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New to the world of SCSI...need serious help!!!

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  • New to the world of SCSI...need serious help!!!

    I'm looking in to building a new computer using a SCSI as my main drive, but i figure i should do my homework before dumping $300 on a SCSI system.
    I understand the fact that you have to have a scsi adapter and and hard drive of the same pin setting (i can find a 68 pin set card but not an 80 pin set); I do not know what the port in the back of the card is for, what precautions (i know there are some) have to be taken when using peripherals with a scsi, and i don't know the differences between adapter types. About the only thing I know how to do is hook the damn thing up!!!
    Could someone please explain the rest of the gorey details to me and possibly make some suggestions on what to buy (right now i'm looking at an Adaptec 64-bit PCI to SCSI Controller Card and a Maxtor/Quantum 36.7GB 10,000RPM SCSI Ultra 320 68 pin Hard Drive).

  • #2
    The external port on the card's bracket is for external SCSI devices...

    For internal 50-pin and 80-pin are older, but you're more likely to see a 50-pin connector than an 80-pin, since some SCSI optical drives use them.

    68-pin is the newest, so let's stick with that.

    For a SCSI system, you need a contoller card, SCSI drive, and a terminator---and the cable of course. Since SCSI acts as a bus, the terminator is necessary. Most of the time a retail SCSI card will come with them, but you can get them separate. Some SCSI cables come with a terminator at one end, but as long as it's after the last SCSI device, you're fine.

    While Adaptec is fine, you might want to check out cards from Tekram, or any that use an LSI chip. These are generally better performing than Adaptec stuff.
    2nd. There are a few different types of PCI slots: the normal 32-bit/33MHz.
    Then you have 64-bit/33MHz and 64-bit/66MHz. Some of these cards are backwards compatible with 32-bit/33MHz PCI slots, but check before you buy.

    Some really good info on SCSI can be had over @ StorageReview . I'm pretty much a SCSI n00b myself, but I've wanted to play with it for a long time.


    • #3
      80pin SCSI is not old. It is used to connect SCSI drives to backplanes. It carrys - in addition to the data signals - the power and the ID settings.

      First of all, why would you now start using SCSI?

      One answer would be, that you allways used it, and you have allready a nice controller at your hand. But I I don't think that is the point ;)

      Second would be speed. For sure there are quite some fast SCSI drives out there. But with the new WD Raptor drives, there are some very fast SATA drives avalible too.
      Next problem is, that much of the speed gained, depents on what usage the firmware is optimized. Desktop use or server use. Most SCSI are optimized for the second type of usage. That means they are a lot faster than any (S)ATA drives when it comes to multiple access operations in a tight timeframe. But they give away some of their raw speed when it comes typical desktop usage (mostly running only one harddrive consuming process at a time).
      So a 72GB WD Raptor (10k RPM) is often not slower, than a modern 15k SCSI drive.
      The next problem is, that a SCSI hostbus adapter has to use the slow PCI bus. Unless you have a decent board with 66MHz/64Bit or X-PCI. The (S)ATA controller that a integrated in the southbridge of modern chipsets, have a greater bandwidth to play with.

      Third point would be reliability. And yes, thats still a real reason to go with SCSI. But not every SCSI dive is great in that domain.
      To get a good reliably drive, I would go (means I'm going) with a 10k Fujitsu or a 15K Seagate drive. The (third generation) 15k Seagte drive is more quite and a lot faster than the 10k Fujitsu. The 15k Fujitsu drives are ok, but to loud.

      Point 4 is the overall handling. The possibility to map out defunct sectors, without having to delete the harddrive content, is a nice feature nearly every controller provides. A possible cabel length of 12m, when using LVD SCSI components is nice too.

      If you are still willing to go with SCSI, we can start talking about controllers and cabeling.

      Regards, Lars