Hitachi HDS728080PLAT20 Specifications - Page 172
Read Sectors 20h/21h
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12.23 Read Sectors (20h/21h) Table 117: Read Sectors Command (20h/21h) Command Block Output Registers Register 7 6 5 4 3 2 1 0 Data Feature Sector Count V V V V V V V V Sector Number V V V V V V V V Cylinder Low V V V V V V V V Cylinder High V V V V V V V V Device/Head 1 L 1 D H H H H Command 0 0 1 0 0 0 0 R 76 CRC UNC 0V Error Register 54 3 2 1 0 0 IDN 0 ABT T0N AMN 0V 0 V 0 0 Command Block Input Registers Register 7 6 5 4 3 2 1 0 Data Error see below Sector Count V V V V V V V V Sector Number V V V V V V V V Cylinder Low V V V V V V V V Cylinder High V V V V V V V V Device/Head - - - - H H H H Status see below Status Register 7 654 3 2 1 0 BSY RDY DF DSC DRQ COR IDX ERR 0 V0V - 0 - V The Read Sectors command reads one or more sectors of data from disk media and then transfers the data from the device to the host. The sectors are transferred through the Data Register 16 bits at a time. If an uncorrectable error occurs the read will be terminated at the failing sector. Output parameters to the device Sector Count This indicates the number of continuous sectors to be transferred. If zero is specified, 256 sectors will be transferred. Sector Number This is the sector number of the first sector to be transferred. (L =0) In LBA mode this register contains the LBA bits 0-7. (L = 1) Cylinder High/Low This is the cylinder number of the first sector to be transferred. (L = 0) In LBA mode this register contains the LBA bits 8-15 (Low) and bits 16-23 (High). (L = 1) H This is the head number of the first sector to be transferred. (L = 0) In LBA mode this register contains the LBA bits 24-27. (L = 1) R This is the retry bit, but this bit is ignored. Input parameters from the device Sector Count This is the number of requested sectors not transferred. This will be zero, unless an unrecoverable error occurs. Sector Number This is the sector number of the last transferred sector. (L = 0) In LBA mode this register contains the current LBA bits 0-7. (L = 1) Deskstar 7K80 Hard Disk Drive Specification 168