SCRE2B
SCRE2B is a DOS utility that converts an EXE file to a COM file that works the same.
It is a component of the SCRNCH v1.02 compression software by Graeme W. McRae. It is used by the included COMPRESS.BAT script.
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Discussion
SCRE2B is "high-tech", in that it does more than just strip off the EXE header.
The bulk of the generated COM file corresponds to the code image segment (refer to MS-DOS EXE#Special file positions) of the original EXE file. But the first 14 bytes are different. Following the copied code image segment is most of SCRE2B's boilerplate code.
If you use an executable decompression utility to decompress a SCRNCHed COM or EXE file, in some cases the result might be a COM file in SCRE2B format. Or, it might be such a file, but with an artificial EXE header added.
Identification
The first 10 bytes of a generated file are 8c da 01 16 0c 01 ff 2e 0a 01.
(As mentioned previously, there are plausible workflows in which this format may be put into an EXE container. In such a case, the 8c da... byte sequence apears at the start of the code image segment, usually at offset 32 or 512.)
The string "Program too big to fit in memory." appears toward the end of the file.
Software
- SCRE2B: Part of SCRNCH v1.02
- DeSCRE2B - DOS utility to undo SCRE2B
Sample files
- WHATPORT.ZIP → WHATPORT.COM (Valid but atypical file. SCRE2B has been applied twice.)
- Boston II → DOS/SOUND/MODDMA/MODDMA.COM (hacked file)
