Error waiting for DMA

I have a linux based DVR that stopped recording a few weeks ago. When I ssh'ed into it, the log file had repeated warnings about the space on the second partition being empty. However, df showed that the partition was only 53% full. When I arrived onsight, I ran the CD recovery disk that came with the DVR. It starts e2fsck, and begins to scan /dev/hda2, but freezes with this error message:
e2fsk 1.35 (28-Feb-2004)
/dev/hda2: recovering journal
Checking for bad blocks (read-only test): hda: dma_timer_expiry: dma status ==0x61
hda: error waiting for DMA
hda: dma time out retry: status=0x80 { Busy }

hda: DMA disabled
hdb: DMA disabled
ide0: reset: success
hda: dma_timer_expiry: dma status == 0x21
hda: error waiting for DMA

I tried to boot a SystemRescue CD with the nodma option, but it wont boot because "there are no ipv6 routers present".

I eventually just booted the DVR with a Gentoo LiveCD, mounted /dev/hda2, and ran e2fsck from the console. It completed fine, only a couple errors about bad sectors first pass, and the second pass completed with no errors.

However, the DVR still crashed after a couple days, and the manufacturers rescue cd still halted when running its flavor of e2fsck.

I rebooted with the Gentoo LiveCD, and deleted all the data off of the hda2 partition. I re-re-ran e2fsck from the console, and no errors. only 3% used now.

However, when I returned to the manufacturers rescue cd, it still hangs with the same error message.

I am not familiar with the DMA error message, so I dont know exactly what it is alleging. From my little googling, it seems that it is a mode which can be enabled or disabled (relating to cache?). So:

1) why would DMA crash a manufacturer rescue cd e2fsck, but I can run it no errors from a LiveCD? Is it possible that the Gentoo doesnt load DMA modules by default?

2) how can I fix this? is it symptomatic of a failing HD? Is it possible that a complete low-level reformat (worth the time to try)?

I will try to be fair with points, and spread the love to anybody who answeres any of these questions. I dont know how difficut this is, so I'm not opposed to escalating the points if it turns out to be harder than I thought.

Thanks in advance!

Paul Washburn
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I haven't used a gentoo liveCD for some time, but like with a lot of other such CD's it is necessary that it run on as much hardware as possible, so many features are turned off by default. Check the LiveCD, there may be some bootup cheat codes that allow you to turn on DMA and other modes (I think at least knoppix has such a switch). DMA mode will allow faster transfers from the interface to the HD, as opposed to the PIO mode that is probably used by default.

To me this looks like a HD going bad. You should download the manufacturer's HD test utility and use that to thoroughly test it or download the UBCD which includes most of these utilities. It also includes a linux (DSL based) with GUI that you can also use for testing.


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