HELP DEVICE                                         A.Sloman August 1988

The basic Input/Output (I/O) procedures in POP-11 (which are modelled on
UNIX system calls) all work on objects called DEVICE RECORDS.

A device record is a data structure describing a disk file (or some
actual device such as a terminal or graphics device).

The procedures *SYSOPEN *SYSCREATE *SYSPIPE (Unix) and *SYSMAILBOX (VMS)
create such device records.

*SYSREAD  *SYSWRITE and * SYSFLUSH are used to read and write characters
and other data via devices.

*SYSCLOSE closes a file or other device.

*DEVICE_OPEN_NAME, when applied to a device record returns the file
name used when the device record was created. (Previously this was
DEVNAME)

*ISDEVICE can be used to recognise device records.

*SYS_FILE_STAT can be used to find information about a file, such as its
size, modification date, owner, and protection.

*SYSFILESIZE is a library file defined in terms of it.

For more detailed information on Input/Output procedures see
REF *SYSIO, REF * SYSUTIL, and REF * CHARIO

HELP *PIPEUTILS describe procedures for communicating with sub-processes
via pipes (on Unix only).

--- C.all/help/device --------------------------------------------------
--- Copyright University of Sussex 1988. All rights reserved. ----------
