page length was specified. The X '0A' page length, is provided in consideration of compatibility with previous models, but it is recommended that the page length X '0E' be used by the INIT to support expansions in the specifications in the future.
See Section 2.1, "Data Buffer" concerning specification methods for the "Buffer Full Ratio" and "Buffer Empty Ratio" parameters in this page descriptor and details of data buffer operation.
a.Buffer full ratio
This parameter specifies the timing for the IDD to start reconnection processing in order to transfer data to the INIT by the READ or READ EXTENDED command.
The value specified in this parameter (n) shows the amount of data read to the IDD's data buffer from the disk media as a proportion [n/256] of the total capacity of the data buffer until reconnection processing with the SCSI bus is started. (Note)
If it is possible to transfer the amount of data specified in this parameter to the INIT from the data buffer, reconnection processing is executed and transfer of data to the INIT begins.
The default value for this parameter is X’00’. The host can also specify X’00’ for this parameter. If X’00’is specified, the IDD assigns an appropriate value for this parameter that is determined by IDD.
b.Buffer empty ratio
This parameter specifies the timing for the IDD to start reconnection when it is requested by the INIT to transfer data in the WRITE, WRITE EXTENDED or WRITE AND VERIFY command.
The value specified in this parameter (n) indicates the size of the empty area in the IDD's data buffer as a proportion of the total data buffer capacity of the IDD [n/256]. (Note)
While the IDD is writing data to the disk media, it is using the data
If the total number of bytes in the transferred data block count specified in the command is less than the capacity of the buffer segment, all the data are
The default value for this parameter is X’00’. The host can also specify X’00’ for this parameter. If X’00’is specified, the IDD assigns an appropriate value for this parameter that is determined by IDD.
Note:
If the value specified for the "buffer full ratio" or the "buffer empty ratio" is not within double the integral boundary of the logical data block length, the IDD rounds up the specified value to the value which is the nearest data block boundary. Also, if zero is specified in any of these parameters. If X’00’is specified, the IDD assigns an appropriate value for this parameter that is determined by IDD. However, parameter values specified from the INIT in the MODE SELECT or MODE SELECT EXTENDED command are
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