408 lines
21 KiB
VHS
408 lines
21 KiB
VHS
Build Your Own Vanilla SCSI Tape Backup System
|
|
|
|
by Dr. Kenneth Buchholz
|
|
|
|
Box 430 RD#4, Washington NJ 07882
|
|
|
|
Copyright 1989
|
|
________________________________________________________________________
|
|
|
|
Make Mine Vanilla (Introduction)
|
|
|
|
Last autumn, I assembled my own "vanilla" SCSI hard drive subsystem
|
|
using the Seagate ST277N drive, the Tulin AppleHive case, and CMS SCSI
|
|
Interface Card and saved about $250 by "building my own". Since my first
|
|
online article on the assembly appeared last year, thousands of others
|
|
have followed suit and assembled their own SCSI hard drive, and the
|
|
popularity of these homebrew hard drives is illustrated by the wealth of
|
|
online and magazine articles which have followed.
|
|
|
|
During the following months of helping others assemble their own
|
|
hard drive, giving tutorial presentations before Apple user groups where
|
|
members would assemble their own hard drive during the presentation, and
|
|
writing follow-up articles for online services, my own BBS, magazines and
|
|
newsletters, it became quite apparent to me that what we all needed next
|
|
was an inexpensive SCSI tape backup system. Acquiring and assembling the
|
|
hardware was the easiest part - find the software needed to format, backup
|
|
and restore was the difficult part since Apple, nor anyone else, has
|
|
released either drivers for a SCSI tape system or tape backup software.
|
|
Fortunately more me - and you - a friend of mine was willing and able to
|
|
write the necessary software - HDTAPE - which is now available at a
|
|
shareware price.
|
|
|
|
Tim Grams, author of HDFORMAT (the very popular SCSI hard drive
|
|
formatting software), is the author of HDTAPE. (If you are already familar
|
|
with HDFORMAT or any of Tim's other software products, you already
|
|
appreciate the quality of his work!) HDTAPE is NOT a tape driver; rather,
|
|
it is a ProDOS-8 application which allows you to format, backup to and
|
|
restore from tape. As a ProDOS-8 application, the version of HDTAPE
|
|
described here is specific for the Apple //gs. A GS/OS version as well as
|
|
a version for the Apple //e are planned, and current owners of HDTAPE will
|
|
be notified of the availability of significant upgrades. HDTAPE is
|
|
available by direct order from Tim, and ordering information follows this
|
|
article.
|
|
|
|
If you're a SCSI hard drive owner who has quickly tired of backing up
|
|
your drive to floppy disk, read on: I will lead you through the purchase of
|
|
the hardware, its assembly and use. And before you say "I can't build
|
|
anything" let me say that if you can use a screwdriver, you CAN build your
|
|
own SCSI tape backup system - its THAT easy!
|
|
|
|
|
|
Why A Duck? (Why a SCSI Tape Backup System?)
|
|
|
|
Do you find yourself asking, "Why should I invest in a tape backup
|
|
system when 3.5" disks will do?" There are three reasons which come to
|
|
mind instantly: (1) Using 3.5" disks, you must remain glued to the chair
|
|
in front of your system, swapping disks - lots of disks - and for a 32 meg
|
|
volume this can take well over one hour. Using a tape system, you start
|
|
it up, wander off and do other things while the system is backing itself
|
|
up, and return when its done. (2) The tape system I'll describe here
|
|
uses DC2000 tapes, each of which holds 40 megs, equivalent to 50 3.5"
|
|
disks. Since the DC2000 tapes (which are also used in many of the MS-DOS
|
|
systems and are therefore readily available) can be purchased for as low
|
|
as $15 each, tape backup is more economical than disk backup. (3) And
|
|
finally, since the DC2000 tape is roughly the size of an audio cassette,
|
|
it requires a lot less storage space than do 50 3.5" disks.
|
|
|
|
|
|
Lincoln Logs (The Hardware)
|
|
|
|
The hardware needed for this project is listed below. I provide
|
|
information on vendors and approximate prices (based on what I paid in
|
|
March 1989) at the end of this article.
