Path: utzoo!utgpu!watmath!att!ucbvax!tut.cis.ohio-state.edu!pt.cs.cmu.edu!C7.IUS.CS.CMU.EDU!ralphw From: ralphw@C7.IUS.CS.CMU.EDU (Ralph Hyre) Newsgroups: comp.sys.apple Subject: Re: HomeBrew HDs Message-ID: <5799@pt.cs.cmu.edu> Date: 9 Aug 89 17:39:26 GMT References: <3491@ncsuvx.ncsu.edu><2815@ndsuvax.UUCP> Organization: Carnegie-Mellon University, CS/RI Lines: 45 In article <2815@ndsuvax.UUCP> nuwilken@ndsuvax.UUCP (Scott Wilken) writes: >In article jm7e+@ANDREW.CMU.EDU ("Jeremy G. Mereness") writes: >>often talk about "kits" that come with the drives for installation into >>an AT or XT. Do I need this stuff? Could I get the drive cheaper by >>asking the dealer to just send the drive and not the AT stuff and >>whatever software they throw in? >> >>and where are some good places to look for a case/power supply? >> > >actually I think you are misinterpretting some things here. First of *DONT* >buy the AT kits. The drives they use are *NOT* SCSI. You can buy adapters to >make them work on your apple, but it still wont be SCSI, and you will have big >problems down the road. When ordering a drive, make SURE that it is SCSI. I don't understand what 'big problems down the road might occur.' No drive is can quite be called a 'SCSI' drive, they all have the own peculiar low-level formats which get interfaced to the SCSI bus. The adapters are things like the Adaptec ACB-4000, which convert SCSI signals to whatever signal format the drive expects (usually ST-412 or ST-506 for XT and AT drives, RLL is another format, and a format knows as ESDI is also becoming popular.) ST506 drives are typically going to be cheaper, but you need to add $100 or so for the SCSI<->Native controller format adapter board. Newer drives have what is embedded SCSI; where the drive's interface board has the SCSI interface added on. If this is incompatible with what Apple expects, then you're OK. Apple has different expectation of SCSI than what some drives are prepared to offer, which means you have to be sure that the SCSI your drive talks is compatible with what Apple expects. (So much for standards.) You might be safe buying the same type of drives that Apple uses in their machines, but not necessarily. >As for buying a kit in the first place, you are wasting your money. When >putting together a homebrew drive, you arent BUILDING anything. What you are >doing is taking a pre-built SCSI drive, and putting a power supply and cables >on it. The whole process should take you all of 10 minutes. This depends on what prices you can find for kits vs. assembled units. I'd rather save $100 by handling my own screwdriver. -- - Ralph W. Hyre, Jr. Internet: ralphw@ius3.cs.cmu.edu Phone:(412) CMU-BUGS Amateur Packet Radio: N3FGW@W2XO, or c/o W3VC, CMU Radio Club, Pittsburgh, PA "You can do what you want with my computer, but leave me alone!8-)"