john@bby-bc.UUCP (john) (06/17/88)
I'd like some help with some (perhaps naive) questions. Can a T414 be replaced by a T800 of the same clock speed with no other hardware alteration? As I remember it (please correct me if wrong) the transputer chips take a fixed frequency clock input (5mhz?) regardless of their operating speed - so is it possible to replace say a 15mhz part with a 20mhz part with no other changes (and get the expected performance increase out of the faster part)? What about the timing for external memory? What are reasonable going prices for 15 & 20 mhz T800 and T414 chips? thanks in advance, john ....!fornax!bby-bc!john ....!fornax!sfu_cmpt!chapman
darel@maccs.McMaster.CA (Darel Mesher) (07/07/88)
The Computer Science and Systems department of McMaster University has been using an original IMS B004 evaluation board in an AT host as part of a graduate course covering advanced architectures. The board was purchased late in 1985 when a similar T800 system was not available to us. Well, times have changed, and like everyone else I always keep my ear to the ground for ways to get older equipment to go faster. :-) Early last week we had the pleasure of a visit from Laurence Pegrum of the Central Applications Group of inmos UK. Laurie was visiting several sites in the Toronto area to distribute and demonstrate the latest release of the OCCAM development system and the revised folding editor (very slick). After the demonstration was over I took the opportunity to ask several questions that echo John's questions: In article <289@bby-bc.UUCP> john@bby-bc.UUCP (john) writes: >Can a T414 be replaced by a T800 of the same clock speed with no >other hardware alteration? I was informed that a 20 MHz floating-point T800 will (pin-for -pin) replace a 20 MHz T414. Since the IMS B004 that we have is based on a 15MHz T414, my next question was: > ... is it possible to replace say a >15mhz part with a 20mhz part with no other changes (and get >the expected performance increase out of the faster part)? Laurie smiled and said: 'No... unfortunately a 20 MHz T800 CAN NOT run at 15 MHz' :-( At this point our local inmos suppliers mentioned a complete set of internal documentation for hardware modification to the IMS B004 board to allow the swapping of the 15 MHz T414 with a 20 MHz T800. The modification apparently involves cutting several traces and adding jumpers; because, as John pointed out, not only does the CPU speed have to be increased but the original memory speed must be preserved. These modification notes are not in my hand yet (the entourage has several sites to visit before the supplier will be returning to his office) but if there is enough interest I will post a summary of the procedure to the net, then you can decide whether the task will exceed your technical abilities. >What are reasonable going prices for 15 & 20 mhz T800 and T414 >chips? The Toronto distributor seemed to think (off the top of his head) that a 20 MHz T800 sells for approximately CAN$500 but was unsure of educational prices. But if everything goes as planned John, you might be able buy a slightly used 15 MHz T414 cheap! :-) Finally, the IMS B004 board, altered as described should see a performance improvement of somewhere between 5 and 10 times depending on the application....well worth a little cutting and soldering. :-) Darel. -- Darel Mesher ...!uunet!mnetor!maccs!darel McMaster University darel@maccs.mcmaster.ca