U UNIVAC 1218 - Bitsavers
U UNIVAC 1218 - Bitsavers
U UNIVAC 1218 - Bitsavers
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
2.6.2 INPUT DATA TRANSFER<br />
CHANGE 2<br />
To input data, a message header is sent to the slave to request input of<br />
data or to set up the slave handler for a specific input format and the<br />
subsequent use of the special function. Multiple cards may be read depending<br />
on the memory size of the slave. The input data transfer sequence is;<br />
1) Send the MEFW to the ICCU via an external function command.<br />
2) Initiate an output buffer with a length equal to the word length of<br />
the message header plus one word (number of words not bytes).<br />
3) Accept an external interrupt and accompanying EISW upon completion of<br />
data transfer (channel end interrupt). The command byte of the EISW will<br />
be zero upon termination of data transfer.<br />
4) Initiate an input buffer with a length equal to the number of words<br />
being sent multiplied by the number of characters per word plus one.<br />
5) Send the MEFW to the ICCU via an external function command.<br />
6) Accept input data and upon completion of data transfer accept an<br />
external interrupt and EISW (device end interrupt). The command byte of<br />
the EISW will be zero.<br />
Due to the timing characteristics of the slave handler and the ICCU, the<br />
master should issue the MEFW for input immediately upon receipt of the<br />
first interrupt.<br />
2.6.3 SPECIAL FUNCTIONS<br />
For convenience in performing I/O operations, special functions are provided<br />
as specified in the last message header sent to each device. The handshake<br />
sequence sets up the slave handler to perform as follows.<br />
1) Read one card (80 column), translate to XS-3<br />
2) Punch one card (80 column), translate from XS-3<br />
3) Print one line (120 characters), translate from XS-3<br />
If an I/O function is to be performed other than specified above, a message<br />
header must be sent for that device to reset the slave handler to perform in<br />
the manner desired.<br />
A special function code must be given in the D field of the MEFW in place of<br />
the byte count to use the special function.<br />
II-G-15