

• Threat Analysis
• Risk Assessment
• Mitigation Steps (disaster prevention and damage reduction)
• Response and Recovery Plans
• Damage Assessment Process
• Salvage Procedures
• Rehabiliation Plans.

Business Continuity Management

Business Continuity Management means ensuring the continuity or uninterrupted provision of operations and services. Business Continuity Management is an on-going process with several different but complementary elements. Planning for business continuity is a comprehensive process that includes disaster recovery, business recovery, business resumption, and contingency planning.

Enterprise Risk Management Planning

The Risk Management Planning effort should include the following:

1. Awareness - Awareness should be raised about the need for risk management, contingency, and continuity plans for all elements of the organization and for all those entities on which business depends.
2. Risk Assessment Phase - Review information should be gathered in the Awareness Phase. In this phase the management must first look at the currrent risk management efforts and identify additional areas needing risk management. Then prioritize risks in each area of the operation and finally determine how best to diminish those risks.
3. Planning Phase - The recommendations from the Risk Assessment Phase should be considered. For example: update any internal plans that need adjustment. Develop new plans where they are needed.
4. Testing Phase - Durign this phase an approach to testing must be documented and then actual tests of all the contigency plans should be conducted. Results should be documented and used to determine if particular area plans are adequate in the event of a serious problem.

Disaster Planning

Disaster planning is meant to include the planning and preparations, which are necessary to minimize loss and and ensure continuity of the critical business functions of an organization in the event of disaster. Disaster planning has taken on a new sense of urgency in light of recent terrorist attacks and the increased threat of hackers, computer viruses and the increasing occurrence of emergencies and disaster.

Disaster planning is a crucial component of Enterprise risk management and Business continuity planning. It is essential for ensuring continuity of operations. Prior to the creation of a disaster plan, it is essential to review the entire business continuity plan and to consider the potential impacts of disaster. A business impact analysis must be performed and only then it will be easy to understand the underlying risks. This comprehensive planning process is the foundation upon which a sound disaster plan should be built.