Set Features Command (Ef H ) - Seagate Medalist 1270 Product Manual

Medalist 1270 Product Manual, August 1995
Word Description
Minimum PIO
68
transfer with IORDY
Reserved
69–127
Seagate-reserved
128–159
160– 255 Reserved
3.2.2 Set Features command (EF
The Set Features command (command code EF
enable and disable the multisegmented cache features and to identify
the transfer modes the drive uses. The multisegmented buffer consists
of Read Look-ahead and write-immediate and write-merging features.
The table below lists the features supported by the drive. The features
that are set to default by the factory are indicated in the Feature column.
To use the command:
1. Write the Feature value to the Features register.
2. Write the Set Features command to the command register.
Note. If the value in the Features register is not supported or is invalid,
the drive posts an Aborted Command error.
At power-on or after a hard reset, the feature selections are restored to
the factory-default values.
The following table shows alterable features supported by the drive.
Values that are preset at the factory are indicated as default in the feature
description.
Feature Value Feature
02 Enable write immediate and write merging (default)
H
55 Disable cache
H
82 Disable write immediate and write merging
H
AA Enable cache (default)
H
03 Set transfer mode
H
Value
120 nsec
xxxx
H
xxxx
H
xxxx
H
)
H
) allows the user to
H
31