Re: System 601 Q

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

In article <22nd4u$4dk@wraith.cs.uow.edu.au> david@wraith.cs.uow.edu.au (David E A Wilson) writes:
> 
> Cirtech's SCSI card allows you to assign a chunk of your ProDOS volume to
> Pascal (16MB max for Pascal). I use this and it works well (similarly for
> DOS 3.3 and CP/M).

Back in the good old days, Apple had a utility program which let you
do this, called the Pascal ProFile manager.  It only supported the
ProFile hard drive (a whopping 5 megabytes).  I think it came out at
the same time as Pascal 1.2.

It works by creating a large file called PASCAL.AREA on your ProDOS
volume.  The PASCAL.AREA file sits at the end of the partition
(highest block numbers in ProDOS), has a special ProDOS storage type,
and must be linearly allocated (it has no index blocks).

The Pascal ProFile Manager then supports subdividing this Pascal Area
into multiple volumes, and "mounting" them as required.  You can even
"Krunch" the volumes and create and delete them as required.

There was one limitation: you can't boot from a Pascal Area, since it
is accessed through a device driver which Pascal loads at the end of
the startup sequence.  This means you need a dedicated boot disk
(either your first SCSI partition or a floppy).

Unfortunately, PPM seems to have disappeared.  I have unearthed a
copy, but it really does only support a ProFile.  I should think it
would be possible to modify it to support a SCSI device, but without
the source code, this would mean disassembling a Pascal device driver.

Pascal 1.3 also seems to have trouble with SCSI cards (at least, the
Apple High-Speed SCSI card).  On my system, I can only get Pascal to
work if either the 5.25" drive or SCSI drive is swapped out of the
slots.  If both are available, Pascal hangs during boot.

> If you have an Apple or RAMFast SCSI card you could, if you were prepared
> to boot Pascal 1.3 from a 3.5" floppy make the 2nd partition on your hard
> disk a Pascal partition (Pascal 1.3 can only see the first two partitions
> on a SCSI card [which must be in slot 4, 5 or 6]). Again, Pascal can only
> use up to 16MB (it must use 16 bit signed block numbers).

You wouldn't achieve much by having a 16MB Pascal partition.  Pascal
supports 77 files per disk, and no subdirectoroes.  Anyone for 77 200k
files?  :-)

This really only becomes practical if you can subdivide a partition
into multiple Pascal volumes (it is possible to do this with a simple
device driver, which supports booting from the first "division").
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand