SCSI BUS
Figure 7.16 Data transfer rate in asynchronous mode
(4) Data transfer rate in synchronous mode
Table 7.9 lists parameters for synchronous data transfer that can be performed by the ODD. Values assigned to these parameters are determined by SYNCHRONOUS DATA TRANSFER REQUEST messages transferred between the INIT and TARG. In a system with more than one INIT, parameters may vary from one INIT to another. The data transfer rate is determined by the value assigned to the Transfer Period parameter. To maintain this transfer rate, however, an appropriate value must be assigned to the REQ/ACK Offset parameter considering the INIT's ACK pulse response performance and the interface cable length.
The formulas below give the approximate average data transfer rate that can be achieved on the SCSI bus in synchronous mode. (See Figure 7.17) The notation used in the formulas is as follows:
