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?

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Reply to
mike
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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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Reply to
Arno

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.

Reply to
Vince

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

Best regards,

Iggy

Reply to
Igor Batinic

Vince wrote

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

twisted pairs.

Some do, some dont.

Not much.

Reply to
Rod Speed

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?

Reply to
Vince

Vince Inscribed thus:

The primary point of using 80 conductor cables was impedance matching to reduce the standing waves at the high data rates. It makes little or no difference whether they are twisted or not. Theoretically twisting should improve interference rejection, but I suspect that it would be very difficult to quantify.

Rolling the cable into a tube or using twisted pairs in a tube, probably would have some effect on the air circulation inside the case. Doing smoke tests don't show any real advantage over flat ones. The case design has to be really poor, like some of the "Philips" machines I've seen where the thing is so cramped the air circulation is almost nil.

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Reply to
baron

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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Reply to
Arno

Hi!

Vince wrote: > On 08:58 10 Nov 2009, Rod Speed wrote: >

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.

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

Reply to
Igor Batinic

Vince wrote

twisted pairs.

40-way cables.

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

gave?

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.

Reply to
Rod Speed

"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.

Reply to
nobody >

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:

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With best regards,

Iggy

Reply to
Igor Batinic

That look good.

Presumably the twisting doesn't create extra problems so (apart form cost) why aren't PATA cables like that?

Reply to
Tri Cutter

Essentially because the traditional 80 wire cable is good enough.

They did go for a much smaller serial cable with SATA.

Reply to
Rod Speed

TROLL

I AM PROTEUS

Reply to
Proteus IIV

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