HOW TO INSTALL A 3 1/2 INCH DRIVE by Yves Barbero The Problem Half of my friends and professional contacts have 3 1/2" drives. The other half have 5 1/4" drives. Most of these people do not have modems. I wanted to be able to exchange data with both sets of people so I decided to install a 3 1/2" drive as Drive B. I had a 5 1/4" drive in A and a Hard Disk (C) on my XT Clone. The documentation is not terribly explicit in the PC DOS 3.21 manual although it is mostly there. But as with many things, you have to know eighty percent of the answer before you know what question to ask. I also wanted to have the option of formatting B: to 730K since such disks are 4 times more expensive and the larger format is convenient and makes up for some of the extra cost, along with the convenience of not worrying about folding and damaging them. You can just stick the hard-back plastic disks in your pocket. Nevertheless, 5 1/4" disks are going to be around for a long time so don't give up that drive just yet. I propose to cover three subjects. a) The mechanics of the installation b) The alterations to the CONFIG.SYS necessary to format for both 730K and higher density disks. c) Some additional uses of the 3 1/2" disks. A) Mechanics (I'm going to be more detailed than most people need for the minority who have had no experience with this sort of thing. Read this section through before touching a tool. If you lack the confidence and/or you're especially nervous, pay your money and get a professional to do it.) 1. Turn OFF the power completely. I advise turning the switch off on the spike suppressor (if you don't have one, buy one! It could easily save your computer). Unsure? Pull the plug from the wall. 2. Remove the cover from the computer. On most XT models I've seen, there are five screws, one on each back corner and one in the back center top. They'll be along the edges. You do not have to disconnect the cords to the printer and monitor, joystick, mouse etc., if the power is OFF. Most covers will slide forward and off. If you encounter resistance, it may be that yours comes off differently. Don't be afraid to use your eyes. Be careful that nothing, such as loose wires or badly installed devices, is hanging up . 3. If you have two floppy drives without a hard disk, you may want to reconsider installing an unlike drive although you can still do a DISKCOPY A: A: instead of A: B: If you DISK- COPY A: B:, It'll reformat B: to 360K if you had it at 720K. In most cases, you can COPY A:*.* B: and preserve the higher formatting. This won't work if you're making a System disk... at least you won't get a System Disk in B: with the COPY command. 4. You will see a long belt-like strip plugged into one of the boards which is sticking up vertically. The other end of the strip is plugged into either one or two drives depending on what you have. By physically looking at it, determine which drive is A: (If you have two drives). The one at the very end is A: on my computer and the plug along the strip is B:. This could differ so be sure by using the physical inspection. 5. If you have two floppy drives, disconnect B:. Also disconnect the power supply plug (probably a four wire plug). You'll see it lead to a box with a fan somewhere on it. The on-off switch is also likely to be attached to the power supply box. On mine it is to the back-right of the computer and separate from the mother board which lies on the bottom of the unit. If your Drive B: lies below your Drive A:, you may wish to reverse the strip plug so you don't have to remove A: to get to B:. B: then becomes A: and you can place the new drive B: right on top of it. CAUTION: It's very likely that your hard disk is close by, usually right along side the floppy drive. It'll look like a solid piece with a power plug to it and some sort of strip connector. You don't want to hit it while working with Drive B: I placed a thick piece of cardboard on it while working along-side it and was careful not to touch it. 6. Insert the new drive B: and plug in the strip and one of the power plugs (it doesn't matter which free power plug you use for the system to work but use the one with the shortest lead which reaches Drive B:. You may someday want to plug in an external drive and the extra inch or two of wire may be critical. Plan ahead!) 