BRK (Break) Key
The BREAK key provides the operator with
the capability of generating an interrupt to the
central processor which may be used to suspend
CAP LOCK Key
The CAP LOCK key locks the keyboard in an
uppercase-only operating mode.
The cursor is designed for bottom line data
entry. As lines are entered by the operator, the
previously entered line is advanced upwards on
the screen. This upward motion is triggered by
the operator entering a valid line terminating
character (carriage return/line feed).
The cursor automatically advances to the next
character position in a line of data whenever a
character is entered by the operator. The follow
ing are the available cursor controls:
Upon reception of a carriage return character
from the central processor or from operator
depression of the Return key, the cursor returns
to the first character position of the line (last
line). The line does not advance upwards with this
command; the line feed character is required to
cause upward motion of the line.
LF (Line Feed) Key
A line feed character, received from the
central processor or from operator depression of
the Line Feed key, causes the last line to move
upwards one line position. Any line currently at
the top of the screen is also moved upwards one
line and therefore is lost.
A keyboard alarm bell sounds whenever the
CRT receives a BEL code from the software or
when a character is entered by the operator in
character position 75 of the line. The bell is
intended as a warning that the end of the line is
near. Any data entered by the operator that
exceeds the line character limit (80 characters) is
overwritten in column 80 and is lost.
Level 6 software provides for the transfer and
receipt of data from and to the console through a
series of Input/Output programming commands.
These commands and their associated meanings
are summarized in Table 10-1.
TABLE 10-1. INPUT/OUTPUT COMMAND SUMMARY
Input Interrupt Control
Input Range (ReSidual)
Input Configuration Word A
Input Configuration Word B
Input Status Word
Input Device ID
Input Address (Lower
Input Address (Upper
Input Task Word
Input Attention Character
Output Interrupt Control
Output Address and Range
Output Configuration Word A
Output Configuration Word B
*The low order bit of the channel number of this command specifies the direction of the data transfer (i.e., input or output). The low
order bit of the channel number is ignored on all other commands.
CRT KEYBOARD CONSOLE