Driver for PC IDE hard disks on Atari
IDEPC is special hard disk driver
for Atari ST and compatible computers. Purpose is work with IDE
disks partitioned and formatted on PC computers. It can handle so
called DOS-16 partitions, what are partitions of max 32 MB, and
also BIGDOS partitions up to 2 GB. Program Bigdos from Reiner
Seitel is required for work with partitions larger than 32 MB.
You may download it at: Bigdos homepage .
And of course IDE
interface by Atari specification built in machine is required.
Falcon (and Milan ?) have it serial, but it's possible to build in
every ST and compatible.
I tested driver with couple Seagate, Quantum, Conner and Western
Digital drives, and I didn't observe problems. It worked fine
with drive of 3.2 GB. I tested with 'old' 8 MHz ST machine. Raw
transfer speed is around 250-300 KB/sec. Reason for so low speed
is required high/low byte swap in each word.
No special partitioning is
required. Driver recognizes and works with primary partitions -
it could be more than one primary (usual hidden) partition, and
with logical drives in extended partitions .
Max number of partitions is total 8 on 1 or 2 drive (master &
slave).
By my tests you need at least TOS 1.4 for correct work with
larger drives.
Instructions
and download - old version for old drives without LBA
New driver for LBA disks, CF cards - max 14 partitions, Falcon compatible.
Twisted
solution:
If you are not
satisfied with speed of software high/low swap, try hardware swap!
Fortunately no accelerator chips are required. Only thing to do
is twisting lines 3-18 on IDE cable for 180 degrees, like it is
on every floppy cable with lines 10-16. With this high/low bytes
are swapped, and disk can be accessed with full speed (~1.2 MB/sec
with every newer drive on 8 MHz ST). Of course special driver is required for this solution.
Note: you must make this line twist very carefully, and checking
reliability of contacts. By bad contact, data loss may occur even
with read only driver !
Slight drawback is around 5 sec additional delay after reboot
with TOS 2.06, and no autoboot (without ROM modification) - but
this is otherwise not possible with PC disks...
Download IDEPCTW.PRG - old CHS driver for 'hard' swap.
Copyright: Pera Putnik
Last revised: Aug. 2007