3.5 disk for att 6300?

[George S. Kong]

attached are some old netnews articles that you may find helpful,
including one that i wrote 2 1/2 yrs ago.

George S. Kong,  Silicon Graphics, Inc.,  (415)962-3281
gsk at sgi.com
...{decwrl,allegra,adobe,ucbvax,pyramid,ames}!sgi!gsk

..........................................................................

>From gsk at khaki Tue Sep  8 15:25:14 1987
From: gsk at khaki
Newsgroups: comp.sys.att,comp.sys.ibm.pc
Subject: Re: 3.5 Drive in 6300
Summary: here are some tips
Keywords: Any tips?
Message-ID: <6112 at sgi.SGI.COM>
Organization: Silicon Graphics Inc, Mountain View, CA


i trust you've seen G. P. Wilkin's helpful posting
about 1.4M 3.5" drives. i decided to go with 720K.

the floppy controller in the PC6300 supports two drives.
basically, i bought a 720K drive and plugged it into
the existing controller in my 6300.

there are a number of gotchas involved:


1) you probably don't have a spare drive bay in your 6300,
   if you're already running a 5 1/4" floppy drive and a
   hard drive. you'll thus have to mount something externally.
   you'll need an enclosure, power supply, long cables, etc.

2) the two connectors on the cable inside the 6300 are
   too close together to fit onto both the internal 5 1/4" drive
   and a Toshiba 720K drive at the same time.

3) you need to run DOS 3.2 in order to use 720K drives.
   upgrading a hard disk to a new version of DOS can be a real pain:
   i.e. backup everything to floppies or tape; run fdisk;
   reformat the disk; then restore everything.

   make sure you "set the active partition" with fdisk afterwards.

   you also have to add a "drivparm" line to your config.sys.
   see the DOS 3.2 manual for this.

4) you need to set the switches on the motherboard for 2 floppies.


#1 and #3 were not problems for me, because i simultaneously
added: an external enclosure, a second hard disk, and DOS 3.2.
i installed both hard disks in the external enclosure,
leaving the 5 1/4" floppy and the 3.5" floppy in the system unit.
then i booted DOS 3.2 from floppy and formatted the new hard disk.
then i xcopied my old hard disk to the new one.
then i reformatted my old hard disk with DOS 3.2.

i solved #2 by crimping another connector onto the ribbon cable.

for #4, i can't remember offhand which switches to set.
you'll have to consult the 6300 hardware manuals.


i bought a Toshiba 720K floppy drive ($105) and installation kit ($20)
from a local discount computer store (Technoland in Sunnyvale).

you can order them mail order for comparable prices. be sure you get
both the drive and the "universal" installation kit. the drive alone
is not the right size and does not have the right connector to be
installed in a PC.

good luck.

George S. Kong,  Silicon Graphics, Inc.,  (415)962-3281
gsk at sgi.com

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>From jeffm at mmintl.UUCP Tue Feb 23 15:30:28 1988
From: jeffm at mmintl.UUCP (Jeffrey Miller)
Newsgroups: comp.sys.att
Subject: 1.44 Meg 3.5" drive on AT&T 6300: it works!
Message-ID: <2732 at mmintl.UUCP>
Reply-To: jeffm at mmintl.UUCP (Jeffrey Miller)
Organization: Ashton-Tate, E. Hartford, CT.


*
After months of searching and then finally waiting till I could find a
dealer of 1.44 Meg 3.5" disks, I have reached Nirvana.  I have a 1.44
Meg 3.5" drive as drive B: on my 6300.

The drive also reads/writes 720k disks perfectly.  I got the drive from
Shamrock of Westlake Village, CA (805)373-7847, for $149.  I also needed
a controller card which supports the 500k/sec xfer rate necessary for
the drive to operate at high density.  The card was $100.  It also
controls my existing 5-1/4" drive.

