ShrinkIt

A NuFX archive is an archive file format that supports lossless data compression. It is usually given the file extension SHK; SDK may also be used to specify that the archive describes the entire contents of a disk.

ShrinkIt (named NuFX archive and file format)
Filename extension	.SHK (regular NuFX archives), .SDK (NuFX disk images)
Initial release	1987?
Latest release	1.0.6 (GS), 3.4 (Apple II) GS: 30 April 1992; 33 years ago (1992-04-30), A2: 24 January 1991; 34 years ago (1991-01-24)
Type of format	Data compression
Extended from	.BNY (Binary II envelope) .BQY (squeezed file in Binary II envelope) .BXY (NuFX in Binary II envelope)
Extended to	.SDK NuFX disk image

History

Andy E. Nicholas designed the format as an improved replacement for the Binary II (.BNY) format, adding compression. He introduced it alongside a pkzip-like program called ShrinkIt for Apple II systems, which he later migrated to the Apple IIGS as GS-Shrinkit.

The specification was republished by Apple in its File Type Notes.^[1]

See also

• Comparison of file archivers
• Comparison of archive formats
• List of archive formats
• LZW