Mildly
off-=thread, but there's a mini-chess (5*5
oard, each player has
king, queen, bishop, knight, rook and 5 pawns, no
castling, no en passant
capture) for the HP41 calculator (!). I think it
meeds a CV (or a C with
3 RAM moudles?) and will print the board on the HP41
thermal printer.
It's hardly a good player, but it's impressive (to
me) that it could be
done at all).
I vaguely remember the 41 coming in different models
(*C, *CV), so I assume that's what you're referring
to. Pity I didn't buy one back in the day.
Yes. THe original HP41 was the HP41C (C = Continuous Memory -- that is,
the memory contents are preserved when you turn the machine off). It has
64 'registers' of memory, 1 'register' being 7 Bytes (don't ask...)
All HP41s have 4 module sockets, and one module available for the 41C was
a memory module containing another 64 registers of RAM. You could plug 4
of those into the HP41C, but of course you then had no spare sockets for
ROMs or peripherals. Later on there was a 'quad memory module' which
added 256 registers, using only 1 socket. You could only plug one of
those in (so you were limited to the same total memory), but of course
you had 3 sockets empty if you sued that.
The HP41CV ('V' = 5 in roamn numerals) was effectively a 41C with a quad
memory module built-in (and thys 5 times the memory of a C). You couldn't
add any more RAM to this machine [1] but of course you had 4 empty
sockets for ROMs and peripherals
[1] Later on there was something called 'Extended Memory Modules'. These
appeared to the user ad a file-structured device. There was an extended
functions/memory moduel, which added the commands needed to access this
memory (and other useful commands as well) along with some extended
memory. You could add 2 further extended memory modules. This would work
in any HP41 machine.
Fianlly there was the HP41CX. This was an HP41CV with an extended
functions/memory module uilt in (you could add the 2 extra extended
memory modules in the sockets if you wanted them), a time module built in
(real time clock, alarms, stopwatch) and some extra functions not
available on any other HP41 or module.
All these machines exist in the original 'Fullnut' construction (seaprate
logic PCB connected to the keyoard/display by zebrastrip-like connectors)
and the later 'halfnut' construction (everything on one PCB.
SOme enthusiasts i nthe user groups did some very non-HP things. Like
putting 2 memory modules, or 2 extended memory modules, into one casing,
thus saving a socket. Or making a 'port extender' -- a unit that allowed
several physical modules to be connected to one socket on the HP41. THere
were many restrictions on what you could and could not do, which is one
reason HP never sold such a unit (although the HP41 service manual
mentions it at one point).
IMHO these machines are classic computers. They're over 10 years old,
they have a microcomputer-like architecture. They handle text as well as
numbers. ANd they'll link to peripherals -- disk drives, tape drives,
printers, plotters, RS232 interfaces, HPIB interfaces, GPIO interfaces,
video display interfaces, data loggers, and so on.
The machines are not rare in my experience. But fiding some of the
add-ons is non-trivial.
-tony
