tjs@MSC.EDU (Tim Salo) (04/19/91)
> Hi. A recent discussion of the comparative merits of slide latches versus > screw/thumbscrew as a means of attaching a cable to a system port ... Screw connectors have never brought down our network. Slide-lock connectors, on the other hand, have fallen off, (with or without help), and brought down parts of our network. (I once believed, without evidence, that slide- lock connectors were the largest single source of [LAN] network downtime.) Does anyone have experience replacing Ethernet slide-lock connectors with screw connectors? (Is there a reasonably easy way to do this?) Tim Salo Minnesota Supercomputer Center (612) 626-3047 tjs@msc.edu
roy@phri.nyu.edu (Roy Smith) (04/23/91)
In article <9104191503.AA25029@uh.msc.umn.edu> tjs@MSC.EDU (Tim Salo) writes: > I once believed, without evidence, that slide-lock connectors were the > largest single source of [LAN] network downtime. And something happend to change your mind? I am firmly convinced that not only are they the largest single source of network problems, but they are larger than all other sources combined. > Does anyone have experience replacing Ethernet slide-lock connectors > with screw connectors? (Is there a reasonably easy way to do this?) We do it all the time. If you take apart the end of a cable and/or a board-mounted connector, you will usually find that the slide-lock mechanism can be removed fairly easily by undoing a few small (4-40?) screws and/or nuts. This leaves you with mounting holes on the cable and board connector that align. Just insert plain old RS-232-style mounting screws that you can get from Inmac, or anyplace else, and suddenly you've got a connector that you can count on not to fall out. It won't meet official 802.3 standards, but the standards people know what they can do with themselves (I'm usually a pretty rabid pro-standards kind of guy, but when the standard is so obviously brain dead, I gotta be a little practical, you know?) I'm certainly no fan of U/B, as I think I've ocassionaly made clear on the net, but one thing they did right (in my mind) was to violate the standard and put screw-mount connectors on their gear. I once heard a horror story (probably on the net but I've long since forgotten when and who told it) about a tranciever cable that came partially detached. The power and transmit pins made contact, but the receive circuit was broken; the damn thing could talk, but couldn't hear. Apparantly it did very bizarre things to the network. -- Roy Smith, Public Health Research Institute 455 First Avenue, New York, NY 10016 roy@alanine.phri.nyu.edu -OR- {att,cmcl2,rutgers,hombre}!phri!roy "Arcane? Did you say arcane? It wouldn't be Unix if it wasn't arcane!"
owens@acsu.buffalo.edu (bill owens) (04/23/91)
In article <1991Apr23.001727.26953@phri.nyu.edu> roy@phri.nyu.edu (Roy Smith) writes: >In article <9104191503.AA25029@uh.msc.umn.edu> tjs@MSC.EDU (Tim Salo) writes: >> I once believed, without evidence, that slide-lock connectors were the >> largest single source of [LAN] network downtime. They're certainly the biggest cause of sudden network failures, anytime someone has to do anything inside a crowded rack cabinet they're liable to wipe out whole buildings. They're the only component that, once it works, is likely to fail 'spontaneously'. Coax, taps, etc. may not work immediately, but once they're set they seldom give you any more trouble... I have had some luck 'tuning' the slide-locks by bending them with pliers or a screwdriver, but that's obviously not practical for the hundreds we have in use. Unfortunately, replacing them with screws is also considered impracitcal for the same reason. > I once heard a horror story (probably on the net but I've long >since forgotten when and who told it) about a tranciever cable that came >partially detached. The power and transmit pins made contact, but the >receive circuit was broken; the damn thing could talk, but couldn't hear. >Apparantly it did very bizarre things to the network. That just happened to me two weeks ago; someone moved a small EOT to see its lights, and partially disconnected the cable; the power and receive pins were still in contact, but not transmit. So it could hear, but couldn't talk; my traffic was getting there, but his wasn't coming back. About two hours to find the problem... Bill.
