Re: Pet 8088 coprocessor board for sale on Ebay

From: Marko Mäkelä <msmakela_at_gmail.com>
Date: Mon, 17 Jan 2011 21:04:51 +0200
Message-ID: <20110117190451.GA2637@x60s>
Hi Michał,

On Mon, Jan 17, 2011 at 06:42:43PM +0100, Michał Pleban wrote:
>If you look at the D80 file with a hex editor, you will see the FAT
>table starting at $0100, then FAT copy starting at $0300, then MS-DOS
>directory starting at $0500. Looking at the FAT contents and file sizes,
>I conclude that FAT clusters are of 2 kB size. But I can't quite figure
>out which physical sectors correspond to FAT clusters. There are some
>strange one, two or three-sector gaps filled with 00, and I can't
>comprehend that.

This sounds like the Commodore CP/M disk format, which (in the C64 Z80 
cartridge or in the C128 or both) reserve a fixed number of sectors per 
track. A long time ago, I implemented support for the Commodore 128 CP/M 
disk format in cbmconvert. You might find that useful.

>BTW, yes, I took the D80 file I got from Ed Shockley, and I put in onto 
>a diskette to make a bootable disk. I did it with cbmlink, there were 
>no problems with that.

cbmlink just copies disk images sector by sector, doing nothing fancy.  
It steps to the next track when it gets an 'illegal track or sector' 
error.

Best regards,

	Marko

       Message was sent through the cbm-hackers mailing list
Received on 2011-01-17 20:00:08

Archive generated by hypermail 2.2.0.