Specifications

Operating System Routines
EXE$READ
• If MMG$IOLOCK fails, it returns SS$_ACCVIO, SS$_INSFWSL, or page
fault status to EXE$READLOCKR.
If either EXE$READCHKR or MMG$IOLOCK returns an error status other than
a page fault condition, EXE$READLOCKR transfers control to EXE$ABORTIO.
In the event of a page fault, EXE$READLOCKR adjusts direct I/O count and
AST count to the values they held before the I/O request, deallocates the IRP, and
restarts the I/O request at the $QIO system service. This procedure is carried
out so that the user process can receive ASTs while it waits for the page fault to
complete. Once the page is faulted into memory, the $QIO system service will
resubmit the I/O request.
3–49