jstahlhu@athena.mit.edu (Julie Kozaczka Stahlhut) (04/24/91)
Speaking of slide lock connectors, does anyone know of a source for those little screw adapters for them? Some vendors supply them with LAN cards, but I just need a bag 'o adapters and matching screws. We have the fiber and 10 Base T network of the future, held together with those miserable 15-pin connectors of the past. In the tradition of educational institutions with lots of equipment but no space, our computer room here at Harvard Medical School is impossibly cramped. Five minutes of work on any connection behind our rack is likely to dislodge two or three subnets from their connections into our two routers. I've also had only a minimum of luck with electrical tape, abusing the latches with screwdrivers, ad nauseam. Not that the little stamped-metal-and-screw jobbers work that well, but they're the best of a bad lot as far as I can tell. Who invented those slide latches, anyway? I'd like to meet this person, maybe shake his or her throat ..... :-( -- Julie Kozaczka Stahlhut "I'm not especially responsible but it's not my employer's fault."
logier@cheops.qld.tne.oz.au (Rob Logie) (04/25/91)
jstahlhu@athena.mit.edu (Julie Kozaczka Stahlhut) writes: >Speaking of slide lock connectors, does anyone know of a source for those >little screw adapters for them? Some vendors supply them with LAN cards, but I just need a bag 'o adapters and matching screws. >We have the fiber and 10 Base T network of the future, held together with those >miserable 15-pin connectors of the past. In the tradition of educational >institutions with lots of equipment but no space, our computer room here at >Harvard Medical School is impossibly cramped. Five minutes of work on any >connection behind our rack is likely to dislodge two or three subnets from >their connections into our two routers. I've also had only a minimum of luck >with electrical tape, abusing the latches with screwdrivers, ad nauseam. >Not that the little stamped-metal-and-screw jobbers work that well, but they're >the best of a bad lot as far as I can tell. >Who invented those slide latches, anyway? I'd like to meet this person, >maybe shake his or her throat ..... :-( >-- >Julie Kozaczka Stahlhut >"I'm not especially responsible but it's not my employer's fault." The first thing I do when I get anything using AUI cables with slide locks is to remve the slide locks and place them in the rubbish bin where they belong. I then replace them with normal old screws (Like on RS232 connections) They never move when there screwed down. I think slide locks are someones idea of a sick joke .. Regards -- Rob Logie EMAIL: logier@cheops.qld.tne.oz.au Telecom Australia FAX: +61 7 837 4704 TNE Computer Support Services PH: +61 7 837 5174 Brisbane Office "These are my opinions alone"
ron@Eyring.COM (Ron Holt) (04/30/91)
In article <1991Apr23.172533.20781@athena.mit.edu> jstahlhu@athena.mit.edu (Julie Kozaczka Stahlhut) writes: >Who invented those slide latches, anyway? I'd like to meet this person, >maybe shake his or her throat ..... :-( His name is Rich Seifert. He wrote an article for the January 1991 issue of "Byte" called "Ethernet: Ten Years After". In the article he discusses what he and the other members of the original Ethernet design group would change if they could do it over again. He says "Personally, I would have saved every Ethernet user a lot of grief by not specifying the dreaded slide-latch connector... We really had good intentions. I was fed up with the RS-232C connectors that fell off because the tiny screw driver necessary to tighten them down was never handy. I just didn't realize that the side latch was so flimsy and unreliable until it was too late. Ethernet installers around the world must curse me every day." Now you know the name to curse :^) You can e-curse him at seifert@asylum.sf.ca.us -- Ron Holt ron@Eyring.COM uunet!lanai!ron Eyring Inc. +1 801-375-2434 x434
smb@ulysses.att.com (Steven Bellovin) (04/30/91)
In article <1991Apr30.010639.1288@Eyring.COM>, ron@Eyring.COM (Ron Holt) writes: > His name is Rich Seifert. .... I was fed up > with the RS-232C connectors that fell off because the tiny screw driver > necessary to tighten them down was never handy. Amen! While it's now obvious to everyone that the slide latch doesn't work well, I have the suspicion that many of its critics haven't used RS-232 very much. For those of us who've fought with missing screwdrivers, inconsistent use of male vs. female connectors, protruding nuts bumping into each other, gender benders, strange and wondrous uses of RTS and CTS, and disagreements about the True Meaning of DSR and CD, the Ethernet spec is a marvel of consistency. They were certainly an experiment worth trying.
