IBM DTTA-351010 Hard Drive Specifications - Page 95

From this point, the protected area cannot be accessed till next Set Max LBA/CYL command is issued. Any BIOSes, device drivers, or application software access the H D D as if that is the 6.2GB device because the device acts exactly same as real 6.2GB device does. 3. Conventional usage without system software support Since the H D D works as 6.2GB device, there are no special care to use this device for normal use. 4. Advanced usage using protected area The data in protected area is accessed by following. Issue Read Native Max LBA/CYL command to get the real device maximum LBA. Returned value shows that native device maximum LBA is 12,692,735 (C1ACFFh) regardless of the current setting. Make entire device be accessible including the protected area by setting device maximum LBA as 12,692,735 (C1ACFFh) via Set Max LBA/CYL command with volatile option. By using this option, unexpected power removal or reset will not make the protected area remained accessible. Read information data from protected area. Issue hard reset or P O R to inhibit any access to the protected area. 10.9 Write Cache Function Write cache is a performance enhancement whereby the device reports as completing the write command (Write Sectors, Write Multiple and Write DMA) to the host as soon as the device has received all of the data into its buffer. And the device assumes responsibility to write the data subsequently onto the disk. While writing data after completed acknowledgment of a write command, soft reset or hard reset does not affect its operation. But power off terminates writing operation immediately and unwritten data are to be lost. Soft reset, Check Power Mode and Flush Cache commands during writing the cached data are executed after the completion of writing to media. So the host system can confirm the completion of write cache operation by issuing Soft reset, Check Power Mode command or Flush Cache command and then confirming its completion. We developer of the device recommend that a host system checks the completion of write cache operation by issuing Soft reset, Check Power Mode command or Flush Cache command to the device before power off. The retry bit of Write Sectors is ignored when write cache is enabled. 10.10 Reassign Function Reassign Function is used with read commands and write commands. The sectors of data for reassignment are prepared as the spare data sector. This reassignment information is registered internally, and the information is available right after completing the reassign function. Also the information is used on next power on reset or hard reset. If the number of the spare sector reaches 0 sector, the reassign function will be disabled automatically. The spare sectors for reassignment are located at the end of device. As a result of reassignment, the physical location of logically sequenced sectors will be dispersed. General Operation Descriptions 87