The floppy controller on the 6300 mboard had to be disabled.  All that
is necessary is to lift pin 17 of the 12L10 PAL at location 6E next to
the 2 ROM chips (thanks to Pete Fales for that info).  The only switch
change necessary was DIPSW-1 sw7 to OFF, to tell the machine there are
2 floppies now.  (When you lift pins, always lift them *very* slowly.
This helps prevent metal fatigue.  Just lift it enough to clear the
socket).

The drive came with everything necessary: mounting hardware for 3-1/2 and
5-1/4 enclosures, drivers, and as an extra, a fast backup program called
TakeTwo.  The instructions were very clear.  If you should try this, re-
member that for the 3-1/2" drive, pin 34 of the connector must be connected
to the controller.  But you'll have to put a piece of tape over the same
position on the 5-1/4" drive's connector, which must remain open to the
controller.

I did have one minor problem with the driver.  The installation program
was looking for a file called FTDRIVE.SYS, which didn't exist.  But
there was another .SYS file available.  So I went into the install .com
file, patched in the name of the existing .SYS file, and everything
worked fine.  When contacted, Shamrock said this was missed in the
first ones shipped.

Unfortunately, Shamrock did not have enclosures when I bought my drive.
I checked with them for about 2 months and they still did not have them
ready, so I bought one from some company, maybe Jameco or PC Source.  But
the drive cable had no way to get out of the machine.  So I picked up
some 34-pin socket connectors from Jameco and some cable, and made up
a short cable which I ran out of an empty slot space in the back.  It
just goes up to the case and everythings fine.  Ideally, the slot mount
on the controller card itself should have a cutout in which I mount a
34-pin connector and run the cable from the back, but no problem.  By the
way, the drive comes with the capability to use both a socket connector

                      :::::::::::::::::

like this, or an edge connector, a very nice feature through the use of
a small adapter circuit board.  I used the socket since room was limited
inside the enclosure.

All in all, the disk access is not the fastest, but having that much
storage on a floppy is great.  I had a hard time finding 1.44 Meg disks.
The best price I saw was $39 per box of 10, but like all the other places,
they had none in stock.  I finally found some for $42 at Richard Young
Products, Deerfield Beach, FL (800)325-0136.  Last night I received them
and that's why I'm posting today.  I wanted to make sure.

I recommend the stuff highly.  And of course the usual disclaimers.

Jeff
-- 
* Jeff Miller:  Ashton-Tate  52 Oakland Ave., E. Hartford, CT  06108-9911  *
* (203) 522-2116 x257  UUCP: ...!seismo!utah-cs!utah-gr!pwa-b!mmintl!jeffm *
*                         or ...!ihnp4!philabs!pwa-b!mmintl!jeffm          *

..........................................................................

From: aptr at uhura.cc.rochester.edu (John Werner)
Newsgroups: comp.sys.att,comp.sys.ibm.pc
Subject: 6300 Upgrades - adding 1.2 and 1.44 Meg disks (long)
Keywords: CompatiCard
Message-ID: <562 at ur-cc.UUCP>
Organization: Univ. of Rochester, Computing Center
Xref: sgi comp.sys.att:5810 comp.sys.ibm.pc:25892

NOTE: This article is being cross posted to two newsgroups,
comp.sys.att and comp.sys.ibm.pc because it applies to both groups.
Please edit the Newsgroups lines appropriately.  If you wish to make a
comment directly to me, please us e-mail.  I read both groups, but not
as much as I would like to.  (I recently threw away 2000+ unread
articles in comp.sys.ibm.pc.)

------
I have just finished adding a pair of new disk drives to my AT&T 6300
clone.  It is actually a Xerox 6064 given to me by my father who works
for Xerox.  The drives I added are a 1.2 Meg 5.25" and a 1.44 Meg
3.5".  Currently, both of these are sitting on top of topless computer
waiting for a case to arrive from Mead.  At this point, everything
seems to run fine, but I have not had a chance to try the 3.5" drive
at 1.44 Meg.  I didn't have a chance to get 1.44 Meg disks for it, and
the 720k disks won't format at 1.44 Meg.

