Boot

"To boot up" a computer is to load an operating system into the computer's main memory or random access memory (RAM). Once the operating system is loaded (and, for example, on a PC, you see the initial Windows or Mac desktop screen), it's ready for users to run applications. Sometimes you'll see an instruction to "reboot" the operating system. This simply means to reload the operating system (the most familiar way to do this on PCs is pressing the Ctrl, Alt, and Delete keys at the same time).

Operating System

An operating system (sometimes abbreviated as "OS") is the program that, after being initially loaded into the computer by a boot program, manages all the other programs in a computer. The other programs are called applications or application programs. The application programs make use of the operating system by making requests for services through a defined application program interface (API). In addition, users can interact directly with the operating system through a user interface such as a command language or a graphical user interface (GUI).

File Allocation Table (FAT)

A table that the operating systems uses to locate files on a disk. Due to fragmentation, a file may be divided into many sections that are scattered around the disk. The FAT keeps track of all these pieces.

In DOS systems, FATs are stored just after the bootsector.

The FAT system for older versions of Windows 95 is called FAT16, and the one for new versions of Windows 95 and Windows 98 is called FAT 32.

Partition

When referring to a computer hard disk drive, a partition is a segment of the hard drive that is separated from other portions of the hard disk drive. Partitions help enable users easily divide a computer hard disk drive into different drives and/or into different portions for multiple operating systems to run on the same drive.

With older file allocation tables, such as FAT 16, creating smaller partitions allows a computer hard disk drive to run more efficiently and save more disk space. However, with new file allocation tables, such as FAT32, this is no longer the case.

Scan for and attempt recovery of bad sectors

Disk Defragmenter

Disk Defragmenter is a computer program designed to increase access speed (and sometimes increase the amount of usable space) by rearranging files stored on a disk to occupy contiguous storage locations, or defragmenting. The purpose is to optimize the time it takes to read and write files to/from the disk by minimizing head travel time and maximizing the transfer rate.

Speed Up your PC

Free up disk space

By freeing disk space, you can improve the performance of your computer. The Disk Cleanup tool helps you free up space on your hard disk. The utility identifies files that you can safely delete, and then enables you to choose whether you want to delete some or all of the identified files.

Use Disk Cleanup to:

•	Remove temporary Internet files.
•	Remove downloaded program files (such as Microsoft ActiveX controls and Java applets).
•	Empty the Recycle Bin.
•	Remove Windows temporary files.
•	Remove optional Windows components that you don't use.
•	Remove installed programs that you no longer use.

Typically, temporary Internet files take the most amount of space because the browser caches each page you visit for faster access later.

To use Disk Cleanup

1.	Click Start, point to All Programs, point to Accessories, point to System Tools, and then click Disk Cleanup. If several drives are available, you might be prompted to specify which drive you want to clean.
2.	In the Disk Cleanup for dialog box, scroll through the content of the Files to delete list. Choose the files that you want to delete.
3.	Clear the check boxes for files that you don't want to delete, and then click OK.
4.	When prompted to confirm that you want to delete the specified files, click Yes.

After a few minutes, the process completes and the Disk Cleanup dialog box closes, leaving your computer cleaner and performing better.

Speed up access to data

Disk fragmentation slows the overall performance of your system. When files are fragmented, the computer must search the hard disk when the file is opened to piece it back together. The response time can be significantly longer.

Disk Defragmenter is a Windows utility that consolidates fragmented files and folders on your computer's hard disk so that each occupies a single space on the disk. With your files stored neatly end-to-end, without fragmentation, reading and writing to the disk speeds up.

When to run Disk Defragmenter
In addition to running Disk Defragmenter at regular intervals—monthly is optimal—there are other times you should run it too, such as when:

•	You add a large number of files.
•	Your free disk space totals 15 percent or less.
•	You install new programs or a new version of Windows.

To use Disk Defragmenter:

1. Click Start, point to All Programs, point to Accessories, point to System Tools, and then click Disk Defragmenter.

	Image of the Disk Defragmenter dialog boxClick Analyze to start the Disk Defragmenter.
2.	In the Disk Defragmenter dialog box, click the drives that you want to defragment, and then click the Analyze button. After the disk is analyzed, a dialog box appears, letting you know whether you should defragment the analyzed drives. Tip: You should analyze a volume before defragmenting it to get an estimate of how long the defragmentation process will take.
3.	To defragment the selected drive or drives, click the Defragment button. Note: In Windows Vista, there is no graphical user interface to demonstrate the progress—but your hard drive is still being defragmented. After the defragmentation is complete, Disk Defragmenter displays the results.
4.	To display detailed information about the defragmented disk or partition, click View Report.
5.	To close the View Report dialog box, click Close.
6.	To close the Disk Defragmenter utility, click the Close button on the title bar of the window.

