IBM IC25N020ATDA04 Hard Drive Specifications - Page 129
DEVICE CONFIGURATION FREEZE LOCK, 2.3 DEVICE CONFIGURATION IDENTIFY subcommand C2h, subcommand C1h
View all IBM IC25N020ATDA04 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 129 highlights
13.2.2 DEVICE CONFIGURATION FREEZE LOCK (subcommand C1h) The DEVICE CONFIGURATION FREEZE LOCK command prevents accidental modification of the Device Configuration Overlay settings. After successful execution of a DEVICE CONFIGURATION FREEZE LOCK command, all DEVICE CONFIGURATION SET, DEVICE CONFIGURATION FREEZE LOCK, DEVICE CONFIGURATION IDENTIFY, and DEVICE CONFIGURATION RESTORE commands are aborted by the device. The DEVICE CONFIGURATION FREEZE LOCK condition shall be cleared by a power-down. The DEVICE CONFIGURATION FREEZE LOCK condition shall not be cleared by hardware or software reset. 13.2.3 DEVICE CONFIGURATION IDENTIFY (subcommand C2h) The DEVICE CONFIGURATION IDENTIFY command returns a 512 byte data structure via PIO data-in transfer. The content of this data structure indicates the selectable commands, modes, and feature sets that the device is capable of supporting. If a DEVICE CONFIGURATION SET command has been issued reducing the capabilities, the response to an IDENTIFY DEVICE or IDENTIFY PACKET DEVICE command will reflect the reduced set of capabilities, while the DEVICE CONFIGURATION IDENTIFY command will reflect the entire set of selectable capabilities. The format of the Device Configuration Overlay Data structure is shown on the next page. 13.2.4 DEVICE CONFIGURATION SET (subcommand C3h) The DEVICE CONFIGURATION SET command allows a device manufacturer or a personal computer system manufacturer to reduce the set of optional commands, modes, or feature sets supported by a device as indicated by a DEVICE CONFIGURATION IDENTIFY command. The DEVICE CONFIGURATION SET command transfers an overlay that modifies some of the bits set in words 63, 82, 83, 84, and 88 of the IDENTIFY DEVICE command response. When the bits in these words are cleared, the device no longer supports the indicated command, mode, or feature set. If a bit is set in the overlay transmitted by the device that is not set in the overlay received from a DEVICE CONFIGURATION IDENTIFY command, no action is taken for that bit. The format of the overlay transmitted by the device is described in Figure 78 on page 116. The restrictions on changing these bits is described in the text following that table. If any of the bit modification restrictions described are violated or any setting is changed with DEVICE CONFIGURATION SET command, the device shall return command aborted. In that case an error reason code is returned to the sector count register, an invalid word location is returned to cylinder high register, and an invalid bit location is returned to the cylinder low register. The Definition of error information is shown in Figure 79 on page 117. ERROR INFORMATION EXAMPLE 1: If a protected area has been established with SET MAX address and if a user attempts to change maximum LBA address (DC SET or DC RESTORE), the device aborts that command and returns an error reason code as below. Cylinder high Cylinder low Sector count : 03h : 00h : 06h = word 3 is invalid this register is not assigned in this case = Protected area is now established Travelstar 48GH, 30GN & 15GN hard disk drive specifications 115