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The '''GE-635''' was a [[transistor]] [[mainframe]] computer; the largest of the [[GE 600 series‎]] family. It is notable mostly for being the design base of the [[GE-645]], a descendant created for the [[Multics]] project (after [[International Business Machines|IBM]] refused to add necessary features such as [[virtual memory]] to the [[IBM System/360|System 360]]). The [[Dartmouth Time Sharing System]], where [[BASIC]] was developed, also ran on the GE-635.

The basic overall [[architecture]] of the GE-635 was inherited by the later Multics systems: it was a [[tightly-coupled]] [[multi-processor]], with all the [[Central Processing Unit|CPUs]] sharing access to a collection of [[multi-port memory]] modules. [[Input/output|I/O]] activities were handled by Input/Output Controller modules, similarly sharing access to the memory modules.

The GE-635 was intended for [[multi-tasking|multi-programming]]; a CPU operated in either Master mode, in which there were no limitations on its operation, or Slave mode, in which [[base and bounds]] type [[memory management]] applied.

The GE-635 was a 36-bit machine, as was common for scientific computers in that period. The CPU included a single double-width [[register|accumulator]], and eight [[index register]]s (18 bits wide; the size of [[address]]es in the GE-635). The [[Program Counter]] was also 18 bits.

The GE-625 was identical to the GE-635; they differed only in the speed of the [[main memory]].

==External links==

* [http://www.bitsavers.org/pdf/ge/GE-6xx/CPB-371A_GE-635_System_Man_196407.pdf GE-635 System Manual]
* [http://www.bitsavers.org/pdf/ge/GE-6xx/CPB-1004_GE-635_Prog_Ref_Man_196407.pdf GE-635 Programming Reference Manual] - 1964 edition
* [http://www.bitsavers.org/pdf/ge/GE-6xx/CPB-1004F_GE-635_Prog_Ref_Man_196907.pdf GE-635 Programming Reference Manual] - 1969 edition
* [https://multicians.org/ge635.html The GE-635s at Project MAC and BTL]
* [http://www.starringthecomputer.com/computer.html?c=427 Starring the Computer - GE-635] - images of GE-635's used as props

[[Category: Mainframes]]

@@ Line 7: / Line 7: @@
 The GE-635 was a 36-bit machine, as was common for scientific computers in that period. The CPU included a single double-width [[register|accumulator]], and eight [[index register]]s (18 bits wide; the size of [[address]]es in the GE-635). The [[Program Counter]] was also 18 bits.
-The GE-625 was identical to the GE-635; they differed only in the speed of the [[main memory]].
+The GE-635 was apparently derived from the GE M236 computer, which was produced in the early 60s by [[General Electric|GE]] for the US Air Force. The GE-625 was identical to the GE-635; they differed only in the speed of the [[main memory]].
 ==External links==

GE-635 - Revision history

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