In 1970, MOS memory chips were just becoming popular, but were still very expensive. Intel had released their first product the previous year, the 3101 RAM chip with 64 bits of storage.[1] For this chip (with enough storage to hold the word "aardvark") you'd pay $99.50. To avoid these astronomical prices, some computers used the cheaper alternative of shift register memory. Intel's 1405 shift register provided 512 bits of storage - 8 times as much as their RAM chip - at a significantly lower price. In a shift register memory, the bits go around and around in a circle, with one bit available at each step. The big disadvantage is that you need to wait for the bit you want to come around, which can take half a millisecond.
22.12.2014