|
|
|
|
1 - 3M brand MCD-40 DM/SCSI tape unit
|
|
1 - Tulin AppleHive case with 30 watt power supply &
|
|
fan; includes all internal cabling; the optional
|
|
open face plate is highly recommended
|
|
1 - Apple SCSI Interface Card (ROM version C)
|
|
1 - SCSI Interface Cable terminating in a DB-25 pin
|
|
connector on one end and Centronics-like 50-
|
|
pin connector on the other end
|
|
1 - Standard Power Cord (as used on the Apple // line)
|
|
1 - DC2000 40 meg (250') SCSI tape cartridge
|
|
1 - HDTAPE (Formatting, Backup & Restore Software)
|
|
|
|
|
|
Ummm...A Frozen TV Dinner! (The Assembly)
|
|
|
|
For the initial assembly and connection, I'm going to provide
|
|
directions assuming that your SCSI tape backup system will be operating
|
|
on a seperate Apple SCSI Interface card from your hard drive. Operation
|
|
on the same SCSI chain (i.e., Interface Card) as your hard drive requires
|
|
a few extra steps, which will also be explained.
|
|
|
|
1. If your tape unit arrived with the attachment brackets already
|
|
installed, skip down to Step 3.
|
|
|
|
2. Attach the brackets to either side of the tape unit using the 4
|
|
screws supplied. When facing the tape unit's front panel, the
|
|
tape ejection button should be below the tape insertion opening.
|
|
|
|
3. If you purchased the optional open face plate from Tulin, skip
|
|
to Step 4; if not, you will need to cut a hole in the face plate:
|
|
Using a sabre saw with sheet metal blade, cut a rectangular hole
|
|
in the AppleHive face plate measuring 4.25" wide and 1.5" high.
|
|
The lower left corner of this hole should be 1" from the left
|
|
edge and 0.25" up from the bottom of the face plate (on the
|
|
bottom half of the face plate when facing the AppleHive). When
|
|
cutting this hole, be sure to make the cut far away from the
|
|
tape unit itself - preferrably in another room - to keep metal
|
|
shavings from coming in contact with the drive and case. Use a
|
|
metal file to round the cut edges smooth.
|
|
|
|
4. With one hand, hold the tape unit so that its underside is facing
|
|
UP. (The tape's eject button is on the bottom front of the unit.)
|
|
With your other hand, grab the distal end of the flat, 50-wire
|
|
ribbon cable coming from the connectors on the back plate of the
|
|
case and extend the cable so that it is NOT twisted. Insert the
|
|
connector at the end of this cable into the 50-pin connector at
|
|
the back of the tape unit. Be careful to insert this connector
|
|
properly so that no pins are bent, broken or sticking out. When
|
|
you press the connector into the back of the tape unit, the
|
|
latches on either side of the tape unit's connector should lock
|
|
the cable in place. Once this connection has been secured,
|
|
rotate the tape unit so that it is right side UP, resulting in
|
|
the 50-pin cable having a 180 degree twist in it.
|
|
|
|
5. Connect the 4-prong power line connector from the power supply
|
|
unit in the case to the tape unit. Note that this power
|
|
connector is D-shaped, and can only be inserted into the tape
|
|
unit's power plug receptor one way (the correct way!).
|
|
|
|
6. Gently set the tape unit onto the base plate of the case. Hold
|
|
securely to the case base plate and turn the entire assembly
|
|
upside down while continuing to hold the tape unit firmly against
|
|
the base plate. Using the 4 flathead screws provided with the
|
|
case, secure the tape unit to the bottom plate by inserting the
|
|
screws through the holes in the bottom plate and into the bottom
|
|
of the brackets on either side of the tape unit. Tighten securely.
|
|
Turn the assembly right side UP.
|
|
|
|
7. Check that the settings of the DIP switch bank (on left side of
|
|
drive when facing drive from the front) are properly set (Dips
|
|
1-6 should be towards the bottom of the drive, 7-8 towards the
|
|
top of the drive). The SCSI ID of the tape unit should be LOWER
|
|
than that of your SCSI hard drive; setting the tape unit ID to 0
|
|
is a safe bet since most commercial hard drives are shipped with
|
|
SCSI ID = 6.
|
|
|
|
8. Install the case cover and face plate, and fasten securely using
|
|
the screws supplied. Attach the power cord and SCSI interface
|
|
cable to the connectors on the back of the case, but do not yet
|
|
plug the power cable into a wall outlet.
|
|
|
|
9. Install the Apple SCSI Interface Card into your Apple as per the
|
|
manufacturer's directions.
|
|
|
|
10. Attach the SCSI Interface Cable from the tape unit to the Apple
|
|
SCSI connector on the back of your computer.
