Re: hard disk solution

[dempson@actrix.gen.nz (David Empson)]

In article <msg3433.838333356@leserveur.com>, 100041.1464@compuserve.com wrote:

>From: 100041.1464@compuserve.com (Stephan van Radecke)
>Subject: hard disk solution
>Date: Thu, 25 Jul 1996 21:37:49 GMT
>
>I'm searching for a hard drive solution for my IIe, which is supported
>by PRODOS and UCSD.

Two solutions come to mind.

1. A SCSI hard drive partitioned for ProDOS and Pascal, with Apple
   Pascal 1.3.  I have done this (briefly) with an Apple SCSI card.  The
   SCSI card must be in slot 4, 5 or 6, and you MUST use Pascal 1.3.  I
   also found that I had to disable my 5.25" drives to get it to work.

2. An Apple ProFile, with the Apple Pascal ProFile Manager software,
   and Apple Pascal 1.2 (1.3 will probably work).

In both cases, only one operating system can be booted from the hard
drive: whatever is on the first partition for a SCSI drive, must be ProDOS
for a ProFile (the Pascal area reserves space at the end of the ProFile,
and appears as an inaccessible file in the ProDOS directory).

Apple Pascal has at least one major limitation that causes problems when
using it with a hard drive: the directory structure is fixed (and doesn't
support subdirectories), and you can only have 77 files on a volume. 
(There is probably also a limit on the size of each file, and on the
volume size.  Another point to remember is that Pascal stores its files
contiguously, so large volumes will be very difficult to use.)

This means that you need to create a lot of small partitions, which is not
practical, and won't work in the case of a SCSI drive (Pascal will only
see the first two partitions).

Pascal ProFile Manager gets around this by subdividing the Pascal area
into seperate logical volumes.  You can mount selected volumes (a limited
number at the same time), and can create and delete entire volumes as
required, using an extended "crunch" operation to shuffle them around on
the disk as required.

There might be a Pascal device driver that provides a similar function on
a SCSI volume.


There are three main problems with the ProFile/PPM option: locating the
Pascal ProFile Manager software, getting hold a reliable ProFile (and
controller card), and the lack of space on a ProFile (5 MB).

In theory, the Pascal ProFile Manager software could be modifed to work
with other hard drives, but I have never investigated this.  It would
probably require reverse engineering of compiled Pascal programs and
disassembly of P-Code.  Not fun, especially without any tools.


There might be third-party drives (e.g. the Sider) which support Pascal
and ProDOS simultaneously, but I haven't had any experience of them.


> Which is the best and affordable, too. I heard of an IDE solution
> to use cheap IDE disks.

I would expect an IDE drive to be useable in the same manner as a SCSI
drive, given that it has a standard ProDOS block driver on the card, which
will be supported by Apple Pascal 1.3 in the same manner as an Apple SCSI
card.  Note that the IDE card would have to be in slot 4, 5 or 6 to be
recognised by Pascal.

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, NEW ZEALAND