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Ask Dave
by Dave Hamilton

He from whom all Mac knowledge flows...

SCSI-USB Conversion, Upgrade Advice, & AGP Voodoo3 Cards
January 21st, 2000

Greetings, folks. Today we talk about migrations -- migrating SCSI devices from older Mac's to newer iMacs and PowerMac's, and migrating a 3dfx Voodoo3 AGP card into a G4-based machine. It's bound to be a good one, so read on! If you have a question of your own, you can either e-mail it or post in the Ask Dave! Forums and we'll get you all fixed up. Enjoy!

Sandy writes, "I just bought an iMac and wanted to use my Zip 100 ext. drive which is SCSI. So I bought an adapter (USB Xpress SCSI from Microtech). I downloaded Zip tools, etc. from I installed the driver that came with Xpress. I terminated the Zip and tried both 5 and 6 ID on the Zip, restarting after each move. Still I could not mount the Zip drive (it wouldn't appear on the desktop). I called Microtech and a service technician said it's because the Zip drive has no 'termination power' which is supposed to 'send a 5v signal back to the chain giving power to the SCSI converter.' He said I should daisy-chain another SCSI accessory after the Zip which does have "termination power" and then the Zip Drive would work. Short of buying a USB-cabled Zip drive, what can I do? Is there any other interface or adapter that will provide 'termination power'?"

Sandy -- You're running into a problem that MANY new iMac owners are having (and G3/G4 owners without internal SCSI cards, too) -- The current USB to SCSI solutions have very limited successful application. It's a great idea, and you can get *some* scanners to work, etc., but it's very dependent on the devices involved and the integrity of the SCSI chain. Most card (or motherboard) based SCSI solutions are tolerant of some inconsistencies in the SCSI chain (improper termination, not enough term. power to the bus, different "width" SCSI devices on the same chain, etc.). Unfortunately, the USB to SCSI solutions are VERY strict with their reliance on a perfectly tuned SCSI chain (something that's quite rare with "standard" setups). My recommendation is to "follow the new path" that Apple has laid out for us and migrate to USB (or FireWire if your iMac supports it). That's going to save you from hours of headache and (possibly) hundreds of dollars in consulting fees to keep things running smoothly.

Michael N. Lewis writes, "I recently elected to install a 20GB Seagate HD on my PowerMac 6500 and had thought about putting a G3 card in until I found out that OS X is only going to support a true G3, and not an upgrade card (like Newer or Crescendo). On that note: 1.) Did I waste money on this 20GB HD? It set me back US$200. 2.) Should I put this CPU up for sale and try to get the current price and put that towards a new G4 with a SCSI card so I don't have to buy a new Scanner, Zip, Jaz, and Printer?"

Well, if the only SCSI device you had was this hard drive, then that might have been a waste of money. However, with a SCSI Scanner, Zip drive, and Jaz drive, you're going to be putting a SCSI card in any machine you get next. It's much cheaper to spend US$100 on a SCSI card than it is to replace all those peripherals (but make sure you get a card and not just a USB to SCSI solution like we discussed above!). So, I would say, no, you didn't waste your money. As far as upgrading your machine, well, there's always a reason to replace rather than upgrade, and you're probably in the right "time zone" to do it. You can still get SOMETHING for your machine, and the money you spend on a G4 today is going to last you a while. I'd do it sooner than later. You'll appreciate the speed benefit immediately, and you'll be ready for Mac OS X later this year.

Jay Thompson writes, "I noticed and liked your article on the Voodoo3 PCI boards, but my question is, does the G4 have an AGP slot that I can use with the Voodoo 3 AGP card? If so would this be a recommended upgrade for graphics and games?

The reason for the question is I have ordered a G4 from Apple, and I do have an extra V3 AGP card I would like to utilize.

P.S. This is My first Mac (which is not here yet), and I apologize if this is a rudimentary question.."

Not rudimentary at all, sir! All the currently shipping G4's have AGP slots (there was a time when the low-end model ran on a different motherboard, but that is no longer the case), and yes, the AGP-based Voodoo3 card should work fine in that machine. HOWEVER, the Voodoo3 cards require that you flash the ROM before it will work in a Mac. Mac's and PC's deal with initializing the video differently, and so they each require different ROM code. You can download and install it, but the AGP presents a problem -- you need to be able to have the Voodoo3 card in the machine at the same time as another card (i.e. until you flash the ROM of the Voodoo3, you can't use it, but you have to have the Voodoo3 in the machine to flash the ROM!). The G4 system comes with an AGP video card installed, so to do this, you'll need a separate PCI video card to make it work (I guess if you have a PCI Voodoo3, you could put that in, flash it's ROM, connect your monitor to that, install the AGP version, flash THAT ROM, connect your monitor to the AGP card, and then flash the PCI version back to "PC mode". -- Whew!). Good luck, and congrats on getting a Mac!

That's it for this week, folks! E-mail your questions to [email protected], or join the Ask Dave! Forums for reader-supported discussion of all your computer woes!

P.S. Have a Nice Day.

is President and CEO of The Mac Observer, Inc. He has worked in the computer industry as a consultant, trainer, network engineer, webmaster, and a programmer for most of the last 10 years. During that time he has worked on the Mac, all the various Windows flavors, Be, a few brands of Unix, and it is rumored he once saw an OS/2 machine in action. Before that he ran some of the earliest Bulletin Board systems, but most of the charges have since been dropped, and not even the FBI requests that he check in more than twice a year.

Ask Dave is here to answer all the Mac questions you have. Networking, system conflicts, hardware, you ask it, he can answer it. He is the person from whom all Mac knowledge flows....

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