TeleExchange Proceedings, 5th, Orlando, FL, June 1984.

The COMPUTER That Will Not Die:






Keith G. Calkins
Manager, Technical Support
Andrews University Computing Center
Berrien Springs, Michigan

June 1984

SDS SIGMA is the trademark of and
Scientific Data Systems is used under license from
Santa Monica, Californiaof Braintree, Massachusetts.
Xerox Data Systems

This is found on the inside of the PCP of all Sigma computers.




  Xerox won't woo you with sweet promises,
deliver a machine, and then disappear in the night.
  We're still old-fashioned enough to believe
in meaningful relationships. So when you get a
Xerox machine, you also get a Xerox commitment.
  Xerox technical representatives will keep
that equipment in good working condition with
tender, loving care.
  We'll keep improving our equipment, even
after it's yours. And we'll make those improve-
ments right in your office. So the longer you have
it, the better it gets.
  And you can feel secure in knowing that
there'll always be a Xerox service center
that you can count on.
  Only Xerox gives you a Xerox commitment.
And you can get it whether you buy or lease.
  At Xerox, we don't love you and leave you.
Because anything and everything we do for you
is a labor or love.


This advertisement is of unknown origin.

                         |                         |
     S                   |      D           D      |     S
     S                   |      D            D     |     S
      SSSSSSSSSSSSS      |      D             D    |      SSSSSSSSSSSSS
                   S     |      D             D    |                   S
                    S    |      D            D     |                    S
                   S     |      D           D      |                   S
                         |                         |
-------------------------+                         +-------------------------



  +-------------------------+ | | XX XX | DDDDDDDDDDD | SSSSSSSSSSSSSSS XX XX | D D | S XX XX | D D | S XXX | D D | SSSSSSSSSSSSS XXX | D D | S XX XX | D D | S XX XX | D D | S XX XX | DDDDDDDDDDD | SSSSSSSSSSSSSS | | -------------------------+ +-------------------------

These logos are found on most SDS and XDS documents. The XDS version was found on a "punch card" during the conversion of the Users Group library. There was on tape, binary card images of character information. I wrote a program to convert this to a readable form without having to punch it and the above image would not convert.

                        TABLE OF CONTENTS

Preface  . . . . . . . . . . . . . . . . . . . . . . . .  1

Abbreviations  . . . . . . . . . . . . . . . . . . . . .  2

Introduction  Snow White, the Seven Dwarfs, and SDS  . .  3

Chapter 1     SDS and the 900-series Computers . . . . .  4

Chapter 2     The 16-bit Sigma and Xerox Computers . . .  8

Chapter 3     The 32-bit Sigma and Xerox Computers . . . 11

Chapter 4     The Follow-ups . . . . . . . . . . . . . . 15

Chapter 5     Memories and IOPs  . . . . . . . . . . . . 18

Chapter 6     Peripherals  . . . . . . . . . . . . . . . 20

Chapter 7     Operating Systems  . . . . . . . . . . . . 21

Chapter 8     Maintenance Companies  . . . . . . . . . . 24

Appendix      Equipment production and sales . . . . . . 28



The purpose of this paper is to outline the past, present, and future of the SDS (later XDS) Sigma 7, related computers, associated peripherals, and operating systems.

Items I had hoped to go into detail on are:

Information I had hoped to include for each computer is: Such information takes time and energy to recover, so this has become an ongoing project.





IBM - International Business Machines
RCA - Radio Corporation of America
GE - General Electric
CDC - Control Data Corporation
NCR - National Cash Register
DEC - Digital Equipment Corporation
SDS - Scientific Data Systems
XDS - Xerox Data Systems
RXDS - Rank Xerox Data Systems
HIS - Honeywell Information Systems
SDSi - Scientific Data Systems, Israel
CSC - Consolidated Systems Corporation
JPL - Jet Propulsion Laboratory
NASA - National Aeronautics and Space Administration

Computing terms:

CPU - Central Processing Unit
IOP - Input/Output Processor
GP - General Purpose, Solid State Digital Computer
K - 1024 (usually words)
Mb - Megabytes (1048576 or often 1000000 bytes)
byte - unit of information (typically 8 bits)
bit - binary digit
port - accessway into memory



Snow White, the Seven Dwarfs, and SDS


Snow White (IBM) and the seven dwarfs (RCA, Univac, GE, Honeywell, CDC, Burroughs, and NCR) had all emerged in the computer industry before SDS was formed in 1961. (DEC was formed in 1959 just prior to SDS.) SDS had about 1% of the total computer market when it was acquired by Xerox in 1969 to become XDS.

If anyone wanted to advance XDS to dwarf status when first GE [1970] and later RCA [1971] withdrew from the computer industry nobody said so. The references after those withdrawals were rather "and then there were six," and later, "and then there were five."
Xerox withdrew from the mainframe computer industry on July 21, 1975 -- never quite achieving dwarfdom.

In spite of the rough path that users of SDS and XDS computer equipment have had, many are still seeking equipment that will meet their needs. The future is bright before us. Options other than Big Blue (and others such as DEC), Honeywell CP-6, and Telefile are emerging. Our past is slowly being forgotten -- even unknown to many, in many of our sites. At present the computer equipment moves from place to place as management, personnel, and the constraints (demand, space, time, and money) on the computing resources change.

Why is the equipment still in service almost 20 years after it was designed? How will the real-time applications cope? What is to become of the tremendous software investment?



SDS and the 24 (12) Bit Computers

SDS was founded in September 1961 by Max Palevsky (President) and eleven other computer scientists. Their first computers, the SDS 910 and 920 were delivered in August 1962 (within 1 year of forming!) and included the following features new to the industry:

  1. ) The only small GP with an extensive but separate I/O system
  2. ) Programmed OPerations (POPs).
"The first commercial computer with all silicon semiconductors ever delivered by any manufacturer was the SDS 910."

Emil Borgers (Manager of Programming, later a Vice President, and a founder) stressed that the hardware and software were designed together as a package. The sale price included "the most efficient and comprehensive software package in the small computer field." The software included: utility programs, assembly programs, mathematical subroutines, and FORTRAN II. FORTRAN II was a subset of the 900-series FORTRAN compiler. The SDS 920 was "the only computer that, without magnetic tape units, can process FORTRAN II programs in one pass."

Advertised first users included: JPL, Bell Labs, NASA, Motorola, GE, Honeywell, RCA, Dow Chemical Company, Edwards Air Force Base, and Los Alamos Scientific Laboratory.

The SDS 910 and 920 were initially advertised as "half the price of" or alternately "worth twice as much as" "comparable machines." Later the SDS 9300 was advertised as twice as fast and one quarter the price of a[n IBM] 7090.

The SDS 9300 was announced in June 1963. SDS was not yet two years


old, announcing its third computer, and in the black. The SDS 9300 is logically and electrically similar to the 920 with which it is program and peripheral compatible. Optional features include: priority interrupts (up to 1024 channels), and floating point arithmetic. Up to eight buffered I/O channels are available. The 32 K-word address space is divided into 2 parts with a program controlled select switch to determine which of the halves is connected. Memory protect registers are available. It is designed for scientific computations and integration in real-time simulation and telemetry systems.

By December 1963, SDS claimed more than 75 installations of SDS 910s and 920s when it announced the SDS 930, it's fourth computer.

By August 1964, SDS announced the SDS 925 and SDS 92. The next month brought the "new 930" evidently about 12% faster than the original. The SDS 92 was "the first commercial computer to make extensive use of monolithic integrated circuits." ICs were used on about one half of the 100 circuit cards.

By February 1966, SDS announced the SDS 940, a time-sharing system which was backward compatible with the previous systems (except the SDS 92 which was a 12 bit computer). It had monitor and user modes, dynamic program relocation, automatic memory fragmentation, and system protection. "You'll still be contented using your 940 system five years from now" - was advertised in 1966. Today (1984) SDS 940s still run Tymshare's Tymnet and Comshare uses at least two. The University of California at Berkeley worked with Tymshare and SDS on this early time-sharing system.

In 1968 the SDS 945 was advertised as an SDS 940 with less expandibility but just as much compute power. The design of the SDS 940 is very complex because of the backward compatibility with the 930 etc. and the needed changes to support time-sharing. The design of the Sigma 7 can readily be seen as a simplification and extension.


The following is a short description of the 900 series computer:

Instruction format:

    | | |0   op code  | | EM  |      Address         |
    |U|X|             |I|----------------------------|
    | | |1     POP    | | block |    Address         |
     0 1 2 3         8 910111213                   23
    U      SYSPOP vs POP (940)
           user/monitor map (930)
    X      Indexing -- multi-level (pre-indexing)
    POP    Programmed Operational code
    Opcode Operational code
    I      Indirect Addressing -- multi-level
    EM     Memory extension register (10-EM2, 11=EM3, 930)
    Block  3-bit virtual maps to 5-bit physical block number
    Fixed point data is in two's complement form (bit 0 sign).
    Floating point is 24 or 39 bit mantissa with 9 bit exponent.
Most documentation tents to be in octal for these machines. This is readily understandable when you realize 24 is divisible by 3 and the opcode is aligned such that it ends at bit 8.


                 SDS    SDS     SDS   SDS    SDS    SDS    SDS    SDS
Computer         910    920    9300   930    925    92     940    945
                 ---    ---    ----   ---    ---    --     ---    ---

Announcement     Jul 62 Jul 62 Jun 63 Dec 63 Aug 64 Aug 64 Feb 66 Jul 68
Installation     Aug 62 Sep 62 Dec 63 Jun 64 Feb 65 Mar 65 Apr 66 ???

Bits             24     24     24     24     24     12     24     24
Maximum memory   16Kw   16Kw   32Kw   32Kw   16Kw   16Kw   64Kw   64Kw?

24 bit fixed Add 16     16     1.75   4/3.5  3.5           3.5
48 bit fixed Add               3.5
24x24 bit Mul    248    32     7.0    8/7    54.25         7.0
24/48 bit Div                  19.25  20                   17.5

33 bit float Add 432    352           74     95.5
             Mul 464    248           54     101.5
48 bit float Add 896    384    14     83     196
             Mul 1696   656    12.25  138    371
      Jul 62     41,000 89,000
      Jan 63     48,000 98,000
      Jun 63                   215,000
      Dec 63     41,000 83,000        108,000
      Aug 64                                 81,000 29,000
      Sep 64                          /95,000
      Oct 64                   150,000

      Dec 81                           give-aways             
    Times are in microseconds
    Prices are in dollars and include CPU, memory, I/O, basic peripherals.


The 16-bit Sigma and Xerox Computers

SDS delivered the Sigma 2 in December 1966, the same month as the Sigma 7. It is based on the same circuit card series, similar memory, and interchangeable peripherals. The T series integrated circuit module family combines monolithic DTL integrated circuits: flip-flops, inverters, and buffer amplifiers with close tolerance, discrete diode-resistor gates and output pull-up resistors.

The Sigma 3 was first delivered in 1969 and made the Sigma 2 "obsolete". It has greater I/O capabilities and more maintenance features.

The Xerox 530 was announced in January 1973 and delivered in July 1973. It replaces both the Sigma 2 and the Sigma 3. The software is upward compatible.

The 16-bit processors use one- or two-word instructions. Most of the instructions are one-word types consisting of a 4-bit operation code, a 4-bit address control field, and an 8-bit address field.

The opcodes are:

    0   WD             Write Direct
    1   RD,IO,2-word   Read Direct, Input/Output, 2 word
    2   Shifts         Arithmetic, Circular, left/right,
    3   MUL,FMP        Multiply, Floating Multiply
    4   Branch         Unconditional
    5   DIV,FDV        Divide, Floating Divide
    6   Branch         Conditional
    7   Register       ADD, AND, CLR, CPY, EOR, OR
    8   LDA,FLD        Load Register A, Floating load
    9   AND            Logical AND
    A   ADD,FAD        Add word, Floating add
    B   SUB,FSB        Subtract, Floating subtract
    C   LDX            Load Index
    D   CP,FCP         Compare, Floating compare

    E   STA,FST        Store Register A, Floating store
    F   IM             Increment memory

    The address control field is:

            R - Self-relative address  (eliminates S)
            I - Indirect address       (only one level)
            X - Post-indexing
            S - Pre-indexing
    The 8 16-bit registers have specific purposes:
         0  Zero-source
         1  Program Address
         2  Link Address
         3  Temporary Storage
         4  Index 1 (Post index)
         5  Index 2 (Pre index)
         6  Extended Accumulator
         7  Accumulator

The floating point instructions are controlled by a bit in the PSD. The processors can run protected (master/slave). There is a set of 16 16-bit write protect registers, 2 condition codes (overflow, carry), and 2 interrupt inhibit bits (internal, external).

I know of no efforts being made to produce a computer that is software compatible with the Sigma/Xerox 16-bit processors.


Computer             Sigma 2    Sigma 3   Xerox 530
                     -------    -------    -------

Announcement        Aug 1966   Jan 1969    Jan 1973                           
Installation        Jan 1967   Jul 1969    Jul 1973                     

all are 16-bit
max memory is 64K

fixed point binary
    16 bit ADD                                1.92
    32 bit ADD                     3.2
    16x16  MUL                     7.8        8.0
    16/32  DIV                     8.1       13.4
floating point
           ADD          ---        ---       10.7
           MUL          ---        ---       32.96
           DIV          ---        ---       77.56
max ext int             132                     24
Standard Instructions   35          37          67
Optional Instructions    2 MUL,DIV   0           7 floating
                                                 8 field addressing
                                                   (bit string)
      Sep 66       26,000        
      Jun 75                    31,500      20,000
      Jan 84        3,000        3,000       7,500
    Times are in microseconds
    Prices are in dollars and include CPU, memory and I/O only (no peripherals)


The 32-bit Sigma and Xerox Computers

The SDS Sigma 7 was the first 32-bit computer which SDS produced. SDS claimed that it was the only computer (then available) to handle all computer applications effectively (i.e. Scientific, Commercial, and Real-time). It was announced March 15, 1966, delivered yet that year (on-time) and was hailed as ambitious in the literature. It's major competition was the IBM 360 - with which it shares many similarities (announced April 7, 1964, 360/40 delivered May 1965).

The SDS Sigma 5 with no decimal, map, or byte-string instructions was delivered one year later for both real-time and time-sharing use.

The next item is not a computer but a new name for the company. Xerox and SDS agreed to a merger in March 1969. It was voted on by the shareholders May 15, 1969. One share of Xerox common stock would be exchanged for each two shares of SDS common stock. SDS was then considered by some to be the eighth largest computer manufacturer. Xerox's stock was reported worth $930 million, whereas SDS's stock was worth $30.7 million. Others state the sales price as $908 million. At that time SDS had installed over 1000 computers, a large percentage of which were either Sigma series or 940's.

The Xerox Sigma 6 was next. It is a Sigma 7 CPU with redesigned memory and IOPs which include a maintenance feature. It has many items standard which were optional on the Sigma 7. This brought XDS into the business marketplace whereas SDS had concentrated on the neglected scientific community. Supposedly its name (distinct from Sigma 7) was necessitated because of some foreign marketing arrangement SDS made with


CII of France. Any further Information on this would be appreciated.

The Xerox Sigma 9 followed. It is the most powerful of the Sigma series. It was the first to overcome the physical equal to virtual address space limitation. The two instruction look-ahead contributed to its speed increase. It was developed with multi-processing in mind and contains more maintenance features in an integrated manner than the Sigma 6. Walter Hollingsworth has been called by some the father of the Sigma 9.

The Xerox Sigma 8 and Sigma 9 mod 3 were primarily update paths for Sigma 5 users. (There was also a Sigma 9 mod 2.)

The Xerox 550 and 560 were a total repackaging with big boards, newer technology and less space. The Xerox withdrawal from the mainframe industry had it primary effect on users of these machines because of the dissimilarity of the hardware and the small number built. Taurus is a code name for this series.

At the time of Xerox's departure from the computer field they had about 1700 computers install in the U.S. and 400 abroad. They agreed to provide support for its customers for at least seven years. Parts which were considered salable were the rights to CP-V, the installed user base, the service operation, and manufacturing rights to some of all of XDS' computers. Orders were at record levels. The XDS 550 and 560 were being well received. Getting even more favorable attention was the CP-V operating system, called one of the world's five fully versatile operating systems. During 1976 Xerox and Honeywell worked together to provide user support. Now in 1984 all maintenance contracts are expired and Honeywell is not renewing them, forcing uses to abandon Honeywell or convert to CP-6.

CII of France seems to have produced Sigma compatible computers specifically Iris 80, perhaps others in the early 1970's.

Project Leo or the Xerox 590 was a yet to be announced product, technologically similar to the Taurus, but more powerful.


Honeywell announced it was building Sigma 9's in the late 70's early 80's, but I have no production figures.

Between 1980 and 1982 Modutest built and sold ten "Mod 9's"-Sigma 9 equivalents. They also supplied the materials for five more which Comshare built.

Brief Instruction Format description:

     |I|   Op Code   |   R   |  X  |        Reference Address       |
      0 1           7 8    1112  1415                              31

    1   I       Indirect bit (one level)
    7   Op Code Operational Code
    4   R       Register (0-15)
    3   X       Index Register (one level, post-indexing, 1-7)
   17   Ref Add Reference Address

    Fixed point is 32 bits (0 bit sign)
    Floating point is signed with 7 bit biased exponent and 24/56 
    bit mantissa.

Sigma 7, serial number one was running in March of 1984 at the Cyclotron lab, Michigan State University, Lansing Michigan. The original hand-wired backplanes have been replaced with machine wrapped ones under Honeywell. It has since been sold - perhaps for scrap (particularly gold).

Numbers two and three were at Martin Marietta, Denver Aerospace Division. They suffered water damage early in their careers.


            Sigma Sigma Sigma Sigma Sigma Sigma Sigma Xerox Xerox
              7     5     6     9     8   9Mod3 9Mod2  550   560
            ----- ----- ----- ----- ----- ----- ----- ----- -----
announcement 3/66                                      2/74  2/74
installation12/66  8/67  6/70 10/71  2/72 mid73   ?    4Q74  4Q74

all are 32 bit computers
floating pt. opt   opt   opt   std   std   std   std    ?    std
decimal      opt    --   std   std    --    --   std    ?    std
byte string  std    --   std   std    ?     ?     ?     ?    std
max memory   128K  128K  128K  512K  128K  512K  256K   ?    256K
memory map   opt    --   std   std    --   std   std    ?    std
look-ahead    1     0     1     2     2     2     2     ?     ?
max reg blk  32    16    32     4     4     4     4     4     4
max ext blk  14    14    14    14    14    14    14     4*    4*
watch-dog timer standard on all
fixed point 32 bit binary arithmetic
  AW,SW,CW    2.0   2.0   2.0   0.7   0.7   0.7   1.1
  MW          5.0   7.2   5.0   3.8   3.8   3.8   5.2
  DW         12.6  15.8  12.6   9.5   9.5   9.5  17.8
  LW          1.8   2.0   1.8   0.7   0.7   0.7   1.0
  STW         2.6   2.5   2.6   1.5   1.5   1.5   2.3
floating point arithmetic
  FAS,FSS     3.3   4.8   3.3   2.2   2.2   2.2   4.0
  FMS         6.0  10.0   6.0   4.0   4.0   4.0   5.5
  FDS        12.4  14.0  12.4   7.7   7.7   7.7  15.0
  FAL,FSL     4.1   9.0   4.1   2.7   2.7   2.7   4.1
  FML         9.1  16.0   9.1   7.0   7.0   7.0   8.6
  FDL        25.4  25.3  25.4  17.4  17.4  17.4  30.5
decimal arithmetic
  DA         19.4+.3D           5.8+.4D
  DM         62.3+.4DN         38.2+.28DN
  DD         30.8+.8K          18.5+.5K
byte string
  MBS         4.2+3.4N          7.6+.6N         8.6+1.1N
  WA             +0.8N
  CBS         4.1+3.9N          7.6+.6N +1.1N   8.6+1.1N
  AW  - Add Word            FAS - Floating Add Short
  SW  - Subtract Word       FSS - Floating Subtract Short
  CW  - Compare Word        FMS - Floating Multipy Short
  MW  - Multiply Word       FDS - Floating Divide Short
  LW  - Load Word           FAL - Floating Add Long
  STW - Store Word          FSL - Float Short [sic s/b Subtract] Long
  DA  - Decimal Add         FML - Floating Multiply Long
  DM  - Decimal Multiply    FDL - Floating Divide Long
  DD  - Decimal Divide      MBS - Move Byte String
                            CBS - Compare Byte String
  WA  - Word aligned MBS
  D   - Number of non-zero digits
  N   - number of bytes/digits
  K   - (D+6)(16-Q)
  Q   - Number of leading zeros in quotient                            



The Follow-ups

Telefile's T-85 was the first Sigma replacement available. It was up running CP-V the first time on Oct 24, 1979. It was available for demonstration near the June 1980 Exchange meeting in Philadelphia. Martin Marietta, Denver Aerospace Division Beta test sited it in February 1981. The T-85 is micro-programmed and can emulate the instruction set of all the 32-bit Sigma computers. In addition, the instruction set has been expanded to provide new instructions (logical immediates, queue, quad, and environment), to expand the versatility and speed. Telefile is committed to developing an operating system to make better use of multiple processors. Due to the micro-programming, different algorithms are used to perform various instructions, which can produce different intermediate results. Since some instructions can be interrupted this can be problematic in a mixed CPU multiprocessing environment. The T-85 series was developed to be quite interchangeable with the Sigma computers. As a result the memories, I/O processors and peripherals are usable on the Sigma series.


Ilene Industries Data Systems is nearing completion on a Sigma replacement: the MOD 9000. Production preparation and Beta-test siting at NASA Huntsville should be complete in fourth quarter 1984. The MOD 9000 contains logical immediate, quad precision floating point, and other instructions in addition to the standard Sigma 9 instruction set. The MOD 9000 hardware is different enough so that the CPU, memory, and I/O processors must all be replaced together, although provision is made to


make use of existing peripherals. IBM peripherals will be compatible also. The MOD 9000 combines some microcoding with fixed hardware design using Multiwire printed circuit boards.


Realtime Computer Equipment Inc. has begun work on a Sigma replacement: the RCE-9. Beta-test site times could not be determined. It will be piecewise replaceable with the Sigma computers (CPU, memory, I/O processors), and will contain provision to support IBM peripherals. It will make extensive use of the Sigma 9 logic struction using programmable Logic Arrays.


Although these processors are backward compatible with the Sigma 9, there are substantial differences, with each manufacturer going in a slightly different direction.


                Telefile   Modutest    Ilene     Real-time           
                  T-85       Mod 9   Model 9000    RCE-9              
                --------   --------   --------   --------
announcement      1975       1979     Sep 1983   Jan 1984
installation      1980       1980      (1984)     (1985)                          

fixed point 32 bit binary arithmetic
  AW,SW,CW         1.2        0.7       0.3       0.35
  MW               2.4        3.8       1.2       1.9
  DW               9.4        9.4       4.2       4.7
  LW               1.2        0.7        .1       0.35
  STW              1.2        1.5        .1       0.75

T-85 timings are based on a preliminary release
Mod 9 timings are the same as the Sigma 9.
Model 9000 timings are design estimates (optimistic?).
RCE-9 timings are design estimates (at least twice a Sigma 9
                                    perhaps four times).



Memories and Input Output Processors

Many memories are interchangeable, but various restrictions apply. This list was prepared to help explain what options were available other than the space and energy consuming core. I would like to get production figures and dates of production if possible.


Sigma 2 external memory (max 64K, 2 port)
Sigma 3 memory (max 64K, 4 port)

Old-style Sigma 5/7 core memory (max 128K, 3/6 port)
New-style Sigma 6 core memory (mas 128K, 8 port)
Sigma 9 core memory (max ????K, 12 port)
Honeywell Sigma MOS memory (Max 512K/16Mb, 8 port)
Ampex ARM-9 core memory (Max 256K, 8 port)
Telefile single density core memory
Telefile double density core memory
Telefile MOS memory (Max 16Mb, 12 port)
In additon to these commercially availabe memories many companies such as DREP, Brookhaven, OCLC (MOS in ARM-9 Cabinets), developed their own.


Sigma 2 IIOP - Integral IOP shares memory port with CPU,
     8 bit, 4 I/O channels basic, 20 maximum.
Sigma 3 IIOP - Integral IOP shares memory port with CPU,
     8 bit, 4 I/O channels basic, 12 maximum.
Sigma 3 EIOP - External IOP multiplexing, 8 or 16 bit,
     8 I/O channels basic, 16 maximum
Sigma 5 IIOP - Integral IOP shares memory port with CPU,
     8 bit, multiplexing
8 bit Sigma 5/7 MIOP 32 I/O channels maximum, 8 Multi-channel
32 bit Sigma 5/7 MIOP 24 I/O channels maximum,
     8 Multi-channel, supports 1 or 4 byte data path          
32 bit Sigma 6 MIOP (with Maintenance subcontroller), 24 I/O channels
     maximum, 8 Multi-channel, supports 1 or 4 byte data path
SIOP Selector IOP for Sigma 5/7, 1 or 4 byte data path,
     1 busy device at a time, 32 I/O channels maximum
Sigma 9 MIOP A/B
HSRIOP - High-speed Rad IOP for Sigma 8/9, up to 4 7212 Rads
IOPs for Taurus, T-85s, etc.               




     7-track tape drives
           7361/7362 37.5 IPS, 556 BPI
           7371/7372 75 IPS, 200/556/800 BPI - Wang
     9-track tape drives
           7315/7316, 7320/7322 75 IPS, 800 BPI - Wang
                          7323 150 IPS, 800 BPI - Wang
           7330/7332,7333 75/150 IPS, 1600 BPI - Potter
           125 IPS 800/1600, 1600/6250 BPI Honeywell (MPC) - CDC
     RADs Rapid Access Device
           7202/03/04 360 byte sectors, 16 S/T 128/256/512 tracks
           7232 High Performance 12 S/T 512 Tracks
           7212 High Speed 82 S/T 64 Bands
           3212/3214 Taurus 11 S/T 256 Tracks
     Disk Drives
           7242 24.5 Mb      6 S/T   204 T
           7261             11 S/T   204 T
           7271 49 Mb        6 S/T   400 T
           7275 CDC 86 Mb   11 S/T   404 T
           3275             12 S/T   404 T

     CR - Card Readers
           7121 200 Cards per minute - Uptime
           7122 400 Cards per minute - Uptime
           7140 1500 Cards per minute
     CP - Card Punch
           7160 300 Card per minute -Univac
           7165 100 Card per minute -

     LP - Line Printers - the Xerox sore spot!
     TY - Teletype (Console)



Operating Systems

24 Bit Computers

I do not have any information on these operating systems. [MONARCH]

16 Bit Computers

BCM - Basic Control Monitor RBM - Real-time Batch Monitor

32 Bit Computers

JANUS - Michigan State University

BCM - Basic Control Monitor

BPM - Batch Processing Monitor

BTM - Batch Time-sharing Monitor

XOS - Xerox Operating System

A Xerox variant of the UTS designed by CII of France for systems in the IRIS series but unable on the Sigma 6 and Sigma 9.


UTS - Universal Time-Sharing System


The Universal time-sharing system (UTS), announced in 1966 as a multipurpose system that would, in effect, be all things to all people, encountered numerous delays before its release to the field. BTM was developed as an interim system. UTS was delivered early in 1971, primarily as a time-sharing system. It evolved through eight versions and numerous enhancements into a true multi-purpose operating system with batch, remote batch, interactive time-sharing, and terminal oriented inquiry/response (TP) capabilities.

           UTS - A00 Early 1971
           UTS - B00
           UTS - C00


UTS - D00 January 1973 final (eighth) version Large Sigma 9 support Disk Swapping Exit Control

CP-V - Control-Program fiVe

CP-V replaced UTS and XOS in mid-1973. It culminated Xerox's efforts to develop a comprehensive, multi-purpose operating system for the Sigma 6 and Sigma 9 computers. CP-V was based on the earlier UTS operating system, and supported five modes of operation:

           Multi-programmed batch
           Remote batch
           Transaction processing
     CP-V - A00   August 1973
           Remote Processing
           Symbiont enhancements
           Resource Management
     CP-V - B00   April 1974
           Real-time processing
           Extended user size
           RMA enhancements
           File Management enhancements
     CP-V - C00   November 1974
           Transaction Processing (the fifth facet of CP-V)
           Xerox 560 support
           15 major development projects and many fixes
     CP-V - C01   May 1975
           Internal technical documenation
           3270 support
           Fsave/Fres private packs
           Security fixes including password scrambling
     CP-V - D00   December 1975
           Multiprocessing Sigma 9
           Model 3625 Front-end support
           Internal reliability and performance improvements
     CP-V - E00   November 1976
           Xerox 560 multiprocessor support
           254 user system support
           online VOLINIT
           Library Editor and Maintenance Utility Routine
           Command files
     CP-V - E01   December 1977
           MPC disk support


Sigma 5 support Multiaccount private pack CP-V - F00 MPC tape support Multi-processing Sigma 6/7 Systems Sigma MOS memory TCP-V - Telefile Control Program fiVe TCP-V - G00,G01,G02,G03 May 1982+ "Based on Xerox's D00 Public Release of CP-V"

All major user oriented (i.e. non-device support) functional enhancements in Honeywell's E00,E01,F00 have been scheduled for implementation. Much help was received from Martin Marietta, Denver and University of Wisconsin, Green Bay.

     TCP-V - H00
           Anonymous processor support
CP-R - Control Program Realtime

     CP-R - A00
     CP-R - B00
     CP-R - C00
     CP-R - D00   Xerox
     CP-R - E00   Honeywell

TCP-R - Telefile Control Program Realtime

     TCP-R - G00  Telefile
     TCP-R - G01 
     TCP-R - H00
           New file directory format
           Ethernet device support
           New Save/Restore processor
CP-6 Control Program

Honeywell's answer to Sigma computer users was CP-6, a new operating system very similar to CP-V but running on Honeywell hardware. Science Dynamics was the first customer in late 1978, delivery was expected in mid 1979, and production use by early 1980. Today Honeywell has about 45 user sites, mainly the larger Universities which were using Sigmas. Shell Klee directed the software development effort.



Maintenance Companies

There have been and are many companies involved in maintenance and manufacture of Sigma compatible computers. What follows is a sketchy outline of the history and contribution of each known company in alphabetical order.


Comshare was founded in 1966 and started it's time-sharing operation with SDS 940's. In 1968 it had offices in Ann Arbor (main office), Chicago, Houston, and New York. In 1984 they are running a total of 52 Sigma 9's at 4 sites (Ann Arbor(24), London(20), Canada(6), Japan(2)) as dual processors (i.e. 26 systems).

CPX Computer Parts Exchange

Merge into Modutest March 1977. Bob Macgonigal former president.


Edgar Valdivia.

Dial Data

An independent company offering early time-sharing services using SDS 940's.

Honeywell (HIS - Honeywell Information Systmes

Honeywell makes great thermostats.

ICE International Computer Equipment, Inc.

Professional training.

ICX Independent Computer Exchange


Dave Randel, Masel.

Ilene Industries Data SystemsInc

Bill Smith,Don Freedman.

IPI Computer

Specialized in RAD repair, refurbishment, (conversions). Yair Kaner, Rene Bonniot, Edgar Valdivia, Tim Hinsche, Werner Contag, Allan Pliener.


Modutest, G&L

Gene Zeitler, Lothar Mueller.

Modutest Systems Inc.

Guy Grouper, Bruce Grouper.

OCLC Ohio Computer Library Center

In 1984 OCLC is using 15 Sigma 9's ten for production use as dual processors.



Larry Levinson, vice president of Quelex of Northridge, Calif., claimed to be three times as large as Valcomp in Sep. 1975. Tymshare put up $1.5 million to expand its maintenane operation by buying Quelex in November 1975.