|
|
|
|
11. Plug the tape power cord into a wall socket and turn the tape
|
|
unit ON.
|
|
|
|
12. Turn your computer and hard drive ON, and boot the HDTAPE disk.
|
|
Follow the instructions below for using HDTAPE.
|
|
|
|
|
|
Solo Flight (Using The Tape System On A Single SCSI Chain)
|
|
|
|
If you will be chaining your tape backup system off your existing
|
|
SCSI hard drive, you will need to (1) make sure that the SCSI tape backup
|
|
system is the last device in the chain and (2) remove the terminator
|
|
packs from the hard drive.
|
|
|
|
To remove the terminators from your hard drive, open your hard drive
|
|
case and remove the hard drive unit itself. Locate the terminator packs
|
|
(usually 2-3 small, thin yellow units which vaguely resemble catapillars
|
|
on the underside (circuit board) of the hard drive) by gently pulling them
|
|
off. Be careful not to bend or break any of their pins. Also note how
|
|
they are attached to the drive (which side is "up") so that you can
|
|
properly reinsert them at a later date if necessary.
|
|
|
|
If you remove all terminators for all drives, including the tape
|
|
drive, you can chain or remove drives at will, providing you attach an
|
|
Apple SCSI Terminator to the daisy chain port of the last drive on the
|
|
chain. This will require that you purchase an Apple SCSI Terminator at
|
|
additional cost.
|
|
|
|
After reassembling your hard drive, connect the SCSI Interface Cable
|
|
from your tape backup system to one of the connectors on the back of your
|
|
SCSI hard drive. You are now ready to boot HDTAPE and begin your backup.
|
|
|
|
|
|
Its Soft Where? (Using HDTAPE)
|
|
|
|
With your computer, hard drive and tape backup systems ON, boot the
|
|
HDTAPE disk. After the program boots and the credits screen is displayed
|
|
(indicating the version of HDTAPE you're using), HDTAPE checks for the
|
|
presence of an Apple SCSI Interface Card and tape drive, and then
|
|
instructs you to insert a tape. When you receive this instruction,
|
|
insert a brand new, unformatted tape.
|
|
|
|
Your tape drive will perform about 30 seconds worth of tape access.
|
|
During this time, it is checking the tape. It will determine that the
|
|
tape needs to be formatted and will issue a message indicating this.
|
|
When you see the menu line
|
|
|
|
0=Backup 1=Restore 2=Format 3=Diagnostics Q=Quit
|
|
|
|
select 2 to format the new tape. Formatting takes approximately 38-40
|
|
minutes, so go grab an iced tea and watch a rerun of Taxi.
|
|
|
|
When Taxi is over, so is your formatting of the tape. The menu line
|
|
is again displayed and you're all set to begin backing up your hard drive.
|
|
Fortunately you will only format each tape you use once and never again,
|
|
so you may want to take the time to format all your tapes now and get
|
|
that out of the way for good.
|
|
|
|
HDTAPE is a ProDOS-8 application using the old Slot and Drive
|
|
designations for the volume to backup. To backup a volume, select 0 from
|
|
the menu line. HDTAPE responds with questions on which Slot and then
|
|
which Drive you wish to backup. If you have a 60 meg hard drive attached
|
|
to slot 6 and wish to backup the first volume, select Slot 6 Drive 1; to
|
|
backup the second volume in that hard drive, select Slot 6 Drive 2.
|
|
|
|
Three hexidecimal numbers are displayed during the backup process:
|
|
the total number of ProDOS blocks that will be backed up, the number of
|
|
blocks read from the volume, and the number of blocks written to the tape.
|
|
The number of blocks written to the tape will eventually go higher than
|
|
the number of blocks read from the volume being backed up due to
|
|
buffering and differences in the block sizes of the two devices (hard
|
|
drive and tape drive); this is of no importance to the backup process
|
|
itself, so don't be alarmed! In general, each megabyte being backed up
|
|
takes about 2-2.5 minutes, so estimate how long the entire backup process
|
|
will take based upon the size of the volume being backed up, and go have
|
|
some fun while the backup occurs.
|
|
|
|
Note that if you wish to cancel a backup or restoration, you can
|
|
press ESCAPE to return to HDTAPE's main menu - but beware that the tape
|
|
(if backing up) or hard drive (if restoring) will contain incomplete data.
