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SCSI questions

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  • SCSI questions

    I was wondering if anyone could give me a good explanation of the difference in the Adaptec products, the $99 ones compared to the $250 and up ones, the features/benefits of each, and a real world example of the type of system each would be used in, thank you...

  • #2
    Sorry that ya havn't got an answer to this but most of us don't use SCSI here though a couple of non frequents do but they havn't been around lately. :smokin:


    • #3
      I was wondering the same thing about which SCSI card to get... hoping to renew this thread so some SCSI-totin' dude will give us some advice!


      • #4
        Hmmm... never saw this thread when it first posted. Sorry.

        Though not a SCSI aficionado, I may be able to help clear up at least some of the basic questions.

        There are a lot of different varieties of SCSI available today, and they are not all created equal. As a general rule, the numbers associated with any particular variety will denote the maximum burst speeds of that type. From there, you start getting into SCSI 1, SCSI 2, SCSI 3, Ultra SCSI, Ultra-Wide SCSI... as you can see, there are a lot of different types. That's where the differences start to appear.

        Besides the speed boosts that are common with SCSI in certain situations, one of it's biggest selling points is the idea of daisy chaining several devices. Of course, with ATA speeds increasing dramatically recently, the speed issues are no longer a huge benefit with the SCSI setups.

        For more information concerning SCSI and what it's all about, try checking out this article from PC Guide.
        Old age and treachery will overcome youth and skill
        My Toys


        • #5
          for a typical desktop application, I would get a single SCSI- ultra3 (Ultra 160) drive with a 68 pin connector - not 80 pins they're for hot swap trays. Seagate's are the only ones I've ever bought

          The SCSI controller would need at least 1 68 pin internal connector (obviously) some come with 2 68 pin channels or a 68pin + a 50 pin for leagacy drives. Some cards also come with an external connector typically for a tape back up - or an external drive/array- an Adaptec 19160 would work fine for a desk top & it only requires a 32bit PCI slot. SCSI controllers w/RAID run a lot more money & ususally require a 64bit PCI slot - unless you're setting up a server I doubt you would need it. I've only ever set up (2) Adaptec contollers - I know tekram makes SCSI controllers that are a bit cheaper, but I don't know if they're any good.

          You'd also need an LVD SCSI cable ( as oppse to single ended SCSI) - either with built-in termination or get a separate LVD terminator - one may already be included with the controller card. Unlike IDE channels - it's common for a SCSI channel to support up to 15 devices over >10 meters of cables - so finding the right cable takes a bit more research than it does for an IDE set up.

          SCSI drives usually come from the factory with the ID set at 0, and controllers are usually preset at 7 - so you'd likely not need to change any of them with only a single drive. Multiple drives require unique ID's

          Drives also come from the factory with a low level format - If you choose to do it again - DO NOT stop part way through or you'll likely end up with an unmountable drive

          MAke sure you have a good power supply - typically a SCSI drive uses less than 1A under normal conditions, but during start up it uses considerably more, especially during the very first start up - I'm not sure why that is...may those 10000 rpm bearings need to get worked it a bit. If you have a crappy PS and it cuts out while you writing to you disk @10000rpm's, you can kiss some or all of you SCSI drive capacity good buy (I've seen it happen).

          I'm is the process of setting up a new server at work with 4 x 73.4GB SCSI-3 disks - it's relatively simple to do... as long as you read the instructions first.