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71B vs 75D
04-15-2021, 06:10 PM
Post: #25
RE: 71B vs 75D
(04-15-2021 04:32 PM)hth Wrote:  Yes, this was my thinking also. I am very much into ISAs and architectures and Capricorn is really interesting. I think the HP-75 is let down by the lack of RAM and I am not sure if it is possible to replace ROMs, there seems to be no plug-in feature.

You have 3 ROM plugin ports - ROMs are bankswitched, all very similar to the Series-80s.
One could also make something like the ROM emulator which was available from HP and plugged via cable to the ROM ports or something like the "Modem/RAM-Disk Pod".
The ROMs have some "intelligence" as they monitor a certain address and switch themselves on/off as needed.
The difficulty is probably more in finding or making proper connectors. Today it could be easier with 3D printing and individual contact springs?

Martin
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Messages In This Thread
71B vs 75D - dhe - 04-13-2021, 03:47 AM
RE: 71B vs 75D - rprosperi - 04-13-2021, 01:22 PM
RE: 71B vs 75D - Maximilian Hohmann - 04-13-2021, 01:54 PM
RE: 71B vs 75D - Gene - 04-13-2021, 03:18 PM
RE: 71B vs 75D - Dave Britten - 04-13-2021, 04:51 PM
RE: 71B vs 75D - rprosperi - 04-13-2021, 05:29 PM
RE: 71B vs 75D - Sylvain Cote - 04-13-2021, 06:21 PM
RE: 71B vs 75D - dhe - 04-13-2021, 08:26 PM
RE: 71B vs 75D - rprosperi - 04-13-2021, 10:34 PM
RE: 71B vs 75D - Andres - 04-13-2021, 11:52 PM
RE: 71B vs 75D - Dave Frederickson - 04-14-2021, 12:23 AM
RE: 71B vs 75D - Andres - 04-14-2021, 02:01 PM
RE: 71B vs 75D - Sylvain Cote - 04-14-2021, 12:15 AM
RE: 71B vs 75D - Garth Wilson - 04-14-2021, 02:04 AM
RE: 71B vs 75D - Dave Frederickson - 04-14-2021, 02:19 AM
RE: 71B vs 75D - Sylvain Cote - 04-14-2021, 02:49 AM
RE: 71B vs 75D - hth - 04-14-2021, 04:50 PM
RE: 71B vs 75D - rprosperi - 04-14-2021, 05:18 PM
RE: 71B vs 75D - hth - 04-14-2021, 08:32 PM
RE: 71B vs 75D - rprosperi - 04-14-2021, 11:28 PM
RE: 71B vs 75D - Martin Hepperle - 04-15-2021, 11:10 AM
RE: 71B vs 75D - J-F Garnier - 04-15-2021, 12:30 PM
RE: 71B vs 75D - Sylvain Cote - 04-15-2021, 03:45 PM
RE: 71B vs 75D - hth - 04-15-2021, 04:32 PM
RE: 71B vs 75D - Martin Hepperle - 04-15-2021 06:10 PM
RE: 71B vs 75D - Sylvain Cote - 04-15-2021, 06:28 PM
RE: 71B vs 75D - Didier Lachieze - 04-15-2021, 06:57 PM



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