Has anyone noticed data corruption when using an external HD enclosure like the Integral P2NES and the Integral P2SATA from Akasa?
I have both and they started to give me some trouble.
Just found this blog with a very interesting discussion about a hardware problem affecting several of these HD enclosures.

Nice report, thanks.

Though I am perplexed about the "started to give", I mean, if it's a conceptual defect in the schematics, it either works with the resistor at it's place or it doesn't, there should be anything connected to "use" or "wear", maybe the enclosure was defective since day 0 and you just happened to notice the problem after some time of use?

jaclaz

"started to give" = I've noticed

What happens is that I recently started to use a program (SecondCopy) to backup files to the enclosures. After copying it compares (bit by bit) the copy to the original. In fact I've been using the enclosure to synchronize files between home and work (back and forth, daily). That's when I detected the problem. According to what people are reporting, the data corruption occurs very rarely (once in 50-100 GB). I've already removed the resistor from the P2SATA (but not from the P2NES) and I'm using a batch file (modified from the blog) to continuously write and compare a 4.4 GB file to the enclosures. So far the P2SATA went through 200 cicles of writing/comparing (equivalent to more than 800 GB worth of data) without problems. The P2NES stopped after less than 100 cicles but I'm not sure if the problem wasn't that I did not connect a secondary USB 5 V power connection. I'm going to repeat the test next weekend.

Well, that's why mothers tell to their children:



So it's like a funnel, you fill it too much and the liquid goes out of the bottle?

It's strange that a resistor plays this kind of trick, most probably is something related to some timing of the polling of something else, like the SATA hot plug, see this (in a reply on the mentioned blog):
http://bigacid.wordpress.com/2008/12/08/jm...ption-solution/


jaclaz

I had problems with similar devices on a notebook.
Reason always was as I later found out power-supply issues.
When i connected several 2.5 inch USB disks using one USB-connector for each one only my notebook produced problems as soon as I used more than two of this devices.
Using 3 produced random disk-write errors.

Finished testing the P2NES on a desktop computer (the same I've used to test the P2SATA) this afternoon. This time I used the extra USB power cable alongside the USB data cable to make sure the problem is not power related. Detected data corruption just after 20 cycles of writing/verifying (again a 4.4 GB file). Well, now I'm going to remove the infamous resistor and test it again. I'll report back the results.

Just came back from a friend of mine who has a similar P2SATA enclosure. Data corruption in the first attempt!!! He is now running the checking script on a different computer.

Removed the R15 from the P2NES. No data corruption after 150 cycles of writing/verifying (the same 4.4 GB file). So I think it's fixed too.

However, as I've posted in the original blog, it’s appalling that several enclosures from different manufacturers (using the same JM20337 chip and nearly identical circuitry) are still being marketed worldwide.

@sanbarrow:
I think your're right and the problems you had were power-supply issues and not related to the one I've mentioned. An USB port can supply a maximum of 500 mA. Most 2.5 laptop HDs need 1000-1200 mA at startup.

Reporting back again.
My Akasa ENP2SATA enclosure functioned OK for a while after I removed the R15. Two weeks ago I noticed the corruption problem again. Now it went to right place where it belongs: the thrash bin.
The final solution: just bought an Western Digital MyBook external hard drive. Working fine. I’ll never again buy those cheap enclosures.