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Try to find another piece on eBay. You can set the "search watch" and then you will get a message when someone adds a suitable item. Sometimes you can find just "case" or "plastic". But be patient.


The earlier 704 also had a decrement part in the instruction, and the 7090 can emulate the 704, so one should look at the smaller instruction set of the 704 for reasons for this design decision. As the IBM 704 manual states on page 12, there are 5 "Type A" instructions which contain both a a decrement and an address field, namely TIX, TNX, TXH, TXL, TXI (...


Did any 360-compatible machine ever actually implement its registers with magnetic cores? Yes, of course, in fact, it was standard for low end machines. Beside IBM, as Ross Ridge details, many early compatible manufacturers did so. Examples are Sperry's Univac 9000 series, RCA's low end Spectra 70 models 15 and 25, or Siemens 4004/15.


Yes, for the IBM 360/30 at least the 16 32-bit registers (and 4 64-bit floating-point registers) were stored in the same core memory as the main memory. The IBM 360/30 used the IBM 2030 Processing Unit as it's CPU, and the IBM 2030 Processing Unit Field Theory of Operation manual states on the page 1-4 that "The sixteen general registers and the four ...


The fascinating thing to me is the way in which the media is a hybrid of a punched card and a floppy. It's more like a floppy - especially in its original version, the IBM 2321 Data Cell Drive of 1964 (see below). MagCards are a downscale from the 2321, which was, at its time the top end of random accessible online storage. They provide much larger storage ...


I'm not sure why you're calling it a "hybrid" — it clearly has nothing in common with a punched card, other than the approximate shape and size of the card, which may have been chosen to take advantage of the storage facilities that already existed for punched cards. It is clear from the video that there is a pair of counter-rotating drive wheels, ...

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