CM-1 lacks floating-point hardware, which anecdotally made it unsuitable for the typical supercomputer number-crunching tasks, that makes 1GFLOP somewhat questionable. Hillis' thesis quotes 1000MIPS for the 4MHz prototype. I believe that production CM-1s had higher clock speed than 4MHz, probably 10MHz, which would change that to 2500MIPS for 64k CPU CM-1.

It's been a long time since I'd read about the connection machine, so my memory may be foggy.

They didn't know what instructions would be useful, so each 8 bit alu supports all 256 instructions.

      zero   nand     ones
       0      1   ... 256
    ---------------------
       0      1         1  
       0      0         1
       ...
       0      0         1

and then a bunch of software support around around 'zectors' like a vector, with a zillion elements.

so I think you could do float, but you have 3 zectors, the low bits, the high bits and the mantissa, you might need another one for sign.

I think it was tough to give an apples to apples comparison, because it wasn't optimized for floats, but could do floats. it could also do bizarre things with bitmaps, if you could think of the right instruction to get your result. So for some problems, it was much faster than any alternative. But floats are readily accessible and well understood, so it's natural to reach for that tool first.

Anywho, my memory is foggy. I might be mischaracterizing the design. But I think that's about right.

I assume that there were two completely different CMLisp/StarLisp implementations as the language described by Hillis' disertation and StarLisp paper (ie. with xexctors and xaps) is significantly different in the overall design from the StarLisp as described in CM-2 manuals and as implemented by the Common Lisp CM SDK (it can be found somewhere on the internet and works in SBCL). The newer version is significantly lower-level and does not have the xector concept (and its design is similar to C and Fortran APIs for CM). I feel that the reason for this change was to make collective communication operations more explicit, probably because the store-and-forward communication network of CM-1/2 isn't exactly fast at doing arbitrary global permutations.

it was almost certainly less. while the cm2 had floating point chips from weitek lashed to the side, the cm1 ran one single bit instruction every .. ours was running a little over 4mhz, so 250ns. floating point was done in software.