A. File Compression

Explain that file compression is an important aspect of file, folder, and disk data management. Your objective is maximizing the amount of available disk space at all times. There are several ways to manage data more efficiently:

• Delete unnecessary files (temp files, Internet cache, etc.).
• Make backups of your data that can be stored on removable media (Zip drives, CD-R).
• Compress files.

All three must be practiced on a regular basis. This objective focuses on one ,file compression of NTFS files in Windows 2000. Mention that files are usually compressed to about half their original size, which is very efficient compression.

1. Enabling File Compression

There are three ways to use the file compression utility:

• My Computer, using right-click
• Windows Explorer, using right-click
• Command line, by typing the filename compact[.exe] and identifying the files to be compressed. The switches used with compact are listed on page 201 .

The Exam Watch on page 201 says, "It is possible to compress any volume under Windows 2000 Professional, even your system and boot partitions. The only file that may not be compressed is Pagefile.sys, your swap file." Some scenarios when you might want to compress an entire volume:

• Copy to another computer
• Copy to another partition
• System backup
• Testing
• _____ (Add others you may be familiar with)

2. Rules for Compression Attributes

• You cannot compress pagefile.sys.
• It’s useful to learn how to create batch files to automate compressing and uncompressing.
• Data in compressed files performs more slowly.
• Check the file attributes on hidden or system files before attempting to compress them, and reset them (as necessary) afterwards.
• Files remain compressed when they are sent over the network by Windows 2000, making file transfer quicker and more efficient.
• For most consistent compressed file transfer, make sure the attributes are set the same on both sending and receiving machines.

3. Exceptions to the Rules

The exception to copy and move compressed file transfers is when encryption is in use, which overrules compression.

4. Viewing Compression with Alternate Colors

Use different colors to identify compressed files in My Computer or Explorer. Use Figure 4-1 on page 203 to show how to do this.

B. Using NTFS Permissions to Control Access to Files and Folders

This section discusses controlling file and folder permissions at the local level – meaning on a single machine, rather than across the network. However, by setting proper permission settings on the local machine, the files and folders are also protected across the network. Permissions means setting specific NTFS file attributes using the Properties dialog box (Figures 4-2 and 4-3 on pages 205 and 206).

One thing all programs have in common is the file, which could be termed the lingua franca of computers. Understanding the file is a prerequisite to performing any work with the computer. Knowing how to recognize different kinds of files, how to create them, and how they are stored and organized, is key to using software productively and managing data effectively.

The file is a group of related records, or a collection of related data, identified and stored with a unique name. It’s the primary unit of data storage in Windows computers (as well as most others). A file may contain either program instructions or data. There are several kinds of files:

• Files that are unique to the operating system.
• Files that both the operating system (and operating environment) and applications use, such as printer drivers.
• Files with data only — not programs — created by users while working with a program or application, such as a word processing document or database report.

The OS stores files on a disk in directories, or folders. A directory is a list of the files stored on a disk or a portion of a disk. The primary directory is called the root directory, and every disk has one. Windows 2000 also allows you to create additional subdirectories under the root directory. Subdirectories help keep programs and data well organized and easy to find. Each application program is stored in its own subdirectory, and can have a number of subdirectories of its own that store ancillary programs as well as data files.

Working with directories has become easier for Windows users because of the Macintosh-like folder. The folder is, in reality, a directory, but it appears on the screen as a folder. The folders are organized in the same way Windows organizes directories.

1. Folder Permissions

Setting file and folder permissions is essentially the same, except that folder permissions are actually a logical group of special permissions for its files, or contents.. The following items, although they appear also in Table 4-1, are important:

• Change Permissions Allows or denies changing permissions for the file or folder.
• Create Files, Write Data Allows or denies creating files in a folder. Write Data allows or denies appending new data to a file and overwriting existing information.
• Create Folders, Append Data Allows or denies creating folders within a folder. Append Data allows or denies appending new data to a file without changing the existing content of that file.
• Delete Subfolders and Files Allows or denies deleting subfolders and files.
• Delete Allows or denies deleting the file or folder.
• List Folder, Read Data Allows or denies viewing file or subfolder names. Read Data allows or denies reading data in a file.
• Read Attributes Allows or denies viewing the attributes of a file or folder.
• Read Extended Attributes Allows or denies a user viewing the extended attributes of a file or folder. (Extended attributes are generated by programs and differ from system attributes.)
• Read Permissions Allows or denies reading permissions of the file or folder.
• Synchronize Allows or denies different threads to synchronize with other threads.
• Take Ownership Allows or denies taking ownership of the file or folder.
• Traverse Folder, Execute File Allows or denies browsing through folders to reach other files or folders.
• Write Attributes Allows or denies changing attributes of a file or folder.
• Write Extended Attributes Allows or denies changing extended attributes of a file/folder.

2. Advanced Permissions

• Rule 1: The user’s permission to a file or folder is the least-restrictive permission allowed.
• Rule 2: Group permission (or denial of permission) always overrides individual user permission.

