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A warning to those using a USB to SATA and IDE converter and those usi

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a b G Storage
July 22, 2010 1:51:53 AM

A warning to those using a USB to SATA and IDE converter and those using a USB hard drive. Many of these devices suffer from data corruption when reading files from the IDE hard drive. The error rate can vary from device to device and can vary from on average one error in every 2-3 Gig transferred to one error in every 10 Gig transferred. All of the affected devices use the JM20337 controller chip which is very common and is used in most of these devices. Removal of the resistor R15 4.7K (472) connected to pin 34 cures the problem in every case. Removal of this resistor also stops hot swapping on the SATA drive, but it is not much of a hardship to unplug the USB cable when changing the SATA drive. When testing these devices it is important to use a test file that’s much larger than your computers memory size to prevent the data from being fetched from cache. For more information check out this web site.

http://bigacid.wordpress.com/2008/12/08/jm20337-read-da...
a b G Storage
July 24, 2010 2:25:08 AM

No comments? I would have thought that a lot of people would be concerned about this as the controller chip is used in a lot of USB devices if not the majority of USB to SATA converters. An error rate of one in 3-4 Gig may not sound much but if you use one of these devices to backup somebody’s typical amount of data say around 20 Gig you would get 4 or 5 files corrupted.
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