HP 21MX M-Series

The M-Series machines were the first in the 21-MX Series (although they were not referred to as the M-Series until after the introduction of the E-Series in 1976). The first two models were the 2105A (priced at $4150) and the 2108A (priced at $5300), introduced early in 1974. These computers were followed by the 2112A (priced at $6200) later in the year. All of the machines incorporated the new semiconductor memory. The new RAM technology enabled the computers to feature much larger memory than was available on the old 2100 computers. Maximum memory capacity for the 2105A, 2108A and 2112A within the mainframe was respectively 64 KB, 640 KB and 1.2 MB.