7. If you only had one drive (as I did), you're going to have to tell the computer that Drive B: is active. There are some dip switches on the mother board. On mine (DTK), there are eight together and I merely had to move switch 7 to its opposite condition. Yours may differ. You can check with the people who sold it to you. They're tiny. You're going to have to look. On my DTK, they are located in the back-right quadrant of the mother board close to the power supply. 8. You may want to check it before putting the cover back on. If you're nervous, put the cover back on, being careful not to hang up any wires but don't screw it in until you're satisfied it works. Make sure you've removed tools and nuts and bolts. With the cover off (or on but not fastened), turn ON the power, using one hand only for electrical safety. A very tiny amount of amps can kill a person but a circuit has to be complete. Using one hand prevents a circuit from being completed through the heart should you get shocked. With one hand, you may feel a shock through your fingers and you'll know better next time. If you do, kill the power and put the cover back on before proceeding. 9. Place a blank disk in Drive B: and give the command FORMAT B: If it formats it, you're in. 10. Kill the power and fasten down your cover. Again, if you lack the confidence to do any of the physical installation, pay your money and have a professional do it. Remember, I can only be responsible for what I do, not what you do. I give these instructions without any guarantee, written or implied. *** The CONFIG.SYS changes for formatting. If you don't have a CONFIG.SYS, read your favorite DOS manual and set one up. You should have one for a lot of reasons. Through your favorite word processor or the DOS EDLIN command (which is also explained in your DOS manual), add the following line for a 720-730KB format. DEVICE=DRIVER.SYS /D:1 Implied is the Command DEVICE=DRIVER.SYS /D:1 /F:2 but /F:2 is a default setting so it can, but doesn't have to be written. Also implied are default settings /T:80 & /S:9. See your DOS manual if you're curious. /D:1 means that the 3 1/2 inch drive is PHYSICALLY connected to the Drive B: /F:2 means, format to 720 or 730 KB. If you're using a word processor, make sure that you save your changes in ASCII. Edlin automatically does this. Refer to your word processing manual if you don't know what ASCII is. You must, of course, reboot for this to work. You now have two options. You can use the command FORMAT B: which will give you a 360K format or you can use the command FORMAT D: which will give you 720-730K If you place a disk in B: and you've just formatted in that physical drive as D:, the computer will ask you to place the diskette in B: so it doesn't matter if you forget. Just hit the Enter key. It'll read 720K in B: very nicely. You only need to call it D: for formatting purposes. *** Higher Density Disks I don't have one of these nor have I access to an AT so I can only relate what I understand from the PC-DOS 3.21 manual. It should be okay for a 1.2MB drive. Unlike the above, however, I haven't tested it. Add to your CONFIG.SYS the following. DEVICE=DRIVER.SYS /D:1 /T:80 /S:15 /H:2 /F:1 /D:1 means it's physical drive B: /T:80 means 80 tracks (You may not need this. It could be a default) /S:15 refers to sectors for a 1.2MB /H:2 refers to heads (It could be a default) /C for AT computers. Leave off if you have an XT (couldn't check this.) It goes between /H:2 and /F:1. /F:1 means to format for 1.2MB Refer to your DOS manual for more details. By the way, when counting "physical" drives as opposed to "tagged" drives /D:0 refers to Drive A, /D:1 refers to B and /D:2 refers to the first hard disk and so on. *** A Handy Application for rarely used large programs I solved a small problem with my new 3 1/2 inch 730K drive. I had a number of strategy games crowding my hard disk. They were a bit too valuable (and large) to entrust to a floppy so I use a few of the 3 1/2 inch diskettes as mini-hard disks, stick them in Drive B: and have my batch commands for these games direct all the appropriate commands to B: instead of C: I cleared two megabytes of Hard Disk space for the ever-increasing demands of desktop publishing this way. With a little imagination, you can increase your capabilities with two different drives. (c) Yves Barbero (415) 285-4358 1073 Dolores Street San Francisco, CA 94110 Yes, I do a bit of consulting. And I'm an expert on Ventura Publishing. I publish a newsletter called the HARD HAT NEWS on my home computer. If you or your group need training or someone to do it for you, call me. References available. -end-