IBM 129 Card Data Recorder

Another blast from the past, again probably before my time. An IBM 129 Card Data Recorder. Anyone got any experience with these? I can see the valves have been upgraded to a newer technology. Something I recognise - circuit boards!

Edit: Mirrored the images here.

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Nice! I think those sugar cube components are SLT modules - see Ken Shirriff’s blog for more info:

Although other manufacturers used integrated circuits for their third generation computers, IBM used modules called SLT (Solid Logic Technology), which were not quite integrated circuits. Each thumbnail-sized SLT module contained a few discrete transistors, diodes, and resistors on a square ceramic substrate. An SLT module was capped with a square metal case, giving it a distinct appearance. Although an SLT module doesn’t achieve the integration of an IC, it provides a density improvement over individual components. Each small SLT module was roughly equivalent to a complete SMS card, but much more reliable. By 1966, IBM was producing over 100 million SLT modules per year at a cost of 40 cents per module.


Excellent link, I had a skim through but the history behind the technology really is fascinating. Bookmarked for later reading, thanks! :+1:

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