(4)Mode = 0, 0, 1, 1: Buffer descriptor

When this mode is specified, the IDD transfers only the 4-byte buffer descriptor to the INIT. the IDD’s data buffer attributes are indicated in the 4-byte buffer descriptor. Zero must be specified in the “Buffer offset” field in the CDB when this mode is specified. The IDD transfers the data length specified in the “Transfer byte length” field in the CDB or 4 bytes, whichever portion of data is smaller, to the INIT. When zero is specified in the “Transfer byte length” field, this command is terminated without executing a data transfer.

Byte

Bit

7

6

5

4

3

 

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

X’02’ Addressing Boundary

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

X’78’ Buffer Capacity (MSB)

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

X’00’

Buffer Capacity

 

 

 

 

 

 

 

 

 

 

 

 

3

 

 

X’00’ Buffer Capacity (LSB)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 3.26 READ BUFFER command: buffer descriptor

The "Addressing boundary" field in the buffer descriptor indicates the addressing boundary in the data buffer which can be specified in the WRITE BUFFER Command and the READ BUFFER Command as a "Power" when expressed as a "Power of 2." The IDDs report X'02' (=22), indicating that it is possible to specify the address in 4-byte units. Also, the "Buffer capacity" field indicates the byte length of the size of the data buffer which can be operated by the WRITE BUFFER and READ BUFFER commands.

Note: Exercise caution regarding the following points when using this command.

If the WRITE BUFFER command or READ BUFFER command is used under a multi-initiator or multitask environment, it is necessary to be careful of the contents of the data buffer being changed by another initiator or a command that issues another task during the interval between completion of WRITE BUFFER command execution and execution of the READ BUFFER command. In order to avoid this problem, it is necessary either to issue the commands with the READ BUFFER command linked to the WRITE BUFFER command or, in the case of a multi- initiator environment, to reserve the IDD by the RESERVE UNIT command.

C141-E124-01EN

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Fujitsu MAN3184, MAN3367, MAN3735 SERIES DISK DRIVES specifications Read Buffer command buffer descriptor
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MAN3735, MAN3184, MAN3367, MAN3735 SERIES DISK DRIVES, MAN3367, MAN3184 specifications

Fujitsu's MAN3184, MAN3367, and MAN3735 series disk drives represent a significant advancement in storage technology, catering to the needs of businesses seeking reliability, performance, and high capacity. These drives are designed for enterprise environments, providing exceptional data integrity and speed essential for effective data management.

The MAN3184 series is renowned for its high rotational speed of 10,000 RPM, which significantly enhances data access times. With a capacity of up to 18.4 GB, these drives are suitable for applications requiring quick read and write operations. The series employs an improved read/write head technology, which reduces latency and increases overall performance. This technology is complemented by advanced error correction mechanisms, ensuring the reliability necessary for critical data applications.

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