Buying a hard drive in the early '90s was a traumatic process for some users, and outright impossible for the majority. The idea of investing hundreds of dollars just to gain access to a handful of megabytes never quite sat well, but everyone needed more space, and that gave rise to some very interesting solutions. In the Mac universe, two stood out: the compression software DiskDoubler and the accelerator card DoubleUp.
MS-DOS users fondly remember the DoubleSpace and DriveSpace tools, not only for their promises of freeing up space on our disks through compression, but also for the problems they carried (data loss and massive memory consumption at the top of the list). Why did we take the risk? Simple: hard drive prices struck genuine terror into our hearts. As a reference, a portable 20 MB hard drive cost more than $1,300 in the mid-1980s (more than $3,500 adjusted for inflation), and internal models weren't far off.
Mac users were not immune to this. Colin of the YouTube channel This Does Not Compute explains that an average Mac system came with a 40 MB disk in the early '90s, enough for casual tasks but not for high-productivity environments. Applications like StuffIt and PackIt quickly gained popularity; however, in 1990 an alternative called DiskDoubler appeared, followed by a dedicated card, DoubleUp.
DiskDoubler + DoubleUp: Mac disk compression that DOS envied (for a while)
DiskDoubler was the creation of Terry Morse and Lloyd Chambers. After unsuccessfully approaching Symantec to speed up its commercialization, the two received $25,000 from Guy Kawasaki (one of Apple's early "evangelists") and founded Salient Software. Within a few months, DiskDoubler's popularity exploded thanks to its ease of use (everything needed to compress and decompress was inside a menu in the Finder) and a much more reasonable price (barely $60 against $300-400 for a hard drive).
The most important extension for DiskDoubler was AutoDoubler, which essentially eliminated the manual factor, enabling compression and decompression of files "on the fly" in the background. Salient also offered a free decompressor for users who received compressed files, but there was still room for optimization: performance. That brings us to the DoubleUp card from Sigma Desgins, a hardware accelerator for DiskDoubler and AutoDoubler. The 9703 chip from Stac Electronics took care of fully relieving the processor and handling all compression and decompression tasks.
The result? A performance increase ranging between 200 and 300 percent. Purchasing the package consisting of the card and DiskDoubler was still a reasonable option, with a price under $200. However, Salient and DiskDoubler's story ends with their acquisition by Fifth Generation Systems in 1992, which in turn was bought by Symantec in October 1993. Symantec never expressed interest in the technology beyond a few promotional bundles, and the market did the rest: hard drives multiplied their capacity and prices plummeted, making dedicated compression solutions obsolete.
