Con; Disk - ZiLOG Z80-RIO Operating System User's Manual

Nonetheless, it responds with a completion code implying
completion of operation.
I/O Request
READ LINE
READ BINARY
All others
Action
completion code
=
C9H (end of
file), data length
=
0
completion code
=
80H
(operation completed)
This device provides a destination to which unwanted output
can be diverted. It also provides a convenient way to
check the integrity of a file. A file that can be copied
to NULL has no record pointer errors, since a complete READ
operation is performed. In the same way, all files on a
disk can be copied to the NULL device with a single
command, thus checking the file structure of the entire
disk.
3.4.4
CON
CON is the default RIO console driver especially designed
for CRT terminals.
It is linked as part of the file as
which is loaded during system bootstrap. It allows the
user to define the line and character delete symbols and
supports arbitrary tab settings within a
134
character
line length. The standard RIO I/O vector format is used
in communicating with CON (see Appendix
F).
During READ operations, entering the single character
delete symbol (default
=
ASCII backspace, 08H) causes the
last character placed in the buffer to be logically
deleted. A backspace, space, backspace sequence is sent to
the console to erase the character from the screen and
reposition the cursor.
The line feed character (ASCII OAH) forces the cursor to
the start of the next line and places a space (ASCII 20H)
in the buffer. This provides a convenient way to force the
cursor or print mechanism to the beginning of the next line
without terminating input. Note that no carriage return is
placed in the buffer, i.e., input is logically a single
line.
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