Re: CBM900 hard disk timeout

From: Clockmeister <>
Date: Tue, 26 Aug 2014 11:59:26 +0800
Message-ID: <>
On 26/08/2014 11:47 AM, William Levak wrote:
> It's been a long time since I worked on drives like this.  There are 
> two kinds of format.  Normal high level format and low level format.  
> Low level format can sometimes be done from BIOS, but sometimes it was 
> done from a routine on floppy disk.  I remeber that at least some 
> Western Digital drives did the low level format from routine on floppy 
> disk.
> Most commands from the disk controller assume a low level format. If 
> the low level format is corrupted, it returns read errors.
> If the first sector on the disk is bad, nothing can be done.  If you 
> get read errors on sector 2, you can set sector 2 bad in the low level 
> format and bypas it.
> If you cannot do a low level format, you have mechanical or electrical 
> problems.
> There are utility programs that will read any sector on a hard drive 
> directly, ignoring the directory and partition tables. I don't have 
> one that works on SASI drives.

If there is a low level formatting program in the controller ROM it 
should be easy to find in the controller ROM dump with a hex editor.

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Received on 2014-08-26 05:00:03

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