Hitachi C4K60 Specifications - Page 36

7.2. General Operations 7.2.1. 48-bit Addressing Feature Set The 48-bit Addressing Feature set allows device with capacities up to 281,474,976,710.655 sectors (144,115,188,075,855,360 bytes). In addition, the number of sectors that may be transferred by a single command are increased by increasing the allowable sector count to 16-bits. Commands unique to the 48-bit Address feature set are: − FLUSH CACHE EXT − READ SECTORS EXT, READ MULTIPLE EXT, READ VERIFY SECTORS EXT, READ DMA EXT − READ NATIVE MAX ADDRESS EXT − SET MAX ADDRESS EXT − WRITE DMA FUA EXT, WRITE MULTIPLE FUA EXT − WRITE SECTOR EXT, WRITE MULTIPLE EXT, WRITE DMA EXT − READ LOG EXT, WRITE LOG EXT The 48-bit Address feature operates in LBA only. Device also implements commands set using 28-bit addressing. 28-bit and 48-bit commands may be intermixed. In the device, the Features Register, the Sector Count Register, the LBA Low Register, the LBA Mid Register, and the LBA High Register are each a two byte deep FIFO. Each time one of these registers is written, the new content written is placed into the "most recently written" location and the previous content of the register is moved to "previous content" location. The host may read the "previous content" of the Sector Count, LBA Low, LBA Mid, and LBA High Registers by first setting the High Order Bit (HOB, bit 7) of the Device Control register to one and then reading the desired register. If HOB (bit 7) in the Device Control register is cleared to zero the host reads the "most recently written" content when the register is read. A write to any Command Block register causes the device to clear the HOB bit to zero in the Device Control register. The "most recently written" content always gets written by a register write regardless of the state of HOB (bit 7) in the Device Control register. Support of the 48-bit Address feature set is indicated in the IDENTIFY DEVICE command response bit 10 word 83. In addition, the maximum user LBA address accessible by 48-bit addressable commands is contained in Identify Device response words 100 through 103. When the 48-bit Address feature set is implemented, the native maximum address is the value returned by a READ NATIVE MAX ADDRESS EXT command. If the native maximum address is equal to or less than 268,435,455, a READ NATIVE MAX ADDRESS command returns the native maximum address. If the native maximum address is greater than 268,435,455, a READ NATIVE MAX ADDRESS command returns a value of 268,435,455. K6610170 Rev.2 Dec 22, 2004 - 36 -