There is at least one seller in the Mac sections of Ebay who loudly touts "50 pin SCSI" drives which are really adapted SCA (80 pin) drives. If you read his Item Description closely down near the bottom somewhere he'll mention that you can get a 68 pin drive instaed of a 50 pin drive, and, of course, what he really means, is that he'll include a SCA to 68 pin adapter instead of a SCA to 50 pin adapter.
Nowhere in the Item Description does he explicitly mention that he's really selling dirt cheap SCA drives with adapters as "50 pin SCSI drives".
I don't remember the seller's ID, but his auction motif is fairly distinctive with a lot of red, IIRC.
SCA drives with adapters can be made to work, but proper termination is a big issue of which most folks are ignorant. Having an adapter which is capable of handling termination properly is an issue too. And the termination must be handled differently depending on whether the drive is at the end or in the middle of the chain in non-obvious ways.
I wrote some pretty long explanations on this topic in the news groups (comp.sys.mac.***) back when, either under
trag@io.com or some variation on walther or jwalther@tnrcc.... Although those explanations may have been for adapting 68 pin wide drives to 50 pins. The principles are the same though.
As for 4GB Seagate SCSI drives...
If the drive you find is an ST15150N, I would avoid it. I had some of those back when they were new and expensive. They are *loud*, *hot* and in my experience, unreliable, but htat could have been a function of the heat. Even with proper cooling, they're still loud. These were some of the earliest, if not the first Barracuda drive and the first 7200 RPM drives were loud.
Another one to avoid is the 2 GB ST32550N. They were kick-bum in their day, but now days they're just loud and slow. Their best real-world data transfer rate is about 6MB/s.
Newer drives than those are probably faster and quieter. I mention those two, because I have experience with them and because I saw many many of them flood the used market when they came out of servers.
The Acard line of SCSI to IDE adapters has support for devices larger than 128 or 137 GB. So, in theory, you can put that $100 500GB drive in your SE/30. What's the maxium volume size on the SE/30? How many disk icons will that give you?
SCSI to IDE adapters are nice, though. IDE drives are common, inexpensive and with modern drives, quiet, cool and low power (relatively speaking). There can be issues about which drives are supported. In my experience, I've never had an IDE drive fail to work with the adapter, but I've read reports from others who have found drives with which their adapter was finicky. Still, IDE drives can be had so cheaply, how expensive is it to try a different drive?
I haven't posted to the Trading Post forum yet, because I want to take some pictures and such, but I have several Acard 7220U SCSI to IDE adapters for sale for $39 + shipping. Or $44 + ship with a 3.5" to 2.5" adapter included.
trag@io.com