SSDs had origins in the 1950s with two similar technologies: magnetic core memory and card capacitor read-only store (CCROS).[12][13] These auxiliary memory units (as contemporaries called them) emerged during the era of vacuum-tube computers. But with the introduction of cheaper drum storage units their use ceased.[14]
Later, in the 1970s and 1980s, SSDs were implemented in semiconductor memory for early supercomputers of IBM, Amdahl and Cray;[15] however, the prohibitively high price of the built-to-order SSDs made them quite seldom used. In the late 1970s, General Instruments produced an electrically alterable ROM (EAROM) which operated somewhat like the later NAND flash memory. Unfortunately, a ten-year life was not achievable and many companies abandoned the technology.[16] In 1976 Dataram started selling a product called Bulk Core, which provided up to 2 MB of solid state storage compatible with Digital Equipment Corporation (DEC) and Data General (DG) computers.[17] In 1978, Texas Memory Systems introduced a 16 kilobyte RAM solid-state drive to be used by oil companies for seismic data acquisition.[18] The following year, StorageTek developed the first RAM solid-state drive.[19]
The Sharp PC-5000, introduced in 1983, used 128-kilobyte solid-state storage cartridges containing bubble memory.[20] In 1984 Tallgrass Technologies Corporation had a tape backup unit of 40 MB with a solid state 20 MB unit built in. The 20 MB unit could be used instead of a hard drive.[citation needed] In September 1986, Santa Clara Systems introduced BatRam, a 4 megabyte mass storage system expandable to 20 MB using 4 MB memory modules. The package included a rechargeable battery to preserve the memory chip contents when the array was not powered.[21] 1987 saw the entry of EMC Corporation (EMC) into the SSD market, with drives introduced for the mini-computer market. However, by 1993 EMC had exited the SSD market.[22][23]
Software-based RAM Disks were still used as of 2009 because they are an order of magnitude faster than other technology, though they consume CPU resources and cost much more on a per-GB basis