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SCSI --> USB adapter cables, any good?
Posted by: Byrd on 2011-04-25 18:22:50
Hi,

I'm currently archiving and downloading as much 68K/PPC software as I can, and looking for ways to transfer it simply and easily to my older machines with SCSI. Since networking isn't so great under Snow Leopard, I'm tempted to pick up a SCSI --> USB adapter cable to plug my HD20 (with 9GB HD inside) into my 10.6 machine for backups.

I recall the adapters were popular around the CRT iMac era, but they weren't that great - can anyone recommend if they work well with SCSI hard disks, or are they really only useful for things like scanners?

Thanks

JB
Posted by: Trash80toHP_Mini on 2011-04-25 19:23:02
I don't recall such a thing. It would have been great if they existed and I'd sure like to have one!

I use ZIP Drives/Disks to Sneaker-Net between the old goodies, the middle aged bad-@$$ macs and the fugly/new iPoo!
Posted by: jruschme on 2011-04-25 20:18:42
A few companies made them, though the two I'm familiar with are Adaptec and Xircom.

IIRC, neither have drivers for Mac OS X, just 9.x (as well as Windows 9x through XP). I have both, but have only ever really used the Adaptec and that was with a Jaz drive under XP. I can say that it worked pretty well for that application, though. As I recall, the adapter loaded firmware upon initial plugin, reset, and then presented the drives as a standard USB block device.

Ironically, I think I saw a NIB Adaptec in a closet at $WORK, the other day.
Posted by: tmtomh on 2011-04-25 20:37:46
There are old threads about this on Appelfritter. Here are the basics:

SCSI-USB adapters do exist, and they do work under OS X, with the following qualifications:

(1) You can connect only one SCSI device at a time - even if the adapter says multiple SCSI devices can be daisy-chained.

(2) The SCSI ID of the external drive MUST be set to zero. This is clearly related to why you can only use one device at a time, even though you can daisy chain them under OS 8/9 and some versions of Windows. As an FYI, if you set the SCSI ID to something other than zero, the device will show up multiple times on the desktop. For example, if you set the ID to 3, it'll show up as 4 identical drives on the OS X desktop.

(3) The SCSI device must be terminated AND supply termination power. This is key. Most external hard drives supply term power, but not all. And especially with an older Apple external HD, you probably have to attach an external terminator.

(4) As the above indicates, this will only work if the SCSI device has an ID selector that you can set to 0. That rules out ZIP drives (which IIRC only allow you to select 5 or 6).

As for brands, only Adaptec ever claimed to allow daisy chaining - and therefore escape the "SCSI ID set to zero" requirement - under OS X. But unless you can find one in a closet at $WORK 🙂 they're very rare and expensive.

More common are the Microtech adapters, and they work fine with the above caveats.

Good luck - though
Posted by: Trash80toHP_Mini on 2011-04-25 21:01:41
You don't need one for ZIP Drives, they're readily available as USB devices.

I was thinking SCSI <-> USB or USB -> SCSI, not just SCSI -> USB!

I'd STILL love to get my hands on a USB -> SCSI on older Macs type adapter!
Posted by: jongleur on 2011-04-25 22:45:38
Byrd, I was looking at a similar requirement, but I've changed my mind (again) and I'm going down the Zip Drive path instead. One of the PB Duo kits I rescued recently from being trashed had a SCSI Zip Drive, and as I allready had a USB one, I figured that my collection of 100 and 250 MB disks would be big enough and convenient enough to store and transfer data and programs.
Posted by: Byrd on 2011-04-26 02:40:55
Thanks all for your advice. If I see one cheap, I'll give it a shot, they do seem to be expensive new on eBay.

Another option could be a PCI SCSI card, that works in OS X .... 🙂

JB
Posted by: Trash80toHP_Mini on 2011-04-26 06:27:50
If you've got a SCSI card in your PC/whatever, you can dedicate one of your IDE equipped PBs as a SCSI Disk Mode X-fer device and skip the ZIP! [😉] ]'>

As a side note:

I keep my basic set of installers for utilities, including Iomega Guest and a couple of standard programs on a New2MeMacCD, on a ZIP and a skeleton set of the above on Floppies.

Doing this allows me to get er' done quickly when it comes to verifying what's on/in any new arrival! :approve:

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