Dear colleagues in vintage computing ;-) In the last years there has been substantial interest in the Apollo Guidance Computer (AGC). So maybe someone might be interested what happened outside of the United States in the 1960ties: Over the last few years I restored a 920M computer which was (among others) used as the guidance computer in the Europa rocket. This was the ancestor of the European Ariane sapce launcher: https://en.wikipedia.org/wiki/European_Launcher_Development_Organisation Although not well known, this machine is a contemporary of the AGC, it also uses integrated, SMD mounted circuits and is realized in DTL techology (Diode Transistor Technology). Its word width is 18bit, 8k of core store where standard within a show-box sized chassis. 2us and later down to 1us instruction time where stadnard. In contrast to the AGC, this machine was a member of a whole series of airborne computers - some of which are still in use TODAY (2021). After core and the DTL chips became obsolete, this architecture even was re-implemented by BAE systems using the AMD29XX chipset in the same chassis as drop-in replacement. The 920M never had core rope memory, and for rocket guidance 8k have been enough although adding a 2nd box extending the core was possible. Tte architecture is able to support up to 256k words of 18 bit. Of course, the instruction set is very archaic - no carry flag, no stack but it served its purpose with 18 bit choosen as the perfect word length to give reasonable resolution without need for double-word calculation in most applications; http://www.programmer-electronic-control.de/Elliott920FactsCard.pdf If this triggered some interest, you may watch my recently released video on the 920M (covers applications, internals and some software is shown running)... https://www.youtube.com/watch?v=v-gF5g0nnoE ...or visit my project page regarding the work of restoring three different members of this computer family to working condition: http://www.programmer-electronic-control.de/index.html Happy computing to all of you, best wishes, Erik. P.S. Just wanted to point out, that also in Europe there have been relevant developments regarding spaceborne computing in parallel to the Apollo programme! In no ways I want to diminish the achievemets of the Apollo development team... ''~`` ( o o ) +------------------------.oooO--(_)--Oooo.--------------------------+ | Dr. Erik Baigar Inertial Navigation & | | erik at baigar.de .oooO Vintage Computer | | www.baigar.de ( ) Oooo. Hobbyist | +---------------------------\ (----( )----------------------------+ \_) ) / (_/ Dr. Erik Baigar Scientific Lead Spectroscopy Systems Technologie Team Spectroscopy THORLABS GmbH M?nchner Weg 1 85232 Bergkirchen Germany Tel.: +49 (0) 8131 5956-40147 Fax.: ?+49 (0) 8131 5956-99 Mail: ?EBaigar at thorlabs.com Web: ?www.thorlabs.com General Manager: Dr. Bruno Gross HRB No: 85345, M?nchen