Hello dear readers,
I tried to install an Adaptec 1200A ATA RAID cotroller into my PE 2400. Everything went seemingly fine: BIOS recognized the card, and Windows NT (4.0 SP6a) was able to recognize the new harddisk with drivers installed. One thing worries me though. After the addition of the card everytime the Disk Administrator is initializing the whole system locks up for a few moments. When the Disk Administrator has completed its initialization, the system becomes responsive again. I've also noticed that the ATA RAID card is sharing an IRQ with PERC 2/Si. Could this be the culprit, or maybe the fact that I have disabled and just powered off a tape drive that was previously present in the system?
Another thing to mention is that when I tried to copy a large file from the PERC drive to the ATA drive no lock-up occured whatsoever.
The IRQ share COULD be a problem once you have heavy I/O on the two cards but is not likely to be the problem in this case. I suspect your Disk Administrator does not know how to handle the third party RAID card, and runs into a time out trying to access it. Can you manage the ATA RAID card using the Disk Administrator? If not, then this is likely the problem.
I discovered that this appears to be a normal behaviour of the Disk Administrator in NT4, since it locks up during the initialization regardless of the presence or absence of the ATA RAID card. As for the IRQ sharing: do you know how can I force the ATA RAID card to use different IRQ? IRQs 2, 7, 9, 13, and 15 appear to be free (in NT4 they are all used by MPS 1.4 - APIC platform, including IRQ 14, which is being shared). I'm aware of the RCU, which can be used for assigning IRQs to the specific PCI slots. Though, when I tried to assign IRQ 15 to the PCI slot occupied by the ATA RAID card, it wasn't listed as available in RCU. I haven't tried the rest of the "free" IRQs as I was unsure whether they were already occupied or not.
In the RCU advanced menu select "View additional system information menu" and "Used Resources" to view current assignments, and "Available Resources" to see if there are any unused IRQ's, you may need to disable the serial, USB or parallel ports to free up enough IRQ's.