Thread View: net.micro.cpm
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Started by prindle
Wed, 29 Oct 1986 19:35
Query on CP/M disk formats
Author: prindle
Date: Wed, 29 Oct 1986 19:35
Date: Wed, 29 Oct 1986 19:35
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1519 bytes
The Digital Research documentation on CP/M would seem to indicate that these are the variables (the BDOS cares about) among different 5.25" MFM diskette formats: . physical sector size . number of physical sectors per track . number of tracks on diskette . allocation unit size . number of directory entries . number of reserved system tracks . number of checksummed directory entries Furthermore, the BIOS will undoubtedly need these facts: . origin of physical sector numbering on each track (0 or 1) . track numbering philosophy of physical sectors on a double sided disk: - both sides considered one track - even tracks on side 0, odd tracks on side 1 - first half of tracks on side 0, second half on side 1 - something even more bizarre Are there any other parameters which are necessary to describe diskette formats? For example, are there variations within the format of a physical sector itself (number of syncs between header and data, checksumming technique, etc)? Thanks in advance, Frank Prindle Prindle@NADC.arpa
Re: Query on CP/M disk formats
Author: Michael Kersenbrock
Date: Fri, 31 Oct 1986 05:17
Date: Fri, 31 Oct 1986 05:17
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There also is the interleave factor (physical to logical sector number mapping) that will vary from disk to disk. -- Mike Kersenbrock Tektronix Computer Aided Software Engineering Aloha, Oregon
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