Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!usc!samsung!emory!hubcap!mark
From: mark@hubcap.clemson.edu (Mark Smotherman)
Newsgroups: comp.arch
Subject: Re: Info on GE-635
Message-ID: <12828@hubcap.clemson.edu>
Date: 29 Jan 91 22:34:33 GMT
References: <1665@digi.lonestar.org>
Organization: Clemson University, Clemson, SC
Lines: 55

From crichmon@digi.lonestar.org (Charles Richmond):
> I have read several posts about the old General Electric 635 mainframe.
> Can anyone give more information about this computer?  Specifically:

From GE-625/635 Programming Reference Manual, July 1964 (Rev. April 1968,
Rev. July 1969), No. CPB-1004F.

>   1)  What was the word size?
36 bits

>   2)  What character code did it use?
"Alphanumeric data are represented by six-bit or nine-bit characters."
"The character set used is the Computer Equipment Department Standard
Character Set, which is readily convertible to and from the ASCII
character set."

>   3)  How many registers did it have?
Registers accessible to the program:
Accumulator Register		AQ	72 bits
Eight Index Registers (X0..X7)	Xn	18 bits each
Exponent Register		E	8 bits
Base Address Register		BAR	18 bits
Indicator Register		IR	18 bits
Timer Register			TR	24 bits
Instruction Counter		IC	18 bits

>   4)  How fast could it execute instructions?
Appendix A gives basic timings that vary; e.g.:
1.9 microseconds for Load A and Add to A
2.1 usec for Store A
7.6 usec for Multiply Integer
15.1 usec for Divide Integer
2.8 usec for Floating Add
6.5 usec for Floating Multiply
31 usec for Floating Divide
1.7 usec for conditional transfers
Additionally a section on "Calculation of Instruction Execution Times"
gives eight categories of timing adjustments including data dependencies
between instructions spanning different instruction pairs, transfers of
control at and to odd storage locations, and certain address modifications.

>   5)  Did it support any form of floating point?
Single precision and double.  "The upper 8 bits represent the integral
exponent E in the two's complement form, and the lower 28 or 64 bits
represent the fractional mantissa M in 2's complement form."

>   6)  What languages were available for it?
The reference manual lists programming manuals for Fortran-IV and COBOL-61
(plus it contains information on the assembly language, GMAP).

>   7)  Does anyone still have one of these beasts?
???
-- 
Mark Smotherman, Comp. Sci. Dept., Clemson University, Clemson, SC 29634
INTERNET: mark@hubcap.clemson.edu    UUCP: gatech!hubcap!mark