Error message

[nolanjason1]

What does this mean?

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Severity Type Date Time Message
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Error System 5/30/2015 5:45:43 PM Read disk ST310004 24CS 0041 at position 635445443584 failed after 2 attempts. The semaphore timeout period has expired (121)

[Alt]

Most likely that means that R-Studio couldn't read this disk sector because it is bad.