The card is a dual channel SCSI, using two of the NCR 53c720 SCSI controllers. There are two 68-pin internal connectors, channels A and B: the external 68-pin connector is shared with B.
| DIP switches.......................External_B
The DIP switches must be set correctly, or the card will never work. There are 9 or 10 DIP switches depending on the version of the card. The one I have is 10. The switches have two settings, for "Powermac/IIvx/IIfx", and for "All Other Macintosh".
9 switch card......................................10 switch card
OOO||||||.. is for "PowerMac/IIvx/IIfx"....OOO|||||||
OOO|||||O..is for "All Other Macintosh".... OOO|||||O|
The card can run in two modes: normal dual channel, and single channel for digital video. On my card, with IBM Ultra160 DPSS-309170 9 gig SCSI drives, I got the following benchmarks using Norton Utilities on my Quadra 840av, running Mac OS 7.6.1:
Non-RAID, HFS 4gig partition, dual channel mode:
10.2MB/s write speed, 15.2MB/s read speed.
Non-RAID, HFS 4gig partition, single channel mode for DV capture:
10.6MB/s write speed, 15.6MB/s read speed.
RAID-0 stripe using 2 disks, 4gig partition, single channel for DV capture:
10.2MB/s write speed, 4.6MB/s read speed. (yes, read speed was terrible)
When using modern fast SCSI disks, RAID is a bad idea. In normal non-RAID the card is very fast, beating the FWB Jackhammer in both read and write speed on the same system with same disks. The dual channel setting is slower, but still is faster than the FWB Jackhammer. The mode of the card is set from the Raven Pro Manager software.
This card has benefits, and limitations. Some are serious, so consider them before trying to use it in your system.
I'll first list the limitations:
- The card cannot use ANY drives until they have been formatted with RAVEN PRO MANAGER (v1.1.1)
- It is not SCSI Manager 4.3 compliant.
- The maximum partition size is 4gig; the manager software wont let you create larger volumes.
- Mac OS 8.x is NOT supported, DO NOT use this card with that OS! It is buggy as all hell, crashing, freezing up, and will drive you crazy if you attempt to use it on OS 8.x.
- The manager software can only create HFS partitions, not HFS+. (Even if you managed to get it to work in OS 8.x you would still not benefit from HFS+).
- Most SCSI software cannot detect the card at all, that includes the Apple System Profiler.
- The card is physically a maximum length card, so will not fit in all Nubus systems.
It has some nice benefits:
- Blazing fast, one of the fastest Nubus SCSI cards ever made.
- This card is BOOTABLE in OS 7.
- This card can boot off a 4gig partition on a 68k mac! <--only SCSI I ever saw that could do this on 68k.
- With two separate SCSI buses, you can run your internal drives off one bus, and the external ones off another.
- No extensions or control panels are used. ALL setup and adjustment for the card/disks is done via the
Raven Pro Manager software.
Some things to consider:
My 840AV has a Videovision Studio Telecast system. When benchmarking the drive for digitizing video using the Telecast through Adobe Premier 4.2.1, the speed difference between dual channel mode and single mode was much more pronounced. The Telecast capture benchmark takes into account all the bandwidths that are used for sound, video, and overhead from the SCSI and Nubus.
In single mode, I got a speed rating of 6.3MB/s available for video capture. With the card in dual channel mode, that dropped to 4.6MB/s.
There is a simple explanation for this drop. In dual channel mode, the card must activate Nubus locking, so the two active SCSI chips don't conflict with each other on the Nubus. This prevents freezes and crashing, but does slow things down a bit.
In single channel mode, Nubus locking isn't needed and the card can run at its best possible speed.
When I first got this card, and tried to use it, it didn't work. The DIP switches were set correctly for any other Mac, but it was not detected by anything in my 840AV, including the Raven Pro Manager. These cards are pretty old, so what I did was remove it, clean it, then gently remove the 3 socketed chips, and reseat them. I also cycled all the dip switches a few times to make sure they were making a good connection. Once I had done all that, the card still did not show up in the software. I was beginning to think it was a dead card. So, out of desperation, I set the card for PowerMac and tried again. The software still didn't detect the card, but by manually selecting the Nubus slot in the Raven Pro Manager, I was able to update the card to dual channel mode. After that I changed it back to the correct DIP switch setting, and it was properly detected by the software.
The settings for dual or single channel seem to be written to a flash chip in the card. So if you get a card, and it seems dead, don't give up so easy. My card is in perfect working order since then, and is proudly in my 840AV to stay.
If you want to run OS 8.x on your Nubus mac, don't bother with this card. With 8.x the best card is the very popular FWB Jackhammer. Its fast, bootable, and has no software problems with OS 8.
I only tried this card in a Centris 650, and Quadra 840AV. If you're using other macs, well, good luck. There is next to zero information about this card online, I searched extensively, and came up with almost nothing. The Raven Pro Manager 1.1.1 software is on a website that you will find if you search for the card. Special thanks to that person for hosting the old software for us to find. Without it, these cards cannot be used at all.
Thanks to my friends on the #68kmla chatroom on freenode IRC for putting up with my endless questions.