What are the really unusual or weird computers?
frustum at pacbell.net
Fri Jun 22 12:55:09 CDT 2007
Christian Corti wrote:
> On Fri, 22 Jun 2007, Sridhar Ayengar wrote:
>> How about the Timex TM100M? It never got past the prototype-stage,
>> but it executes BASIC in hardware.
> Well, so does the Wang 2200.
Not really -- the basic interpreter is written in microcode, but I
wouldn't call that execution in hardware.
Also, I'd argue that the microcode is really nearly an ISA -- there are
no pipeline hazards, the uword is very narrow (20b in the 2200A/B/C/S/T,
23b in the VP/MVP). The only thing that makes it ucode like is that
some instruction formats have control fields to manipulate independent
behaviors, and that jumps are within ucode page. Long jumps take a bit
of extra work.
The power of the first generation 2200 (A/B/C/S/T) was roughly the same
as a 4 MHz Z80, I'd estimate. The VP umachine was effectively about
5x-8x faster, and it was a lot nicer to program too. A factor of 2.7
was due to a faster cycle time (1.6 us vs 600 ns per uinst); a factor of
two was due to the 1st gen being a nibble machine, while the VP could do
8b and 16b ops; the rest was a collection of other improvements.
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