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In article <1991Jun4.133704.21008@cmcl2.nyu.edu> dimitrov@lab.ultra.nyu.edu (Isaac Dimitrovsky) writes:
>
>[]
>Does anyone know what the fastest link you can get between a PC host
>and a transputer on a board is? I was under the impression that it
>was 300Kbytes/sec, which is too slow for us. If we could get up around
>two Mbytes/sec, transputers would look very interesting for our
>application (it involves real time video compression).
>


``Bog-standard'' PC interface cards (like the INMOS B008) do max out
at 300K for the _HARDWARE_. Generally you would need to write your
own (or modify something else) software to achieve this speed in
an application however.

Links themselves have a 1.7Mbyte max data rate and so your 2Mbyte
target would require two simultaneous links. To achieve this look
for boards which use a transputer rather than a link adaptor as
the interface device. I've seen one from Transtech which does 
1Mbyte on one link through a device driver. Can't remember if it
supports multiple links. There are a few other cards out there
doing similar tricks but I forget who makes them.

As another thought, would it be possible to avoid sending 
the data to the PC altogether ? Perhaps by using a JPEG TRAM 
or transuter-based display board ?

David.


David Boreham, INMOS Limited | mail(uk): davidb@inmos.co.uk or ukc!inmos!davidb
Bristol,  England            |     (us): uunet!inmos.com!davidb
+44 454 616616 ex 547        | Internet: davidb@inmos.com

In article <1991Jun4.133704.21008@cmcl2.nyu.edu> dimitrov@lab.ultra.nyu.edu (Isaac Dimitrovsky) writes:
>
>[]
>Does anyone know what the fastest link you can get between a PC host
>and a transputer on a board is? I was under the impression that it
>was 300Kbytes/sec, which is too slow for us. If we could get up around
>two Mbytes/sec, transputers would look very interesting for our
>application (it involves real time video compression).

It is possible to build a link-interface for the AT-Bus, which easily
realizes a overall bandwith (unidirectional) of more than one MB/s.
We have build such a thing around a C011 link-adaptor and two
IDT 7204 4096x9 bit hardware Fifos. The biggest problem was, that you
have to build a 16-bit AT interface, since the 8 bit XT interface is
too slow.
With this design we realize about 1.2 MB/s transfer rate between two
of this adaptors. We have never connected it to a transputer, but i
think, that the transputer would not be the bottleneck.
Yours Stephan Wenger
stewe@opal   stewe@tub

In article <1991Jun4.133704.21008@cmcl2.nyu.edu> dimitrov@lab.ultra.nyu.edu (Isaac Dimitrovsky) writes:
>
>[]
>Does anyone know what the fastest link you can get between a PC host
>and a transputer on a board is? I was under the impression that it
>was 300Kbytes/sec, which is too slow for us. If we could get up around
>two Mbytes/sec, transputers would look very interesting for our
>application (it involves real time video compression).
>

Links wont cut it (unless you use 2 or more and that gets very messy).
So don't use links !  Build a board with a transputer and some ram dual ported
into the host PC address space.  That said you will be pushed to get 2MB
a second out of a PC/AT bus however EISA or MCA will do it.

We get close to 2MB on our EISA boards using this approach however our
product is not a general purpose design that you could adapt.
-- 
John Pettitt, Specialix International, 
Email: jpp@specialix.com Tel +44 (0) 9323 54254 Fax +44 (0) 9323 52781
Disclaimer: Me, say that ?  Never, it's a forged posting !

In article <3589@kraftbus.cs.tu-berlin.de> stewe@opal.cs.tu-berlin.de (Stephan Wenger) writes:
>
>It is possible to build a link-interface for the AT-Bus, which easily
>realizes a overall bandwith (unidirectional) of more than one MB/s.
>We have build such a thing around a C011 link-adaptor and two
>IDT 7204 4096x9 bit hardware Fifos. The biggest problem was, that you
>have to build a 16-bit AT interface, since the 8 bit XT interface is
>too slow.
>With this design we realize about 1.2 MB/s transfer rate between two
                                   ^^^^^^^^
>of this adaptors. We have never connected it to a transputer, but i
>think, that the transputer would not be the bottleneck.
                                           

Hmm. This sounds too high. I've never done any detailed measurements
but simulations predict no more than 1Mbyte/s from any link adaptor 
under any operating conditions. Are you sure you are measuring the
correct thing and that ACKs are matching the right data packets ?

David Boreham, INMOS Limited | mail(uk): davidb@inmos.co.uk or ukc!inmos!davidb
Bristol,  England            |     (us): uunet!inmos.com!davidb
+44 454 616616 ex 547        | Internet: davidb@inmos.com

In <16455@ganymede.inmos.co.uk> davidb@brac.inmos.co.uk (David Boreham) writes:
>In article <3589@kraftbus.cs.tu-berlin.de> stewe@opal.cs.tu-berlin.de (Stephan Wenger) writes:
>>
>>With this design we realize about 1.2 MB/s transfer rate between two
>                                   ^^^^^^^^
>>of this adaptors. We have never connected it to a transputer, but i
>>think, that the transputer would not be the bottleneck.
>                                           

>Hmm. This sounds too high. I've never done any detailed measurements
>but simulations predict no more than 1Mbyte/s from any link adaptor 
>under any operating conditions. Are you sure you are measuring the
>correct thing and that ACKs are matching the right data packets ?

A former colleague achieved the same transfer rate through a C011 with
a very simple VMEbus interface and no fifos to a T800 downloading
bitmaps into video ram. 

He didn't check wether the ACKs matched the right data packets though. :-)

-- 
Christoph Badura					Karlsruhe, Deutschland
bad@flatlin.ka.sub.org					+49 721 606137