RK

File Format
Name	RK
Ontology	Electronic File Formats Archiving RK
Extension(s)	.rk
Released	≤2000 (RK), 2004 (WinRK)

RK is a proprietary compressed archive format developed by RK Software (later M Software). It is the native format of RK Archiver. This article also covers the successor format and software, WinRK. The term "RK format" generally encompasses all formats that use the .rk file extension, including WinRK format, though this article may use it to refer specifically to the RK Archiver format.

RK is the successor of RKIVE (.rkv).

See also these related formats:

• RK Audio
• RK Image
• RKUC

Disambiguation

This has no connection to a different WinRK, which appears to be a UK-based database of ringers... of bells, probably?

Discussion

There are at least 5 significantly different archive file formats in the RKIVE/RK/WinRK series:

• RKIVE 1.0-1.1 (see RKIVE for the "RKIVE" formats)
• RKIVE 1.2-1.4
• RKIVE 1.92beta1 (Don't know if there are any other 1.9x versions.)
• RK 1.4.1alpha (There are earlier versions of RK; don't know what format they use.)
• WinRK (All versions? At least v1.1.3 to v3.1.2.)

Even within these classes, different versions are not necessarily compatible.

Identification

(This assumes the format is not RKIVE v1.92beta1 -- read RKIVE#Identification first.)

RK/WinRK archives end with a 2-byte signature: ASCII "RK". The three bytes preceding this signature contain version information, though for WinRK it's really just dummy information. The major version number is the low 6 bits of the 5th byte from the end of the file. It is 1 for RK, 2 for WinRK.

WinRK archives are observed to start with these 13 bytes: aa 04 00 00 00 00 ad bb da 04 00 00 00. They always end with 02 00 00 'R' 'K'.

For RK format, there is no header at the beginning of the file. The v1.4.1alpha version info bytes are 0x81 0x04 0x01. But there are earlier versions of RK which, even assuming they use this format variant, would have different version numbers.

Software

• RK v1.04.1 alpha for DOS
• RK v1.04.1 alpha for Windows (console)
• WinRK v1.1.3 (Windows GUI)
• WinRK v3.1.2 (32-bit) (Windows GUI)
• WinRK v3.1.2 (64-bit) (Windows GUI)
• RK Software downloads page (from archive.org)
• WinRK

Links

• RK Software (last Wayback Machine capture, 2004-12-16)
• M Software
  • RK Format