Re: PCT newbie questions

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

In article <20mqgd$26r@meaddata.meaddata.com> johnt@meaddata.com (John Townsend) writes:
> I've just bought a used PCT and am in the process of configuring it
> for my IIgs system.  My IIgs has Apple 3.5" FDHD drives on a
> SuperDrive controller and hopefully soon an AppleCD SC drive on a
> RamFAST controller.  Can I use the FDHD drives with the PCT to read
> and write 1.4MB MS-DOS disks?

Yes.  I have a PCT and a SuperDrive (which is connected to its own
controller card).  The PC Transporter is configured to use the
SuperDrive as A: (ProDOS drive, slot 6 drive 1 in my case).

There are two major catches, and one minor one:

1. The PC Transporter polls ProDOS drives at startup to find out how
many blocks are on the disk.  It then uses this information to work
out what mapping to use for the PC's track/sector/head numbers to
ProDOS block numbers.

Because this information is sampled once, it means you are stuck using
one size of disk (1.44MB or 720k) during the PC session.  If you want
to use a disk of the other size, you must quit all the way back to
ProDOS, and launch AEPC.SYSTEM again.  It isn't sufficient to reboot
the PC Transporter, because the disk size is sampled when AEPC.SYSTEM
is loaded.

You must also make sure that a disk of the appropriate size is placed
in the drive while starting AEPC.SYSTEM, and then eject it before the
PC Transporter tries to boot from the drive.

2. The SuperDrive cannot format a 720k disk.  If you try to format a
low density disk, it will be physically formatted at 800k, and the PC
will write utter rubbish in the boot sector, making the disk unusable
until you reformat it.  The SuperDrive is quite happy to read and write
720k disks, though, so you can format them on a real PC and use them on
the PCT.

3. Watch out for disks formatted on a real PC.  These will usually
have a 1:1 physical interleave.  The SuperDrive has built-in track
caching for read operations, so there is no problem reading the disks,
but writing to them is EXTREMELY slow - it takes at least 9 times longer
to write to a disk formatted at 1:1 instead of 2:1.

Whenever I get a box of "pre-formatted" MS-DOS disks, I always
reformat them using the PC Transporter so that they have a 2:1
interleave.  This doesn't seem to affect their use on a normal PC.


You must be running MS-DOS 3.3 or later to support 1.44 MB disks.

> Will I be able to run MS-DOS applications from CD-ROM?

I don't know.  MS-DOS CD-ROM drives usually use a device driver, and
this wouldn't work with the PC Transporter.

> And by the way, what's your "top 10 list" of things to do with a PCT
> (besides getting the lights on your extended keyboard to work!)?

I mainly use it to transfer files to MS-DOS format (I can read files
from MS-DOS disks under GS/OS, but can't go in the other direction yet.

On rare occasions, I use it to continue work that I've brought home.
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand