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ESC & p 2u - 1p 1C Backspace one record on the right
cartridge tape unit.
ESC & p 1u
+
3p 2C Forward space three files on the
left cartridge tape unit.
[< "from" device code> s]
[< "to" device code> d]
[<control parameter>p][<device code>u]
< control code> c
Device Control
The characters b, c, f, m, r, w, and -
(lower case
A)
indicate a command is to be performed. All other letters
define parameters for the commands. For a given escape
sequence, only one command character may be specified.
Also, a device operation (other than a status request)
should not be initiated before the previous device opera-
tion has been completed. For example, after initiating a
read command, the data record must be read by the CPU
before another device operation is initiated. Otherwise,
the read operation may not be executed properly.
During the execution of a command, input from the data
communications interface is ignored and the keyboard is
locked out except for the
E
key during device-to-
device transfer and read file operations. Pressing the
B
key will terminate the operation in progress, set a
flag to indicate user interrupt to the CPU, and unlock
the keyboard. Other operations (such as rewind, condi-
tion tape, etc.), cannot be terminated by the return key.
Any errors in the escape sequence will cause the entire
sequence to be ignored by the terminal. This may cause
the CPU to go into a wait loop if a response is expected
from the escape sequence. A programmed time-out can be
used to counteract this problem.
ESC & p
Examples:
ESC & p 2u OC
ESC & p 1u 6p 2C
ESC & p 2u 3C
ESC & p 1u 4C
ESC
&
p 2u 5C
Rewind the right cartridge tape
unit.
Find the sixth file on the left car-
tridge tape unit.
Locate end-of-data mark on the
right cartridge tape unit.
Condition the tape on the left car-
tridge tape unit.
Record a file mark on the right car-
tridge tape unit.
where device codes are:
SELECTING INPUT/OUTPUT DEVICES
The devices to be controlled are selected by the following
escape sequence format:
ESC & p
[< "from" device code> s]
[< "to" device code> d]
ESC & p 2u 6C
ESC & p 1u 7C
ESC & p -5p 8C
Record end-of-data mark on the
right cartridge tape unit.
Perform a cartridge tape test on
the left cartridge tape unit.
Backspace
five
records
im-
mediately without recording end-
of-data mark on the "to" device.
1
=
left cartridge tape unit
2 = right cartridge tape unit
3
=
display
4
=
printer
ESC & p 9C
ESC &
p
10C
Turn on write-backspace-read
mode.
Turn off write-backspace-read
mode.
Example:
ESC & p 2s 1d 4D
(Specifies the right cartridge tape unit as the source of the
information, and the left cartridge tape unit and printer as
destinations for the information).
Only one "from" device may be specified for a given escape
sequence. Multiple "to" devices may be specified.
At power on or hard reset, the "preset" assignments are
left tape unit for "from" device and right tape unit for "to"
device.
CONTROLLING THE DEVICES
The device functions are controlled by escape sequences in
the following format:
4-2
If the (p) parameter is omitted (control code 1,2, or
8)
or
zero is specified, a default value of
+
1 is assumed.
CARTRIDGE TAPES
For the skip record functions (lor 8), all movements are
relative. Backspacing is indicated with a minus (-) sign
preceding the p parameter number, while forward spacing
is indicated by a plus
(+)
sign or no sign preceding the
number. If a file mark is the last record encountered while
backspacing, the tape is spaced forward so that the tape is
positioned immediately after the file mark (i.e., just before
the first record of the file). Also, the end-of-file mark
status bit is set (bit 4 of cartridge tape unit status byte 0).
In order to backspace past a file mark, you must specify at
least 2 records.
For the locate file function (2), the (p) parameter may be
either an absolute file number, or a relative file count
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