Oddest mismatch in hardware for a given purpose...
derschjo at mail.msu.edu
Thu Jun 11 03:53:29 CDT 2009
Jules Richardson wrote:
> Josh Dersch wrote:
>> Internally though, they're 100% different -- the processor in the
>> MK-85 is a Russian PDP-11 knockoff. It's not a power-efficient CPU
>> by any means, so to ensure decent battery life the CPU speed is
>> severely limited. Not sure exactly what speed it runs at (anyone out
>> there know?) but the result is by far the slowest calculator I've
>> ever used.
> That's interesting. Does it have provision for AC input? Just curious
> if it auto-magically ups the clock speed when not running from the
> battery, as that would be kinda cool (and an early example of a
> power-saving mode :-)
It has an external power input, via some weird connector on the side.
It _does_ have a "high speed" mode -- if you turn it on while holding
"+" it runs 6 or 7 times faster (tested by running a program that just
runs a FOR loop from 0 to 1000 -- ~28 seconds in "normal" mode, ~4
seconds in "high speed" mode). No idea how it affects battery life, but
I can't imagine it's good :).
>> (The BASIC implementation is also incredibly buggy, mostly due to
>> poor argument checking... see
>> http://www.pisi.com.pl/piotr433/mk85mc1e.htm for a cool example of
>> exploiting a bug in INPUT to do machine-language coding, in a way
>> only a contortionist could love...)
> Gah, one of the home micro BASICs did something similar, so you could
> throw MC in there as a character string and 'trick' the BASIC into
> executing it by tripping the parser up - but my brain's refusing to
> tell me which one it was now.
>> Anyone else know of examples of odd-duck machines like this, where the
> > hardware is probably not the best choice for the application?
> Anything ever done using an IBM-compatible PC?
>> (But it's cool anyway?)
> Oh. Scratch that, then.
More information about the cctech