davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (12/10/90)
IDE has the controller on the disk drive, and the interface between
the drive and the bus is a glorified parallel port. The claim is that
the noise is lower because the cable lengths are short, but the reason
is that there is more profit in it. The drive manufacturer gets the
profit from the controller and if you have more than one drive you get
to pay for more than one controller.
The interface costs virtually nothing to add to the motherboard, so
vendors add it and call it a feature. If you want to use full size disks
be very sure that you can disable the "feature."
For one drive the total system cost is probably lower than an
equivalent esdi, so it's not a liabinity if you can live with just one
of the little drives. If you need capacity in the GB range, you lose.
Note that I saw the CDC 766MB drives on year end clearance in one of
the mags for $1450. That's less than a pair of 208MB IDE, so you really
pay for capacity. And 1.2GB for <$2k... wish I hadn't just bought a pair
of 320MBs.
--
bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen)
sysop *IX BBS and Public Access UNIX
moderator of comp.binaries.ibm.pc and 80386 mailing list
"Stupidity, like virtue, is its own reward" -medavidsen@sixhub.UUCP (Wm E. Davidsen Jr) (12/13/90)
In article <1990Dec10.175003.17183@amd.com> phil@brahms.amd.com (Phil Ngai) writes: | If you want to sit around and theorize, then also consider that IDE | has the advantage over ESDI that it can (and does) use Zone Bit Recording, | where the outer tracks hold more sectors than the inner tracks since | they are longer. (SCSI can do this too but I disrecommend SCSI at | this point for lack of standards. I could be wrong, however.) As long as the ZBR is hidden so that the disk looks as if it has a constant number of sectors, most software will be able to handle it. A someone noted, you can't reformat the IDE drives, or actually, you need some special software and possibly hardware to do it. We mix drives and controllers with SCSI and seem to have no trouble with it. I'm not sure what you mean by lack of standard. The Mac disk interface is SCSI, and there doesn't seem to be a problem. | If you want to look at actual prices, which is what I think counts, | the small (40 to 80) meg IDE drives are very attractively priced. | | So I wouldn't put IDE down like that. I made that point, and you even quoted me, so I'm not sure how I'm "putting them down." | > For one drive the total system cost is probably lower than an | >equivalent esdi, so it's not a liabinity if you can live with just one | >of the little drives. If you need capacity in the GB range, you lose. | | You would think that the controller cost would be constant and so for | the larger drives, a smaller percentage of the total cost, meaning IDE | ought to be a better buy in the larger sizes. But I admit I haven't | looked at the price of large IDE drives. I haven't seen any drives larger than about 208MB, and certainly not the big cheap drives you get with ESDI. I thought my 320MB for $900 was neat until I saw someone in _PC Week_ dumping Wren's for 766MB/$1450 and 1.2GB/$1950. Now *that's* cheap. -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc and 80386 mailing list "Stupidity, like virtue, is its own reward" -me