Jerome Fine replies: If I can add a comment, might I suggest that part of Megan's confusion is that while many 3rd party manufactures did produce ESDI disk controllers (if pressed very hard, I can probably think of about a dozen different ESDI models from Dilog, Emulex and Sigma to name just 3 companies) all of which also used MSCP as far as the Qbus interface to the PDP-11 was concerned, DEC never did bother. Thus, maybe Megan became used to thinking of the RQDX3 an MSCP interface - which it is - rather than the actual MFM hardware interface. In addition, not only DEC (although DEC was probably last to do so) but also all of the above named 3rd party manufactures also produced controllers (more correctly call host adapters) which were a SCSI hardware interface along with the MSCP command set. And of course, many of those 3rd party manufactures produced controllers which accepted MFM drives which also used MSCP. Finally, there were also controllers which handled SMD drives that also used the MSCP command set. Where Megan might have become confused was that the RQDX1,2,3 from DEC accepted only a trivial number of MFM hard disk drives for which DEC charged "interesting prices" - the markup was about 1000% - whereas the 3rd party companies accepted a wide range of different MFM drives, ESDI drives and SCSI drives although with the SCSI host adapter from DEC (RQZX1) probably all SCSI hard drives were allowed - Megan can you verify that? NOTE: As others have pointed out (implicitly) any given controller with a specific interface (MFM, SMD, ESDI and SCSI) required a hard disk drive which was built to use that interface. And last but not least, the RA81 type drives probably also used an MSCP interface, but I can't remember the controller. Also, the very last and probably least was the RC25 drive from DEC (probably the worst hard drive that DEC ever produced from what I have heard from others - never had the problem of having one myself) which also used MSCP. Is the above TOO MUCH? There is probably more I have missed as well like the Unibus controllers and host adapters. Plus, most, probably all of the controllers and host adapters can also be used with a VAX of the appropriate hardware backplane which also has a VMS device driver that uses MSCP as well. Sincerely yours, Jerome Fine -- If you attempted to send a reply and the original e-mail address has been discontinued due a high volume of junk e-mail, then the semi-permanent e-mail address can be obtained by replacing the four characters preceding the 'at' with the four digits of the current year.

--- Andreas Freiherr <Andreas.Freiherr(a)Vishay.com> wrote: The VAXBI controller is the KDB50. I do not know what any parts of an HSC50 are named. -ethan __________________________________________________ Do You Yahoo!? Yahoo! Shopping - Mother's Day is May 12th! http://shopping.yahoo.com

Jerome Fine replies: I heard from a number of individuals of their terrible experiences with their RC25. In one case, they even had a tossing of the RC25 media into the dumpster party when their PDP-11 was finally removed. By that time, the RC25 had been taken off maintenance and failed again shortly thereafter. I never heard from anyone that the RC25 was even a reasonable drive, let alone good. You are the first person to report anything approaching a reasonable experience with the RC25. By 1990, SCSI disk drives were so large and even removable magnetic optical media like the Sony SMO S-501 and other similar drives were so much better and larger in capacity that the RC25 was probably no longer able to offer much competition in any case - even if the hardware had been perfect. I switched one PDP-11 system from RL02 media to the Sony SMO S-501 in 1990. They skipped right past the RDxx drives right to the magneto optical storage since their primary requirement was removable media. Each cartridge (actually each side of the cartridge - there are 290 MBytes on each side) replaced about 15 RL02 packs. They had a total of 75 RL02 packs. Three media replaced three cabinets of RL02 packs. Three copies (nine magneto optical cartridges - the size of a small loaf of bread) were required in all. The additional two copied replaced 150 magnetic tapes - one for each RL02 pack. I am NOT saying that the RL02 was a bad drive, just how the storage situation changed between 1983 and 1990 when the RL02 and the RC25 had become a wee bit out of date. Sincerely yours, Jerome Fine -- If you attempted to send a reply and the original e-mail address has been discontinued due a high volume of junk e-mail, then the semi-permanent e-mail address can be obtained by replacing the four characters preceding the 'at' with the four digits of the current year.

On Thursday, May 9, 2002, Jerome H. Fine wrote: There was a potential rescue last year (didn't pan out AFAIK) that involved a bunch of third-party PDP-11 stuff from a major newspaper. Most of their drives had been replaced by Iomega 1GB Jaz drives. -- Jeffrey Sharp The email address lists(a)subatomix.com is for mailing list traffic. Please send off-list mail to roach jay ess ess at wasp subatomix beetle dot com. You may need to remove some bugs first.

IIRC that was a CDC drive rebadged and interfaced to a DEC controller... It looked good but was fragile as hell in real life. DEC customers liked more solid stuff... Bill