RED (Knowledge Dynamics)

File Format
Name	RED (Knowledge Dynamics)
Ontology	Electronic File Formats Archiving RED (Knowledge Dynamics)
Extension(s)	.red, .lif, .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).

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.

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

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.

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.

Identification

RED files apparently start with bytes 'R' 'R' 0x01 0x29.

Software

• Reduce - INSTALL Format Librarian (An interactive DOS utility)
  • Reduce v3.20.02: [1]
  • Reduce v3.20.04: [2]
  • Reduce v3.31: [3]

Sample files

• BBS Software Directory: PCBOARD → pcb153-*.zip → ...
• dexvert samples — archive/redArchive

Links

• INSTALL website (1999 archive)