🚀 go-pugleaf

In article <1080@m1.cs.man.ac.uk> mshute@r4.UUCP (Malcolm Shute) writes:
|What you have described seems to me to be a description of any SISD
|machine which can be implemented using bitslicing.  There's nothing
|wrong in that, of course.  My question to the net is, however, what is
|the value of the classification scheme if we can lump all bitwise-parallel
|von Neumann computers into the SIMD slot.

|Viewed the other way, if all of the processors access memory addresses
|in strict harmony like this, then they are only biting off parts of
|the *same* data stream.  (And hence all qualify as being SISD).
|Surely, it is only the MAMD machines which you mentioned later
|which can claim to qualify as true SIMD.

If I understand you correctly, you are missing an important part of
(at least some) SIMD architectures.  Take TMI's connection machine;
it has and interconnection network that can permute a word from each
processor to any other processor in a constant amount of time (well,
not quite, there is a factor of log2(number of PE's) in the equation,
but constant for a given machine size).  This network is a very important
part of the computational capacity of the machine.

Gerry Gleason