The text read off it
[02.07.02]
The greater the length of a block, the greater will be the percentage of useful information that can be stored on a length of tape. However, large blocks do require large storage allocations which if too large, may not result in the most efficient balance between input/output and internal processing (computing). Blocks of 200 to 500 words will probably provide for the optimum processing of master records within the Commercial Translator system.
4. Buffers
The Loader reserves a portion of core storage for use by the I/O system as operating storage. This storage area is subdivided into buffers into which all input blocks of data are read and from which all output blocks of data are written. Since the IOCS routine attempts dynamic optimization of buffer assignments, data blocks of a particular file may be located within any of the buffers associated with this or several files.
5. Locate and Transmit
In the 709/7090 Commercial Translator system it is possible to process the records of an input file in the buffers or in an area(s) reserved for them outside the buffer area; all records in a file must be processed in the same manner.
a) Locate Mode of Operation
The GET command when dealing with a record to be processed in the buffer area
i. 'locates' the next record in the file, i.e., determines the position of the record within the buffer area, and
ii. adjusts all program references to data within the record to reflect the new base reference address of the record within the buffer area.
b) Transmit Mode of Operation
The GET command when dealing with a record to be processed in an area assigned outside of the buffer area
i. locates the next record in the file, and
ii. 'transmits' the record to its assigned area. As the area assignment is fixed no adjustment of references to data within the record is necessary.