|
|
|
|
When the backup is done, select Q from the menu line and HDTAPE will
|
|
rewind the tape for quick mounting the next time that tape is used. After
|
|
rewinding, HDTAPE will ask you if you wish to either quit the program or
|
|
process another tape.
|
|
|
|
Restoring a backup from tape is just as easy as backing up to tape.
|
|
Select 1 from the menu line to restore, and tell HDTAPE which Slot and
|
|
Drive you wish to restore to - the rest is automatic. And yes, it is
|
|
THAT easy!
|
|
|
|
|
|
Slurpies (Potential Problems)
|
|
|
|
There are a variety of cases that can be used instead of the Tulin
|
|
AppleHive. If you purchase a case with an "open" front plate, you will
|
|
not need to cut a rectangular hole in the front as we did with the Tulin
|
|
AppleHive case; the "open" front plate cases already have that opening.
|
|
The one problem that can crop up with any case/power supply/fan
|
|
combination you choose is magnetism.
|
|
|
|
Unlike hard drives, tape drive units are open and not as well
|
|
protected as hard drives are from magnetic fields, dust and other data
|
|
goblins. Many of the power supplies and fans in popular hard drive
|
|
cases emit enough magnetism to interfer with the operation of the tape
|
|
unit. If you find that your tape unit does not operate properly, try
|
|
removing the case covering and carefully try using the system opened.
|
|
If the tape unit works under these conditions, chances are that enough
|
|
magnetism is being created when you close up the case to interfer with
|
|
the tape unit's performance. If this is true, try this home remedy:
|
|
cut a piece of cardboard box to make a "lid with sides" which can stand
|
|
over the tape drive and along either side of the tape drive for its length.
|
|
(I used part of the tape drive shipping box, which was the perfect size.)
|
|
This "lid with sides" should fit so that there is sufficient space between
|
|
it and all components of the tape drive itself. Completely encase this
|
|
cover with aluminum kitchen foil, taping all edges so that the foil edges
|
|
can not unravel and touch any of the tape drive components. Set this
|
|
aluminum-covered cardboard lid over the tape drive so that is surrounds
|
|
the tape drive and provides a physical barrier between the tape drive and
|
|
the power supply and fan. You may also want to place a sheet of plastic
|
|
film between the bottom of the tape unit and the case (I used a plastic
|
|
page protector trimmed to the size of the tape unit's footprint). Also
|
|
check that all cable connections are secure.
|
|
|
|
Another problem which ocassionally occurs is a bad tape. Just like
|
|
disks, you can ocassionally receive a bad tape. If your tape unit seems
|
|
to function properly but you receive an error during the format process,
|
|
try another new tape or two - you may simply have a bad tape (or two if
|
|
its your unlucky day).
|
|
|
|
Finally, note that tapes can wear out after prolonged use. To help
|
|
extend the life of your tapes, always store them in a clean, out-of-the-way
|
|
place away from magnetic fields.
|
|
|
|
|
|
"I Love You" & Other Lies (Warranties & Promises)
|
|
|
|
One of the major concerns for all do-it-yourself projects is the
|
|
warranty. One of the first questions posed to me when I built my vanilla
|
|
SCSI hard drive is, "What about a warranty?" If you purchase a new drive,
|
|
you should receive the manufacturer's warranty - which usually runs about
|
|
one year. This is the same as is usually given on commercially-assembled
|
|
tape backup systems. Check with the vendor of the case/power supply on
|
|
their warranty; Tulin offers a 6-month warranty on the AppleHive case.
|
|
Apple offers their standard, chintzy 90-day warranty on the SCSI
|
|
Interface Card. In general, with the possible exception of a shorter
|
|
warranty on the case & power supply, the warranty on the tape unit itself
|
|
and the Apple SCSI Interface Card are the same as if you purchased a
|
|
commercial tape backup system. The big difference in assembling your own
|
|
system, of course, is price.
|
|
|
|
|
|
The Bottom Line (Price)
|
|
|
|
I purchase my brand new 3M tape unit for $299. The Tulin AppleHive
|
|
case with 30 watt power supply is $119. The Apple SCSI Interface Card can
|
|
be purchased mail order for about $100, the SCSI Interface Cable and power
|
|
cord together will cost you another $30 or so, and HDTAPE $50. The bottom
|
|
line comes to around $600, excluding tapes. (If you already have a SCSI
|
|
hard drive with Apple SCSI Interface Card, your tape backup system can run
|
|
less than $500 complete.) Scouring the local computer faires and Computer
|
|
Shopper, you might be able to save $50 on a case with power supply, and if
|
|
you make your own SCSI Interface Cable, you can save another $20 or so.
