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Q: IDE cables longer than 18" without getting errors? ( Answered 5 out of 5 stars,   0 Comments )
Subject: IDE cables longer than 18" without getting errors?
Category: Computers > Hardware
Asked by: mxnmatch-ga
List Price: $3.00
Posted: 30 May 2003 17:25 PDT
Expires: 29 Jun 2003 17:25 PDT
Question ID: 210955
It's my understanding that IDE cables start causing errors once
they're more than 18" long. Some of my drives are simply not close
enough to the controller cards to allow me to use anything shorter
than 24" cables. Is there some way to put IDE hard drives on longer
cables without causing errors? Do ULTRA ATA cables have the same
length limit? If I use ULTRA ATA cables with a normal IDE controller
card then will that work and if so would I have to go back to the 18"
Subject: Re: IDE cables longer than 18" without getting errors?
Answered By: haversian-ga on 31 May 2003 12:48 PDT
Rated:5 out of 5 stars
Hi mxnmatch!

Interesting question.  18" is quite limiting, even for modest-sized

Standard IDE cables are limited to 18", but using higher quality
components can extend this limit considerably without causing errors. 
The cabling standard is actually quite conservative - one can build by
hand a 3-foot IDE cable with CAT5e (network) cables and get it to work
flawlessly.  Many companies exist which will provide workable
solutions in the 18-36" range.  In fact, 3Ware, a company which
manufacturers IDE RAID cards, ships >18" cables, knowing that they
will be used in server applications.  The longer length is not at all

Cable length is unimportant - what matters is what the increased cable
length means in terms of signal propagation, degradation, etc.  As
long as those variables can be maintained, by using higher-quality
connectors, cables, etc., the cable should work fine.  There is
nothing inherent in the IDE cabling specification which guarantees
errors at longer cable lengths than 18".

A general answer to your question therefore is that good quality
cables have considerable headroom in them, and 24+" is not
impractical.  Cables from reputable companies such as 3Ware ( ) or Granite Digital ( ) will work

I hope this answer is satisfactory; if not, do not hesitate to request
a clarification.


Request for Answer Clarification by mxnmatch-ga on 31 May 2003 19:05 PDT
For my hard drives which are S.M.A.R.T., what information should I
look at to see if there are problems with my 24" cables? I have a few
of those cables, but I have no idea how good they are. What
information would S.M.A.R.T. provide which would indicate problems
that would be caused by the cables? The 24" cables I just purchased
are "Vaster ULTRA ATA 133 ROUND CABLE 80 PIN Shielded UL 20276, 24
INCH 2 DRIVE" cables. I would assume that if they went to the effort
to add shielding then that would indicate that the cables themselves
are higher quality. But maybe that's not a good assumption? The
easiest thing would be to just look at the S.M.A.R.T. info to
empirically see if a cable is good or not, but I don't know what to
look at.

Clarification of Answer by haversian-ga on 01 Jun 2003 14:13 PDT
Some drive manufacturers ship a diagnostic disk with tools to probe
the SMART codes generated by the hard drive.  While these codes
primarily test the drive itself, some cabling problems will be
visible, such as CRC errors.  For example, this page lists SMART codes
for Western digital drives ( ).  If you tell
me what model(s) drives you have, I can get you diagnostic tools and
what error codes to check for.
mxnmatch-ga rated this answer:5 out of 5 stars and gave an additional tip of: $2.00

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