From owner-freebsd-chat Thu Apr 2 21:04:36 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id VAA17447 for freebsd-chat-outgoing; Thu, 2 Apr 1998 21:04:36 -0800 (PST) (envelope-from owner-freebsd-chat@FreeBSD.ORG) Received: from wcc.wcc.net (wcc.wcc.net [208.6.232.10]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id VAA17427 for ; Thu, 2 Apr 1998 21:04:23 -0800 (PST) (envelope-from piquan@wcc.wcc.net) Received: from detlev.UUCP (tnt243.wcc.net [208.10.139.243]) by wcc.wcc.net (8.8.8/8.8.8) with ESMTP id XAA25224; Thu, 2 Apr 1998 23:00:03 -0600 (CST) Received: (from joelh@localhost) by detlev.UUCP (8.8.8/8.8.8) id XAA02362; Thu, 2 Apr 1998 23:04:19 -0600 (CST) (envelope-from joelh) Date: Thu, 2 Apr 1998 23:04:19 -0600 (CST) Message-Id: <199804030504.XAA02362@detlev.UUCP> To: dkelly@hiwaay.net CC: freebsd-chat@FreeBSD.ORG In-reply-to: <199804030322.VAA15771@nospam.hiwaay.net> (message from David Kelly on Thu, 02 Apr 1998 21:22:03 -0600) Subject: Re: Crimping SCSI cables From: Joel Ray Holveck Reply-to: joelh@gnu.org References: <199804030322.VAA15771@nospam.hiwaay.net> Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org >> I am using an AHA-1542C host adapter. This adapter, I am told, is >> very sensitive to cabling problems. I need a SCSI cable with all 8 >> connectors, but haven't seen any in what I would consider a reasonable >> price range (most are >$80 or so). Does anybody know if I should >> expect a problem if I crimp my own? > I have not observed my 1542CF was all that sensitive to cabling. I haven't noticed a real problem with it, but then I've only used one cable. Again, this is just what I read. (I have noticed it choking rather horribly if there's something wrong with the termination, but that's to be expected.) > Your 1542C? Not CF? Not "Fast"? Then at 5 MHz SCSI bus speed it > would be comparably immune to lots of the nasty stuff that bites > others. I've wondered about this one. The card's bios ID's it as a C, and doesn't mention CF anywhere I could find, but the kernel driver says it reports board ID 0x44, which is CF. (0x43 is the C.) > "Active Termination" cures lots of ills. I've considered that, too. > I make my own cables all the time. Keep meaning to buy the special tool, > as even the stamped steel made-in-China $30 cheapie tool works better > than a cast iron vice. And its easier to carry around. :-) We have the tool at work. I make ribbon cables when I need 'em (which is infrequent, but happens). Problem is, we lost a plastic holder in the tool, so I'm back to the vice. > Some IDC connectors have a keying tab in the middle on one side. That's > a good thing, look for it when you buy. As long as all your connectors > are on the cable right, that tab will/should prevent you from > connecting the cable to your devices wrong. Yes, I bought a cable w/o tabs not long ago. Hooked it up and all, with host adapter, three HDs, tape drive, then 2 cd-roms. Coulda sworn I had ascertained which pin on that tape drive was pin 1. Guess I was wrong. But I have no sense of smell, so I didn't know my cable's shielding was melting away until I started tasting the fumes. I wondered why nothing would ID in the bootup scan. Haven't tested the tape drive yet, but everything else still runs. > Doesn't it sound awful? All this for $2 connectors and $1/foot cable. > Pre-built cables are often $3 to $5 (cheaper than I can buy the parts). > The problem is, I can make my own internal SCSI cable that fits > exactly, rather than make do with pre-built cables. Funny, all the prebuilt 8-connector SCSI cables I could find were custom-built, upwards of $80 or so. AMP has a part for it at $15, but I only need one and they have a 25-piece minimum. Thanks for the info, joelh -- Joel Ray Holveck - joelh@gnu.org - http://www.wp.com/piquan Fourth law of programming: Anything that can go wrong wi sendmail: segmentation violation - core dumped To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message