DiskCopy 4.2 format specification

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Revision as of 23:34, 12 October 2010 by Lord Nightmare (talk | contribs) (fix table)
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File format for Apple disk copy 4.2 definition, wiki version based on 0.99
by Jonathan Gevaryahu AKA Lord Nightmare
Much information comes from the CiderPress and MiniVmac source codes.
More authoritave information comes from http://www.nulib.com/library/FTN.e00005.htm
This is also used in DiskCopy 4.1. DiskCopy 6.3.3 uses a version with tags omitted.
DART is a variant which adds compression.
DC42 File format Overview
offset type/size contents
0x00 byte Length of image name string ('Pascal name length')
0x01-0x3f 63 bytes Image name, in ascii, padded with NULs
0x40-0x43 BE_UINT32 Data size in bytes (of block starting at 0x54)
0x44-0x47 BE_UINT32 Tag size in bytes (of block starting after end of Data block)
0x48-0x4B BE_UINT32 Data checksum
0x4c-0x4F BE_UINT32 Tag checksum
0x50 byte Disk encoding
0x51 byte Format Byte
0x52-0x53 BE_UINT16 '0x01 0x00' ('Private Word') AKA Magic Number
0x54-... variable Image data
...-EOF variable Tag data