SDSi - Scientific Data Systems, Israel

Nachim Inlander


Telefile Computer Corp. (Telefile Computer products, Inc.)

Telefile was founded in 1968. The rights to the name Telefile were purchased from Bunker-Ramo which once produced a computer by that name (Teleregister Telefile, late 1957).

In 1977 Telefile billed

itself as a computer enhancenment company, dedicated to prolonging the useful life of older cpu's whose speed and

efficientcy never were fully tapped before they were effectively obsoleted by their manufacturers in one way or another.

In 1975 Telefile attempted to purchase manufacturing rights to some or all of the XDS's computers. Sam Edens, president got only "frustration and dismay" in the attempt to negotiate with XDS. The plan in November was
to purchase the entire lease base and all maintenance contracts on our own, directly from the users. The following rates applied:
     Sigma 3,5  up to 55% of purchase price
     Sigma 6    "  "  66% "  "        "
     Sigma 7    "  "  77% "  "        "
     Sigma 8,9  "  "  88% "  "        "
     Xerox 530  "  "  60% "  "        "
     Xerox 550,560 "  73% "  "        "
Telefile produced several models of TCP-16, an emulator for Lockheed's MAC-16 (LEC-16).

In November 1977, Datamation wrote that Telefile's TCP-32 a Sigma 9-like computer scheduled for delivery in late 1978. In August 1978 the name of the new computer was Phoenix. A Sigma 9 followon hd been billed Sigma 11, but "Sigma" had been tied up for 10 years by Sigma Instruments, Telefile had long manufactured a line of Xerox-compatible peripherals.

Tymshare, Inc.

Ed O'neal, Frank Dragovitz. At one time claimed to be largest independent supplier of refurbished XDS computer equipment. Tymshare was recently purchased by McDonnell Douglas Corp.


John Cool joined SDS at age 22, starting up field engineering and directed it for five years. Years later in late 1971 after getting out of school, he purchased a one-third interest in and became president of, a computer maintenance company called Valcomp (formerly Valley computer) headquartered in Los Angeles' San Fernando Valley. Valcomp's specialty was assuring long operating life for process control computer systems.

Valcomp grew from 10 people and $250,000 in 1971 to 25 people and $1.5


million in 1975 annual revenues. Valcomp was acquired in January 1973 by Tymshare, Inc. Valcomp maintained, refurbished, and supplied spares for Xerox computers.

Western Computer Systems

Mike James, President. Today Western is called by some the largest source of maintenance for Sigma/Xerox computers.




SDS would not submit nor comment on production and installation figures for their computers. In February 1969 Computers and Automation published a table of estimates for total installed SDS computers. This table was used with little modification until August 1974 when they published their last computer census. Evidently little effort was made to update their figures.

                      February 1968     August 1974
         SDS-92            7                 47
             910         153                180
             920          93                132
             925          20                  -
             930         159                173
             940          28                 37
             9300         21                 34
         Sigma 2          56                199
               3          16                 28
               5          15                 48
               6                              4
               7          24                 40
               8                              7
               9                             13
         Xerox 530                           14
         Telefile T-85
         Modutest Mod-9              15 total produced 1980-82
I understand that after the Honeywell take-over, Sigma 9 CPU backplanes were discovered in the Phoenix warehouse. Any help as to the number manufactured for any SDS/Sigma/Xerox (and compatible) computers would be greatly appreciated. [Note: I understand California had an excessive inventory tax which is why so many companies had offices in Phoenix.]


Sep '75 Datamation pg 102-107 "Xerox's Frustrating Drive for Dwarfdom"
Sep '66 Datamation pg 40-54 "Changes in Computer performance" SDS910,920
Sep '68 Datamation pg 31-35 "Evolving Computer Performance 1963-1 67"
SDS 9300, 930, 925, 92, 940, Sigma 7, 2.
Feb '69 Datamation pg 53-59 "Computing at Stanford" SDS925,930
Mar '82 Datamation pg 198-204 "Transforming an Operating System"
SDS 940 Computer Reference Manual
Xerox Sigma 3 Computer Reference Manual
Xerox 530 Computer Reference Manual
Datapro Xerox Sigma Series Oct 74/Jun 75
Datapro Xerox 530, 550, & 560 Nov 74/Jun 75

SDS Sigma 7 Computer reference manual.
SDS Sigma 5 Computer reference manual.
Xerox Sigma 6 Computer reference manual.
Xerox Sigma 9 Computer reference manual.
Xerox 560 Computer reference manual.

Telefile T80 series LVM-CPU reference manual.
Preliminary Technical manual for Ilene Industries model 9000 computer system.
Real-time Computer Equipment RCE-9 announcement sheet