src@cs.odu.edu (Scott R. Chilcote) (11/17/90)
In article <1990Nov16.003735.14049@contact.uucp> rrwood@contact.uucp (roy wood) writes: > >Someone posted an ad for used ST equipment and made mention of "a Supra Hard >Drive Interface" and a Seagate hard drive. From this I infer that Supra >markets an interface that allows one to use a nice cheap IBM style hard-drive >on one's ST. Is this correct? And if it is so cheap to get set up with the >interface and drive, why would anyone choose anything else for his or her ST? > >-Roy Wood. Why wouldn't anyone want to buy an interface and use a standard hard disk? Is that your question? Here's my answer... A Supra hard drive interface costs $100, if you can still get one. There is a better product out now (I should know, I bought the Supra) from ICD, and it's about $130 mail order. This is called a HOST ADAPTER. Everything is an interface these days, so let's keep things clear. The Host Adapter plugs into the ST's DMA port (one of the very wise parts of an ST) and converts these signals to be SCSI compatible. You can have up to 10 DMA devices, and data rates have the potential to be 2 Megs per second through this port. Fast! Okay, so that's a start. You mentioned cheap IBM-PC style drives. But now we only have SCSI compatibility. Whoops! So you need to convert from SCSI to ST-412/506 now, if you want to use an off-the-shelf MFM or RLL-encoded PC type hard disk. What now? Well, the best and easiest choice is to get an SCSI compatible drive instead. This costs $30-$150 more than an equivalent ST-412/506 hard disk. The other choice is to buy a second "adapter", which converts from SCSI to ST-412/506. These come in both MFM and RLL flavors, and Adaptec is a good choice. They sell them for about $130, depending on the model. It will let you connect TWO cheap PC-type hard disks with one board. An extra savings... But now you need a hard disk, and hopefully one that's supported by the Supra or ICD formatting software. Otherwise you need a lot of specific information about your disks. And you need a box. And you need a power supply. And you need cabling. And you need the luck of the Irish, because if just one of all those connections you made is flaky, it is a long, arduous trail. It takes very sophisticated equipment to debug a hard disk setup -- or lots of trial and error. If you approach the chore correctly, you can do all this, save $50 - $200 over the cost of a mail-order ready made hard drive, and have a dependable machine. If, say, you get a bad part in the mail (which one) it is sheer hell. I went through all of this about two years ago, and wound up with a 65 Meg hard disk after six months of struggle. Not only did I get a bad hard disk, I got a bad Adaptek SCSI-RLL adapter! I'd still do it again, rather than buy a new setup. It has run without fail since then, and I need more space now. _________________ src@cs.odu.edu Scott R. Chilcote