| 摘要 |
<p>PURPOSE:To attain read access and write access accurately at all times by devising the system such that a data storage unit compares a unit specific data included in a command sent from a controller with a unit specific data stored in itself and applies a requested access when both are coincident. CONSTITUTION:A data carrier 20A sends an initial status signal IS comprising a synchronizing character DC No and a status to a controller 10. The controller 10 receives the IS to send an No revision command No CD to the carrier 20A when no other data carrier exists in the operating area AE thereby fixing the DC No of the carrier 20A to zero. In case of, e.g., read access to the carrier 20A. the DC No is designated, a read command is sent and a read response thereto is received. Thus, even if plural data storage units exist in the accessible range, the data access is applied accurately without duplication.</p> |
