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DiskDoubler 4.0 Plus Autodoubler, DD Expand & DiskTester

Your rating: None Average: 3.9 (8 votes)
Year released:


[www].se [ftp].se [mirror].us [mirror].de
diskdoublertm-4-sit.bin (352.25 KB)
MD5: ddfad526576f0ac03cd5d181e3fdd944
For System 7.0 - 7.6 - Mac OS 9
[www].se [ftp].se [mirror].us [mirror].de
DiskDoubler_Pro_4.1.sit_.hqx (1.02 MB)
MD5: 2ccc3a54b9d58755d6d809bcbeff8467
For System 7.0 - 7.6 - Mac OS 9
This app works with: SheepShaver, Basilisk II, Mini vMac

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.


2nd DL added is the last version (4.1) of DiskDoubler.

Architecture: 68k PPC

Mac OS 7.x.x - 9.2.2


MadMac's picture
by MadMac - 2010, October 3 - 5:15am

At that time (mids 90s), storing encrypted data files in a diskette was really a russian roulette. Of course is totally safe if you only compress archives and use the right kind of support to store them (usb-cds-dvd-HDs). The encryption system used by diskdoubler was some of the first of this kind, and well, today not even stuffit can keep a password for a file.

bertyboy's picture
by bertyboy - 2010, October 2 - 9:39pm

About to compress files with DiskDoubler, in the case you have a compressed and password encryted file that gets corrupted, forget about it.

I think what you're trying to say is that it's like playing rrussian roulette with your data, with an automatic pistol. I remember the awful press these got in MacUser when it wasn't able to decompress users files, and if the disk had issues (and they did then) forget about Norton or DiskWarrior scavenging your files.

I remember vivdly how we got by with 40MB or less of disk (I still have 35MB in my SE). This suite of software was a very attractive proposition, but after the issues made MacUser, I always found the funds for more disk instead.

MadMac's picture
by MadMac - 2010, September 2 - 6:42am

Vitoarc, if i tell you how i get this program, ill probably lie. But yes, it will save precious disk space.

There is a special warning about the Autodoubler, because it works compressing internal resources and some compressed resources in a control panel-program or extensions (specially the ones in 68k code only) will work like crap or not work at all under PPC Processors.

If you re familiar with the use of ResEdit, you know what a compressed resource is.
I suggest to test every program/control panel or extension you compress first via previous backup.

FAT binary seems to not be affected.

This strange behaviour has been observed in a MacOS 8.1 - Performa 6320CD - PPC 603e 120MHhz - 1.2GB Hd HFS+.

About to compress files with DiskDoubler, in the case you have a compressed and password encryted file that gets corrupted, forget about it.
DiskDoubler runs a checksum on this files, and if it dont macht, will not decompress.

Vitoarc's picture
by Vitoarc - 2010, September 1 - 6:42pm

What a great upload this is! I remember back when, this program really cost some $$$ so I never bought it even though I really wanted it. This will do wonders for my 700MB HD. Smile

MadMac's picture
by MadMac - 2010, August 18 - 3:39am

Yeap, and you were not the only one, i was checking the web looking for this, then i think... maybe i need to scavenge my old LClll backup disk, and there it was! Symantec make a real mistake leaving this app out of bussiness.

themacmeister's picture
by themacmeister - 2010, August 16 - 11:06am

I spent ages just finding the DD Expand app recently (HOURS!), but this post is superb. I trust that these are all 4.0 versions. Many thanks indeed!