The drives are being run off a Compaticard from Micro Solutions.  The
Compaticard costs about $175 and is somewhat unique in it ability to
be configured to be any drive contoller.  Unlike most drive
contollers, it does not insist on being the primary drive contoller.
This allows it to be used in computers that have built in controllers
(i.e. AT&T 6300).  The board also supports just about any type of
drive you could ever want.  It even supports 8" disk drives.  (Oh, I
do have a pair of 8" drives from a Xerox 16/8 PC that I plan to hook
up soon so I can transfer some long forgotten files from CP/m to
MS-DOS.)


INSTALLATION
	Installation of the card is relatively easy and painless if
you do not make the mistakes I did.  Jumpers on the Compati Card
select which controller the card will be.  In my case, I told it to be
controller 2.  You can run up to four controllers on one machine.
Each controller supports 4 drives and has four drive connectors (2
parrallel (sp?) wired pairs), so you can have a total of 16 drives.
There is an edge connector paired with a 34 pin connector, and a 24
pin connector paired with a 37 pin D-connector on the back of the
card.  Each pair of connectors is capable of running two drives.  For
my system, I chose to use the edge connector.

To connect the drives, you need to have a cable that runs from the
connector on the board to the drives.  If you want, you can wire two
drives with one cable, but on one of the drives, 10 to 16 on the
connector must be reversed in order.  The twist in the cable is so
that you do not have to change jumpers on the drives.  By twisting the
cable, the control lines are reversed so that what used to be the
control lines for drive 2 are now the control lines for drive 1.  Most
disk drives are now shipped as drive 2.

Once the drives are set wired up and powered (you will have to give
them power, but if they are in a case this is not too much of a
problem), you can have to install driver software in the Config.sys
file of your boot disk.  This software is used to allow DOS to access
the disks.  I have no idea what is need to run Xenix or UN*X or
whatever because I have never had to worry about it.  The manual does
provide information on how to do low level (DMA) access of the drives.
The manual is is slightly better then the UN*X man pages, but not by
too much.

Once this is all done, you are ready to run.  After re-booting the
computer, the drives are ready to test.  If you can format a disk on
the drives, then the installation worked.  (There is a special format
program provided so that you can use the drives even if your DOS
version does not support the format and/or drive.)  After this, they
should run with out any problem.

Now, having described the installation process, I will describe the
mistakes I made on the way.

1)  When building the original cable, I somehow managed to do it so
that the connectors where not seated well enough to make contact with
the wires in the ribbon cable.  I spent several hours on Christmas Eve
trying to figure out the problem.  Eventually, my father and I decided
to rebuild the cables.  This solved the problem.

Although the installation manual that comes with it has a trouble
shooting section, we could not find the solution there.  On Christmas
Eve, we decided that calling for technical support was not going to
get us very far because no one would willingly be there on a Saturday
to answer technical questions, not to mention this particular
Saturday.  The symptoms of the problem were that the drive light would
never come on no matter how we tried to orientate the connector.

2)  When we built the cable, we decided not to twist the wires 10 to
16 on one of the connectors and just use the drive select plug on the
1.2 Meg drive to drive 0 from drive 1.  The problem with this approach
was that the jumper on the 1.2Meg drive only changed which drive
select line was accessed, not which motor was turned on.  Hence,
although we could turn the drive light on, we couldn't do anything
else with the drive.  Most of my father's and my experience with disk
drive wiring was with 8" drives in the days of CP/m.  On an 8" drive,
the motor is always running, so you never have to wory about toggling
it on or off.

This morning (Christmas morning) it finally occurred to me what the
problem was, and I discovered that the only easy way to get both
drives to work was to use a twisted cable for one.

3)  The last problem occurred when I put in the twist in the cable.
Somehow, I once again managed to get a poor connection on the to one
of the connectors and spent some time finding the problem.  (Some
problems are just _too_ obvious to consider.)

COMPATIBILTY
	So far, every program can access the disks as normal DOS
devices without any problems.  I can format, write, and read disks
without any hitches.  There are some little inconviences that some
software is giving me.

