19 Apr
2004
19 Apr
'04
11:30 p.m.
Hi Steve,
The 1050 uses the "standard" Atari 9 volt AC
wall-wart that also powers the
early computers (400 / 800). It was a 31 Watt unit. They came out with a
"beefier" unit later, but for the 1050 the earlier one is fine. As such
polarity is a non-issue. If you plug the unit in without a computer
connected and power it up, the LED on the drive will come ON and you can
hear the spindle motor turn ON and hear the head stepper motor "seeking"
track zero, and then the LED goes out and the spindle and stepper motors
stop.
Last night, I took the drive apart and checked it out (all looks good), I
could see a rectifier on the input, so I concur that it is AC.
I cobbled together a 9V ac supply and powered it up - I did observe exactly
what you indicate, the drive comes on, spins, and the head steps out and back
from and to track zero.
The software that came with the 1050 only made it a
"dual density" as they
called it drive. It actually provided 1.5 times the capacity. Later 3rd
parity software provided actual "double density" performance. The disks are
not IBM compatible. I could probably find a disk for you if I look hard
enough.
Your last question is kind of a "trick" question. On Ebay you can
buy a SIO2PC cable that will allow your PC to emulate an Atari disk drive,
and there are "images" that can be downloaded to do this function.
The Atari disk drives contain a "micro-computer" system (6502 based) that
talks to the floppy disk controller and interfaces to the Atari computer
over a 19.2 KBaud serial data link. You can send commands directly to the
drives (without DOS) to do "primates" like Format a disk, and data sector
puts / gets. I hope this helps.
If I connect the drive to a computer, I observed the following:
With not disk in the drive, the computer rapidly issues "Boot error" messages
continuously, and the drive remains stopped.
With a disk in the drive (not an Aari disk), the drive activates, and the
computer issues "Boot error" much more slowly - clearly it is trying to read
the unformatted disk.
So - I think the drive is working.
I was unable to find any way to get the system up with the drive connected,
so I don't see how there could be DOS in ROM as some people have suggested.
Any ideas? Is it possible to do anything with the disk without a DOS boot
disk.
This sounds like a very simiar arrangement to the C64 1541 drive, except
that the commodore boots "normally" in BASIC and you can send commands to the
drive via BASIC file operations - the Atari appears to want to boot from the
drive before you can do anything.
I'm planning to build a SIO2PC cable as soon as I can dig up an extra Atari
peripheral cable.
Regards,
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Vintage computing equipment collector.