Fullscreen HTML5Med Res (??MB)HTML4

COMPUTER BITS BY JASON COLE Tuning up your hard disc drive The hard disc drive on your PC requires regular main­tenance for trouble-free Windows 95 operation. The procedure is straightforward but there are some simple rules that must be followed to avoid losing data. With Windows 95 there is one thing you must do: clean your hard disk drive (HDD) on a regular basis. This is known as house cleaning and just like you do at home, you put things away first and then make the place nice and neat. The same goes for the HDD, which needs to be cleaned up on a regular basis. Just how often you should do this is determined by how often the HDD is written to. In addition, there is a strict procedure that must be followed because you can lose data if it is not done correctly. The two programs that you use to clean up your HDD are ScanDisk and Defrag. Let’s take a closer look at these. Fig.1: the hard disc drive (HDD) is checked for errors by running ScanDisk. The standard test will usually suffice but you should occasionally run the thorough test to scan for any disc surface errors. 54  Silicon Chip ScanDisk in Windows 95 is similar to CHKDSK in DOS. Basi­cally, it goes through the HDD and checks all the files against the File Allocation Table (FAT). It then reports any errors that may be there and gives you an opportunity to fix them. ScanDisk is not a particularly powerful program but it is an excellent one to use to ensure the integrity of the data on the HDD. Defrag, which is short for Defrag­ menter, does just that – it defrag­ ments your data. When a drive has been used for some time and a lot of data has been saved and deleted, “holes” appear between the various files that are created on the HDD. That’s because the various files are not necessarily stored on the disc in a contig­uous fashion. What happens is that the Disk Operating System (DOS) always starts looking for space from the beginning of the drive. If it finds that there is already data in the first cluster, it checks the next cluster and so on until it finds space. If your file requires two clusters of drive space and the first available space is only one cluster in length it will write what it can there. It then looks for the next free space to write the remain­ing data and that could be several sectors away. As a result, the file can be split into two or more sepa­rate pieces on the HDD; in other words, it becomes fragmented. And, like the disorder in your home, the longer you leave it, the more defragmented the HDD becomes. Of course, when you access the file, it appears to be all in one piece. That’s because the HDD keeps a record (in the file allocation table) of where all the fragments are. When you access the file, the HDD simply looks for all the fragments so that the file can be reassembled. Fig.2 (left): this is the message that appears if ScanDisk finds no errors on the disc. If errors are found and fixed, it’s wise to run ScanDisk again until it goes through without finding any errors. Fig.3 (below) shows the dialog box that appears when you start the Windows 95 Defrag program. The advantage of this technique is that you can store a lot more data on the HDD. The downside is that if your files are badly defragmented, it takes longer for them to be read from the HDD. In addition, errors are far more likely to occur. By running Defrag, all those fragmented files are moved and written back to the HDD so that they are now in contiguous blocks. Depending on the settings you give the Defrag program, the files can be simply defrag­mented leaving spaces between them, or the files can all be moved to the beginning of the drive, thereby eliminating any “holes” that may have previously been created. But what happens if the drive has an error, such as a file that is given the wrong size in the FAT? If the computer has been told that a file is larger than it actually is, the amount of the oversize may actually overlap an adjacent file. If you run Defrag without first checking for this type of error, the computer will move the oversized file and also take part of the adjacent file with it. The first file may still work but the header of the second may be gone and without it that file cannot be opened. Run ScanDisc first So how can we clean up the HDD and not lose anything? The trick is to correct any disc errors for running ScanDisc first. The procedure is as follows: (1) Click on the Start button, then click Programs, Accessories, System Tools, ScanDisk. A dialog box will appear as shown in Fig.1 (2) If this is the first time you have ever checked your HDD or it hasn’t been done for some time, then make sure you select the “Thorough” option. This not only checks the files and folders for errors but also scans the disk surface for defects. Do not select the “Automatically fix errors” option as it is always best to know what has gone wrong (and to what file) so that you can do something about it. (3) Select the drive to be scanned and click the Start button ScanDisk will now go through your HDD and check for any errors. The Standard test should only take about 20 seconds (depending on the size of the disc and how many files you have). If you chose the Thorough option, however, then get a cup of coffee because it can take over 90 minutes to scan every sector of the HDD for errors. I will not go through all the possible errors that can occur because there are so many of them. However, one of the most common errors is: Lost