Fujitsu MJA2500BH Maintenance Manual - Page 87

Outline of the Shadow Block Register, Table 5.3, Shadow Block Register

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5.2 Logical Interface 5.2.2 Outline of the Shadow Block Register Each transport layer in the host system and device has a block register, which is called a Shadow Block Register in the host system, and a Block Register in the device. These registers are used when the host system issues a command to the device. Table 5.3 Shadow Block Register Command Block registers Read Write Data Port Error Features Sector Count (exp) Sector Count Sector Count (exp) Sector Count Sector Number (exp) Sector Number Sector Number (exp) Sector Number Cylinder Low (exp) Cylinder Low Cylinder Low (exp) Cylinder Low Cylinder High (exp) Cylinder High Cylinder High (exp) Cylinder High Device / Head Status Command Control Block registers Alternate Status Device Control Note: Each of the Sector Count, Sector Number, Cylinder Low, and Cylinder High fields has a higher-order field used for issuing the Ext command. The fields are called Sector Count exp, Sector Number exp, Cylinder Low exp, and Cylinder High exp, respectively. For information on writing data to these fields, see "Device Control Field." C141-E293 5-13

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5.2
Logical Interface
C141-E293
5-13
5.2.2
Outline of the Shadow Block Register
Each transport layer in the host system and device has a block register, which is
called a Shadow Block Register in the host system, and a Block Register in the
device.
These registers are used when the host system issues a command to the device.
Table 5.3
Shadow Block Register
Command Block registers
Read
Write
Data Port
Error
Features
Sector Count (exp)
Sector Count
Sector Count (exp)
Sector Count
Sector Number (exp)
Sector Number
Sector Number (exp)
Sector Number
Cylinder Low (exp)
Cylinder Low
Cylinder Low (exp)
Cylinder Low
Cylinder High (exp)
Cylinder High
Cylinder High (exp)
Cylinder High
Device / Head
Status
Command
Control Block registers
Alternate Status
Device Control
Note:
Each of the Sector Count, Sector Number, Cylinder Low, and Cylinder
High fields has a higher-order field used for issuing the Ext command.
The fields are called Sector Count exp, Sector Number exp, Cylinder
Low exp, and Cylinder High exp, respectively.
For information on
writing data to these fields, see "Device Control Field."