O/S error:(OS 121) The semophore timeout period has expired

Hi,
On one of our database ,there is RMAN differential incremental backup strategy.
On Wednesday there was level 1 backup, but BAckup failed due to following errors:
RMAN-03009 - Failure of backup commnand
ORA-19502 - Write error on file
ORA-27072 - skgfdisp : I/O error
OSD-04008 - Write file() failure unable to write to file.
O/S error : (OS 121) The semophore timeout period has expired.

Can u please tell why this error occured? What does mean OS 121 error and how to fix it?

Thanks in advance.

Urgent help is highly appriciable.

Post your OS name and backup script.

check your semaphores setting using 'ipcs' and list them too....along with your os / oracle versions.

Thank you,

The OS is Windows 2000 Service pack 4. As far as script is concern, we are using the same script since last 6 to 7 months. I've never come across such error.

I hope this helps.

Please let me know the problable reason and the solution for it.

Thanks for your time.