... as did Seagate, Miniscribe, and others. Maxtor even made a couple of 1.2GB models. Dick ----- Original Message ----- From: "Julius Sridhar" <vance(a)ikickass.org> To: "Russ Blakeman" <rhblakeman(a)kih.net> Cc: <classiccmp(a)classiccmp.org> Sent: Friday, February 01, 2002 12:53 PM Subject: RE: Large ESDI Disks

On Fri, 1 Feb 2002, Jeff Hellige wrote: The later ESDI drives were used in later IBM AS/400's and some SNI Pyramids. Peace... Sridhar

Gee! I've never seen one that SMALL in the flesh, though I guess I read that there had been such things. The smallest I ever owned was 150, and that was just because it was half-height, meaning it would fit in the bay above the floppies ... Unfortunately for the PC community, ESDI controllers sophisticated enough to have sector translation schemes that would allow a drive to have more than 1024 cylinders were few and far between. None of the WD controllers I have used had that feature, and it would have been really helpful. The Lark Associates controller (smoked some time back) had the ability to masquerade a drives as two physical drives, in which case it wouldn't use the second data cable, sadly, but that allowed you to use a Maxtor 4380 or something of that ilk. It didn't do much for the 8760, though. Dick ----- Original Message ----- From: "Russ Blakeman" <rhblakeman(a)kih.net> To: <classiccmp(a)classiccmp.org> Sent: Friday, February 01, 2002 12:35 PM Subject: RE: Large ESDI Disks

According to what I. Dal Allen told an audience some 15+ years back, ESDI was an outgrowth of SMD, having been designed to fit the smaller form factor of the the-current 5-1/4" drive technology. Like other schemes that migrated controller functions onto the drive, albeit less than most, it put functions such as formatting on the drive, so that all one had to do was send the drive the command to format a track, along with some parameters such as sector size, sometimes jumpered on the drive, and sector interleave, etc, and the drive did the dirty work, including recovery of data, thereby eliminating the costly PLL normally found on the controller. Unfortunately, the relative intelligence interms of such functions as command queueing, seek overlaps, error management, etc, were still left to the controller, hence, though it transferred data at a pretty high rate, the actual performance was no better than an average SCSI. If ESDI lives on, I don't know why. The old Miniscribe drives I still have, I've kept because they have logic boards that allow them to be switched to SCSI, though that doesn't preserve the resident data. It's not a particularly good reason to keep 'em, but it serves as an excuse. Dick ----- Original Message ----- From: <jpero(a)sympatico.ca> To: <classiccmp(a)classiccmp.org> Sent: Friday, February 01, 2002 2:24 PM Subject: Re: Large ESDI Disks that was