SCSI Mini-FAQ v0.9b1

[danb@pro-newton.cts.com (Dan Brown)]

OK, Joe, you asked for it...


HARD DRIVE MINI-FAQ v0.9b1
How to build your own hard drive and save $$$
October 15, 1993


NOTE:  This is a draft version of this document.  Please notify me at
danb@pro-newton.cts.com if you notice any errors, ommissions, or unclear
sections.  Thanks!

INTRODUCTION

	It's been said that there are two kinds of Apple IIgs users--those who
know they need a hard drive and those who don't.  Anyone who has used software
such as GraphicWriter III or AppleWorks GS, let alone System 6, certainly falls
into the first category.  While prices of hard drives are continually coming
down, there is yet more money to be saved in building your own drive from
parts.  Don't worry if you aren't a mechanical genius; the process only takes a
handful of screws and a few electrical connections.

	This document will describe the process of assembling an external SCSI
hard drive, suitable for use with an Apple IIgs, IIe, or any flavor of
Macintosh since the Mac Plus.  If there are any errors, ommissions, or
questions, please mail them to danb@pro-newton.cts.com.


PREPARATION

	You need three major components for a hard drive on an Apple II. 
First, you need a drive mechanism.  These are produced by several
manufacturers, including Seagate, Conner, Quantum, and others.  IMHO, Quantum
is the best available for drives <500 megs.  Second, you need a case and power
supply to hold the drive; and third, you need a SCSI interface card for your
computer.

	Drive mechanisms are available from many vendors, several of which
advertise in _Computer Shopper_.  It's a good investment of $3.00 to pick up a
copy and scan the ads.  You should be able to find a Quantum 170 meg SCSI drive
for under $200, and a 240 meg unit for under $270 (some vendors are as low as
$250).  Look also for a return policy and a money-back guarantee.  Once you've
selected a vendor, go ahead and place the order.

	For the case, Alltech Electronics Co. in Oceanside, CA, has by far the
best price I've seen.  For $49, they provide an external case with a power
supply, internal cabling, and all hardware necessary to install the drive in
the case.

	By far the best choice for a controller card is the RamFAST SCSI card,
now being produced by Sequential Systems, Inc. in Lafyette, CO.  It currently
sells for $159.95.  If you want to save a little money at the expense of a lot
of speed, the Apple High Speed SCSI Card is available from Quality Computers
for $109.95.

	You will also need a cable to hook the drive up to the computer.  The
cable is a DB-25M to Centonics-50 cable, also known as a SCSI System Cable. 
Alltech has them for $9.95.  A SCSI terminator, though not necessary, would
also be a good idea.

	As far as tools are concerned, a #1 Phillips-head screwdriver is
required, and some form of continuity checker is a very good idea, be it a
light, buzzer, or ohmmeter.  If you elected to buy an Apple card, beg, borrow,
or steal a copy of Chinook SCSI Utilities, v1.5.


ASSEMBLY

	Open the case assembly, which may require removing four small screws
near the corners.

	Inside the case, you should see three cables.  One, a very wide (2.5")
ribbon cable, is the main SCSI cable for the drive.  It will plug into the back
of your drive mechanism.  With the drive right side up, it should plug in
without twisting.  The second cable is the power cable.  Plug it into the
mating connector on the drive, usually next to the SCSI connector.

	The third cable you'll see should have two three-pin connectors.  These
will attach to the SCSI ID selectors on the drive.  For their location, consult
the manual that came with the drive.  If you don't have a manual, look for two
rows of three pins labeled A0, A1, A2 or S0, S1, S2.

	If you have a continuity light, set the SCSI ID switch on the back of
the case to 6.  Now start poking around on the connectors.  One of them (the
"common" connector) should have all three pins shorted together (i.e.,
continuity between all of them).  You should also have continuity between two
of the pins (the middle pin, and one of the end ones) on the other connector
and the common one.

	Diagram:

	4  2  1		<-- Indicate SCSI ID selected by this pin
	o  o  o		    4 and 2 are shorted to ground, giving an ID of 6
	|  |
	o--o--o		"Common" connector

	A line indicates continuity.

	The pins on the drive should have a similar layout:

	A2 A1 A0
	o  o  o

	o--o--o

	Plug the "common" connector into the bottom row of pins (which all have
continuity), and the other one into the top row, with the "4" pin at "A2".

	OK, now take a break from assembling the drive and install the SCSI
card in your computer, following the directions included with the card.  Plug
the drive into the computer, and power them both up.  If you have a RamFAST
card, you should see the RamFAST Utilities screen, indicating that it sees a
SCSI Hard Drive at ID 6.  If you see this, congratulations!  Your new drive is
working!  If not, turn off the power, check all your connections, and try
again.

	If you have an Apple SCSI card, turn on the computer and hard drive,
and boot the Chinook SCSI Utilities disk.  CSU should (like the RamFAST)
indicate that it has found a hard drive at ID 6.  If it does not, again, power
down and check all your connections.

	With either card, you should now partition your hard drive.  There are
few rules to this, except that ProDOS can only use a 32 meg volume.  To
completely use a 170 meg drive under ProDOS, therefore, requires 6 partitions. 
If you have a GS, you may wish to use some of the drive as a HFS partition,
eliminating the size restriction and allowing longer file names.  In any event,
you'll want at least one ProDOS partition to boot from.

	OK, now that you're sure the drive works, turn everything off and
finish assembling the drive.  If you purchased an external terminator, remove
the terminator packs from the drive.  They should be located right next to the
SCSI connector at the back of the drive; if you have any trouble finding them,
consult the drive's manual.  Four screws hold the drive in the case, and four
more hold the case together.  If you purchased an external terminator, attach
it to one of the SCSI connectors on the back of the case now.

	You're done!  Go ahead and install whatever software, etc. you need,
and away you go!


VENDORS:

Dirt Cheap Drives (Just what the name says)
1110 NASA Road One, Suite 304
Houston, TX  77058
800-473-0960
MasterCard, Visa, American Express, Discover

Sequential Systems, Inc.  (RamFAST SCSI Card)
1200 Diamond Circle
Lafyette, CO  80026
800-759-4549
MasterCard, Visa

Quality Computers  (Apple High Speed SCSI Card)
20200 E. Nine Mile Road
St. Clair Shores, MI  48080
800-777-3642
MasterCard, Visa, American Express, Discover

Alltech Electronics Co.  (HD Case & Power Supply)
602 Garrison Street
Oceanside, CA  92054
800-995-7773 Orders
619-721-7733 Info & Tech Support
 ----------------------------------
Dan Brown, Sysop of pro-newton     Internet: danb@pro-newton.cts.com
 Above opinions are not those of Mensa, which has no opinions.