I recently acquired an HP-71B, and am exploring it as time permits. I didn't get any documentation, but have the Museum CDs (and thus the Owners and Reference Manuals). The unit has two plugin modules, one labeled "USA REV 0 M114A1 1 OF 2", and the second the same except "2 OF 2". The modules seem to be 64K and 32K RAM modules, respectively. (I've learned the MEM and SHOW PORT commands.) I've removed the second module and the first seems to remain available as RAM. I guess my question is, can these modules be used independently, as on different machines? Does the 1 0F 2 label merely indicate the port precedence or required order if more than one module is used, or is it locked into use in PORT 1? Likewise with 2 OF 2? Just trying to figure out how flexibly these modules can be used.




Bill, what is the version of your HP71? (type, VER$) The older 1BBBB versions don't do a complete SHOWPORT without the add-on lex file, "SHOWPORT" (they didn't show non-freeported RAM). SHOWPORT should show that the type of your modules is type 2, which is ROM, not RAM. Those modules were apparently used by the US Army to calculate munition trajectories. I have them myself and if I remember correctly, they are "PRIVATE", so you can't even view their contents (they contain BASIC programs) without some special techniques.


I just checked the version last night --it is 2CDCC. I didn't check the ROM number, but will tonight.

Military trajectory programs, huh? Don't imagine they will be of immediate use to a soils engineer.


More properly, your module set likely contains equations to compute artillery shell trajectories and required propellent load, elevation and azimuth settings to account for range-reach and prevailing winds. The M114A was a 155mm towed howitzer that was used during the Viet Nam era. I think it was used by both the Army and the Marines.

The ballistic equations are pretty much straight text-book stuff (and therefore not sensitive), but the modules likely also contain tables of ballistic coefficients for various shells and tables of propellent load (powder) all of which would be sensitive, hence the private designation.

The HP-71B (with these modules) was likely used as a back-up computer for the primary computer system used to compute fire solutions. All the services had / have ruggedized, mil-Spec hardward as their primary systems. Systems like the HP were then provided as a fallback in the event of disaster, like having your command bunker hit by counter-artillery fire...

I'm sure that others here can provide more accurate information...


Yes, I was able to read the file names on the ROMs, and the names match well with your descriptions. Most are BASIC files, all seem to be private.

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