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anaxagoras

Long IDE cable

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does anyone have any experience with long ide cables?

after havine done a bit of reading here i've found that rounded cables are not reccomended, i already have 2 x 36" antec 'cobra cables' which are shielded, twisted pair, round cables. I want to replace them with standard ribbon cables.

I think I can get by with 24" cables. These are all for use to connect IDE hard drives in a double wide server case. Or are there any other options i might have? 18" cables are just not long enough. Does anyone have any experience with 24" and 36" ribbon cables?

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My experience with 36" ribbon cables is we used them to generate CRC errors on the PATA interface during UDMA/100 fault injection testing.

PATA cables are spec'ed at 18", for good reason. Since PATA uses such an archaic electrical interface (5V TTL), the signal timing can get screwed up over longer distances. And because PATA does not have CRC-protection over all operations, there's a good chance you can corrupt data on the drive using a non-spec cable.

If you really need a long PATA cable and there is no way around it, you might want to limit your transfer rate to UDMA/66 or even UDMA/33. That will reduce the chance of errors.

If you need performance, reliability, and long cables, better just bite the bullet and go SATA or SCSI.

You might try PATA/SATA adapters if you are on a budget and have a lot of old PATA drives. Then you can use a 1 meter SATA cable without worries about questionable engineering:

http://www.highpoint-tech.com/original/USA/rh100.htm

Highpoint is pretty good with SATA compatibility. I think these run about $25, maybe less if you buy in bulk.

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Yeah anything longer then 18" would be out of spec and would cause your drive to run in a degraded mode, perhaps DMA 1-2-3-4 but perhaps as bad as pio mode. My experience has been that longer then 18" causes a negative effect. I made some custom 22" ribbon cables one time for a full tower, they caused pio.

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ok, so i'll go the sata to ide adapter route as i don't have the money to replace all 10 of my drives right now. of course only 4 need long cables...

this means that i'll also need a sata controller card. any reccomendations? just something cheap preferably a single card that can handle at least 4 devices. I don't really need raid as when i do raid i will do a software setup.

and just one more question, anyone know of any software to test the integrity of the data going to that drive? i'm assuming something that does many read/write operations of a set of known data would do the trick. I"m running NetBSD on that machine.

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Matching SATA controller to the adapter manufacturer is a good idea to avoid compatibility problems.

I'd go for a Highpoint 1640, they run about $90:

http://www.highpoint-tech.com/USA/rr1640.htm

It's a RAID card, but you can set it up as JBOD. They have FreeBSD drivers, not sure if that's compatible with NetBSD?

Considering your OS you might need to roll your own S/W for testing. Just make sure you tag each 512 byte block with the unique LBA# for the read/compare.

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Been using (CoolerMaster) 24-inch round cables and hadn't had any such problems such as degraded DMA modes or reverting to PIO modes. All running at UDMA5 or ATA100 modes.. The reason for using them is I had drives in the 5.25" bays and my IDE was located near the southbridge I.C (at the bottom of the casing!). I've also had an PCI IDE card using this cable.. Anyway, all my data are always have checksum, thus I will know if any corruption occurs.. and so far, NONE whatsoever... :D

As for problems with long cables, perhaps cable type and quality does matter.. For example, the CAT5/CAT5E cable compared to a normal multi-core cable like those used for analog phone lines.. Using normal cables for LAN will cause networking lag and problems (lots of packet errors, or packet losses). However using CAT5 cables are OK. ;)

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the cables i had are shielded and have a grounding strap. But looking at the smart data the drives that were on those cables had a high raw read error rate, and high udma crc error counts.

The quality of the 36" cables i had were very good, but 36" is just too long. I managed to get most of my drives to work with standard 18" ribbon cables... albeit some have a bit of tension on them which i don't like.

there are only 2 drives that i can't reach.

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the cables i had are shielded and have a grounding strap. But looking at the smart data the drives that were on those cables had a high raw read error rate, and high udma crc error counts.
Hmm.... High UDMA CRC error counts? I don't have that either... Question.. What hard drives are you using by the way? :blink:
there are only 2 drives that i can't reach.
Tell me about it.. Standard 18-inch cables couldn't reach some of my drives, thus have to resort to 24-inch ones... :rolleyes:

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I have 6 Western Digital WD200JB drives and 2 seagate ST32000822a drives, baracuda 7200.7's i beleive they are. all 200 gig drives. I can't reach 2 older western digitals a 120 gig and a 160 gig.

the smart errors reported were very significant on the segates using long cable, I'd assume that seagates give a more realistic smart value. I was also using 2 WD drives on long cable and while they did have error rates on the smart, it was nowhere near as high as the seagates, i'd assume the WD's probably hide their error data more and only report the more significant stuff.

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