Rounding IDE Cables

Rounding IDE cables this looks as if it could cause electrical problems on the PATA cables. Is it really as safe as he suggests it
is?
http://cpu-central.com/Articles.asp?article_idr49&decor_int '
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Depends. With UDMA 3 or before you can get data corruption. I had this with a burner that did not support data checksums on UDMA 3. Most HDDs do suuport these checksums, but the standard does not require it before UDMA 4. For all UDMA levels you can get command corruption, checksums on commands are not present before SATA.
It also depends on lenght. My experiences are (If I remember correctly): 30cm - works, 45cm - data corruption with the burner, 60cm - command problems with HDDs, 90cm - basically unusable with HDDs being dropped by the kernel within minutes. Cable quality can influence that in both directions.
Arno
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On 23:10 9 Nov 2009, Arno wrote:

The home made mod doesn't seem to have as much protection from intereference.
Ready made rounded PATA/IDE cables arrange the wires (signal and ground) as twisted pairs.
Don't know how much difference this makes.
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Hi!
Vince wrote:

Actually, a lot. Therefore, creating "home-made" ATA cables from ordinary ATA cables is not a very good idea.
Best regards,
Iggy
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Vince wrote

True, but neither did the original 40 wire cables either.

Some do, some dont.

Not much.
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On Tue, 10 Nov 2009 19:58:03 +1100, "Rod Speed"

I think the ATA standard is very conservative. I have some braided 40 pin cables out of an old IBM tape drive that I have, strung together out 2 meters beyond the stock 15" or so and a CD/DVD burner has been running just fine. I have no problems burning CDs at 48x. Occasionally I also put a hard drive on this cable. That works too.
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On 08:58 10 Nov 2009, Rod Speed wrote:

My impression is that the 80-way PATA cables were a big improvement on the old 40-way cables. Does anyone know of any data or tests which shows how much improvement they gave?
In this thread Igor Batinic says twisted pair is quite an improvement over untwisted. Does anyone know of any tests or comparisons for this?
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Look into the standard. They made UDMA speeds of 66MHz and above possible by adjusted impedance and inter-wire shilding. It is not so much about a better cable as one adjusted to what you intend to send over it.

That is historic by now. Look into any undergraduate text on signal transmission.
Arno
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Hi!
Vince wrote: > On 08:58 10 Nov 2009, Rod Speed wrote: > >> Not much. > > My impression is that the 80-way PATA cables were a big improvement on > the old 40-way cables. Does anyone know of any data or tests which > shows how much improvement they gave?
It is hard to find exact tests, cause we'll need separate tests for all possible combinations - new cable is defined in standard, maybe you can find some tests via Google.
> In this thread Igor Batinic says twisted pair is quite an improvement > over untwisted. Does anyone know of any tests or comparisons for this?
A plenty of that, also Google a little bit. Therefore, whenever you have any kind of high-speed copper connection, twisted pair must be used to reduce the noise in the cable. You can find, also, twisted ribbon cable (pretty standard cable in SCSI).
Best regards,
Iggy
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Igor Batinic wrote:

"twisted pair must be used" isn't totally accurate. TP technology has been the design of choice for over a century, but it doesn't lend itself to two constraints on cabling for computers.. cheap and compact.
The sig-gnd-sig-gnd layout of an 80 wire EIDE cable does work well.
I've seen/used twisted-pair ribbon cables, but I didn't have to buy them.
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Hi!
nobody > wrote:

It was more a figure of speech than a technical law. :o)
But, of course, it is in specific areas.

Of course it does, if you keep it the way it is supposed to.
Which means, if you don't cut it and try to create "rounded" cable of it. Then you can expect some problems. Therefore good rounded cables have completely different cable schematics.

It was almost a non-written standard in all latest SCSI implementations. Of course you will not need it for ATA implementation (and I doubt you can find something like that).
For instance, IBM FRU PN 37L5558:
http://www.aykat.com/ebay/kabel/kabel_scsi_5x_68pin/kabel_scsi_5x_68pin_3.jpg
With best regards,
Iggy
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On 13:40 12 Nov 2009, Igor Batinic wrote:

That look good.
Presumably the twisting doesn't create extra problems so (apart form cost) why aren't PATA cables like that?
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Tri Cutter wrote:

Essentially because the traditional 80 wire cable is good enough.
They did go for a much smaller serial cable with SATA.
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Vince wrote

Only because the controllers refused to use the faster modes unless an 80 wire cable is used.

It wouldnt be that hard to test, just make up a 40 wire cable that pretends to be 80 wire as far as the controller is concerned and monitor the SMART error data. Dunno if anyone has bothered.

There have been plenty on the general concept. Presumably someone has done that with the round IDE cables.
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