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Thread: FireWire 12MB/s or 48MB/s?

  1. #1
    Join Date
    May 2002
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    I just started using granite digital firewire/ide enclosure (oxford 911 bridge) with an IBM deskstar 80G/7200 drive. It works fine (at last), and am doing some tests with it. First, I am assuming 48MB is 48 mega bytes, right? (right?) Well it seems that I only get 12MB/s from my drive.
    Hardware

    Copying a 300 MB file from my machine (TiBook 400MHz/10G/384M/OS10.1.4) to the drive takes @ 25 sec wall clock time. I should expect it to take about 6 or 7 seconds. Copying from *partition*to*partition* on the firewire drive itself, takes about 43 seconds, implying it has to travel to the OS first?

    Any ideas or comments would be appreciated..

  2. #2
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    I've never done any testing of Firewire harddrive speed but a couple of things come to mind.

    Firewire is a 400 megabit per second max through-put bus. That's very roughly 50 Megabyte per second. This is a maximum BUS through-put and really doesn't relate well to drive performance.

    Your case with it's Oxford chipset also has all the constraints of IDE, I think ATA66 but I haven't tried to remember all the Firewire specs so don't take that as given.

    You didn't mention which model IBM you were running but I would be surprised if it was capable on a native ATA66 bus of much over 25-30 MB/sec actual (as opposed to benchtest) through-put.

    When you add up all the places where you waste speed, and adapters always cost in speed I would guess that you should see in the mid teens in actual performance.

    One given with ANY IDE device is that the bus only is capable of doing one thing at a time. There is some independence today with both Ultra DMA buses and Firewire buses from the cpu, but when you are reading and then writing back to a partition or even another drive on the same IDE bus the data has to be stored in ram as it's read and then copied as the read stops. Only ONE access at a time.

    That will only be true with a scsi device if the partition was on the same drive. SCSI can read from one device while concurrently writing to another on the same cable or bus.

    There are many other factors in real world testing such as you're doing. What format you used on the drive, how fragmented the drive is, what type of data is being written and so on. One nice thing with benchtest programs is you test with a given method everytime, but there are still many variables that can skew your results.

    You might try ATTO Express Pro Tools as a benchtest utility to see how you stack up. It's free, you can get it from www.attotech.com or off the macgurus ftp stite in the ATTO Stuff folder.

    Rick

  3. #3
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    Tim,

    With FW you should expect 25MB/s. On older original FW cases it use to be 11-16MB/s or more like ATA/33 speeds with 5400 rpm, small cache would be. ON B&W G3 OEM IDE I would get 29MB/s sustained writes, would only see 33-35MB/s off PCI IDE (ATA/66 Tempo).

    IDE drives have had trouble getting even 40MB/s and Firewire even less. FireWire for storage is okay for replacing tape maybe, or for large slow storage, but I think Apple either has to do a lot to make it work better but the idea that it would ever replace SCSI - they've had three years and as you can see it hasn't. Maybe FireWire 800 or 1600 someday, but it seems to be slow and taking way too long to bring it out.

    The TiBook is on the slow side for iDE, although there are now 5400 rpm drives they usually use 4200 or 4800 I think. If you haven't yet, I'd look at the reports in the drive database on www.xlr8yourmac.com to see what kind of results for FW and for TiBook drives deliver. One of the few things I find fast in OS X is copying files between drives which outperforms OS 9 by huge margins.

    Assuming you formatted it in either Drive Setup or Disk Utility, the only other real option is probably HDT 4.5.2 or HDST 3.5 and see if they help.

    Gregory

  4. #4
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    Apr 2001
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    Bowling Green, KY, USA
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    Here is a pretty good article on ATA HD's in Firewire cases. http://www.barefeats.com/fire25.html I bought the recommended setup--IBM 120 GXP 80 GB in a Granite Digital "911" case. In OS X QuickBench reports 31 MB/sec Reads and 32 MB/sec writes. Seems to copy files pretty fast.

  5. #5
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    May 2002
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    So how do I calculate throughput? One website stated that it was filesize*2 / wallclock time. Does this sound right?

    I know there are other metrics for testing device performance, but this is the one that matters most of the time.

  6. #6
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    May 2002
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    Sorry - forgot to ask about ATTO tools. I go to their site to get their toolset, but from the "Applications/Tools/Utilities" link, the package selections are:

    Express PCI Host Adapter Utilities
    BridgeTools for FireBridge 1100...
    BridgeTools for FireBridge 1180...

    Which of these is the vaunted Atto Express Pro Tool utility?

    Thanks!

  7. #7
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    Read this post it will explain it..... I had the same question.
    http://www.macgurus.com/ubb/Forum26/HTML/000173.html

    Randy

  8. #8
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    If you are talking about the Pro Tools that can benchmark your drives Read and Write performance, go here http://www.attotech.com/protools.html

  9. #9
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    May 2002
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    Thanks! I finally downloaded the right utilities (v. 2.7, I hope is the latest). It seems like I get 14MB/s sustained write and a smoking 178MB/s sustained read. Is this really possible?

    Thanks to everyone for their help..

  10. #10
    Join Date
    Aug 2000
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    Concord, CA
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    Set EPT for 8MB, 2 segments, and leave System Disk Cache unchecked. k

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