3B1 Expansions - where'd they all go? (LONG)

Thu Mar 23 08:57:39 AEST 1989

In article <635 at shade.UUCP> steveb at shade.Ann-Arbor.MI.US (Steve Barber) writes:
|>
...
|>1) Whatever happened to IDT, who was supposed to be making a SCSI board
|>   for the 3B1?  I haven't heard anything about them or the board lately,
|>   and when I sent mail to them a few months ago I got no reply (not even
|>   a bounced message).  Is there or is there not a SCSI board available now?

Well IDT is no longer committed to the UNIX pc world.  They gave up on their
SCSI board after a very short beta-testing period.  It was rumored they had
the board developed but gave up on the software since it was becoming
increasingly hard to develop when AT&T didn't provide the needed information.
I, like others out there, were hoping they would just release the board,
specs, etc.. and whatever they had for a nominal fee, and let the net-at-large
do the rest of the development.  Therefore, they had no need to really
support anything, it would be a net-wide project.

|>2) I also don't remember seeing anything in recent months about the two
|>   or three different upgrade kits that were being made that would allow
|>   the use of a 2nd drive and drives with higher capacities.  Are any of
|>   these kits available now, or did they fizzle out?
|>   
Well the discussions were around for quite some time.  There are ways
of doing it *NOW*.   Gil Kloepfer, Jr. (gil at limbic.UUCP) and I have
released the plans to build your own 2nd hard drive expansion board to 
put on your UNIX pc.  It was posted to the net, and I'll repeat the pertinent
information here for those who still missed it...  For those who still want
more information should write either Gil or I, and we'll be happy to help you.

John Milton (jbm at uncle) is working on something similar, except the fact he's
building the boards for a price.  Although he hasn't go into production yet.
So if you're electronically inclined, and you'll have no problem building it
yourself, the ICUS Upgrade Manual is for you!

|Article 3215 of unix-pc.general:
|Path: icus!limbic!gil
|>From: gil at limbic.UUCP (Gil Kloepfer Jr.)
|Newsgroups: unix-pc.general,comp.sys.att
|Subject: UNIX-pc Second Hard Drive - Information (lengthy)
|Message-ID: <466 at limbic.UUCP>
|Date: 16 Feb 89 04:22:32 GMT
|Organization: ICUS Software Systems, Islip, NY
... 
|
|The ICUS upgrade is a manual, not a kit.  It provides the items outlined
|below:
|
|	1.  Schematic diagram of the upgrade (extension) board
|	2.  Full instructions regarding the motherboard
|	    modifications and assembly of the extension board
|	3.  Theory of operation of the modification
|	4.  Photographs (aproximately 10) showing the more
|	    difficult portions of the upgrade (sections of the
|	    motherboard where wires were routed, socket installed,
|	    a section where wires are soldered to pads instead of
|	    chips, construction of the extension board)
|	5.  Diagrams (where the photos fall short) and construction
|	    hints
|
|For an additional fee of $5, we will also send a disk with the extended
|diagnostic on it (this contains commands which allow larger disks to
|be formatted [ie. disks with more than 1024 cylinders] and tested, and
|it also allows you to partition your disk into multiple smaller partitions).
|
|To order the upgrade plans, send a check (or money order) for the correct
|amount:
|
|	$30 - Hard disk upgrade plans
|	$35 - Hard disk upgrade plans with diagnostic disk
|
|...and NET ADDRESS to:
|
|		ICUS Software Systems
|		Hard disk expansion plans
|		c/o Lenny Tropiano
|		P. O. Box 1
|		Islip Terrace, NY  11752
|
|Make checks payable to Lenny Tropiano or Gil Kloepfer.
|
|We are requesting that you send us your net address so that we can send
|you e-mail when we send out your plans, and so that if any problems are
|discovered after we mail your plans, that we can contact you in the
|future.

|>3) How slow is slow?  I.e. if I opt for a slow (say 40ms) 2nd drive onto
|>   which I would probably place /usr/spool, whatever source code I keep
|>   online, and other misc. stuff that's not speed-critical it shouldn't
|>   be too big of a deal.  But if I were compiling on that drive, what
|>   kind of an impact on speed would I see?  Are there any drives bigger
|>   than 40 Mb that are ~40ms avg. access time?  (I'm looking for as much
|>   capacity for as little $$$ as I can without sacrificing too much speed).
|>   (I have 3 Mb of memory installed and a lot of disk buffers allocated in
|>   3.51a)
|>
The biggest problem with the seek time speed is really how fragmented you
let that partition get.  The more scattered the blocks are, the more seeking
you'll have to do, and hence the longer you'll have to wait.  The the blocks
are contiguous, then seeking from track to track should be quite fast.  Note
the ~40ms access time is an average, some track-to-track seeking will be 
faster, and some will be slower.   /usr/spool will get rather fragmented, but
the nice part about putting two drives online, you can easily backup the 
partition and mkfs(1M) [make filesystem] the partition again, and then 
restoring the data back on, in contiguous block space.   If you aren't
too concerned on how long it takes you to unbatch news, how long it takes
you to read articles ... then ~40ms isn't too bad.  If price is a big factor,
the ~40ms access time isn't that bad.  The old PC7300 10MB and 20MB drives
had ~67ms seek time.  This is quite slow, especially since you are using that
speed for the system drive!

