5 ms·

A transistorized shift register box, built in 1965 for Apollo testing

80 points by parsecs 5y ago

kens 5y ago
Author here for all your questions about obscure Apollo hardware :-)
- jetrink 5y ago
  Do you think that this device was entirely bespoke or do you think that the designers adapted another design (perhaps a commercial product)?
  - kens 5y ago
    This device seems specific to its particular task. I wonder about the strange construction technique of pseudo-integrated-circuits on mini PCBs. It's hard to imagine that Control Data would come up with that specifically for this device. If I come across any other CDC systems that use the same technique, it will be informative.
    - neuralRiot 5y ago
      Probably it was done to save down time in the event of a failure, if something happened you’d just replace the affected module instead of the whole test box or to match certain characteristics, you build several modules and use the ones with similar parameters.
    - squarefoot 5y ago
      As a kid, in the mid 70s, I recall playing with a board similar to the one depicted in the article, purchased for a few coins at a surplus store. It had rows and columns of small modules stacked that way which consisted of one transistor, a few diodes and a bunch of resistors. All modules pretty much the same, but much smaller, with only one transistor and a few other parts, unlike the ones showed in the article. The equivalent circuit was indeed some sort of basic logic gate. Transistors were all TO72 packaged; I can't recall the manufacturer, possibly Motorola or SGS, and showed an unknown label as they were probably high grade parts relabeled for that customer which btw I'm sure wasn't NASA since I'm in central Italy. I salvaged what I could and ditched the board, so now you know who to blame if a rare piece of computer history has been lost forever:)
      - denton-scratch 5y ago
        I used to work at Burroughs, once upon a time. The groovy thing for proving you were an old-timer was a gate from a B5000, potted in perspex, and used as a paperweight. The gate consisted of two circuit boards, each about 2" square, with the discrete components wired between them, holding the two boards about 2" apart; so a gate was roughly a 2" cube. It's a long time ago, and I haven't seen one for 40 years; but I think these things had two transistors in them. No ICs.
        kens 5y ago
        "Cordwood" is the name for that type of construction. It was used in the Apollo Guidance Computer and by Control Data, among other uses.
    - projectileboy 5y ago
      CDC shaped the computing landscape in Minneapolis and St. Paul for many many years. Too bad Mr. Cray isn’t still with us; he could probably answer a lot of these sorts of questions.
anonymousisme 5y ago
Perhaps this was the inspiration for Boundary Scan (IEEE-1149.1) also known as JTAG.
lolc 5y ago
What strikes me about a unit like that is how it's just a small part in an undertaking where thousands of similar components had to be ready and interoperable within the decade.
- kens 5y ago
  Yes, it's like fractal levels of complexity. This box is a small part of the system to test a small part of a subsystem that's a small part of the Moon landing, but even this one piece is complicated, and had pages and pages of specifications.
  - jsrcout 5y ago
    I always think of building a system of this complexity as building a pyramid where each block is its own entire pyramid.
    - kens 5y ago
      What you're describing is the fractal Sierpinski pyramid :-) Picture: https://commons.wikimedia.org/wiki/File:Sierpinski_pyramid.png https://commons.wikimedia.org/wiki/File:Sierpinski_pyramid.p...
mulmen 5y ago
In my day job I do data pipeline development and operations. That involves a bunch of AWS services and some custom wrappers we developed in-house. I spend a lot of time clicking around in web interfaces. Recently I have fantasized about what it would be like to operate my environment with something like the ACE control room. Need to set a flag on some Spark option? That’s literally a switch. Is something on fire? Look for a flashing red light. Need to send the output of a task to some other process? That’s a knob. I think about this both in terms of literally making a control panel/room or a web interface equivalent. A control room seems like something that needs a lot of forethought and deep understanding. How would that requirement along with the difficulty of pushing changes influence the design of a web interface? Recently Ken obtained and shared some of the Roto-Tellite switches from mission control. Is that the 1960’s version of jQuery?
- TedDoesntTalk 5y ago
  You can forget automation then :)
  - mulmen 5y ago
    Why? Apollo was automated. The LEM could land itself. The control room just… controls. Why can’t my control room have a “backfill” station that takes inputs for begin and end date and dispatches that to the correct system?
    - KineticLensman 5y ago
      > The LEM could land itself No, really it couldn’t. Someone had to reset all those 1201 alarms while manually hovering it down to a boulder free site
      - mulmen 5y ago
        I suggest watching this excellent presentation: https://youtu.be/B1J2RMorJXM https://youtu.be/B1J2RMorJXM. He goes in to great depth in explaining how the LEM was in fact capable of landing itself. Automation was widespread in the development and execution of the Apollo program.
h2odragon 5y ago
Correct me if I'm wrong, but they really did need such extreme measures against humidity etc then, right? The components we have today are better sealed, the materials are less likely to be affected by humidity, etc etc. Years of marginal improvements in epoxies mostly I think.
- kens 5y ago
  One of the testing documents describes the problems they had with corrosion, so it was a genuine problem. Part of the solution was more air conditioning, and the other part was making the units more resistant to humidity. Keep in mind that they were on the Florida coast, so there was a lot of humidity and salt.
timonoko 5y ago
I remember two versions of Finnish parliament voting machine. 1965 it was like restaurant refrigerator and 1975 it was just one wire-wrap board in a lunchbox. Never has there been such a giant leap in few years, methinks. And this is probably due to the Apollo program.

