RED (Knowledge Dynamics)
| Line 2: | Line 2: | ||
|formattype=electronic | |formattype=electronic | ||
|subcat=Archiving | |subcat=Archiving | ||
| − | |extensions={{ext|red}}, {{ext|lif}}, others | + | |extensions={{ext|red}}, {{ext|lif}}, {{ext|001}}, ..., others |
}} | }} | ||
'''.RED''' is an installer-archive format, apparently associated with ''INSTALL'' for DOS, and maybe other software from Knowledge Dynamics Corporation (of Canyon Lake, Texas, later San Antonio). | '''.RED''' is an installer-archive format, apparently associated with ''INSTALL'' for DOS, and maybe other software from Knowledge Dynamics Corporation (of Canyon Lake, Texas, later San Antonio). | ||
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''[This section contains unofficial information based on reverse engineering. It was written for the fileformats.archiveteam.org wiki.]'' | ''[This section contains unofficial information based on reverse engineering. It was written for the fileformats.archiveteam.org wiki.]'' | ||
| − | A RED archive is a sequence of member file structures, each with the following fields | + | A RED archive is a sequence of member file structures, each with the following fields. If a file is split over multiple volumes, each fragment has a header. |
{| class="wikitable" | {| class="wikitable" | ||
| Line 26: | Line 26: | ||
|4 || 4 || [[MS-DOS date/time|DOS time, date]] | |4 || 4 || [[MS-DOS date/time|DOS time, date]] | ||
|- | |- | ||
| − | |8 || 4 || Compressed size | + | |8 || 4 || Compressed size (of this fragment, for split files) |
|- | |- | ||
|12 || 4 || Decompressed size | |12 || 4 || Decompressed size | ||
| Line 34: | Line 34: | ||
|18 || 2 || CRC of decompressed data | |18 || 2 || CRC of decompressed data | ||
|- | |- | ||
| − | |20 || 2 || | + | |20 || 2 || Fragment number, if the file is split over multiple volumes. The first fragment is 1. This field is 0 for files that are not split. |
|- | |- | ||
| − | |22 || 2 || "Is last | + | |22 || 2 || "Is last fragment" flag. This field is 1 for files that are not split. |
|- | |- | ||
| − | |24 || 2 || Compression scheme. 1 is uncompressed. See below for scheme 11. | + | |24 || 2 || Compression scheme. Two schemes are known to exist. 1 is uncompressed. See below for scheme 11. |
|- | |- | ||
|26 || 13 || Filename | |26 || 13 || Filename | ||
| Line 48: | Line 48: | ||
=== Compression === | === Compression === | ||
| − | Compression scheme 11 compresses the data with [[LHA]]'s "lh5" scheme, then segments it. The compressed data is split into segments of 4094 bytes (fewer for the last segment), and a two-byte CRC (of the compressed data in the segment) is inserted at the end of each segment. | + | Compression scheme 11 compresses the data with [[LHA]]'s "lh5" scheme, then segments it. The compressed data is split into segments of 4094 bytes (fewer for the last segment of each file or fragment), and a two-byte CRC (of the compressed data in the segment) is inserted at the end of each segment. |
=== CRC === | === CRC === | ||
Latest revision as of 16:56, 19 February 2026
.RED is an installer-archive format, apparently associated with INSTALL for DOS, and maybe other software from Knowledge Dynamics Corporation (of Canyon Lake, Texas, later San Antonio).
The identifier "RED" is probably derived from "Reduce", which is the name of a software component and a proprietary compression algorithm.
See also LIF (Knowledge Dynamics), the presumed predecessor format.
Contents |
[edit] Format details
[This section contains unofficial information based on reverse engineering. It was written for the fileformats.archiveteam.org wiki.]
A RED archive is a sequence of member file structures, each with the following fields. If a file is split over multiple volumes, each fragment has a header.
| Offset | Size | Description |
|---|---|---|
| 0 | 2 | Signature: ASCII "RR"
|
| 2 | 1 | Unknown, always 0x01. |
| 3 | 1 | Header size, from the start of the RR signature. Always(?) 41.
|
| 4 | 4 | DOS time, date |
| 8 | 4 | Compressed size (of this fragment, for split files) |
| 12 | 4 | Decompressed size |
| 16 | 2 | Probably reserved for CRC of compressed data, but none of the known compression schemes use it. |
| 18 | 2 | CRC of decompressed data |
| 20 | 2 | Fragment number, if the file is split over multiple volumes. The first fragment is 1. This field is 0 for files that are not split. |
| 22 | 2 | "Is last fragment" flag. This field is 1 for files that are not split. |
| 24 | 2 | Compression scheme. Two schemes are known to exist. 1 is uncompressed. See below for scheme 11. |
| 26 | 13 | Filename |
| 39 | 2 | CRC of header, excluding the signature and this field. |
| 41 | ... | Compressed data |
[edit] Compression
Compression scheme 11 compresses the data with LHA's "lh5" scheme, then segments it. The compressed data is split into segments of 4094 bytes (fewer for the last segment of each file or fragment), and a two-byte CRC (of the compressed data in the segment) is inserted at the end of each segment.
[edit] CRC
The CRC algorithm is CRC-16/IBM-3740. Though RED is mainly a little-endian format, some of the CRC fields use big-endian byte order.
[edit] Identification
RED files apparently start with bytes 'R' 'R' 0x01 0x29.
[edit] Software
- Reduce - INSTALL Format Librarian (An interactive DOS utility)
[edit] Sample files
- BBS Software Directory: PCBOARD → pcb153-*.zip → ...
- dexvert samples — archive/redArchive
