40 vs. 80-pin IDE cables

Discussion in 'Computer Information' started by mrT, Oct 28, 2003.

  1. mrT

    mrT Guest

    I just read that using a 40-pin cable with a ATA/66 or 100 drive
    forces the drive into ATA/33 mode. Just wondering: how does the drive
    know it's on a 40-pin cable, if the other 40 wires on an 80-pin cable
    are just grounds?

    Also, since the 40 ground wires were added to prevent bad EMI, surely
    chopping up the cable and tying it together defeats their purpose to
    some extent?

    Thanks.
     
    mrT, Oct 28, 2003
    #1
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  2. mrT

    Thor Guest

    According to the spec, the cable should have one line designated for the
    purpose of identifying to the motherboard that it is 80 conductor.
    I've wondered this as well, but have yet to see any reports of a problem
    with cut and bundled round IDE cables.
     
    Thor, Oct 28, 2003
    #2
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  3. mrT

    V W Wall Guest

    Pin 34 is used to detect the presence of the correct 80 conductor cable.
    (Only on a drive and motherboard that are set up to use this
    information.)
    It seems to depend on how the "round" cables are made. No drive now
    made saturates even the ATA100 interface. More problems can occur if
    the middle connector is used and the end "stub" is left unconnected.
    That's why the end connector is labled "master", although except for
    pin 28, (CSEL), used for cable select, they are wired identically.

    Virg Wall
     
    V W Wall, Oct 29, 2003
    #3
  4. mrT

    V W Wall Guest

    Didn't see your response until after writing mine. Earthlink's news
    server seems to be lagging behind. At least we said the same thing!

    Virg Wall
     
    V W Wall, Oct 29, 2003
    #4
  5. mrT

    derek / nul Guest

    I don't know of any drive that can go as fast as ata33!!
     
    derek / nul, Oct 29, 2003
    #5
  6. mrT

    Thor Guest

    It seems to depend on how the "round" cables are made. No drive now
    The've have surpassed that actually. For example, the western digital 200GB
    7200RPM ATA drive has been rated to transfer about 56MB/sec on the outer
    tracks, and 33MB/sec on the inner tracks, putting it's sustained average
    transfer rate capability above ATA/33's limits.

    http://www.storagereview.com/articles/200210/20021018WD2000xB_2.html

    Then consider that the new Raptor 10K ATA drives managed to sequentially
    (sustained) transfer a *minimum* of 45MB/sec and a maximum of 63MB/sec
    putting them within spitting distance of the ATA/66 spec at least on outer
    zone reads. Either way, it pretty much proves that you don't want to
    bottleneck your newer ATA drives with an ATA/33 interface. :)


    http://www.storagereview.com/articles/200303/20030320WD360GD_2.html
     
    Thor, Oct 29, 2003
    #6
  7. mrT

    V W Wall Guest

    I agree! Just didn't want to start a debate with someone claming they
    had one! Most of the higher ATA specs are pure hype. At least SATA
    at 150 to start has a clear route to acheiving higher burst rates, if
    somebody figures out how to get the drives to do it.

    Any drive can dump the buffer at a higher rate than the drive latency
    permits. I haven't seen many programs that take advantage of that.
    My new 7200RPM has an 8MB buffer. It seems to defrag much faster
    than the 7200/5400 would suggest. Does it use larger the buffer?

    Being tied to "legacy" formats has limited drive performance. We can
    hope the SATA interface is radical enough to allow some new drive
    techniques.

    Virg Wall
     
    V W Wall, Oct 29, 2003
    #7
  8. mrT

    mrT Guest

    Thanks for the info (Thor too!)...

    I suppose even if EMI did become a problem, most errors would be
    corrected invisibly, right? But I guess that would slow down
    transfers, right? :)
     
    mrT, Oct 29, 2003
    #8
  9. mrT

    Thor Guest

    There is built-in CRC checking of the data when it is transferred. If it
    requires correction, a retransmit occurs, which obviously would slow down
    overall throughput to a degree.
     
    Thor, Oct 29, 2003
    #9
  10. mrT

    V W Wall Guest

    Depending on the nature of the EMI, and the error correcting capability
    of the drive electronics, a slow dowm might be the only visable result.
    But why tempt the computer gods? Just don't leave dangling un-connected
    stubs. The round cables seem to be OK.

    Virg Wall
     
    V W Wall, Oct 29, 2003
    #10
  11. mrT

    V W Wall Guest

    There's sure no reason to do so. ATA/100 is much easier to achieve
    than real drive thru-put. I just ran a test on a new Seagate 7200RPM Ultra ATA/100 drive
    (ST380013A).
    The specs show INTERNAL TRANSFER RATE (whatever that is) of up to
    85.4MB/sec,
    and a SUSTAINED TRANSFER RATE up to 58MB/sec. EXTERNAL TRANSFER RATE
    up to 100MB/sec. That's where they get the Ultra ATA/100.

    Test showed a max of 52MB/sec and a min of 42MB/sec. Looks like we're
    even coming close to the hype! As you indicate, 10,000RPM drives can
    even stress ATA/66. Note: All measurements are in mutliples of 10^3,
    (1000), not 2^10, (1024). ;-)

    SATA should end some of the marketing hype, though we'll probably be
    seeing SATA2 or SATA3 soon, as if 150MB/sec were not enough.

    Virg Wall
     
    V W Wall, Oct 29, 2003
    #11
  12. mrT

    Trent© Guest

    They don't make 80-pin IDE cables AFAIK.


    Have a nice week...

    Trent

    Follow Joan Rivers' example --- get pre-embalmed!
     
    Trent©, Oct 31, 2003
    #12
  13. mrT

    V W Wall Guest

    Did it take you all the time from the OP on Tuesday, to count yours?

    Virg Wall
     
    V W Wall, Nov 1, 2003
    #13
  14. mrT

    Trent© Guest

    You mean I'm CORRECT??!!! lol


    Have a nice week...

    Trent

    Follow Joan Rivers' example --- get pre-embalmed!
     
    Trent©, Nov 1, 2003
    #14
  15. mrT

    DeMoN LaG Guest

    Of course. There is no such thing as an 80 pin IDE cable. I believe the
    only hard drives that use an 80 pin cable are SCSI drives with a SCA
    connector. The OP (hopefully) meant 80 /conductor/ cable.

    --
    AIM: FrznFoodClerk (actually me)
    email: [email protected]_cast.net (_ = m)
    website: under construction
    Need a technician in the south Jersey area?
    email/IM for rates/services
     
    DeMoN LaG, Nov 1, 2003
    #15
  16. mrT

    Trent© Guest

    I just thought it might be nice if somebody TOLD him that. lol


    Have a nice week...

    Trent

    Follow Joan Rivers' example --- get pre-embalmed!
     
    Trent©, Nov 1, 2003
    #16
  17. mrT

    mrT Guest

    Of course the OP meant 80 _conductor_!
     
    mrT, Nov 3, 2003
    #17
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