USB flash drives taking lot of time to respond to IN sometimes

[Vinesh]

I observe that after I write to flash drive of 512 bytes using Bulk only transport, and then Do several INs/Reads continuously, then after few hours the response of IN from pendrive(with data) is unusually slow, it pauses for over a second . After that it again works as expected.

Is it common for pendrives to pause for more than a second or so without responding for IN ?

This prolem occurs in many varities of flash drives.

[Jan Axelson]

I'm not aware of this. That doesn't mean it doesn't occur.

Jan

[Barry Twycross]

It wouldn't surprise me. A flash filing system has to occasionally do housekeeping tasks (erasing old blocks etc), which can take a while.

[Bret]

If the tests are always being done on the same computer, it's possible it's a host controller issue.  I have an older laptop that periodically receives Master Abort signals from the PCI bus hardware, which forces a hard reset of the host controller.  Of course, this forces re-enumeration of all attached devices, which usually takes a few seconds.

[Vinesh]

Barry,
How much time it takes for house keeping tasks of flash file system to be done, any pointers or idea will be helpful in this regard.

[Vinesh]

How much time it takes for house keeping tasks of flash file system to be done ?

ANY answers/pointers will be helpful

[Bret]

I've never seen any data on the actual times involved, but the word search I think you need to start with is Static Wear Leveling.