Quantum DAT 24 Drive Guia do Utilizador descarregar pdf (Página 176)

Page 164 DDS-4 SCSI Interface Manual, Rev. B

WRITE DATA BUFFER (3Bh)

The WRITE DATA BUFFER command is used in conjunction with the READ DATA

BUFFER command as a diagnostic function for testing the data buffer memory of

the drive and confirming the SCSI bus integrity. The medium is not accessed during

the execution of this command.

The WRITE DATA BUFFER command can also be used to download the controller

firmware if the drive is equipped with flash EEPROM. Only firmware supplied by

Seagate should be downloaded. Once the valid firmware is downloaded to the

buffer, the flash EEPROM is programmed. Then, within 30 seconds, control is

transferred to the new firmware and a power-on reset occurs. The drive is then

ready to accept further commands.

WRITE DATA BUFFER Command Descriptor Block

The following table shows the layout of the Command Descriptor Block.

Byte

Bits

7 6 5 4 3 2 1 0

0 0 0 1 1 1 0 1 1

1 0 0 0 0 0 | MODE

2 Buffer ID

3 MSB-ADRS

4 ADRS

5 ADRS—LSB

6 MSB—Byte Transfer Length

7 Byte Transfer Length

8 Byte Transfer Length—LSB

9 vendor unique* 0 0 0 0 Flag Link

* This vendor-unique field is reserved and must be set to zero.

ADRS is the buffer offset for Mode 2 and is the buffer address for Modes 4 and 5.

1 2 ... 171 172 173 174 175 176 177 178 179 180 181

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Quantum DAT 24 Drive Guia do Utilizador Página 176