jbvb@FTP.COM (James B. Van Bokkelen) (05/01/91)
You can e-curse him at seifert@asylum.sf.ca.us He said he's sorry, and he can't go back in time and fix it, so I suggest that flames be directed to /dev/null, or the IEEE/ISO. They're the current owner of the standard, and they seem quite willing to issue addendums long after the initial standard came out... James B. VanBokkelen 26 Princess St., Wakefield, MA 01880 FTP Software Inc. voice: (617) 246-0900 fax: (617) 246-0901
ron@lanai.UUCP (Ron Holt) (05/01/91)
James B. Van Bokkelen writes: > >> You can e-curse him at seifert@asylum.sf.ca.us > > He said he's sorry, and he can't go back in time and fix it, so I suggest > that flames be directed to /dev/null, or the IEEE/ISO. They're the current > owner of the standard, and they seem quite willing to issue addendums long > after the initial standard came out... > > James B. VanBokkelen 26 Princess St., Wakefield, MA 01880 > FTP Software Inc. voice: (617) 246-0900 fax: (617) 246-0901 Yes, I realize this. Perhaps I should have added a smiley face after the last line of my message. I thought it was clear from my quote that the problem is recognized and it's not something that can be changed now. Byte magazine mentioned his email address for reference and so did I in my message. I think most people would realize it would be rather pointless to flame anybody now about this issue. My only reason for posting my message was to share with others some interesting insights into Ethernet from Seifert's article. Ron Holt ron@Eyring.COM uunet!lanai!ron Eyring Inc. +1 801-375-2434 x434
romkey@ASYLUM.SF.CA.US (John Romkey) (05/01/91)
From: decwrl!uunet.UU.NET!lanai!ron (Ron Holt) Date: Tue, 30 Apr 91 12:21:09 MDT X-Mailer: ELM [version 2.3 PL0] Byte magazine mentioned his email address for reference and so did I in my message. I think most people would realize it would be rather pointless Byte mentioned an email address off BIX? That's a first! In an article I co-wrote for them recently, I put my email address in my bio, they removed it, I put it back in in the proofs, and they took it out again...they were very closed minded about telling their readers about how to reach anyone off BIX. - john romkey Epilogue Technology USENET/UUCP/Internet: romkey@asylum.sf.ca.us voice/fax: 415 594-1141
mcdonald@aries.scs.uiuc.edu (Doug McDonald) (05/01/91)
In article <1991Apr30.010639.1288@Eyring.COM> ron@Eyring.COM (Ron Holt) writes: >In article <1991Apr23.172533.20781@athena.mit.edu> jstahlhu@athena.mit.edu (Julie Kozaczka Stahlhut) writes: > >>Who invented those slide latches, anyway? I'd like to meet this person, >>maybe shake his or her throat ..... :-( > What is a slide latch? The Ethernet cable connects to most all the computers I have ever seen with a BNC T connector. My particular one sits at the end of the line so it has a 50 ohm terminator instead of a T. I know this has little to do with TCP-IP but.......... Doug McDonald
phil@brahms.amd.com (Phil Ngai) (05/02/91)
jbvb@FTP.COM (James B. Van Bokkelen) writes: >IEEE/ISO. They're the current >owner of the standard, and they seem quite willing to issue addendums long >after the initial standard came out... No kidding! Standards? We got lots of em! A new one every year... --
rlstewart@eng.xyplex.com (Bob Stewart) (05/02/91)
Don't worry about e-cursing Rich Siefert. He has a thick skin and can e-curse right back if necessary. He might even like to get a few messages from people with an interest in Etherhistory. Bob