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Why did IBM decide to use 8 bits for EBCDIC? Because the /360 ISA defined a byte to consist of 8 bits - which in turn was chosen as it allows to store two decimal numerals (BCD) within a byte. 7 bits per character seems reasonable, since 2^7 = 128 symbols which is enough for all English letters and special symbols. For one, there is not just English - a ...


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CTSS at MIT was one of the first timesharing systems ever built. It ran on a modified IBM 7094 mainframe. This is from the 1963-1966 time frame. Memory protection was extremely primitive. There were two banks of memory, one for the system and the other for the current user. The user program could only clobber its own memory. Users could develop programs ...


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Most large System/360 and System/370 installations were multiuser. I never saw a University whose S/360 or S/370 was not multiuser, and I never worked on a machine larger than a 360/50I that was not multiuser. CP-67, TSO and VM were common, to say nothing of the services running multi-user APL software. As for single threading command interpretation, that ...


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