Re: PCT newbie questions

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

In article <1993Jul01.180522.15191@edsi.plexus.COM> cranem@edsi.plexus.COM (Mike Crane) writes:
> Previously johnt@meaddata.com (John Townsend) wrote:
> >[1.4MB MS-DOS disks in a SuperDrive on its own card, with a PCT]
> 
> I've found that this works just fine as long as the disk is formatted on
> an IBM system.  The SuperDrive will then read and write them just fine.
> Unfortunately, the PCT software isn't particularly intelligent about
> formatting the things - I've had it work once and fail many times.

I have no trouble formatting 1.44MB disks in a SuperDrive from the
PCT, using MS-DOS 3.3 or MS-DOS 5.0.

720k disks will not format at all.  800k disks will, but you can't
boot from them (the PC's boot code doesn't seem to like "odd" disk
sizes).

Note: the SuperDrive is connected to its own card, and NOT to the PC
Transporter's drive connector.

The main problem with the SuperDrive and the PCT is that you must put a
disk of the size you intend to use into the SuperDrive BEFORE you
launch AEPC.SYSTEM (and eject it during the memory test, if you don't
want to boot from it).  AEPC.SYSTEM samples each ProDOS drive to
determine its size, so a disk of the correct type must be in the drive
for the PCT to be able to use it.  It probably has to be formatted,
but can be a ProDOS disk.

This also means you can't switch disk sizes while the PCT is active.
You have to quit to ProDOS, insert a disk of the appropriate size, and
restart AEPC.SYSTEM.

> Previously Herbert Fung wrote:
> >Well I never really got too much use out of my PCT. The most useful thing
> >about it was that I could use it as a ramdisk. Since you have a
> >SuperDrive card I'm assuming you have it in slot 5, so the GS's native
> >ramdisk is rendered inoperative, so RAMAEPC could be quite useful.
> 
> Actually, with the advent of the RAM5 driver in System 6.0.1 you *can*
> access the ramdisk while in GS/OS, even if the slot is set to "Your
> Card."

Unfortunately, I use RAM5 from ProDOS-8 rather a lot, so this doesn't
help me.  I have the SuperDrive card in slot 6, so I can still use
RAM5 and the Apple 3.5 drive connected to my drive port (better
software compatibility, e.g. with ZZCopy and FTA software).

> >As I understand it, you will be able to read MS-DOS disks straight from
> >your TransDrives with the MS-DOS FST in System 6.0.1. Since the MS-DOS
> >FST is read only, you can use the PCT to write to MS-DOS disks.
> 
> We could only hope that this would be true, but unfortunately, it's not.
> FST's only work while GS/OS is active; they don't work under P8 which is
> what the PC Transporter works with.  Now if some enterprising soul
> wants to disassemble and rewrite the PCT driver code to run under GS/OS
> instead of P8....

You are mistaken.  The PCT's "driver" is actually code loaded into the
PC Transporter to make it act as a standard ProDOS block device (with
SmartPort support).  GS/OS is able to access SmartPort devices by
generating a driver at boot time, if there isn't a specific driver for
the device on the system disk.

The PC Transporter has no ROM, hence it must be pre-loaded with the
device driver before PRODOS is loaded.  This is why the PCINSTALL
program patches the PRODOS file - the patch code installs the device
driver code into the PC Transporter, then returns control to the
original code.

For a ProDOS-8 boot disk, ProDOS then locates all the devices,
including the PC Transporter (which it sees as a SmartPort device
supporting the devices you specified in PCT.SWAP).

For a GS/OS boot disk, the PRODOS file kick-starts the GS/OS boot
sequence.  When the device drivers have been loaded, a driver is
automatically generated for all slots which don't have a loaded
driver.  GS/OS is quite able to use RAMAEPC and drives connected to
the PCT.  When you launch ProDOS-8, it sees the already-loaded
SmartPort code in the PC Transporter, and is quite happy to use it.


The problem with accessing MS-DOS disks from GS/OS via a PC
Transporter is that the SmartPort code loaded into the PC Transporter
doesn't support MFM disks in an Apple 3.5 Drive.  That feature is only
supported when the PC Transporter is running as a PC.

I don't have a 3.5" or 5.25" TransDrive, so I don't know if you can
access MFM disks in these drives while in GS/OS.  I expect you would
be able to in a 5.25" TransDrive (giving you access to 360k MS-DOS
disks) but possibly not in a 3.5" drive.
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand