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ATA/66 cable question

Discussion in 'A+' started by tallphil, Jun 24, 2007.

  1. tallphil

    tallphil Bit Poster

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    Mike Meyers writes (A+ Cert Exam Guide 6th ed. p.314 para 1)

    "If you plug an ATA/66 drive into an older controller it will work - just not in ATA/66 mode. The only risky action is to use an ATA/66 controller and hard drive with non-ATA/66 cable. Doing so will almost certainly cause nasty data losses."

    Is this true? Other sources imply 40 wire cable is safe, it just reverts to ATA/33 speed.

    e.g. http://www.hardwaresecrets.com/article/45/6
    "If you have a ATA-66 hard disk or above you have to use an 80-wire flat cable, or your hard disk will achieve only a maximum 33 MB/s transfer rate."
    and many other places.

    I've seen this come up on A+ practice questions so I'd like to get it straight.

    Phil.
     
    WIP: A+
  2. Boycie
    Honorary Member

    Boycie Senior Beer Tester

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    Phil,

    I believe this is correct. The extra wires are earth wires which help prevent data loss.

    This is purely theory - it would be an *old* machine with a 40 IDE cable.

    Boyce

    Cue Harry for a *decent* answer!
     
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  3. tallphil

    tallphil Bit Poster

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    Boyce - which is correct - the first (Meyers) quote or the second?

    Further to original post - Meyers contradicts himself in a review question at the end of the chapter. Question is "John purchased an ATA/66 drive for his ATA/66 capable system. However he forgot to get the special 80-wire cable. If he installs a 40-pin EIDE cable, what will happen?". Answer is "The drive will work but will not run at ATA/66 speed." Meyers comments "ATA/66 drives work fine with a 40-pin cable - they just won't run at ATA/66 speed". No "nasty data losses" then???

    Even more confused...
     
    WIP: A+
  4. Boycie
    Honorary Member

    Boycie Senior Beer Tester

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    Phil,

    I thought it was correct to say the extra wires are needed to help prevent data loss.

    No mention is made of this on the Totalsem website here.
     
    Certifications: MCSA 2003, MCDST, A+, N+, CTT+, MCT
  5. Theprof

    Theprof Petabyte Poster Forum Leader

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    Correct me if I am wrong guys, but I think that the drive should work in a non compatible ATA/66 controller but there is a possibility to loss of data that might occur. Not to mention that the hard drive will work at the slower speed.

    Now is the data loss going to occur constantly I dont know it might.

    tallphil here a little reference I used to read up on it, maybe it will help you. http://en.wikipedia.org/wiki/AT_Attachment
     
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  6. Spilly

    Spilly Kilobyte Poster

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    The extra wires in an 80 pin cable are extra ground wires only.

    The drive will automatically operate at the max speed for a drive with a 40 pin cable ie ATA33.

    Data loss would only occur at ATA66 or above if you could get this speed with a 40 pin cable. Since the controller / drive will auto select the max speeed for any given cable no data loss will occur.

    I retrofit for repair many ATA100 drives to ATA33 controllers with no problem. You may need to select a drive with a cap limiter for the older bios compability issues but thats another story.
     
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  7. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    <grin>

    In theory all that should happen is that the controller/drive reduces to legacy speeds.

    However - there was a period in the changeover where the drives weren't quite right, and running like this could cause corruption.

    What the 'correct to A+' answer is I don't know. :biggrin

    Harry.
     
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  8. tallphil

    tallphil Bit Poster

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    Thanks very much for the replies. I think that clears it up.

    It's rather odd that Mr Meyers holds two opposite views in one chapter though. Wonder if he really writes these books or has a team of minions...

    Phil.
     
    WIP: A+
  9. wizard

    wizard Petabyte Poster

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    Have you contacted him to clarify the answer to the question? I'm sure he's very approachable.
     
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