Home
Support

Knowledge Base

BSPs and drivers
Community resources
Product documentation
Questions?
Contact us

High CPU load when connecting high capacity hard drive via USB
 
________________________________________________________________________

Applicable Environment
________________________________________________________________________
  • Topic: USB hard drive, high CPU load
  • SDP: 6.4.1
  • Target: All supported targets
________________________________________________________________________

Recommendation
________________________________________________________________________

This is due to the FAT being read at mount time. A general rule for FAT32 is 1MB of fat per 1GB of filesystem.

There is a command line option which specifies when the FAT is read. The default for 'fat' is and has always been "fat=nonrmv", which
behaves as:
- "always" on non-removable devices, read FAT at mount time (you will need it during it's lifetime)
- "lazy" on removable devices, read FAT at access time (since there is a chance you might never need to do it before ejected)
- "nonrmv", it depends on how the device is advertised using "DEV_REMOVABLE".

________________________________________________________________________
NOTE: This entry has been validated against the SDP version listed above. Use caution when considering this advice for any other SDP version. For supported releases, please reach out to QNX Technical Support if you have any questions/concerns.
________________________________________________________________________


Related Attachments
 None Found





Please contact us with your questions or concerns.