Corrupted USB Stick Files

[scalegps]

We are experiencing occasional data corruptions on USB sticks used in an embedded system running Windows CE. Most of the time things work fine, but occasionally we will turn on power, only to find that the data on the drive (our executable, log files) has been corrupted. Reformatting and reloading the stick straighten things right out, but sooner or later it happens again.

My main theory is that an open log file might be corrupted if power is removed during a write, but we are seeing errors in many random files. Naturally, the worst is when the executable is corrupted, but this is especially puzzling because the sector that contains the executable is write protected.

Thanks for any info

 

[Tmagic650]

The USB sticks may not be getting enough voltage during the initial write

 

[raybay]

There are so many failures of USB flash drives, and they are now so cheap, that I would just replace them with another brand. Unless I miss my guess, the USB units with which you are having failures are SanDisk or other very low cost drives.

 

[scalegps]

Corrupted Stick Files

RayBay -

Actually, cheap sticks was one of our original thoughts, so we replaced the original A-Data sticks with STEC Industrial level sticks ($140 for 4GB). No change.

I am still concerned about power-up and power-down issues. Power-up is not an obvious concern because the embedded processor does not start talking to the stick for several seconds after power-up. I have verified that the supplies come up very cleanly and are stable before USB comms are initiated.

I am more worried about power-down as we could easily be talking to the stick when power is removed. With a standard Windows PC I expect that a power-down is well controlled, whereas with an embedded system power is removed without any warning.

Even so, when we move our executable and log files to the processor board's on-board FLASH we never see any issues.

 

[raybay]

We do a lot of work with STEC modules, for our government and manufacturing plants. They do provide a standard that is acceptable on contracts... with "industrial Grade" USB modules that offer High Reliability, remarkable built-in security, work well in extreme environments, can be dropped without loss of data, can handle moist enviornments better than most, and offer builds that are consistent from module to module. But they are NOT faster unless they have changed since March. In fact, we found the actual memory components inside the modules were identical to the security version of SanDisk. I would be surprised if they offer a high speed one yet... since we are on they update list and I haven't seen anything.
For high speed, consider IronKey high speed with encryption, Buffalo Ultra High Speed RIF2-S4GWH Memory PRO, (check out their specs compared to STEC., OCZ MagaKart OCZUSBMGK-16GB, and the Corsair Voyager high speed.
If the STEC has recently come out with a high speed, and it didn't work for you, You are sort of out of luck, unless you want to switch to USB drives, or 7200 rpm drives in USB enclosures. They work well, are much more reliable, and faster than flash drives. But on the other side, they are bulky, and very easily damaged for ever from any lateral impact or from dropping.

 

[raybay]

We do a lot of work with STEC modules, for our government and manufacturing plants. They do provide a standard that is acceptable on contracts... with "industrial Grade" USB modules that offer High Reliability, remarkable built-in security, work well in extreme environments, can be dropped without loss of data, can handle moist enviornments better than most, and offer builds that are consistent from module to module. But they are NOT faster unless they have changed since March. In fact, we found the actual memory components inside the modules were identical to the security version of SanDisk. I would be surprised if they offer a high speed one yet... since we are on they update list and I haven't seen anything.
For high speed, consider IronKey high speed with encryption, Buffalo Ultra High Speed RIF2-S4GWH Memory PRO, (check out their specs compared to STEC., OCZ MagaKart OCZUSBMGK-16GB, and the Corsair Voyager high speed.
If the STEC has recently come out with a high speed, and it didn't work for you, You are sort of out of luck, unless you want to switch to USB drives, or 7200 rpm drives in USB enclosures. They work well, are much more reliable, and faster than flash drives. But on the other side, they are bulky, and very easily damaged for ever from any lateral impact or from dropping.

 

[scalegps]

RayBay,

Actually, high speed is really not an issue. We are not trying to pass that much data. In fact, one of the things I am looking at doing is throttling the link back to USB1.1 to see if the characteristics change.

Still, I can't see how that would change the fact that we are corrupting a locked area of the FLASH. I can easily imagine garbage characters getting through during power cycles, but it seems a bit of a stretch that they could cause overwrites as often as they seem to be.