Trapped in a maze of twisty cables, all alike.

October 12, 2004 5:39 PM

Trapped in a maze of twisty cables, all alike: yesterday one of my harddrives (about two years old) started fucking up (I/O errors) whenever I tried to read some directories (like /usr/bin and /sbin, helpful). Boot with knoppix, by some miracle am able to read the drive, fsck it. I switched the cable going from the mobo to the CD drive with that going to the hard drives, and then it worked. At some point my other hard drive (less than a year old) starts to have similar errors, but worked on reboot after a fscking. Today: same problem as before! But, on merely switching which drive was above which, so the cable fit in more naturally, it works! So my question: could simply twisting the cable have caused those errors? If not, where's the error more likely lie—with the drives or the motherboard?
posted by kenko to technology (9 comments total)

Hard drive cables of late are often cheaply manufactured; in some instances, twisting could cause the plastic "female" connectors to open up.

If you try connecting your optical drives in the same spot on the motherboard, and notice similar glitches, it could help determine if the cable or the onboard bus port are faulty.
posted by Smart Dalek at 5:55 PM on October 12, 2004

Yes, simply twisting the cable could have caused these errors. Get some decent "rounded" cable to avoid the problem. It's not likely that the problem is either the drives or the motherboard.

If it turns out to be one of them after installing some quality cable, it's hard to say which would be the more likely culprit. Is your motherboard a cheap piece of shit? Or are your drives crappy Western Digitals? Or are we talking all Tyan / Hitachi quality stuff here?
posted by majick at 6:02 PM on October 12, 2004

In terms of noise immunity, I'd expect a given "rounded" cable to be worse than the traditional flat kind. On the other hand, if a rounded cable is easier to route through the case without twisting or pulling apart the connectors, then it could be a net win.

What particular I/O errors are you seeing? (have you checked the kernel log, um, dmesg(8)?)

I suggest getting a new cable (rounded or flat, so long as it's the right length etc. to go where it needs to go) and see if that helps, since cables are relatively cheap. If it doesn't, keep swapping things around, and keeping notes, to try to isolate the bad component: it could be a cable, a connector, a drive (it's conceivable for one marginally-bad drive on a cable to cause errors when the MB is talking to the other drive), gremlins, etc...
posted by hattifattener at 8:36 PM on October 12, 2004

I'd say it's almost certainly the cable. I drove myself nuts recently trying to pin down similar, multiple intermittent problems. Replacing the cable fixed them all.
posted by rushmc at 10:28 PM on October 12, 2004

Well, I already have rounded cables, actually. I wouldn't be surprised if flat cables would have been better since the cables I have are rather hard to manipulate. Since putting the master above the slave and spaced a bit apart, though, things have been peachy (so far). (And majick, the drives are Maxtor; the motherboard's ASUS av7v600.)

Actually I can't find any errors! The dmesg just has stuff from the last boot, and nothing relevant's in /var/log/messages (perhaps because /var lives on the drive that wasn't working).
posted by kenko at 10:35 PM on October 12, 2004

Swap the cables and see if problems continue. Another possible culprit is the power supply.
posted by Manjusri at 10:43 PM on October 12, 2004

"(And majick, the drives are Maxtor; the motherboard's ASUS av7v600.)"

Chances are, if it's not the cable, it's the Maxtor. While Maxtor's quality problems tend to be more on the disk surface side of things than the logic, I'd lean that way if we were taking bets.
posted by majick at 6:38 AM on October 13, 2004

I'd suggest it *could* be the controller on your motherboard. Run some drive tests to check.

Check if your cables are too long. A lot of manufacturers are going over the 18" IDE spec (anything longer than 18" is out of spec and may cause data corruption).

Maxtor offers plenty of drive testing utilities. Easier than getting them from their website is to download the ultimate boot CD, which you'll find useful for all kinds of other tests.
posted by shepd at 6:44 AM on October 13, 2004

My bad cable was a round one, as is my new one. Round ones can get tweaked too.
posted by rushmc at 9:11 AM on October 13, 2004