Specifications

Writing Device-Driver Tables
4.3 Function Decision Table
Table 4–1 (Cont.) I/O Function Codes
Function Description Equivalent Symbols
Physical I/O
IO$_WRTTMKR† Write tape mark retry IO$_DIAGNOSE† (diagnose), IO$_
SHADMV† (perform mount verification
on shadow set), IO$_PSXSENSECHAR†
(POSIX sense characteristics)
IO$_FORMAT Format IO$_CLEAN† (clean tape)
Logical I/O
IO$_WRITELBLK Write logical block –
IO$_READLBLK Read logical block –
IO$_REWINDOFF Rewind and set offline IO$_READRCTL† (read RCT sector 0)
IO$_SETMODE Set mode –
IO$_REWIND Rewind tape –
IO$_SKIPFILE Skip files IO$_PSXSETMODE† (POSIX set mode )
IO$_SKIPRECORD Skip records IO$_PSXSENSEMODE† (POSIX sense
mode)
IO$_SENSEMODE Sense mode –
IO$_WRITEOF Write end of file IO$_TTY_PORT_BUFIO† (Terminal port
driver FDT routine for buffered I/O)
IO$_TTY_PORT† Terminal port driver FDT
routine
IO$_FREECAP† (return free capacity)
IO$_FLUSH† Flush controller cache IO$_AS_SETMODE† (Asian set mode)
IO$_READLCHUNK† Read large logical block IO$_AS_SENSEMODE† (Asian sense mode)
IO$_WRITELCHUNK† Write large logical block –
Virtual I/O
IO$_WRITEVBLK Write virtual block –
IO$_READVBLK Read virtual block –
IO$_ACCESS Access file IO$_PSXWRITEVBLK† (POSIX write
virtual block)
IO$_CREATE Create file –
IO$_DEACCESS Deaccess file IO$_PSXREADVBLK† (POSIX read virtual
block)
IO$_DELETE Delete file –
IO$_MODIFY Modify file IO$_NETCONTROL† (X.25 network control
function)
IO$_READPROMPT Read terminal with prompt IO$_SETCLOCK (set clock), IO$_AUDIO
(CD–ROM audio)
IO$_ACPCONTROL Miscellaneous ACP control IO$_STARTDATA (start data)
IO$_MOUNT† Mount volume –
IO$_TTYREADALL† Terminal read passall –
†Unsupported; subject to change without notice
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