|>4) What about faster drives?  Would I notice a big speed difference if I
|>   installed an ~18-~20 second drive as my root drive and moved my present
|>   Miniscribe 6085 (28ms) to the 2nd drive position?  Is the 3b1 fast enough
|>   to make good use of a drive that fast?  I do use the system pretty hard.
|>   I realize that access time probably isn't that relavant to this question,
|>   whereas transfer rate probably would be, but I'm just checking.
|>
Yes, definately.  I/O is the biggest hog on this system.  UNIX is very
disk intensive, and anything to speed up the access of programs would be
better!  Craig Votava [att!looney!cmv] placed a CDC Swift 3.5" drive
in his UNIX pc, not only does it have a 100MB capacity, but it's a ~16ms
seek time and half height.  He claims this is a *big* improvement!

|>6) Is the Western Digital controller ([12]010) bright enough to be able to
|>   handle simultaneous requests for both drives at once?  Or can it only
|>   handle one request at a time?
|>
This is a function of the operating system gdisk driver, and only one drive
can be selected at a time.  The additional hardware for the 2nd drive only
multiplexs the data separator between the first and second drive.  

|>7) Has anyone come up with a satisfactory solution to the RF interference
|>   problem found when using external drives?  What about using shielded
|>   round multiconductor cables instead of ribbon cable?
|>   
This has been a problem for our upgrade from the beginning.  Since the drive
is in an external case it's fairly shielded, but the ribbon cables seem to
emit a high amount of RF.  Round shielded cable would be a thought.  Shielded
ribbon cable another one.  Shielded ribbon cable will be easier to work with
since the connectors we use are for ribbon cables, but after looking at the
price of those cables, the round cable might be more economically feasible.

|>8) Any ideas where I can find a cheap case and power supply for an external
|>   drive(s)?  Note: my idea of cheap is less than $100!  I'd kind of like
|>   it to hold both hard disks and maybe a 1.2 or 1.44Mb floppy drive if
|>   anyone has figured out how to do that yet.  I was thinking that a
|>   PC clone tower-style cabinet would look nice and (generally) hold a lot
|>   of drives, but those plus a power supply don't seem to be very affordable.
|>
Well that's is exactly what we were feeling when we set out to purchase
a hard drive case for the upgrades to our machines.  With a little research
we found out that were are lots of companies that sell these things.  We
purchased our cases from a company in Washington state.  

This is the letter of recommendation we got:

The model # of the case is the EXTEC-3, it's a full height case that has
a power supply that can run one full height or two half height drives.  
The two we bought at $98 each, have been operating 24 hours/day 7 days/wk
for over 2 months without any problems.   They remain very cool, with the
fan inside.

|>One other quick unrelated question: can someone mail me the old discussion
|>about replacing 3b1 fans with other AC or DC fans?  Mine is starting to make
|>lots of strange noises when its cold and just starting up, and I may have
|>to replace it soon.
|>

I did the "AC" fan upgrade to my machine when the fan burned out.  After
noticing that the DC fan seemed more susceptible to not starting up, or
just stopping to operate, I replaced it with an equivalent 3" AC fan from
Radio Shack.  The AC fan pulls more air through the machine, and therefore
keeps it cooler (and unfortunately more dusty).  That's been working in
my machine for over 1 year now.   

Hope this answered all your questions .... 
-Lenny
-- 
Lenny Tropiano             ICUS Software Systems         [w] +1 (516) 582-5525
lenny at icus.islp.ny.us      Telex; 154232428 ICUS         [h] +1 (516) 968-8576
{talcott,decuac,boulder,hombre,pacbell,sbcs}!icus!lenny  attmail!icus!lenny
        ICUS Software Systems -- PO Box 1; Islip Terrace, NY  11752

3B1 Expansions - where'd they all go? (*LONG*)

3B1 Expansions - where'd they all go? (LONG)