|
|
Considering that Apple sells their similar SCSI Tape Backup System for
|
|
the Mac, sans Apple SCSI Interface Card, for $1499 list, $600 doesn't
|
|
seem that expensive to begin with!
|
|
|
|
If you are considering assembling your own hard drive AND tape unit
|
|
simultaneously, you can save a few dollars by using the Tulin AppleHive
|
|
case since this case will hold both one half-height hard drive and the 3M
|
|
tape unit. But since the AppleHive comes in two flavours - with a 30
|
|
watts power supply or with a 60 watts power supply - which do you select?
|
|
The Seagate ST277N 60 meg SCSI hard drive draws a maximum of approximately
|
|
12.5 watts (when accessing the drive) and the 3M tape unit draws a maximum
|
|
of 20 watts when moving the tape (but only 9 watts when in stand-by mode).
|
|
Since the two devices are accessed alternately, it appears that the 30
|
|
watts power supply is sufficient to power both devices. Tim is using
|
|
the 30 watts version to power both his Seagate ST277N 60 meg drive and 3M
|
|
tape unit and reports no problems thus far (I have my vanilla tape system
|
|
in a seperate case since I move it between two Apple //gs units), but we
|
|
both suggest that the 60 watts AppleHive be considered just to be safe.
|
|
|
|
The Cast Of Players (The Vendors)
|
|
|
|
HardTimes (1070 Commercial St. San Jose CA 95112; 408-
|
|
452-5700) sells the 3M tape units for $299, while
|
|
their supply lasts.
|
|
|
|
Tulin Corp. (2393 Qume Dr., San Jose CA 95131; 408-432-
|
|
9025) sells the 30 watts AppleHive for $119 and a
|
|
60 watts AppleHive for $169, power cords for $4
|
|
$20 for the SCSI Interface Cable.
|
|
|
|
Mytech Electronics (300 Breesport, San Antonio TX 78216
|
|
800-527-7435) is a good source for cables & other
|
|
electronic components (including all you will need
|
|
to make your own SCSI Interface Cable).
|
|
|
|
Diskette Connection (272 Quigley Blvd., New Castle DE
|
|
19720; 800-451-1849; & other locations around the
|
|
US) is an excellent source of 3M DC2000 tapes for
|
|
$15 each. Quick reliable service & best prices!
|
|
|
|
Tim Grams (P.O. Box 462283, Garland TX 75046) provides
|
|
HDTAPE for $50. When ordering, specify HDTAPE,
|
|
computer type being used, and 3.5 or 5.25 disk.
|
|
Checks or money orders (made payable to Tim) are
|
|
accepted.
|
|
|
|
|
|
The Free Clinic (Sources of Information & Help)
|
|
|
|
The Washington Towne Crier BBS (1-201-689-3649; 8-N-1; 300/1200/2400
|
|
bauds) is a free, public-access BBS specializing in the Apple // family of
|
|
computers. WTC has extensive libraries of public domain and shareware SCSI
|
|
utility software and information files. The author can also be reached at
|
|
WTC via private EasyMail (user #1) or the public forums.
|
|
|
|
|
|
Reach Out & Touch Someone (Contacting the Author)
|
|
|
|
The author may be contacted electronically via the following services:
|
|
|
|
Service: ID:
|
|
---------------------------------- -----------
|
|
The Washington Towne Crier DR. KEN
|
|
AppleLink DR. KEN
|
|
GEnie D.BUCHHOLZ
|
|
CompuServe 75076,412
|
|
|
|
|
|
_________________________________________________________________________
|
|
|
|
Dr. Kenneth Buchholz, Box 430 RD#4, Washington NJ 07882
|
|
_________________________________________________________________________
|
|
|
|
This article may not be reproduced, in whole or in part, for
|
|
commercial redistribution, electronic or otherwise, without prior written
|
|
permission from the author. All rights reserved by the author. The
|
|
author hereby grants limited permission for this article to be distributed
|
|
via Apple user groups' printed newsletters, and via pay subscription
|
|
telecommunications services provided the article is contributed directly
|
|
to the service by the author.
|
|
__________________________________________________________________________
|
|
|
|
|