Re: SCSI Hard Disk Questions

[pubpc1@library.ucla.edu]

Brian Campbell <campbelb@agcs.com> wrote:
>I already checked the A2 FAQ (at least the one I have), and need
>more information.  Any help please?

I'll give it a shot, since I've posted SCSI questions myself.


>I'd like to have multiple hard disks attached to my GS, at least
>temporarily.  They are both SCSI drives attached to an Apple SCSI
>card.  Is there any limit to the number of ProDOS partitions
>that GS/OS can see?  I thought that there was a max of four,
>but apparently not, as the Advanced Disk Utility permitted
>me to create 5 partitions, and GS/OS saw all 5 on my new disk.

Well, if it is an Apple High Speed SCSI card, then you are in
luck.  This Apple card can support 256 volumes.  GS/OS itself
has a limit of 64 volumes online at once, or something.  It
does not matter if the partition is ProDOS or HFS, it will
show up in GS/OS programs if under the GS/OS limit.

Under ProDOS 8, you will see 14 of these volumes.  ProDOS 8
version 2.0.3 will remap the volumes to other slots.


>I've partitioned and initialized the new Drive, installed
>GS/OS and and verified that I can boot from it.  So it seems
>to be fine.  My old drive has 4 partitions.  My new drive has 5.
>Now I'd like to daisy chain the two drives, and copy
>all my other files from the old to the new.

It should work fine.  Only RamFAST SCSI cards have a limit
of 12 volumes showing up at once (on that card, you pick and
chose which volumes show up if you have more).


>OK, now for the questions:
>
>1. Will GS/OS really recognize all nine partitions at once?
>Without any restrictions or risks?  Does GS/OS have an upper limit?
>I'll need to acquire a new cable to make this work.
>They all have unique names so there should be no name
>conflicts.  I know that ProDos 8 is only capable of recognizing
>only the first 2 partitions (w/o that Slot 5 business),
>so that is where I keep my 8-bit specific software.

Yes, GS/OS has no trouble recoginizing all nine partitions at
once.  There are no restrictions or risks.  GS/OS has an
upper limit of 64 volumes, I believe.

The ProDOS 8 that came with System 6.0.1 will recognize 14
volumes online at once.  The feature is not limited to slot 5.


>2. Both disks appear to be internally terminated, as they both
>appear to work fine individually where they and the SCSI card
>are the only things on the chain.  I know I that I orderered
>the old drive internally terminated, and the new drive I'm
>not sure. (There appear to be termination resistors soldered
>inside on the drive's circuit board, but they could be something
>else).  But they both have dual plug-ins to support daisy chaining.
>Will they daisy chain OK, as is, or will I need to remove internal
>termination on one of the drives?

You'll need to remove the termination on one drive.  The
resistor packs are most likely not soldered in, although they
look that way.  They are SIPPs (single inline pin packages)
and actually have little single row pins that plug into tiny
machined holes and end up flush with the circuit board.  Just
take a pair of needle nose pliers and carefully extract both
resistors on the drive you are placing first in your chain.


>For the record here is what I have:
>
>IIGS Rom 1.
>1.25 Megs of Memory.
>GS/OS 5.0.4
>Apple's High Speed SCSI card in Slot 7
>Old Drive: Tulin Hermit Crab 120 Meg
>New Drive: Quantum ProDrive LPS 170 Meg

I don't know if System 5.0.4 will support so many volumes.
I suspect that it does (support 64 volumes) in desktop software,
but does not (support 14 volumes) under ProDOS 8.


>I just realized that my CPU is 10 yrs old almost to the day.
>Even though it is a decade old, I still want
>to keep it.  Thanks in advance for any advice.

It is still a fine machine.  Get System 6.0.1 for it sometime.
It is free and is newer and more powerful than System 5.0.4.
You can, for example, use HFS volumes and make your new 170MB
drive into two 85MB volumes instead of five 32MB ProDOS ones.

If you want to get the most out of System 6.0.1, also consider
more memory.  Four to eight megabytes is ideal and you can use
surplus 1MB SIMMs to populate the GS if you have the right
memory board (see http://www.allelec.com/).

-Scott G.