allocation units found in X chains If you get this message, convert the lost allocation units to files and then have a quick look through them with a text editor to see if they are a part of an important document. These files, by the way, will all have a .chk extension, so they are easy to identify. Going back to our error message, the X chains number tells you how many *.chk files will be made in the root directory. Some of these lost chains can be quite large and I have come across one that was 79Mb in size. However, that was from a system that had a faulty HDD controller. By the way, do not attempt to check your hard disc for errors by running CHKDSK.EXE in a DOS box. If you do, it can pick up open Windows files, such as the Swap File, and show it as an error. CHKDSK.EXE should only be run in DOS itself, while Scan­Disk should be used exclusively in Windows 95 (you can also run Scandisk from DOS). When the scan is completed you should get a message like the one in Fig.2. If you come across an error and elect to fix it, it’s always wise to run ScanDisk again and to keep re-running it until it goes through without finding an error. Defragging the disc Once Scandisk has been run, you can run the Defrag program. This is done by clicking Start, then Programs, Accessories, System Tools, Disk De­ frag­ menter. This will bring up the dialog box shown in Fig.3, allowing you to select the drive to be defrag­ mented. The next dialog box (Fig.4) tells you how badly the disc is fragmented. In this particular case, the reading is only 1% but this figure can be a bit misleading. That’s because it doesn’t really tell you how badly the disc is June 1997  55 Fig.4 (above): this dialog box can be a bit misleading. That’s because it doesn’t really tell you how badly the disc is fragmented at all. Instead, it indicates the degree of file fragmentation which means that there could be lots of “holes” on the disc between the various files. Fig.5 (right): another way to get to ScanDisk and Defrag is to double-click the My Computer icon on the Desktop, then right click on the hard drive of choice and select Proper­ties. You then select the Tools tab to bring up this dialog box. fragmented at all. Instead, it indicates the degree of file fragmentation. This means that while the individual files may be contigu­ous, they can still be all over the place on the disc, with “holes” everywhere between them. And, as explained previously, it is these holes that cause file fragmentation. Clicking the advanced button brings up the Advanced Options dialog box. This lets you select the defrag­mentat­ion method and there is also an option that tells Defrag to scan the disc first for any errors. Clicking OK and then the Start button in the dialog box of Fig.4 sets the Defrag program running and again you can go and make yourself a cup of coffee because the Defrag procedure can take quite some time. Another way to get to Scandisk and Defrag, which is a bit faster, is to double-click the My Computer icon on the Desktop, then right click on the hard drive of choice and select Proper­ties. This brings up a new dialog box, which has several tab options. Selecting the Tools tab brings up the options shown in Fig.5. The Check Now button launches the ScanDisk program, while the Defragment Now button launches the Defrag program. 56  Silicon Chip There is also a Backup Now option but this requires a tape backup unit to work. more likely to fail than a well-organized volume. Important advice Finally, here’s some fun stuff for Windows 95. Are you sick of the front “splash” screen as you load Windows? If so, this “splash” screen can be easily changed using a graphics utility. The opening “splash” screen is a bitmap file called logo.sys. The bitmap size is 320 x 400 with 256 colours. To change the screen, first backup or rename the existing logo.sys file. This done, grab whatever you want as a “splash”, save it as a bitmap (logo. bmp) and rename the file to logo.sys. Here are the splash screen names: Logo.sys – front splash (located in the root directory); Logos.sys – It’s Now Safe To Turn Off Your Computer (located in the Windows directory); Logow.sys – Please Wait While Your Computer Shuts Down (located in the Windows directory). All three files should be backed up before attempting any changes, otherwise it will be necessary to reinstall Windows if you change your mind and want the originals back again. If the new bitmap is too big or corrupted, the computer should still work but the SC picture will not appear. To sum up, you must follow a strict regime when cleaning up your hard disc. The two main points to remember are these: (1) Do not run Defrag without running ScanDisk first; and (2) Do run Defrag immediately after running ScanDisk. If you run ScanDisk and then do something else, such as opening and saving a file or copying files to the HDD, always run ScanDisk again before running Defrag. This rule should be fol­lowed, no matter how trivial the extra work may have been. After all of this, which may seem a little involved but is really quite easy, your computer will operate a lot better. In some systems you may not notice any real difference but a few will see a significant increase in loading speed and overall performance. In either case, your system will be more reliable. By the way, if you are running DriveSpace to get more room, these processes will take a lot longer. Persevere, however, because a badly organized DriveSpace volume is much Some fun stuff