If your NuBus card's firmware uses block transfers (transfers several cycles of data for a single address cycle) then you can get pretty close to 40 MB/s in theory, but still probably not closer than 7/8.
FWB was a good company in the distant past, so I expect that the JackHammer does use/support block transfers.
It doesn't, as far as I know, it's not a very fast card. It is designed with seamless compatibility in mind and thus doesn't use any of the crazy hacks other cards used to increase speed. I have 2 10,000 rpm U160 Seagate Cheetah drives on mine and they rarely get past 10 or 12MB/s. The same drives in a RAID 0 array on an ATTO Silicon Express NuBus card (in the same machine) tunred in close to 30MB/s and would top 20MB/s stand-alone. Thus I can only conclude the card isn't that fast. ATTO SEIV cards are still bootable (after a firmware upgrade) and are a devil to get working, but blow me they FLY, and yes they do use block transfers.
I am not aware of any RAID solutions beyond level 0 and 1 for Macintosh NuBus systems. There was probably something, somewhere, which was rare and expensive, but it certainly wasn't common and probably wasn't a software solution.
Anything above RAID 1 usually either is very slow in proportion to the system for a software solution or requires a hardware solution to get any decent performance, not to mention a bus that can shift more than 320Mbps.
However, for data security on a NuBus system, I would probably pick up a few modern wide SCSI drives which will deliver 20 MB/s of real world performance (this is very different from the advertised interface transfer rates) and RAID them in a level 1 (mirrored) RAID. Each drive will max out the JackHammer during transfers and while writes would probably be at half speed (~10 MB/s because you're writing to two drives) most of the RAID level 1 software will interleave the reads so that you should get close to 20 MB/s on reads.
You can never hope to muster 20MB/s standalone speed on a Jackhammer from what I have tried. If anyone knows something I don't however do tell, I'd love to know how to speed mine up!
Another trick is to get something like a Quadra 900 or 950 and install two JackHammers and spread the drives across the JackHammers. However, Kaye Yum tried this and found that performance was not improved. He may have been using SoftRAID though. I'm not sure if anyone's tried it with an older version of RAID ToolKit. SoftRAID is relatively recent so it may not have optimized NuBus transfers the way it does on PCI systems.
As I said, I got decent performance with the right card from RAID Toolkit. I feel it's a pretty good effort for what it does, and to be honest your unlikely to get much faster speeds on anything that is faster.
-- Mark Benson
AIM - SilValleyPirate MSN - [EMAIL PROTECTED] Visit FlatPackMacs online: <http://fpm.68kmac.com> Visit my Homepage: <http://homepage.mac.com/markbenson>
"Never send a human to do a machine's job."
-The Matrix
-- Vintage Macs is sponsored by <http://lowendmac.com/> and...
Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! |
Support Low End Mac <http://lowendmac.com/lists/support.html>
Vintage Macs list info: <http://lowendmac.com/lists/vintagemacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/vintage.macs%40mail.maclaunch.com/>
Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
