mwandel@tiger.waterloo.edu (Markus Wandel) (04/15/90)
Hello, I am new to this group and I've noticed the occasional bit of discussion in old messages on how to run an ESDI drive off a SCSI bus. Maybe someone can help me. I have a Priam 638 ESDI disk. I am looking for anyone who knows something about these drives. Ultimately, I'd like to connect it to my SCSI system (on an Amiga), so I could use recommendations for SCSI/ESDI controller boards. I so far know of an Adaptec 4520 and an Emulex board of a number which escapes me. Are there others? Price is more of an objective than performance, so long as the board can move, say, 200K/sec. But the big question is another. I got this disk for free because it was a leftover from a project. The project was to adapt the disk to emulate a totally obsolete 8-inch disk with an obsolete interface. To this end, an adapter board was made (by Priam) which bolted onto the disk and converted its ESDI interface to something else with 50 pins (not SCSI, but the same connector). Memory gets very dim here but the old disk was an 80 megabyte unit; I should have written this down but I think it was a Priam 803. Anyway, the bottom line is that in addition to the adapter board being added, the formatting of the disk was almost certainly changed, and Priam documentation being what it is I have not been able to determine if that means the drive will still work. It's apparently a "hard sectored" drive with the sector headers permanently recorded on the disk surface, along with other information such as the bad block map, etc. At any rate, this stuff is likely gone. I recall reading in PC magazines that it's a very bad idea to format a Priam disk as it destroys data which only Priam can record on it. Is my memory correct here? Is the Priam 638 in an unformatted condition basically a boat anchor? The disk's manual says that it has a hard-sectored, 10Mb/s, serial ESDI interface, but doesn't describe very well what that means. So here is my question: Is there a SCSI controller which can take a completely "unformatted" Priam 638 ESDI drive, format it and use it? I will take any other information, especially tidbits about Priam ESDI drives, be they 638's or not, be they used on a SCSI system or elsewhere. This is a very nice disk (330MB, 20ms), it seems mechanically OK and it seems a crying shame not to be able to use it. Lastly, if I were to send this to a hard disk repair place, could it be retrofitted to the SCSI version (738) with just a new circuit board and formatting? Do I basically have a boat anchor? Is there a place where I can FTP an ESDI specification? I've seen a reference to a mail server which has it, but at the time of this writing, I will only have this account for five more days, so I probably need a quicker turnaround time than a mail server provides. Any help would be *much* appreciated. Markus Wandel