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The IBM 650 Magnetic Drum Data-Processing Machine is one of IBM’s early computers, and the world’s first mass-produced computer.〔(IBM Archives: IBM 650 installation with IBM 727 Magnetic Tape Unit and IBM 355 Disk Storage )〕〔(IBM Archives: IBM 650 Assembly at Endicott plant )〕 It was announced in 1953 and in 1956 enhanced as the IBM 650 RAMAC with the addition of up to four disk storage units.〔(IBM 650 RAMAC announcement press release )〕 Almost 2,000 systems were produced, the last in 1962. Support for the 650 and its component units was withdrawn in 1969. The 650 was a two-address, bi-quinary coded decimal computer (both data and addresses were decimal), with memory on a rotating magnetic drum. Character support was provided by the input/output units converting alphabetical and special characters to/from a two-digit decimal code. The 650 was marketed to scientific and engineering users as well as to users of punched card machines who were upgrading from calculating punches, such as the IBM 604, to computers.〔(IBM Archives: 650 Customers )〕 Because of its relatively low cost and ease of programming, the 650 was used to pioneer a wide variety of applications, from modeling submarine crew performance to teaching high school and college students computer programming. The IBM 7070 (signed 10-digit decimal words), announced 1958, was expected to be a "common successor to at least the 650 and the () 705". The IBM 1620 (variable length decimal), introduced in 1959, addressed the lower end of the market. The UNIVAC Solid State (a two-address computer, signed 10-digit decimal words) was announced by Sperry Rand in December 1958 as a response to the 650. None of these had a 650 compatible instruction set. ==Hardware== The basic 650 system consisted of three units:〔(IBM Archives: 650 Components )〕 *IBM 650 Console Unit〔(IBM Archives: IBM 650 Console Unit )〕 *IBM 655 Power Unit〔(IBM Archives: IBM 655 Power Unit )〕 *IBM 533 or IBM 537 Card Read Punch Unit〔Other IBM names for the 533 included ''Input-Output Unit'' and ''Read-Punch Unit''.〕〔(IBM Archives: IBM 533 Card Read Punch )〕〔(IBM Archives: IBM 537 Card Read Punch )〕 The IBM 533 had separate feeds for reading and punching; the IBM 537 had one feed, thus could read and then punch into the same card. Optional units:〔 *IBM 46 Tape To Card Punch, Model 3 *IBM 47 Tape To Card Printing Punch, Model 3 *IBM 355 Disk Storage Unit〔(IBM Archives: IBM 355 Disk Storage )〕 Systems with a disk unit were known as ''IBM 650 RAMAC Data Processing Systems'' *IBM 407 Accounting Machine〔(IBM Archives: IBM 407 accounting machine )〕 *IBM 543 Card Reader Unit *IBM 544 Card Punch Unit *IBM 652 Control Unit (magnetic tape, disk)〔(IBM Archives: IBM 652 Control Unit )〕 *IBM 653 Storage Unit (magnetic tape, disk, core storage, index registers, floating point arithmetic)〔(IBM Archives: IBM 653 Auxiliary Unit )〕 *IBM 654 Auxiliary Alphabetic Unit *IBM 727 Magnetic Tape Unit *IBM 838 Inquiry Station〔(IBM Archives: IBM 838 Inquiry Station )〕 Rotating drum memory models provided 1,000, 2,000, or 4,000 words of memory (a signed 10-digit number or five characters per word) at addresses 0000 to 0999, 1999, or 3999 respectively.〔(IBM Archives: IBM 650 Magnetic Drum )〕〔(IBM Archives: IBM 650 Model 4 announcement )〕 Words on the drums were organized in bands around the drum, fifty words per band, and 20, 40, or 80 bands for the respective models. A word could be accessed when its location on the drum surface passed under the read/write heads during rotation (rotating at 12,500 rpm, the non-optimized average access time was 2.5 ms). Because of this timing, the second address in each instruction was the address of the next instruction. Instructions could then be interleaved, placing many at addresses that would be immediately accessible when execution of the previous instruction was completed. Instructions read from the drum went to a ''program register'' (in current terminology, an instruction register). Data read from the drum went through a 10-digit ''distributor.'' The 650 had a 20-digit ''accumulator'', divided into 10-digit lower and upper accumulators with a common sign. Arithmetic was performed by a one-digit adder. The console (10 digit switches, one sign switch, and 10 bi-quinary display lights), distributor, lower and upper accumulators were all addressable; 8000, 8001, 8002, 8003 respectively. The optional IBM 653 Storage Unit, was introduced on May 3, 1955, providing up to five features: *Magnetic tape controller (for IBM 727 Magnetic Tape units) *Disk storage controller (for IBM 355 Disk Storage Unit) *Sixty 10-digit words of magnetic core memory at addresses 9000 to 9059; a small ''fast memory'' (this device gave a memory access time of 96µs, a 26-fold raw improvement relative to the rotating drum), needed for a tape and disk I/O buffer *Three four-digit index registers at addresses 8005 to 8007; drum addresses were indexed by adding 2000, 4000 or 6000 to them, core addresses were indexed by adding 0200, 0400 or 0600 to them. If the system had the 4000 word drum then indexing was by adding 4000 to the first address for index register A, adding 4000 to the second address for index register B, and by adding 4000 to each of the two addresses for index register C (the indexing for 4000-word systems only applied to the first address). The 4000-word systems required transistorized read/write circuitry for the drum memory and were available before 1963. *Floating point – arithmetic instructions supported an eight-digit mantissa and two-digit characteristic (offset exponent) – MMMMMMMMCC, providing a range of ±0.00000001E-50 to ±0.99999999E+49 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「IBM 650」の詳細全文を読む スポンサード リンク
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