SCSI help

a2jfreaka2jfreak Houston, TX Member
edited November 2004 in Hardware
I know virtually nothing about the different SCSI interfaces.
SCSI I, SCSI II, Ultra, Wide, etc. Whatever.

Two questions:
1) Will this controller work this this tape drive?

2) Where is a good resource for information on SCSI and the different interfaces?

Comments

  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited November 2004
    Yes, but make sure you also get one of these.

    When you do a SCSI chain, it goes controller-->cable-->device-->terminator at the end of the chain. So, for example if you have three connectors on your cable, you'll plug connector 1 into the controller, connector 2 into the tape drive, and the terminator onto connector 3. I'm also not sure if either of those comes with a cable. You may need to get one as well.
  • MediaManMediaMan Powered by loose parts.
    edited November 2004
    Adaptec SCSI controllers do not come with cables or terminators. They only come with the bare minimum of software drivers.
  • MissilemanMissileman Orlando, Florida Icrontian
    edited November 2004
    I beg to differ Prime. You never ever put a terminator after a device leaving a large space like that. You place any blank connectors between the HBA and the last device. Last device should be terminated. Tape drives use passive termination while hard drives are active termination. It takes a special cable with a short stub connector within 2 inches of the last connector in order to correctly use an external terminator. Biggest mistakes I ever saw when I was at Adaptec was termination. It works a lot of times even when it is wrong, but it don't make it right.

    Cable spec calls for a minimum of 12 inches between connectors on a cable (6 inches SCSI-1). A terminator connector must be within 3 inches of the last device. (The short stub connector I mentioned)

    Basic termination rule is First device and last device terminated. All other devices unterminated and spaced equally on the cable (leave blanks between devices. Both end connectors occupied. If possible, a hard drive should be the end device on the cable for its active termination. (Best performance, but not required by spec)

    A2 Check the white papers in the support section at Adaptec to give you a basic rundown on the SCSI interfaces.
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited November 2004
    isn't that pretty much what I said? I'm rereading both of our posts, but I'm confused because I think you misunderstood what I said. End of cable goes to card. Second middle connector goes to tape drive, last connector (like an inch away from the second connector) gets terminated. :confused:

    how else could it be?
  • MissilemanMissileman Orlando, Florida Icrontian
    edited November 2004
    I'm bad. You must be using good quality cables. Most of the cables that I used to run acrossed and see in the stores don't have a special termination connector and just have the 12 inch spacing.

    And I did talk to hundreds of people who had last device>12 inches>terminator. They were always wanting to no why there RAID was failing under heavy load :)


    I'm sorry for misunderstanding you. I should have realized you use the good stuff. Most people don't want to pay $65 for a SCSI cable, but will spend $100 for a set of monster speaker wires ;D
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited November 2004
    Wow, I never even realized that there were LVD cables that DIDN'T have the termination connector.... :)
  • a2jfreaka2jfreak Houston, TX Member
    edited November 2004
    Thanks for your collective help, Brian, Media and Missile.

    Where's a good place on the web to get SCSI cables, or would I be better off going to Frys or CompUSA?

    // Edit: I found an old 68-pin SCSI cable, but since I don't know much about SCSI it seems odd. It's setup like this.
    (C stands for Connector . . . I'll number them C1, C2, etc.)

    C1
    C2----C3---C4---C5---C6

    C1 is labeled Daughtercard.
    C2 is labeled Motherboard.
    C2-6 are not labeled.

    To use this cable would I need a terminating resistor on C1 with C2 plugged into the motherboard, C3 plugged into the tape backup and C4 plugged into another terminating resistor? Will any 68-pin resistor do or does it need to be LVD? Are all 68-pin resistors LVD?
  • TexTex Dallas/Ft. Worth
    edited November 2004
    Get a real lvd cable and terminator. Fighting scsi problems is a easy way to blow through lots a daylight.

    You can get a braided cable with lvd/se terminator on ebay for 10 bucks or get it at frys for $40 either way. I have all my sh*t packed to move or I would just send ya one. I got tons of them laying around. Check ebay for tapes for that thing too. You can probably buy new tapes on ebay for a fraction of the cost localy. Make sure you get the right tape for it. I tend to prefer the dlt tape drives over the dds ones as the tapes seem to last longer and the whole thing seems more sturdy to me anyway.

    tex
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited November 2004
    I agree with Tex. Definitely buy a new cable, it's not worth it to screw around with mystery cables.
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