Generation Gap

You don't know what you've got till it's gone. It may sound trite?it's even immortalized by a Joni Mitchell song?but no one knows this better than owners of Apple's latest computers. For 14 years, every Macintosh had a SCSI (short for small computer system interface and pronounced "scuzzy") connector on the back. Most Mac users take for granted this easy and familiar means of hooking up everything from scanners to hard drives to CD writers. Or, at least, they did.

Apple's decision to replace SCSI with USB on iMacs and both USB and FireWire on the new blue G3s means that now you need to think about something that was never an issue in the past: how do you connect your old SCSI devices to your speedy new Mac?

You might assume that you should bite the bullet and buy all new USB or even FireWire versions of your peripherals. But for once, money won't necessarily solve all your computer problems: USB is much slower than SCSI, and FireWire peripherals are still scarce. Actually, the answer may be as simple as adding in what Apple has taken out?a SCSI card.

If you haven't bought a new blue Power Mac G3 yet, there's an easy?if not perfect?way to reclaim SCSI connectivity. When you buy your computer from Apple's online store, you can ask to have a SCSI card (Adaptec's PowerDomain 2930U) added for an extra $49. Unfortunately, our tests revealed a software issue that can make this card very slow (see the benchmark, "It's No Race"). You can get something faster built into your new Mac by choosing Apple's $340 9GB SCSI hard-drive option. Along with the hard drive, you'll get a SCSI Ultra2 Wide adapter, the Adaptec PowerDomain 2940U2W.

What if you've already got a new G3 and your trusty old scanner is sitting forlornly by its side? Or what if you want a card that's faster (or of a different SCSI type) than what you can get from the Apple Store? We rounded up 16 SCSI cards to see which of them offer the most speed and the fewest problems (see the sidebar, " The Right Card for You," for the results). But we did not stop there: we also gathered tips to help you through every aspect of picking, installing, and troubleshooting the right SCSI card for your needs.

The first thing you might ask is why you'd want to bother opening up your new G3 to fill one of its three precious PCI slots with a SCSI card when you can buy a USB-to-SCSI adapter instead. Indeed, by the time you read this, there should be several of these adapters on the market. All of them let you connect your old SCSI devices to your computer through the USB port.

But there is a catch: if you use a USB adapter, your devices will slow to a crawl. The maximum speed you'll get is 1.5 MBps?the top speed of the USB port. This is pretty pathetic when you're used to at least 5 MBps?the speed SCSI ports on most older Macs can accommodate.

The Out-of-Luck iMac Slow or not, an adapter is the only option for most iMac owners with SCSI devices, because these computers do not have expansion slots. The only exception is the original Bondi blue iMac, which contains one mezzanine slot hidden beneath the plastic case. Formac's $139 iProRaid card (925/855-1063, http://www.formac.com ) takes advantage of this slot to add a SCSI port. Apple has removed the hidden mezzanine slot from the newest iMacs.

Once you've decided that you want a SCSI card, you're faced with a new question: what kind of SCSI? SCSI goes by many names: Ultra, Wide, Ultra2 Wide, Narrow, Fast, and LVD, to recall a few you might have heard of. But there are only two basic types?Narrow and Wide?and each is tailored to a different need: compatibility or power.

People who connect an external hard drive for extra storage space or who scan photos for a personal Web site need an inexpensive, compatible card?a Narrow one. Those who have lots of devices or who use digital-video gear require power and speed?a Wide card. Different varieties of Narrow and Wide SCSI offer various speed advantages and have individual quirks.

Narrow SCSI Narrow SCSI cards have 50 pins on their connectors?25 for transmitting data and 25 for grounding. The cards are inexpensive but relatively slow, offering speeds from 10 to 20 MBps.

Why do we say relatively slow? Because as slow as these cards are, they're still twice as fast as what came built into most old Macs. Before the iMac and new blue G3s, Macs came with SCSI-1?a type of SCSI so sluggish by today's standards that it is no longer available on the market.

Most scanners, removable drives (Zip, Jaz), tape drives, and CD-R drives use Narrow SCSI. The most common types are Fast Narrow and Ultra Narrow. A Narrow card allows you to attach as many as seven devices together in a chain?as long as you keep your cable lengths short. If the cables get too long, the signal begins to fade and you may end up with unmountable drives and frequent crashes. You can have 3.2 to 6.5 feet of total cable on your SCSI chain. This includes both the cables used to connect external devices and the ribbons used to connect internal devices.

Wide SCSI Don't be confused by the fact that Wide SCSI connectors are actually more svelte than the so-called Narrow ones. The name comes from the number of pins?68 in all?that are crammed into that small space and the greater amount of data that passes through them.

These cards are more expensive, but they're faster, supporting speeds between 40 and 80 MBps. They can also handle a greater number of devices?15 in all (only 7 can be Narrow). The most common Wide SCSI devices are hard drives. However, anyone who wants to use Wide devices or needs to connect more than seven devices on the chain will need a Wide card. Common varieties of Wide SCSI are Ultra Wide and Ultra2 Wide. The latter is also known as low-voltage differential (LVD for short).

