PACKIT by MJP
From Just Solve the File Format Problem
- Not to be confused with PackIt.
PACKIT by MJP is the signature of an installer-archive format, used by:
- Offline Mail Executive (OMX), by SysTech Computer Services
- The Blue Wave Offline Mail Reader, by Cutting Edge Computing
Archives appear to be uncompressed, though it's possible that the format supports compression.
Contents |
Discussion
This format is rare, but documented here in part to distinguish it from similar formats.
The original author of OMX is Martin J. Pollard, more than likely the "MJP" in the signature.
In some archives, one of the member files (WELCOME!.000) is a ZIP file. This causes some unzip software to misleadingly behave as if the whole archive were this one member file.
Format details
[Unconfirmed information. Written for the fileformats.archiveteam.org wiki.]
Format of an archive:
- 16-byte signature
- Sequence of member files
- 2-byte trailer:
ff ff
Format of a member file:
- Two unknown bytes, observed to be
ff 00. - Two fields each containing the file size
- Timestamp
- CRC-32/JAMCRC
- Filename size
- Filename
- Unknown byte, observed to be
00. - File contents
Identification
Files start with ASCII "PACKIT by MJP", then bytes 0d 0a 1a.
Sample files
- OMX100.ZIP → INSTALL.DAT
- BW23_DOS.ZIP → BWAVEDOS.INS
- dexvert samples — archive/packItInstallationArchive