In addition to running Disk Cleanup and Disk Defragmenter to optimize the performance of your computer, you can check the integrity of the files stored on your hard disk by running the Error Checking utility.

As you use your hard drive, it can develop bad sectors. Bad sectors slow down hard disk performance and sometimes make data writing (such as file saving) difficult, or even impossible. The Error Checking utility scans the hard drive for bad sectors, and scans for file system errors to see whether certain files or folders are misplaced.

If you use your computer daily, you should run this utility once a week to help prevent data loss.

To run the Error Checking utility:

1.	Close all open files.
2.	Click Start, and then click My Computer.
3.	In the My Computer window, right-click the hard disk you want to search for bad sectors, and then click Properties.
4.	In the Properties dialog box, click the Tools tab.
5.	Click the Check Now button.
6.	In the Check Disk dialog box, select the Scan for and attempt recovery of bad sectors check box, and then click Start.
7.	If bad sectors are found, choose to fix them.

Only select the "Automatically fix file system errors" check box if you think that your disk contains bad sectors.

Disk Defragmenter Utility

As advanced as hard drives have become, one item they are not very good at is housekeeping, or maybe that should be drive keeping. When files are created, deleted, or modified it's almost a certainty they will become fragmented. Fragmented simply means the file is not stored in one place in its entirety, or what computer folks like to call a contiguous location. Different parts of the file are scattered across the hard disk in noncontiguous pieces. The more fragmented files there are on a drive, the more performance and reliability suffer as the drive heads have to search for all the pieces in different locations. The Disk Defragmenter Utility is designed to reorganize noncontiguous files into contiguous files and optimize their placement on the hard drive for increased reliability and performance.

Accessing Disk Defragmenter

Disk Defragmenter can be opened a number of different ways. The most common methods are listed below.

• Start | All Programs | Accessories | System Tools | Disk Defragmenter
• Start | Run | and type dfrg.msc in the Open line. Click OK
• Start | Administrative Tools | Computer Management. Expand Storage and select Disk Defragmenter

The first two methods take you to a standalone window containing Disk Defragmenter. The last method opens Microsoft Management Console and displays Disk Defragmenter as one of the snap-in modules. In all cases, a window similar to the one below will be displayed.

When Disk Defragmenter first opens (Fig. 01) you'll see a list of the hard drives displayed at the top of the screen. The Estimated Disk Usage Before Defragmentation and Estimated Disk Usage After Defragmentation will be blank until a drive is selected and the Analyze button is clicked. In the screen shot above, I've already analyzed the drives as evidenced by the Session Status showing as Analyzed and the Estimated Disk Usage Before Defragmentation area containing a graphical representation of the drive fragmentation.

After the Analyze button has been clicked and the process completes the window shown above (Fig. 02) opens with a brief recommendation of what action Disk Defragmenter thinks should be taken regarding the drive. It's important to note that this is just a recommendation based on the percentage of fragmented files to total files and doesn't prevent the drive from being defragmented if you feel it needs to be done and might improve system performance. If you want to go ahead and defragment without more information, click the Defragment button. If you're in agreement with their recommendation and don't want to defragment, click the Close button. Click the View Report button to view a more detailed drive analysis.

An Analysis Report contains quite a bit of additional information about the selected drive. The report shown above (Fig. 03) details the File Fragmentation status of drive WXP02-D. The top pane provides Volume information, and as you can see there are 3,851 fragmented files. This may not seem like many fragmented files, but consider that this is only a 20GB drive, which is very small by today's standards, and that 81% of the total drive space is currently unused. Look at the Average Fragments Per File number of 1.04 and this tells you that approximately 4% of the files on the drive are in two or more pieces. My experience has been that when this number reaches 1.05 the message in the quick analysis window (Fig. 02) will recommend defragmenting the drive. The bottom pane, Most Fragmented Files, lists the files in descending order that are the most fragmented.

In spite of the recommendation not to defragment this particular disk, I went ahead and clicked the Defragment button. The results of that choice are shown above (Fig. 04) in the Estimated Disk Usage After Defragmentation section. The graphical representation clearly shows that not only have the red lines depicting fragmented files been eliminated, many of the contiguous files indicated by the blue have been repositioned toward the beginning of the drive, reducing the amount of searching the drive heads have to do to locate a file. The drive in this example is not a system drive, nor does it have a paging file which would be indicated by the lime green Unmovable Files color.

After the defragmentation process completes, clicking the View Report button will bring up the Defragmentation Report (Fig. 05). It takes the exact same form as the Analysis Report (Fig. 03) but shows the post defragmentation results. The Total Files and Average File Size remain identical, but notice that Total Fragmented Files and Total Excess Fragments have been reduced to zero (0) and the Average Fragments Per File is now 1.00, indicating most or all of the files are contiguous. In addition, there are no files listed that did not defragment.