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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: motorollin on April 01, 2006, 08:46:31 PM
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I fitted a SCSI kit to my Blizzard 1260 today, and it got me wondering whether the SCSI connector could be used for anything else, like a graphics card? Or is the connector only usable as a SCSI bus? Anyone know any technical details of the SCSI connector on the Blizzard?
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moto
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motorollin wrote:
it got me wondering whether the SCSI connector could be used for anything else, like a graphics card? Or is the connector only usable as a SCSI bus?
moto
if you try hard... who knows what could be connected to this marvelus device!!!
well, seriusly moto, this is a plain scsi device no more no less.
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Well I didn't know whether the bus that the SCSI interface connects to is just a SCSI bus, or some kind of ISA or PCI interface which could be expanded. Looks like no. Oh well at least we have PCI slots now :-)
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moto
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You can have siamese working using some kind of scsi network. People that used it says that it's a lot faster than ethernet.
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i suppose in theory, other devices could be added. years ago i heard of a network adapter for macs that plugged onto the scsi port. but then, god knows how they did this.
even if you were able to get software to use the scsi controller as a bus manager, what kind of glue logic would you need to bolt on GFX cards and the like? and who would write the drivers?
nice idea tho. instead of an external scsi box for desktop A1200s, you have an external card cage? - expanding on this idea, i have seen PCI extenders that use a fair length of ribbon cable, so might it not be more realistic to have some sort of mediator that instead of having pci slots, threw a couple of ribbon lines out to an external card cage where you could bolt in pci cards?
or how about a mediator with no PCI slots, but had an onboard NIC, GFX (or maybe mini pci?), sound, USB etc, in one compact board for desktop machines, and had a breakout box with all the ports on it?
nice idea for the scsi route tho. all of a sudden A500s, A2000s, et al. with scsi can have PCI expension too! :-D
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amije wrote:
well, seriusly moto, this is a plain scsi device no more no less.
Actually, the connector on the Blizzard is a DMA-enabled interface that doesn't have anything to do with SCSI in its own right. It's the add-on card that gives the SCSI ability - so theoretically it should be possible to design a card that fits the connector and bungs data to the Amiga via DMA.
Sounds cool, although probably a lot of hard work...
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Chunder wrote:
Actually, the connector on the Blizzard is a DMA-enabled interface that doesn't have anything to do with SCSI in its own right. It's the add-on card that gives the SCSI ability - so theoretically it should be possible to design a card that fits the connector and bungs data to the Amiga via DMA.
That's what I thought :eureka:
I guess nobody's gonna invest in this though now we have PCI solutions. Though Mediator and Prometheus don't support DMA do they? I wonder whether the Blizzard expansion connector is a wide enough bus for PCI with DMA?
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moto
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Siamese system offers this (even v2.1), however: scsi transfer speeds are limited (IIRC) to around 10Mbs for the full bus, so any devices which are being accessed will slow down network transfer speeds - ethernet (fast anyway) should be around 100Mbs [with the caveat that the crappy lack of DMA from mediator means limited to remaining PCI bus transfers after everyting else (graphics, sound, USB) has been taken off the fast memory ---> mediator transfer speeds].
Furthermore you would need to find a scsi card on the PC side which can change its own SCSI unit number, as the Blizzard scsi device is fixed as unit (0 or 7 - can't remember), and to run the scsi network the two devices MUST have different unit numbers.
I was musing before whether the mini-PCI attachment on the BPPC could be implemented to allow DMA access for the mediator by designing a BPPC - mediator bridge, but since I have no idea how to go about this, and both mediator and PPC appear to use proprietory closed drivers it remains a pipe dream.
Hadn't thought about that for the SCSI mk 4 though....
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Chunder wrote:
the connector on the Blizzard is a DMA-enabled interface that doesn't have anything to do with SCSI in its own right. It's the add-on card that gives the SCSI ability - so theoretically it should be possible to design a card that fits the connector and bungs data to the Amiga via DMA.
that's interesting and i wonder how come and nobody has done anything yet. they have make harware even for the clock port,
something that not even commodore should have dream to do...
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amije wrote:
that's interesting and i wonder how come and nobody has done anything yet. they have make harware even for the clock port,
something that not even commodore should have dream to do...
DCE own manufacturing rights to Phase 5 products, which means that you'd have to go through them in order to get some kind of documentation about the Blizzard 12x0 DMA expansion port, and possibly create a new expansion module for it.
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well, as there is a simm socket on the scsi kit, i'd say it was a fairly reasonable connector on the blizzard 12x0 :-)
but then the connector might be split into two. some pins for the scsi hookup, and some for the memory... i'm getting out of my depth here so i'll shush... :-)
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Yes, go for it :)
BTW, the new beating the dead horse (or is it donkey :lol: ) "smiley" is hilarious...
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Well I thought I would give it a try, so I soldered a ribbon cable from my Voodoo to the SCSI connector on my 1260. It didn't work.
Just kidding.
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moto
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Didn't seem like a 1st April post to me, at first. Theoretically it should be possible.
Anyway.. :horse: :-D
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Heh, well up until my previous post about soldering my Voodoo to my Blizzard, I was dead serious. Nothing wrong with a bit of humour about it though.
But yes, quite :horse:
:lol:
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moto
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On the registration card for the Blizzard, phase 5 actually asked what sort of expansions people wanted to see made for the port. Some choices were a graphics card, network interface, etc. I guess SCSI was all they got around to. :-(
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at least at my german part of the registration card (the english has been send at p5) there isn't anything like that. there are only a fiew questions about the progs that the user intend to use the bliz and a question about the quality of the board. as far as i can tell, don't know german.