Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!uwvax!oddjob!gargoyle!ihnp4!cuae2!ltuxa!ttrdc!ttrde!fjo From: fjo@ttrde.UUCP (Frank Owen ) Newsgroups: comp.sys.mac Subject: Re: Making *own* SCSI Hard Drive Message-ID: <230@ttrde.UUCP> Date: Wed, 15-Jul-87 13:54:47 EDT Article-I.D.: ttrde.230 Posted: Wed Jul 15 13:54:47 1987 Date-Received: Sat, 18-Jul-87 05:53:31 EDT References: <7141@shemp.UCLA.EDU> Distribution: na Organization: AT&T, Skokie, IL Lines: 36 > I leafed through some non-Mac magazines, and indeed it > looks like one can easily get a 40M Seagate sans controller > for less than $450. This stirred considerable enthusiasm in > - what is your estimate of the controller's cost ($300? $50?) You should be able to get controllers for ~$150. You may also be able to get old surplus SASI controllers for less than this. ("Computer Surplus Store" has a bunch of SASI boards for $79. They advertise in the back of Byte Magazine. ph.(408)-280-1740. You'll also need a power supply, case and cables to make a working model. > - I have no idea about how the thing works, so a very stupid > question: would this "poor man's" controller significantly > affect the disk's access time, if at all? The really cheap controllers might not be able to read disks formatted at a 1:1 interleave. (Read entire track in one revolution). The one I got (DTC 520) is limited to a 2:1 interleave factor. This is only an issue if you want to use the drive on an SE or MacII, because the MacPlus is not able to keep up with a 1:1 interleave factor anyway. The MacII (I think) can. (Although it does NOT have a DMA for the drive, it has a faster processor, so it SHOULD be able to keep up with the 1:1 data rate. ) In most cases, however, the greater measure of disk speed comes from the "average seek access time" of the drive itself. This measurement pretty much determines the price of the drive in question. > - are there any serious drawbacks of this solution .... The drawbacks are that you are really on your own in terms of getting the software working to drive your particuliar board/drive combination. You also don't get fancy things like disk-spoolers, and backup utilities (unless you want to spend the time writing them yourself, or find them availible in the public domain) Frank Owen ..ihnp4!ttmcsa!ttrde!fjo