3 ms·
I see. I never realized that machines needed to be random number of bits because they couldn't do double-precision so it was easier to make the word larger and
by AlienRobot 2y ago
I see. I never realized that machines needed to be random number of bits because they couldn't do double-precision so it was easier to make the word larger and do "half" precision instead.
Thanks a lot for your explanation, but does that mean "byte" is any amount of data that can be fetched in a given mode in such machines?
e.g. you have 6-bit, 9-bit, 12-bit, and 18-bit bytes in a 36-bit machine in sixth-word mode, quarter-word mode, third-word mode, and half-word mode, respectively? Which means in full-word mode the "byte" would be 36 bits?
- AnimalMuppet 2y agoI don't think so. In the "normal" world, you can't address anything smaller than a byte, and you can only address in increments of a byte. A "word" is usually the size of the integer registers in the CPU. So the 36-bit machine would have a word size of 36 bits, and either six-bit bytes or nine-bit bytes, depending on how it was configured. At least, if I understood all of this...
- Animats 2y agoOne PDP-10 operating system stored five 7-bit characters in one 36-bit word. This was back when memory cost a million dollars a megabyte in the 1970s.
- Animats 2y agoThe term "byte" was introduced by IBM at the launch of the IBM System/360 in 1964. [1], which event also introduced the term "throughput". IBM never used it officially in reference to their 36-bit machines. By 1969, IBM had discontinued selling their 36-bit machines. UNIVAC and DEC held onto 36 bits for several more decades, though. [1] https://www.ibm.com/history/system-360 https://www.ibm.com/history/system-360