                 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-