bobl@pro-graphics.UUCP (Bob Lindabury) (07/11/89)
Network Comment: to #405 by pnet01!crash!DOCKMASTER.NCSC.MIL!AELevy
Allan wanted the SCSI jumper setting so that CMS drives (an homebrew drives)
would work with the Apple SCSI card.
The jumper is on the back of the CMS drive and is actually a dip switch.
Switch dip 8 to it's non-standard position. I'm not sure if that is closed or
open at this point. If you don't have a CMS, you will have to either jumper
or unjumper the corresponding jumper on the SCSI drive. I will see if I can
get any clearer instructions as I don't use the Apple SCSI myself.
At any rate, here is some more miscellany about SCSI cards and drives...
SCSI NOTEBOOK
Dr. Ken's Notebook of SCSI Miscellany
If you are using the Apple SCSI Interface Card you MUST turn your hard drive
ON & wait for it to come up to speed and position the heads off their
landing (parking) zone BEFORE you turn your computer ON. Using one of
the Seagate STxxxN series of drives, this time is generally about 30
seconds. (In contrast, if you are using the CMS SCSI Interface Card,
you can turn ON the hard drive and computer simultaneously.) If you
fail to do this, the SCSI hard drive will NOT be visible to your
computer. This is a major drawback to BBS SYSOPs who wish to have
their systems autoboot on power in the event a power failure occurs.
If you wish to use the Apple SCSI Interface Card on a CMS drive, you MUST
flip dip switch #8 on the back panel to its non-default position
before the system will recognize the device.
CMS and MacCrate cases have dual DB-25 pin connectors on the back plates,
thus the cable you need is a DB-25 to DB-25. The AppleHive (AHive)
case from Tulin has dual Centronics-like 50-pin SCSI connectors and
thus the cable you need is a DB-25 to Centronics 50-pin (same as used
on the Apple hard drives).
To prepare a hard drive for use with the Apple SCSI card:
1 - Perform the low-level formatting using SCSI HACKER by Joe Jaworski
or HDFORMAT by Tim Grams.
2 - Use the HDSCPARTITION supplied on the Apple SCSI Interface Card
utilities disk to create the partitions. HDSCPARTITION was written
for a max drive size of 40 megs (Apple's own drive) so you will
be setting the partition info on the drive to 2 20 meg partitions.
3 - Use ADU (Advanced Disk Utilities) under GS/OS to alter the size of
the 2 20 meg partitions created by HDSCPARTITION to whatever is
appropriate for your drive. If you use a Seagate ST277N 65 meg
(unformatted size) drive, you can have 2 31 meg partitions.
4 - Use any ProDOS disk formatter to ProDOS-format the partitions.
Using the CMS SCSI Interface Card with a Seagate ST277N drive (including
CMS' own SD60 A2S drive) you can partition the first volume to 30 megs
and the second volume to 32 megs for a total of 62 useable megs - same
as if you use the Apple SCSI Interface Card (which allows 2 31 meg
volumes).
Seagate STxxxN SCSI drives use approximately 12.5 watts power. The fans in
most cases use next to nothing in terms of wattage. Thus a 30 watt
power supply or more is more than sufficient to power 1 or 2 Seagate
drives.
The most inexpensive enclosure you can purchase is a dual half-height
floppy drive case with power supply, starting at $50. Although not
very attractive, you can find these cases which are durable. For
example, Computer Shopper contains several vendors selling such cases
starting at $55, and a visit to any local Ken Gordon computer faire &
flea market can usually turn one or two up. Another alternative is to
use a computer case from a small footprint system, such as a Sanyo
case - more attractive and allows for greater drive expansion (usually
2-4 drives) but it has a slightly larger footprint. Then again, such
a case can usually be placed beneath an Apple //gs & help raise the
monitor up closer to eye level (better on the back and neck, as well as
the eyes).
Apple // SCSI chains allow up to 8 SCSI devices per chain, BUT the SCSI
Interface Card counts as one SCSI device. Thus, you can effectively
chain up to 7 devices off the SCSI Interface Card.
If you are using an Apple //gs and GS/OS, make sure you have the SCSI.DRIVER
in the /SYSTEM/DRIVERS folder.
Seagate STxxxN SCSI drives have auto-parking heads - turn the power OFF and
the heads are moved onto a landing zone. When you turn the hard drive
ON, you will hear noises indicating that the heads are being moved onto
the active disk surfaces from their parking zones. This is normal, so
do not panic... panic if you DON'T hear these noises!
What size drive to buy? First, what can you afford? Second, how much
storage do you currently need? This is comparatively easy to determine
simply by looking at what you currently have & use. (Remember, copy
protected games USUALLY won't allow you to move them entirely over to
a hard drive. See, I told you NOT to buy copy-protected software, but
did you listen? Nooooo!) Usually this will give you a fairly good
idea as to what your present needs are. But what about future storage
needs? This one is tough.
If you look at the Mac & MS-DOS worlds, you can get a fairly good
idea as to the future of software: the move is toward much larger &
more integrated packages requiring much more disk storage simply for
the program software, let alone data. You can see this trend in the
//gs world - look at AppleWorksGS & GS/OS and you see what I mean.
There are two simple options for immediate expansion capabilities:
Buy a larger hard drive than you currently need, or at least purchase
a case & power supply which will allow you to add additional drives as
needed. The second option is one I prefer since hard drive prices
continue to drop, but the first option makes sense if you don't go
over-board with it - the price per meg is lower for a 60 meg drive
than it is for a 20 or 40 meg drive (all else equal, such as brand,
speed, etc.). The last time I ran the calculations, two 60 meg drives
were cheaper than a single 120 meg drive, so the price per meg curve is
indeed bell-shaped. Bottom line - its up to YOU, but shop around since
prices not only change temporarily but also vary among vendors.
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