Re: 64bit PCI slots ?

[David Monro <davidm fuzzbox ml org>]

Dunno about afordable, but Symbios have a 64bit PCI card - dual SCSI Ultra-2
LVD (might be the 53c896 chip? not sure, I'm offline at the moment). You almost
need it for that card - consider the potential bandwidth for 2x80MB/s SCSI
chains - total is 160MB/s, and 32bit PCI only has 132MB/s peak bandwidth. I'd
hardly think the disk subsystem you would need to justify such a beast would be
even remotely affordable though :-)

(Let me see - really fast disks are getting more than 16MB/s sustained transfer
rate these days, so maybe 10 of them (ouch!), 5 on each chain. You'd probably
need some sort of multiplexing raid controllers between you and the drives
though, since I have never been able to get more than about 75% of the
theoretical bandwidth of a SCSI chain when using multiple devices (I guess you
get too much contention on the bus or something). I've no idea what you would
do with that rate of data; even an Alpha is going to have a hard time doing
anything sensible with it!)

64bit graphics cards might make sense, except that the market seems to have
gone for AGP (are they planning AGP on future Alpha boards?). Gigabit ethernet
might also be able to make use of more than the 32bit PCI limitations, and I
guess you might consider it for multi-port 100Mbit cards as well (but probably
only for more than 5 ports at a guess).

Of course, 32 bit cards work fine in 64 bit slots...

	David


> Hallo !
> A few days ago I added a sound card and recognized that my LX-board has
> only left two 64 bit PCI slots for upgrading (both ISA and 32 bit PCI
> slots are used up). I checked several webpages if there are any 64 bit
> cards at all but only found diagnostic cards.
> So a question from the curious (as of now): Are there any 64 bit PCI cards
> like network, graphics, SCSI or simmilar for affordable prices ?
> 
> Thanks for the info.
>
>          Helge
> 
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