Both FastBack 2.01 (Fifth Generation Systems) and PC-Backup (Central
Point Software) refuse to try to use physical drives that are above 3.
The two drives I have installed are physical devices 4 and 5, the
lowest possible ones with the CompatiCard being used as controller 2.
This means that I can not use the nice backup features that these
programs provide on my 1.2 Meg drive. (i.e.  no formatting while
backing up, no special rercoverable format, etc.)  FastBack does allow
the backup to be done to any DOS device, so I was able to run a
backup to the 1.2 Meg drive, but I had to format the disks as normal
DOS disks before doing the backup. This was a bit of pain since I have
60 disks for my backups.  (I have 60 Meg of Harddisk on my system.)

The other problem is a very minor.  Because of the large size of IBM
PC-DOS 3.3 and my using FansiConsole, EMM drives, and now another set
of drivers for the new drives, I no longer have enough memory to run
one program. If I leave out FansiConsole, I barely have enough memory.

[Aside:  FansiConsole now supports the VDC750 in all of its EGA modes,
including 640x400 16 color mode.  It even allows you to use 50 line
display in the above mode.]


OTHER NOTES
	I have already mentioned that the 6300 has a built in drive
controller.  Because the CompatiCard can be configured as any
controller (1-4), it does not have a problem with the 6300s
controller.  The thing to note is that the drive configuration
switches on the motherboard should not be changed since they only make
a difference for the built in controller.  Changing these caused my
system to lock on boot and return "Bad or Missing Command
Interpretter".  (This panicced me a first because there have been some
virus problems on MacIntoshes around here and I thought I might have
gotten hold a PC virus.)

The second note concerns the DMA on the mother board.  Other are
several DMA chips that were used.  Only some of these are fast enough
to keep up with 1.2 and 1.44 Meg drives.  The best way to tell the
difference is to check the number on the DMA.  DMAs that will work are
AMD 95117 and NEC 8237AC-5.  Other DMAs are probably not fast enough.

There are also two different ways that the chips were mounted.  Some
where soldered on and some were socketed.  If you have a socketed DMA,
it is a simple matter to change it.  (The latest replacement
motherboards to come through the Xerox Service Center locally have had
socketed NEC DMA chips.)

If the DMA is soldered on, you may want someone with experience
working with soldering ICs to help.  First off, _do_not_ try to
unsolder the DMA.  If something should go wrong and the plating on the
hole is pulled through, you will lose contace to the inner layers of
the circuit board.  At this point you will have to replace the mother
board.

The best method for dealing with soldered on DMA chips is to carefully
cut the leads to the chip leaving enough length to solder to.  Then
carefully solder the leads of the new DMA to the leads from the old
DMA leads.  This can be tricky because the tolerences at this point
are rather small and it is fairly easy to form a solder bridge.

DISCLAIMER:  I have never actually tried this proccess, but it has
been recommended by many people I have talked to.  I also will not be
liable for any damage you do from either trying this procedure or
having someone else do it.  (I really hate to have to put a disclaimer
in, but I can't afford to buy anybody a new computer right now.)


SUMMARY
 	The CompatiCard from MicroSolutions allows owners of computers
with built in disk controllers to add more disk drives to their
machines.  These drives can be on any format and size (3.5", 5.25",
8").  The software comes with drivers for DOS and enough information
to allow custom drivers to be written.  Installation of the system is
straight forward, but there may be some machine specific problems
encountered.  Overall, it is a very nice and reasonably priced (~$175)
solution to the problem of adding more drives to a 6300.

John Werner
------
John E. Werner    UUCP:   {cmcl2!decvax}!rochester!ur-cc!aptr
     aka          BITNET: aptrccss at uorvm
  The Wumpus	  Internet: aptr at uhura.cc.rochester.edu
Disclaimer: "Who? When? Me? It was the Booze!"  - M. Binkley


-- 
John E. Werner    UUCP:   {cmcl2!decvax}!rochester!ur-cc!aptr
     aka          BITNET: aptrccss at uorvm
  The Wumpus	  Internet: aptr at uhura.cc.rochester.edu
Disclaimer: "Who? When? Me? It was the Booze!"  - M. Binkley