• These file and folder permissions apply only to NTFS.
• Only owners, or those designated by the owner, can change permissions.
• Individuals, or groups with Full Control over a folder, can delete files and subfolders within a folder, regardless of the permissions.
• If the Permissions check boxes are shaded, or if Remove is not available, then the file or folder has inherited permissions from the parent folder.

Managing and troubleshooting is often a big part of administration and that, when accepted for what it is, can be interesting if not actually fun. It is the highest form of troubleshooting and creates good will among users throughout the organization. The process of working with local files and folders is the same as working with shared folders, except that you are working with a local machine, not the network. Therefore, we are building on things we already know to learn how to do something new.

A. Create and Remove Shared Folders

Sharing means exactly what it is; sharing a file, folder, or resource across the network or among users. You create a share by using the Properties dialog box shown in Figure 4-11 on page 217. Then anyone else on the network can access the file. Windows 2000 Professional allows up to 10 concurrent hits on a shared file. As the text suggests, you may want to cut that back to improve access and/or performance. If you need more concurrency, then you must do it from Windows 2000 Server.

B. Using Permissions to Control Access to Shared Folders

Once sharing takes place, it must be followed with security measures. Point out that only administrators, server operators or power users can administer shares and security. Figure 4-12 on page 219 shows share permissions.

There are only three permissions associated with Shares:

Computer viruses

In recent years, computer systems have been plagued by an insidious program called a computer virus, which corrupts, or "infects", computer files by inserting a copy of the virus itself. It takes its name from the similarity it shares with biological viruses. Both biological and computer viruses reproduce themselves, infect another system, and do damage to it.

Computer viruses are contracted from infected disks or files transmitted over the Internet or through e-mail. They normally copy themselves to a hard disk and then onto other floppies used on the same computer before any symptoms are apparent. Their activation may depend upon the number of times they have spread to other diskettes.

Most computer viruses are very small, short programs that enter computer systems via other programs or through communications networks, then hide. A virus can go unnoticed for long periods as it insidiously infects the computer and then, at a predetermined time and date, or often when the computer is powered up, causes it to crash. Some viruses are relatively harmless and merely display a message, whereas others may scramble or erase files and directories.

Viruses are often created by a former employee, seeking revenge on a company; by talented young intruders who want to demonstrate their computer skill; or by programmers with antisocial tendencies or a perverted sense of humor. There have been many virus attacks over the past few years, and although they can be stopped, there does not seem to be a way to prevent them. Viruses can be divided into several categories: worms, Trojan horses, time bombs, file infectors, and boot sector viruses.

Computer worms. A relative of the computer virus is the computer worm, which duplicates itself from one computer’s memory to the next. Once in memory, it continues to propagate itself, over and over, consuming more space until the computer crashes. The most widely publicized worm attack occurred in 1988. Robert Tappan Morris, a graduate computer science student at Cornell University placed a computer virus on ARPANET. It brought 6,000 computers to a halt. Morris was brought to trial and convicted.

Trojan horses. Named for the first Trojan horse, which concealed Greek soldiers. Disguised as a gift to the city of Troy, the huge, wooden horse was welcomed inside the walls of Troy, whereupon the Greek soldiers emerged and destroyed the city. A Trojan horse is disguised as a useful program, but it contains hidden instructions to perform a malicious task instead. Sometimes a Trojan horse is disguised as a game or a utility program that users will find appealing. Then, when the users begin running the "game," they discover that they have loaded another animal entirely. A Trojan horse may erase the data on the hard disk or cause other damage.

Time bombs. Also called logic bombs, these sit harmlessly on a system until a certain event or date causes the program to become active. The most famous time bomb was the Michelangelo virus, named after the great artist. On the artist’s birthday (March 6) each year, this virus is designed to destroy the contents of any hard drive that it is hidden on. Most recently the Chernobyl virus has gained fame. It is designed to activate on the anniversary of the world’s worst nuclear accident, April 26.

File infectors. Most viruses are file infectors that spread from program to program and do damage to code, data, and directories. A file infector virus hidden on a floppy disk will transfer itself to any hard disk that the floppy comes into contact with. When another floppy disk is inserted into the computer containing that hard drive, the virus will copy itself onto that floppy disk. You can see why viruses can spread rapidly through an organization.

Viruses pose a serious threat to computer systems. Thousands of viruses are in existence, and more are being written each day. In addition, some new viruses are self-modifying so that each new copy is slightly different from the previous one, making it necessary to maintain constant vigilance to protect your computer.

Anti-virus software, often called vaccines, provides that constant vigilance. The utility program refers to a database of known viruses and searches your hard drive, either upon booting or at scheduled intervals. When a virus is recognized, there is an alert and in most cases the virus is eliminated. If the virus cannot be removed, the file containing it must be deleted. Other precautions can be taken as well:

• Use anti-virus software and check your system often.

• Scan all diskettes and downloaded files.

• If you don’t know the person sending you an email message with an attachment, delete it immediately from your email program and from your Recycle Bin as well.

• Set the write-protect tab on diskettes, as that will usually block the virus from infecting the disk.

• Minimize the impact of a virus attack by backing up regularly.

C. Caching

Caching in this context is essentially the same as any other form of disk caching, and it improves network performance.

The section continues with instructions for three types of server connections: