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SKIP'S COMPUTER MISCELLANEA #1 (C) Copyright 1988 by C. F. "Skip" Mowery, Jr. Colonel, USAF (Ret.) 406 Van Reed Manor Drive Brandon FL 33511 813-689-4212 "Skip's Computer Miscellanea" is copyrighted material and remains the property of the author, who reserves all rights to its publication, reproduction and distribution, with the following single exception: it may be freely copied and distributed electronically via computer for personal non-commercial use, provided that the content is not modified, that it is not copied to or distributed on any form of print media and that it is not copied or distributed by or for any type of business endeavor without the prior written permission of the author. ***** Your comments about this material and questions about any aspect of computing are welcome. This material originates on the Computer Archives BBS in Tampa, Florida, at 813-968-6220. ***** GETTING ORGANIZED WITH A HARD DISK This article is written for those who are contemplating the purchase of a hard disk or who just got one but aren't quite sure what to do with it and, in either case, who need advice about hard disks but don't want to get bogged down in technical information. It's for those who are pleading: "Please, just tell me what to do -- tell me how, not why." First we'll discuss the pros and cons of having a hard disk, including some comments about backups. Then we'll talk about the sizes and types you should consider, and we'll briefly discuss installation and configuration. This part of the article will conclude with a brief comment about the importance of organization. The article will continue in Issue #2 of "Skip's Computer Miscel- lanea" with a summary of the tools and terms you should understand in order to get organized, plus a brief tutorial on paths. Finally, we'll discuss precisely what to do to organize a hard disk, step-by-step, including specific suggestions about directories, what to put in the root directory, the content of key files, such as the Autoexec.Bat and Config.Sys files, and a lot more. We may not avoid all the why's, but we'll try to emphasize the how's and keep the why's to a minimum and as non-techincal as possible. Do You Need a Hard Disk? If you're tired of swapping floppies during large applications and tired of trying to keep your programs and data files organized across several floppy disks, you need a hard disk. If you think it takes forever to boot up or for programs to load, or if some programs run agonizingly slow because of frequent disk accesses, you need a hard disk. If you've ever seen "insufficient disk space" or "disk full" on your screen or encountered any of the error messages that result when you put the wrong disk in the drive, or put a disk in the wrong drive, or forget to put a disk in the drive or forget to format the disk, then you need a hard disk. Hard disk access is fast! If you have any doubts about how much a hard disk will improve program speed, try this: load and run from a floppy disk the Basic test program at the end of this file. Then load and run the same program from a RAM disk. The program's reported elapsed time via RAM disk should be about half of the time reported via floppy disk. That substantial improvement in speed from using a RAM disk is very similar to what you would get with a hard disk. The speed of operation with a hard disk, of course, will be a little slower than with a RAM disk, but the difference is so slight that, if you use a hard disk, you may never use a RAM disk again. Believe me, it's that fast. The difference is as noticeable and impressive as the difference between running a Basic program under the Basic Interpreter and running a compiled version of the same program. After speed, the next best thing about a hard disk is its huge capacity. No more worrying about whether all the files will fit on the disk. No more panic trips to the computer store for another box of floppies. No more waiting for yet another disk format. Once you format a 20 megabyte (MB) hard disk, it's like having over 50 floppies already formatted and all mounted in one drive so that you never have to touch them again. Imagine getting on a BBS and downloading as many files as you want, without every having to worry about disk space or changing disks. With a hard disk, your hands stay at the keyboard and aren't constantly reaching for floppies. Get the picture? Hard Disk Backups and Organization You can also say goodbye to floppy disk organizational problems when you have a hard disk. Once you've organized the hard disk and then do a complete backup, the backup program will take care of the organization on the floppies. Also, re-organization is much simpler and faster on a hard disk. And speaking of backups, having a hard disk also gives you double backup protection for your commercial software: the original copies are on the distribution disks, the working copies are on your hard disk, and the backup copies are on floppies after you backup the hard disk. Using a backup program regularly to copy files from the hard disk to floppies is essential. I do a complete backup of my hard disk once a month. I also keep a floppy in drive B and copy to it one or more times a day any programs or files that I've worked with that day. (Ok, ok -- I don't do it every day, but I should, and I do the monthly backups religiously.) Hard Disk Problems The reason that backups are