First Love - The Principle of First Engagement

No, this isn't about human romance. Nor is it a theological reflection. Or is it? It certainly is about tenacity and virtue.

Remember your first bicycle or motor car? Or the excitement you had with your very first camera? I am thinking about my very first engagement and love affair with computers, with the Scientific Data Systems 910 and 920. I courted them for seven years from 1965 to 1971 during my time at the Hartebeeshoek Tracking Station. See photo! These were the modest main frames installed at all the NASA Deep Space Network (DSN) facilities around the world. I say modest, because, though state of the art back then, compared to the average home desktop computer today they were very modest indeed! Though slow and awkward they were nevertheless indispensable links in the chain that would eventually put people on the Moon.

For the technically minded, the 920 specifications:

The  SDS  920  is  a  high-speed,  low-cost,  general-purpose digital  computer  with  the  following  characteristics:
24-bit  word  plus  parity  bit
Basic  Core memory  4,096 words  expandable to  16,384 words,  all  addressable
Parity  checking of all  memory  and  input/output operations
Memory  non-volatile  with  power  failure
FORTRAN  II  and  Symbolic  Assembler  as  part of  complete software  package
All  silicon  semiconductors
Dimensions:   66"  x  48"  x  27"
Power: IIOV,  60  cps,  10  amps
Input/Output:
Standard:
30G  character/second Paper  Tape  Reader
60  character/second Paper  Tape  Punch
Automatic  Typewriter
Dual-channel  Priority  Interrupt
Display  and manual  control  of  internal  registers
Optional:
Magnetic  Tape  Systems  (IBM  compatible)
Line  Printer
Direct communication  with  I ~ 7090,  A/D converters,  etc.

Much of this success was due to the use of silicon-based transistors in their earliest designs, the 24-bit SDS 910 and SDS 920 which included a hardware (integer) multiplier. These are arguably the first commercial systems based on silicon, which offered much better performance for no real additional cost. Additionally the SDS machines shipped with a selection of software, notably a FORTRAN compiler, developed by Digitek, that made use of the systems' Programmed OPeratorS (POPS), and could compile, in 4K 24-bit words, programs in a single pass without the need for magnetic tape secondary storage. For scientific users writing small programs, this was a real boon and dramatically improved development turnaround time. - http://en.wikipedia.org/wiki/Scientific_Data_Systems

Oh wow!

The first SDS 910/920's were ordered and built in 1962 and some continued in use as late as 1985. Functionally, the SDS computers took data received from the spacecraft and formatted and recorded it on magnetic tape. A computer at the Jet Propulsion Laboratory  in Pasadena processed the data further.

When I left Hartebeeshoek to enter the ministry, I was presented with a book, This Island Earth, (NASA 1970). It was inscribed with the words, "With best wishes from the 920's" and signed by the Telemetry and Command Processing Staff of DSIF-51. It is a book I treasure to this day, a memento of a first love.

These are the days of miracle and wonder
This is the long distance call
The way the camera follows us in slo-mo
The way we look to us all
The way we look to a distant constellation
That's dying in a corner of the sky
These are the days of miracle and wonder
                                        - Paul Simon
References:
Wikipedia, Scientific Data Systems, http://en.wikipedia.org/wiki/Scientific_Data_Systems
Allen Kent and James G. Williams (Ed), Computers in Spaceflight: The NASA Experience,
Douglas J. Mudgway, Uplink-Downlink: A History of the Deep Space Network,

©Colin G Garvie
HomePage: http://www.garvies.co.za