Xref: utzoo comp.sys.mac:20531 comp.sys.mac.programmer:2474 Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!husc6!endor!olson From: olson@endor.harvard.edu (Eric K. Olson) Newsgroups: comp.sys.mac,comp.sys.mac.programmer Subject: Re: SCSI Cables and Terminators Message-ID: <362@husc6.harvard.edu> Date: 19 Sep 88 16:13:13 GMT References: <883@osupyr.mast.ohio-state.edu> Sender: news@husc6.harvard.edu Reply-To: olson@endor.UUCP (Eric K. Olson) Organization: Lexington Software Design, 72A Lowell St., Lexington, MA 02173 Lines: 45 In a recent article Paul G. Nevai writes: >For starters, did you know for instance, that > Mac -- System Cable -- Hard Disk -- Teminator >is wrong? The right configuration is > Mac -- System Cable -- Teminator -- Hard Disk I've never found any difference between these two configurations. Some hard disks only have one plug, and you have to use the second configuration. >OK? Now, for advanced intermediates, did you know that > Mac -- System Cable -- Cable Extender -- Teminator -- Hard Disk >is wrong? The right configuration is > Mac -- System Cable -- Terminator -- Cable Extender -- Teminator -- > -- Hard Disk In fact, the first terminator should be right after the Mac, but it's not possible to put one there unless you put a terminated hard disk inside (like a Mac II or SE). The bus is long enough to want a terminator at BOTH ends (any long SCSI bus should have a terminator at both ends), but with Apple's cabling you can't plug a terminator right on the computer (because they use a DB25 connector instead of the standard). >Now, for pros, do you know where the terminator goes in > Mac -- System Cable -- Cable Extender -- Hard Disk -- Cable Extender -- > -- System Cable -- Hard Disk ? Use two, at the farthest ends of the bus you can get to: Mac - SystemCable - Term - Extender - HD - Extender - SystemCable - HD - Term >One more questions: why are > ... -- Teminator -- Hard Disk (The End) > ... -- Hard Disk -- Teminator (The End) >different? They aren't. Have you ever had one configuration work and the other fail? >P.S. Though one can have up to 20 feet of SCSI cable in a system, do not >ever dare to test the limits or else you will have spectacular crashes. >Trust me. I run about 10 feet of SCSI cable in my system without problems, but I wouldn't make it much longer and expect it to work right. Lexington Software Design: Tomorrow's Software Yesterday Eric K. Olson olson@endor.harvard.edu harvard!endor!olson D0760 (Name) (ArpaNet) (UseNet) (AppleLink)