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$_RELEASE† Release port IO$_SETCLOCKP† (set clock—physical),
IO$_START_ANALYSIS† (start LAVc
failure analysis)
IO$_OFFSET† Offset read heads IO$_ERASETAPE† (erase tape), IO$_
STARTDATAP† (start data transfer—
physical), IO$_STOP_ANALYSIS† (stop
LAVc failure analysis)
IO$_RETCENTER† Return to center line IO$_QSTOP† (queue stop request), IO$_
START_MONITOR† (start LAVc channel
monitor)
IO$_PACKACK Pack acknowledgment (required
by all disk drivers)
IO$_STOP_MONITOR† (stop LAVc channel
monitor)
IO$_SEARCH Search for sector IO$_SPACERECORD† (space records), IO$_
READRCT† (read replacement and caching
table)
IO$_WRITECHECK Write check data –
IO$_WRITEPBLK Write physical block –
IO$_READPBLK Read physical block –
IO$_WRITEHEAD† Write header and data IO$_RDSTATS† (read statistics), IO$_
CRESHAD† (create a shadow set)
IO$_READHEAD† Read header and data IO$_ADDSHAD† (add member to shadow
set)
IO$_WRITETRACKD† Write track data IO$_COPYSHAD† (perform shadow set copy
operations)
IO$_READTRACKD† Read track data IO$_REMSHAD† (remove member from
shadow set)
IO$_AVAILABLE Set device available (required by
all disk drivers)
–
IO$_SETPRFPATH† Set preferred path –
IO$_DISPLAY† Display MSCP/TMSCP volume
label
–
IO$_DSE Data security erase (and rewind) –
IO$_REREADN† Reread next IO$_DISK_COPY_DATA† (disk copy data)
IO$_REREADP† Reread previous IO$_WHM† (write history management),
IO$_AS_SETCHAR† (Asian set character)
IO$_WRITERET† Write retry IO$_WRITECHECKH† (write check header
and data), IO$_AS_SENSE_CHAR† (Asian
sense characteristics)
IO$_READPRESET† Read in preset IO$_STARTSPNDL† (start spindle)
IO$_SETCHAR Set device characteristics –
IO$_SENSECHAR Sense device characteristics –
IO$_WRITEMARK† Write tape mark IO$_COPYMEM† (copy memory), IO$_
PSXSETCHAR† (POSIX set characteristics)
†Unsupported; subject to change without notice
(continued on next page)
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