Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!mcvax!ukc!dcl-cs!bath63!pes From: pes@ux63.bath.ac.uk (Paul Smee) Newsgroups: comp.sys.atari.st Subject: IBM disks... Message-ID: <1372@bath63.ux63.bath.ac.uk> Date: Mon, 29-Jun-87 16:50:35 EDT Article-I.D.: bath63.1372 Posted: Mon Jun 29 16:50:35 1987 Date-Received: Sat, 4-Jul-87 17:44:46 EDT Reply-To: pes@ux63.bath.ac.uk (Paul Smee) Distribution: world Organization: AUCC c/o University of Bath Lines: 29 Well, at long last we've got a 3.5 inch drive for one of our IBM/PCs. I've determined the following.. Using a disk formatted on the IBM, you can write files on the IBM to be read by the ST, and you can write files on the ST to be read by the IBM. At least as far as I tried it, you can 'mix and match'. That is, you can write some files on the IBM, add some more on the ST, add some more on the IBM, and so on, and everything works. (Though NOTE, keeping Moshe's comments in mind, so far I've only tryed playing with files on the ROOT of the disk. Haven't tried folders/subdirectories. As an experiment, I tried putting some files (on the ST) onto a STANDARD ST formatted disk (formatted from the desktop menu command). As rumoured, the PC could not cope with this disk. However, our PC guru determined that by patching 4 bytes in the disk header, the disk could be made to work on the PC. These were (all values in HEX): offset in boot sector (sector 0) change 00 from 00 to EB 01 from 00 to 34 02 from 4E to 90 36 from 4E to FA (Again, note that's 36 HEX.) The first 3 bytes are a JUMP instruction for an 8086 family micro. It is possible that this change might mean you could not BOOT from this disk on the ST. Byte 36 is the 'media description byte' for a 720K (formatted) disk. A different value is probably required if you are using a single sided disk (we tried DS). The Atari can happily read the patched disk. Cheers, Paul