important is that hard disks, like floppies, are susceptible to the potential for accidental data loss. Hard disks can incur some of the same problems as floppies, such as those caused by power surges, brownouts, power outages, bad disk sectors and various types of system crashes, plus hard disks have some problems of their own. For example, a hard disk is more likely to have bad sectors when you buy it and/or later, and it has the potential for at least three other problems: you can't take a hard disk out to protect it when you move the computer; recovery of data is more difficult if something happens to the File Allocation Table (FAT) on a hard disk; and sometimes a hard disk just doesn't want to cooperate when you turn on the computer. I won't go into a lot of technical explanation about a hard disk's occasional propensity for not wanting to cooperate (primarily because I couldn't if I wanted to). Suffice it to say that sometimes a hard disk may experience a thermal reaction as a result of changes in temperature in the computer room that could cause the hard disk to refuse to acknowledge its existence. In other words, there may be times when the darn thing just won't boot and, during those times, even if you boot from a floppy, the system will tell you that you don't have a hard disk. If you keep trying to boot or just let the system sit there, turned on, eventually you'll be able to access it again. Having a complete backup at those times makes them less worrisome (you don't know if it's just a temporary thermal problem or if the hard disk is really sick and will require reformatting and a total loss of data). As for moving your computer when it has a hard disk installed, there are several programs available to protect the hard disk from damage. The read/write head of a hard disk normally doesn't touch the disk surface. If it does, e.g. because you jostle it when you move the computer, it could damage the disk and/or destroy data recorded at that location. The programs designed to prevent this problem move the read/write head to the center of the disk where no data is stored. Public domain programs for this purpose are available on BBS's. Zenith's version of MS-DOS includes a program called SHIP and your version of MS-DOS may have one also. If the FAT gets damaged or garbled for any reason, there are also programs designed to recover as much as possible of your lost data. (The data isn't really lost in these cases -- the computer just doesn't know where it is because the FAT can't be read.) The MACE Utilities include such a program. Since there are two copies of the FAT on the disk, and if you do regular backups, and if you buy a quality hard disk, it's unlikely that you'll ever need such a recovery program, but it's reassuring to have one. As for bad sectors, which are more likely to exist on a new hard disk or later occur, the configuration and formatting procedures for a hard disk fix things so that no data is written to identified bad sectors. Also, there are programs available (e.g. MACE Utilities) that can identify and lockout bad sectors that occur later, and they don't require reformatting the disk (and hence don't require a complete backup-reformat-restore procedure). On the other hand, the hard disk is in an airtight metal case where you can't touch it and where it's protected from the wide variety of accidents that your floppies may be subjected to. It's virtually impossible to fold, bend, spindle, mutilate or spill coffee on a hard disk, and I've never heard of anyone dropping one on the floor and then either stepping on it or running over it with a chair. In other words, even though hard disks may be susceptible to more or different problems, remedies exist to avoid or correct those problems, one such preventive measure being regular backups. Also, the benefits of speed, organization and enlarged storage gained with a hard disk far outweigh the potential for problems or the inconvenience of regular backups. I've been using a hard disk on almost a daily basis for the past year and a half and I've never experienced a loss of data, despite frequent power outages and brownouts and an occasional thermal problem (which is my own fault for leaving the window open). Choosing a Hard Disk If you insist on getting into a lot of technical considerations, choosing a hard disk can boggle your mind -- and this is not supposed to be a mind-boggling article. So, here's my recommendation: for an IBM PC/XT or compatible computer, look for a 20 MB name-brand unit, such as the Seagate ST225. If you think you need more than 20 MB, I wouldn't go over 40 MB for two reasons: first, your system may have a 32 MB limit and, second, if it does, you'll have to go through the added complication of having more than one partition on the hard disk. Even if you don't think you'll need 20 MB because you don't have a lot of software, I wouldn't recommend a 10 MB unit. For most of you, a 10 MB unit will probably fill up too fast and you'll spend too much time re-organizing, archiving, and trying to decide what to keep on the hard disk and what to store on floppies. Also, for reasons of cluster size, your small files (less than 2K bytes) on a 10 MB unit may waste a lot of disk space, unless you create partitions smaller than about 4K bytes each. (If you know about partitions and plan to use more than one, or are familiar with cluster sizes, you may be wasting your time reading this