Re: Network coprocessor on the F21

[Penio Penev <penev>]

On Thu, 18 May 1995, Eugen Leitl wrote:

> On Thu, 18 May 1995, Penio Penev wrote:

> > The signal has to travel through all intermediate processors, which 
> > imposes a one-bit delay per node. This is essentially a ring topology. 
> 
> This is not so very. No big cluster, then.

It depends on the task at hand. If the algorithm needs only to broadcast
data, this could be very efficient. 

It could be very efficient for a small cluster. 

It could be very efficient for local bidirectional, if the ring direction
can be switched on the fly. 

For certain algorithms F21 is not the right chip. But, as Jeff will say, 
Chuck is in the custom VLSI business, so once the market niche is 
identified, one can order a specification very well tailored to the problem.

> > No, it is not needed. There is no need for arbitration at the network
> > level, since there is only one input and one output. The only arbitration
> > is done for memory access by the memory coprocessor. But then, it is not a
> > crossbar -- the low priority devices just wait. 
> 
> You are making it seem like a plus. 

For certain applications it is a plus.

> For a
> time I thought this to be a kind of 4th Transputer.

P32 might be more closer to a Transputer. It is said to have several
links. But this is coming later in the year. 


--
Penio Penev <Penev@venezia.Rockefeller.edu> 1-212-327-7423