Pocket-sized PDP-11 once more
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I  was searching  for something.  As always,  I have  found many  other
things. In past  months I returnerd a  few of my Sharp  Zauri to (well,
very infrequent) use.

Now, I unearthed my Elektronika MK-85 [1] collection.

You many know than USSR used the CPUs compatible with the PDP-11 rather
extensively. So much  that use of a PDP-11 type  CPU was obvious choice
when designers were tasked with task of making a functional copy of the
Casio FX-770P pocket computer[2]. Or programmable calculator. While the
Casio used an 8-bit CPU the Soviet lookalike used the 16-bit CPU. There
was little speed or  memory size advantage at the time  but the CPU was
widely available an reasonably cheap so  it was used (these Soviet CPUs
are not clones but  they use most of the PDP-11  instruction set - they
are NOT fully compatible with any DEC PDP-11 CPU).

Actually making a device which copies  look and behaviour (up to almost
identical BASIC) of something that actually works was a smart decision.
The users  of nominally more powerful  MK-90 will know (it  uses rather
unoptimised copy of  PDP-11 BASIC from 1970 as it  only environment and
it is not only slow but painful to program on).

There are some  issues (Soviet components don't match  Japanese ones in
quality and  longevity - especially  the LCD is worse;  Soviet plastics
were always quite bad...).

Anyway, a  few FX-770P  bugs were  fixed (and  some original  ones were
added). The MK-85  has no extension/communication port but  can use A/C
adapter (a nice feature to extend battery life).

Back to my machines  - two have dead displays (I think  I bought the as
is, fr  spares, so  this is OK)  but one of  them actually  works (just
display has many leaks), the MK-85M (a more powerful model with doubled
memory)  seems to  be dead.  I have  two working  MK-85s anyway.  After
adding of four LR44 batteries they even ready to be used off-grid! Time
to write some programs!

Is there any other PDP-11 computer which fits in one's pocket?


References:

[1] https://web.archive.org/web/20180131155040/http://www.mk85.republika.pl/
[2] http://www.pisi.com.pl/piotr433/