I've got a
QLA2342 in my O2
. That's a dual 2Gb/s FC card capable of close to 400MB/s throughput (with a suitable array attached). First of all, the 64bit, 33MHz PCI bus of the O2 limits this to ~ 200MB/s. But real (diskperf) numbers are well below that, IIRC 60-70MB/s.
There's also an LVD version of the Adaptec 2940UW, the AHA-2940U2/U2W. I've had one of those in another (195Mhz R10K) O2 at some point. Requires a bit of PCI id hacking in the driver (similar to using an Adaptec 3940 ), but will provide similar performance.
I think the CPU speed doesn't even matter in the end, ultimately the O2's unified memory architecture 'bus' is where the limitation is.
Ultra-3 is LVD. Roughly speaking, SE SCSI (what the O2 has) requires 16 data lines plus ground, and LVD requires 16 differential pairs. So, this would require a redesign of the O2 mainboard and backplane. If you're going to do this, would you please raise the performance limitations of the chipset and allow for faster CPUs' and more RAM while you're at it?
There's also an LVD version of the Adaptec 2940UW, the AHA-2940U2/U2W. I've had one of those in another (195Mhz R10K) O2 at some point. Requires a bit of PCI id hacking in the driver (similar to using an Adaptec 3940 ), but will provide similar performance.
I think the CPU speed doesn't even matter in the end, ultimately the O2's unified memory architecture 'bus' is where the limitation is.
Winnili wrote:
How easy and practical, or even possible, would it be to add an Ultra-3/Ultra160 HBA inside the O2 and to which degree would the O2's overall bandwidth deal with it acceptably? And which of which, if any, work inside the O2?
Ultra-3 is LVD. Roughly speaking, SE SCSI (what the O2 has) requires 16 data lines plus ground, and LVD requires 16 differential pairs. So, this would require a redesign of the O2 mainboard and backplane. If you're going to do this, would you please raise the performance limitations of the chipset and allow for faster CPUs' and more RAM while you're at it?
_________________
Now this is a deep dark secret, so everybody keep it quiet
It turns out that when reset, the WD33C93 defaults to a SCSI ID of 0, and it was simpler to leave it that way... -- Dave Olson, in comp.sys.sgi
Currently in commercial service:
(2x)
In the museum : almost every MIPS/IRIX system.
Wanted : GM1 board for Professional Series GT graphics (030-0076-003, 030-0076-004)
. But you won't be able to boot from it because the O2's PROM can only boot from an Adaptec 2940.
...
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