article.) I also would not advise using a high-density hard disk for normal personal computing. High density hard disks use something called RLL formatting. Some software won't work properly with that type of hard disk. There are other items that you could consider when choosing a hard disk, such as the cluster factor (how much space your file occupies regardless of its actual size) and interleaving (every nth track or physical sector is used for sequential read/write), but we're trying to keep it simple here. I'll just say this: 4 sectors per cluster (or less) and interleave 3 (or at least less than 7). A hard disk with more than 4 sectors per cluster or with an interleave higher than 3 is wasting disk space and seek time, when compared to other available drives. Hard Disk Installation and Configuration There are too many different types of computers and hard disks to be able to advise you in this area, but I can give you a few hints. Read the installation instructions carefully and take your time. Plan how you will do it before you actually start. If you have serious doubts about your ability, get someone else to do it for you. Look for a bad-sector list and don't lose it. It will be a list of cylinder and head numbers. You may find it attached to the hard disk case and, if it is, be sure to copy it on a piece of paper before installation. You may need the list during configuration. By all means, don't throw any pieces of paper away until you finish installa- tion and configuration (and I'd still keep everything after that). The same goes for configuration: read the documentation and understand it before you begin. If you have a choice about partitions, I recommend using the whole disk as one DOS partition, i.e. one you can boot from. A partition is like a separate drive. Except in unusual circumstances, why would you want to convert one drive into two or more? (If you enjoy complicating your life, be my guest.) Why Is Hard Disk Organization Important? I keep everything on my 20 MB hard disk -- every piece of software in my possession: all the programs, all the data files and all the DOS files, even the ones that I never use and the ones that don't apply to my system -- and it's only half full. But, that software is in over 700 files and, if I counted the files in archives, the file count would exceed 1000. If I didn't use directories and subdirectories to organize the files, the DIR command would take forever to scroll a list of all the files on the screen (not to mention the fact that DOS wouldn't let me have that many files in the root directory). And since I'd have to keep stopping the scrolling to be able to read the list, it would take an equally long time to find anything -- especially if I couldn't remember the file name that I was looking for (a not infrequent problem for my muddled brain). It would be like having 25 floppy disks full of files but with no labels on the disks. (If you have 25 disks without labels but full of files, I don't think you'll understand the point I'm trying to make here.) Using directories and subdirectories is like using separate floppies for different applications and different types of files -- except that you don't have to change disks and you don't have to worry about wasting disk space because some applications or categories of files don't fill a disk. Perhaps the best reason for using directories and subdirectories to organize a hard disk is that DOS will limit how many files you can have in the root directory and, eventually, you'll have no choice but to get organized. (More about directories/subdirectories in the next issue.) ***** Part 2 of this article, "Getting Organized With a Hard Disk", is contained in issue #2 of "Skip's Computer Miscellanea". ***** Test Program Below is a Basic program that you can use to compare the speed of operation between a floppy disk and a RAM disk. The difference in speed is similar to the difference between a floppy and a hard disk. If you don't know how to use a RAM disk, your MS-DOS manual probably includes instructions for installing one. (It may be called a virtual disk.) If not, download the file RAMDISK.ARC from a BBS and follow the instructions for setting up a small RAM disk. Run the test program under the Basic Interpreter from a floppy and make a note of the total elapsed time displayed. Then run it from a RAM disk. On my system the test program completed its work in 4.61 seconds from a floppy disk and 2.19 seconds from RAM disk. From my hard disk, the program finished in 2.75 seconds. Thus, as you can see, even though the hard disk is a little slower than the RAM disk, the floppy/RAM comparison is still very similar and, hence, a valid way to make the floppy/hard disk comparison in the absence of a hard disk. 10 CLS:DIM A$(100) 20 FOR Z=1 TO 100:A$(Z)="abcdefghijklmnopqrstuvwxyz":NEXT Z 30 PRINT "Opening TEST.DAT for output and copying 100 strings at ";TIME$ 40 PRINT CHR$(7):X#=TIMER:OPEN "O",1,"TEST.DAT" 50 FOR Z=1 TO 100:PRINT #1,A$(Z):NEXT Z 60 CLOSE:Y#=TIMER 70 PRINT "TEST.DAT closed at ";TIME$;". Elapsed time =";Y#-X#;"seconds." 80 PRINT:PRINT 90 PRINT "Opening TEST.DAT for input and reading 100 strings at ";TIME$ 100 X1#=TIMER:OPEN "I",1,"TEST.DAT" 110 FOR Z=1 TO 100:INPUT #1,A$(Z):NEXT Z 120 CLOSE:Y#=TIMER 130 PRINT "TEST.DAT closed at ";TIME$;". Elapsed time =";Y#-X1#;"seconds." 140 PRINT:PRINT 150 PRINT CHR$(7);"Total elapsed time =";Y#-X#;"seconds." 160 END **********