Wondering which OS to use (PDP-8/A)

[Ethan Dicks]

On 10/22/05, Martin Bishop <mjd.NO.bishop.SPAM at iee.org> wrote:
> QUOTE The 8/A cannot have an EAE UNQUOTE
>
> Don't think this is correct.  Because, such a machine would have no serious
> (integer) arithmetic capability.

The -8/a wasn't always sold to the same crowd as the -8/e.  Lots of
-8/as were used for WPS/8 (the "DataSystems 310" package, for
example).  Never doubt that Marketing is capable of selling systems
that aren't "serious".  In any case, not everybody needs an EAE - I
myself have been using PDP-8s for 23 years, and with the sole
exception of wanting to put together a 12-bit SPACEWAR machine, have
never come close to needing an EAE.

There was an FPP-12 for the KK8A, but they were expensive (by PDP-8
standards) and rare (and not software compatible with the KE8E).  If
you _really_ needed to boost FORTRAN performance, you had that option,
but to my recollection, it wasn't an ordinary add-on.

> Also, the PDP 8/A Minicomputer Handbook
> 1976/77 has a lengthy section [pp9-56 .. 9-65] on the KE8-E (Extended
> Arithmetic Element : EAE).  However, the "PDP-8 Summary of Models and
> Options" (posted by Doug Jones) indicates that the EAE can be fitted iff the
> PDP-8/E CPU boardset is fitted.  That is PDP-8/A models 600/620 were fitted
> with the KK8E CPU and optionally the 8/E EAE.  And, I imagine "field
> specials" were doubtless built.
>
> Another wrinkle; correction invited.

OK... to be pedantically specific... the KK8A CPU cannot have an EAE. 
It's a single hex card with no "over the top" fingers to attach an EAE
to.  I can't speak for the original poster, but frequently, folks
conceptually lump together the box name "PDP-8/a" with the most common
(of its day) CPU "KK8A" and thus the original statement is seen from
time to time.

-ethan