CAR (MylesHi!)
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'''CAR''' is a compressed archive utility, and associated file format, developed by ''MylesHi! Software'' / Chris Campbell. | '''CAR''' is a compressed archive utility, and associated file format, developed by ''MylesHi! Software'' / Chris Campbell. | ||
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| + | == Self-extracting archives == | ||
| + | CAR has a feature to create self-extracting archives, in [[MS-DOS EXE|EXE]] format. The boilerplate part of such archives is pre-compressed with [[LZEXE]]. An embedded CAR archive is in the ''overlay'' segment (refer to [[MS-DOS EXE#Special file positions]]). | ||
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| + | Assuming v1.50 is the only version, identification of such files should be easy, as they're presumably all very similar. But due to the LZEXE compression, they don't have any nice plain-text signatures. A possible signature would be the bytes {{magic|43 41 52 20 53 65 6c d8 f0 6e 23 f8}} at offset 11256, containing remnants of the "CAR Self Extracting Archive" banner message. | ||
== Identification == | == Identification == | ||
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* {the byte value at offset 0} = {the byte value at offset 15} + 25 | * {the byte value at offset 0} = {the byte value at offset 15} + 25 | ||
* bytes {{magic|0x20 0x00 0x00}} appear at offset {{the byte value at offset 15} + 24} | * bytes {{magic|0x20 0x00 0x00}} appear at offset {{the byte value at offset 15} + 24} | ||
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| + | See also the ''Self-extracting archives'' section, elsewhere on this page. | ||
== Specifications == | == Specifications == | ||
Revision as of 13:58, 19 October 2023
CAR is a compressed archive utility, and associated file format, developed by MylesHi! Software / Chris Campbell.
Contents |
Self-extracting archives
CAR has a feature to create self-extracting archives, in EXE format. The boilerplate part of such archives is pre-compressed with LZEXE. An embedded CAR archive is in the overlay segment (refer to MS-DOS EXE#Special file positions).
Assuming v1.50 is the only version, identification of such files should be easy, as they're presumably all very similar. But due to the LZEXE compression, they don't have any nice plain-text signatures. A possible signature would be the bytes 43 41 52 20 53 65 6c d8 f0 6e 23 f8 at offset 11256, containing remnants of the "CAR Self Extracting Archive" banner message.
Identification
This applies to the CAR files produced by version 1.50, which was the first release, and the only one we know of.
CAR format is very similar to LHA format, but it has the header fields in a different order, making it completely incompatible. Unfortunately, it is difficult to reliably distinguish the formats, and maybe impossible to do with perfect accuracy.
A CAR file has the following properties (but so do some valid LHA files):
- ASCII "
-lh5-" or "-lh0-" appears at offset 2 - {the byte value at offset 0} = {the byte value at offset 15} + 25
- bytes
0x20 0x00 0x00appear at offset {{the byte value at offset 15} + 24}
See also the Self-extracting archives section, elsewhere on this page.
Specifications
- car150.zip → CAR.DOC → Appendix G -- CAR technical information