Ultra2 Wide cards offer maximum speed for digital video or large graphics files and also allow longer cable lengths than Narrow or Ultra Wide SCSI. However, these days only a few high-end hard drives use this technology. Also, if you put a non-Ultra2 Wide device on your SCSI chain, the chain will drop back to the speed and cable limits of Ultra Wide.

Mixing and Matching So what should you do if you have several types of SCSI devices? You cannot reliably hook up a Wide device to a Narrow card. However, you can hook up a Narrow device to a Wide card. Because the Wide connectors have more pins, you will need at least one new cable to connect your Narrow devices to the new, wider port.

When you add Narrow devices to your chain, it won't automatically become slower, unless you're using Ultra2 Wide SCSI. But moving your Zip drive to a new Wide card will not make the drive faster, either. Devices have their own built-in speed limitations.

One warning: moving Narrow devices to a Wide card can cause problems. Wide chains are more prone to interference?loss of signal as the length of cable grows?so you'll need shorter, thicker cables with more shielding. Also, if you add a Narrow device and you happen to have low-quality cables, cheap terminators, or multiple devices on a chain that's just a little too long, your new system may begin freezing at start-up or crashing during file transfers.

Installing a SCSI card, and indeed any card, on a blue G3 is pretty darn easy?but make sure to do it right.

Get Grounded Static electricity can fry the delicate electronics on your new card, so when you install it, make sure to discharge any static electricity in your body by touching metal (if you've got a metal casing around your hard drive, try touching that). Also, keep yourself grounded by winding a grounding strap around your wrist and attaching the end to metal. None of the cards we looked at came with a strap, but you can buy one at most electronics stores. Once you're sure you're not a lightning rod, pop the card into any available PCI slot.

Don't Skip the Software After the card is in, you'll probably need to install an extension in your System Folder; most of the cards we tested also came with software to set up?or format?a hard drive. Use this software every time you attach new hard drives to the SCSI port.

Adaptec supplied software on floppies only, which isn't particularly useful for computers without floppy drives. The company says it will soon ship software on CDs. In the meantime you can download it at http://www.adaptec.com/support/files/drivers.html. You must get Orange Micro's software from its Web site.

Get Up-to-Date It's worth checking the company's Web site, as the software that ships with your card may very well be outdated. Updates can solve speed issues and compatibility problems. We had to update the software on the card (also known as firmware) for all three Orange Micro cards, all four Adaptec cards, and the Initio Miles Bluenote.

Installing a card is easy, but by nature SCSI can be a temperamental beast. Here's how to deal with some common problems.

Missing Formatters The Orange Micro cards do not come with formatters in the box. Instead, you'll need to download a version of CharisMac's popular formatter Anubis from the Orange Micro Web site ( http://www.orangemicro.com /bin/anubis.bin). Adaptec also did not include any formatters with the PowerDomain 2930U or SCSI Card 2906, but the company says it will have added them by the time you read this.

Cards That Won't Boot One handy thing about SCSI cards is that if you need to repair your main start-up drive, you can typically use a hard drive hooked up through your card to start, or boot, your computer (as long as that hard drive has system software installed on it). Unfortunately, not all the cards we tested were able to do this.

When new G3s look for the start-up disk, they don't necessarily see the SCSI card?and hence the drive attached to it?unless the card has the right firmware. During testing, we were able to boot up from only 12 of the 16 cards. The Adaptec SCSI

Card 2906 is not a bootable card. The AdvanSys cards were also not bootable, but a firmware update that will fix this problem should be available from the company's Web site by the time you read this.

Mistaken Identity Each SCSI device on the chain must have a unique address so that your computer knows where to send the data. The address, or SCSI ID, is a number from 0 to 7 for Narrow cards and from 0 to 15 for Wide cards. Customarily, both types of cards come preset to 7. If two different devices have the same number, your system may freeze at start-up or only one of the devices may appear on the desktop.

If you're also going to add in old SCSI internal drives, remember that you'll need to pick IDs for them as well. External devices come with dials to pick the ID. Internal devices are trickier?you'll have to muck with the jumpers, little plastic caps that fit over pairs of pins. (By default, internal drives are set to 0.)

Termination Trouble As data travels down the SCSI chain, it needs to know when it's hit the end. For this reason you must terminate your SCSI chain at both ends. Otherwise, your computer might hang or might not see the drives.

If you're connecting only external devices, the card terminates the end of the chain it's on. All you need to do is terminate the other end by inserting a termination plug into the free SCSI port of your last device. If you have internal and external devices, the card detects this and turns termination off. You then need to terminate the last internal device and the last external device.

Old-Device Uncertainty Older SCSI devices, particularly scanners, relied on the way the Mac used to manage SCSI. We checked all these cards with the Umax PowerLook III and had no problems. But if you plan to connect an older scanner (made, say, three or more years ago), make sure the card you want supports the "old" or "classic" SCSI manager. Call the company to make sure your scanner is supported, or else it may be useful only as a paperweight.


You don't have to shun the new Power Mac G3 just because you've sunk a lot of cash into SCSI-based scanners and hard drives. And you certainly don't need to buy USB versions of all your devices. With a modest budget, some common sense, and this guide in hand, you can bring your old SCSI devices and new Mac together and have the best of both worlds.

August 1999 page: 82

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