4. Buffer Register
4.1 Input Buffer
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4. Buffer Register
4.1 Input Buffer
Function and purpose
When the pre-read buffer is empty during a tape operation or RS232C operation, the contents of
the input buffer are immediately transferred to the pre-read buffers and, provided that the data
stored in the input buffer do not exceed 250 x 4 characters, the following data (Max. 250
characters) are read and loaded into the input buffer.
This buffer is designed to eliminate the operational delay originating in the readout time of the tape
reader and to smooth out the block joints.
The pre-reading effects are lost, however, when the block execution time is shorter than the tape
readout time of the following block.
(Buffer size : 250 x 5 characters)
Tape
Input buffer
Memory
Keyboard
MDI data
Mode
switching
Analysis processing
Max. 5 execution blocks
Buffer 4
Arithmetic
processing
Note
: Data equivalent to 1 block are stored in 1 pre-read buffer.
Buffer 3
Buffer 2
Buffer 1
Pre-read
buffer 5
The input buffer has a memory capacity of 250 x 5 characters (including the EOB code).
(1) The contents of the input buffer register are updated in 250-character units.
(2) Only the significant codes in the significant data section are read into the input buffer.
(3) When codes (including "(" and ")") are sandwiched in the control in or control out mode and the
optional block skip function is ON, the data extending from the "/" (slash) code up to the EOB
code are read into the input buffer.
(4) The input buffer contents are cleared with resetting.
(Note 1)
The input buffer size (250 characters) differs according to the model.