Radio Shack TRS-80 Model II Reference Manual page 141

Utility Programs
Using the RAM Buffer
The
RAM
buffer is used to store incoming text (R option) and prepared text
from a disk file (G option) so that it can be sent rapidly. The
RAM
buffer helps
reduce costly hookup time, by letting you perform time-consuming
operations - preparing data or printing it out - while you are off-line.
Size
For 32K Model II systems, the buffer can contain 11,493 bytes of text; for 64K
systems, 44,261.
For 32K systems using 300 baud (i.e., 30 characters per second), it will take
approximately 7 minutes to fill the buffer in the interactive terminal mode; for
64K systems, 25 minutes.
If the buffer becomes filled during a load from disk (G command) or while
receiving data in the interactive terminal mode, a warning message will be
displayed and the buffer will be closed. If you are loading a disk file, you will
be returned to the menu and the buffer will contain the data that was loaded.
If you are in the interactive terminal mode, normall/O will continue, except
that it will no longer be saved in the buffer.
Saving the RAM Buffer
When the buffer is filled in the interactive mode (or when you suspect it will
be soon), do the following:
1.
Transmit a pause or break control character to the host program.
2. Return to the menu by pressing (BREAK) .
3. Copy the
RAM
buffer to a disk file (C command).
4. Reset the
RAM
buffer (R command).
5. Return to the interactive terminal mode (T command).
Opening and Closing the RAM Buffer
Often during interactive I/O, you want to save only portions of the text. The
R command lets you do this. Each time you are about ready to receive some
important data, do the following:
1.
Transmit a pause or break control character to the host program.
2. Return to the menu by pressing
(BREAK) .
3. Toggle the
RAM
buffer status. If it is not off, toggle it again. If it is on, you
have the option of resetting it or leaving it as is. To add new data onto the
end of old, do not reset it. To delete old data, do reset it. For details and
examples, see R command later on.
4. Return to the interactive terminal mode (T command).
5. Direct the host program to resume transmission. The data will now be saved
in the
RAM
buffer as it is received.
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