80 points by parsecs 5y ago

kens 5y ago

Author here for all your questions about obscure Apollo hardware :-)

jetrink 5y ago
Do you think that this device was entirely bespoke or do you think that the designers adapted another design (perhaps a commercial product)?
- kens 5y ago
  This device seems specific to its particular task. I wonder about the strange construction technique of pseudo-integrated-circuits on mini PCBs. It's hard to imagine that Control Data would come up with that specifically for this device. If I come across any other CDC systems that use the same technique, it will be informative.
  - neuralRiot 5y ago
    Probably it was done to save down time in the event of a failure, if something happened you’d just replace the affected module instead of the whole test box or to match certain characteristics, you build several modules and use the ones with similar parameters.
  - squarefoot 5y ago
    As a kid, in the mid 70s, I recall playing with a board similar to the one depicted in the article, purchased for a few coins at a surplus store. It had rows and columns of small modules stacked that way which consisted of one transistor, a few diodes and a bunch of resistors. All modules pretty much the same, but much smaller, with only one transistor and a few other parts, unlike the ones showed in the article. The equivalent circuit was indeed some sort of basic logic gate. Transistors were all TO72 packaged; I can't recall the manufacturer, possibly Motorola or SGS, and showed an unknown label as they were probably high grade parts relabeled for that customer which btw I'm sure wasn't NASA since I'm in central Italy. I salvaged what I could and ditched the board, so now you know who to blame if a rare piece of computer history has been lost forever:)
    - denton-scratch 5y ago
      I used to work at Burroughs, once upon a time. The groovy thing for proving you were an old-timer was a gate from a B5000, potted in perspex, and used as a paperweight. The gate consisted of two circuit boards, each about 2" square, with the discrete components wired between them, holding the two boards about 2" apart; so a gate was roughly a 2" cube. It's a long time ago, and I haven't seen one for 40 years; but I think these things had two transistors in them. No ICs.
      - kens 5y ago
        "Cordwood" is the name for that type of construction. It was used in the Apollo Guidance Computer and by Control Data, among other uses.
  - projectileboy 5y ago
    CDC shaped the computing landscape in Minneapolis and St. Paul for many many years. Too bad Mr. Cray isn’t still with us; he could probably answer a lot of these sorts of questions.

anonymousisme 5y ago

Perhaps this was the inspiration for Boundary Scan (IEEE-1149.1) also known as JTAG.

lolc 5y ago

What strikes me about a unit like that is how it's just a small part in an undertaking where thousands of similar components had to be ready and interoperable within the decade.

kens 5y ago
Yes, it's like fractal levels of complexity. This box is a small part of the system to test a small part of a subsystem that's a small part of the Moon landing, but even this one piece is complicated, and had pages and pages of specifications.
- jsrcout 5y ago
  I always think of building a system of this complexity as building a pyramid where each block is its own entire pyramid.
  - kens 5y ago
    What you're describing is the fractal Sierpinski pyramid :-) Picture: https://commons.wikimedia.org/wiki/File:Sierpinski_pyramid.png https://commons.wikimedia.org/wiki/File:Sierpinski_pyramid.p...

mulmen 5y ago

In my day job I do data pipeline development and operations. That involves a bunch of AWS services and some custom wrappers we developed in-house. I spend a lot of time clicking around in web interfaces. Recently I have fantasized about what it would be like to operate my environment with something like the ACE control room. Need to set a flag on some Spark option? That’s literally a switch. Is something on fire? Look for a flashing red light. Need to send the output of a task to some other process? That’s a knob. I think about this both in terms of literally making a control panel/room or a web interface equivalent. A control room seems like something that needs a lot of forethought and deep understanding. How would that requirement along with the difficulty of pushing changes influence the design of a web interface? Recently Ken obtained and shared some of the Roto-Tellite switches from mission control. Is that the 1960’s version of jQuery?

TedDoesntTalk 5y ago
You can forget automation then :)
- mulmen 5y ago
  Why? Apollo was automated. The LEM could land itself. The control room just… controls. Why can’t my control room have a “backfill” station that takes inputs for begin and end date and dispatches that to the correct system?
  - KineticLensman 5y ago
    > The LEM could land itself No, really it couldn’t. Someone had to reset all those 1201 alarms while manually hovering it down to a boulder free site
    - mulmen 5y ago
      I suggest watching this excellent presentation: https://youtu.be/B1J2RMorJXM https://youtu.be/B1J2RMorJXM. He goes in to great depth in explaining how the LEM was in fact capable of landing itself. Automation was widespread in the development and execution of the Apollo program.

h2odragon 5y ago

Correct me if I'm wrong, but they really did need such extreme measures against humidity etc then, right? The components we have today are better sealed, the materials are less likely to be affected by humidity, etc etc. Years of marginal improvements in epoxies mostly I think.

kens 5y ago
One of the testing documents describes the problems they had with corrosion, so it was a genuine problem. Part of the solution was more air conditioning, and the other part was making the units more resistant to humidity. Keep in mind that they were on the Florida coast, so there was a lot of humidity and salt.

timonoko 5y ago

I remember two versions of Finnish parliament voting machine. 1965 it was like restaurant refrigerator and 1975 it was just one wire-wrap board in a lunchbox. Never has there been such a giant leap in few years, methinks. And this is probably due to the Apollo program.