@@IO_BUSY function returns milliseconds that SQL Server has spent performing input and output operations since last started.
Syntax of @@IO_BUSY Function :
@@IO_BUSY
Return type of an above function is an integer.
Examples of @@IO_BUSY Function :
Example 1 : Use of @@IO_BUSY function in select clause
Output
Above example returns 7 milliseconds spent on I/O operations since sql server has been last started.