DiskDoubler (DD) is a data compression utility for compressing files
on the Apple Macintosh platform.
Unlike most such programs, which compress numerous files into a single
archive for transmission, DiskDoubler was intended to compress single
files "in place" to save space on the drive. When such a file was
opened, DiskDoubler would decompress the file before handing it off to
the application for use. A later addition, AutoDoubler, added
background compression, finding and compressing files automatically
when the computer was idle.
DiskDoubler was created by Terry Morse and Lloyd Chambers, fellow
employees at a small software firm that went out of business in 1989.
Chambers had already released a version of the Unix Compress utility
on the Mac as MacCompress, and while working on another "real"
project, Chambers wrote DiskDoubler in his spare time. When
demonstrating their new product at a local Mac store, they noticed
that it was DiskDoubler that got all of the attention. It was first
shown publicly at the San Francisco MacWorld Expo in April 1990
(normally in January, but delayed that year) and by the end of the
show had sold 500 copies. By the summer they were selling 1000 copies
a month.
Realizing they needed real marketing muscle, they approached Symantec,
who agreed to include it in their Symantec Utilities for Macintosh
(SUM) package for a pittance. Unimpressed by the offer, they instead
asked Guy Kawasaki to front them a $25,000 development loan, raised a
similar amount on their own, and formed Salient Software. After four
months sales were over $50,000 a month. When Mac OS 7 shipped in June
1991 sales took off, as the new system was rather hungry for drive
space. The company was eventually sold to Fifth Generation Systems in
1992. They also repackaged it in a suite as SuperDoubler 4.0,
including AutoDoubler, DiskDoubler, and a file-copy speedup known as
CopyDoubler. For some time, DiskDoubler was the second-best selling
product on the Mac, second only to After Dark, the popular screen
saver. Fifth Generation was later sold, somewhat ironically, to
Symantec, who re-released it as a fat binary as Norton DiskDoubler Pro
1.1. Symantec "sat" on the product and it slowly disappeared over the
next year.
(Wikipedia.org)
2nd DL added is the last version (4.1) of DiskDoubler.
