Hitachi HDS728080PLAT20 Specifications - Page 165
Read Long 22h/23h
UPC - 829686000094
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12.18 Read Long (22h/23h) Table 112: Read Long (22h/23h) Command Block Output Registers Register 7 6 5 4 3 2 1 0 Data Feature Sector Count 0 0 0 0 0 0 0 1 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 1 R 76 CRC UNC 00 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 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 Long command reads the designated one sector of data and the ECC bytes from the disk media. It then transfers the data and ECC bytes from the device to the host. After 512 bytes of data have been transferred, the device will keep setting DRQ = 1 to indicate that the device is ready to transfer the ECC bytes to the host. The data is transferred 16 bits at a time and the ECC bytes are transferred 8 bits at a time. The number of ECC bytes are 4 or 40 according to the setting of Set Feature option. The default setting is 4 bytes of ECC data. The command makes a single attempt to read the data and does not check the data using ECC. Whatever is read is returned to the host. Output parameters to the device Sector Count This indicates the number of continuous sectors to be transferred. The Sector Count must be set to one. Sector Number This indicates the sector number of the sector to be transferred. (L = 0) In LBA mode, this register contains LBA bits 0-7. (L = 1) Cylinder High/Low This indicates the cylinder number of the sector to be transferred. (L = 0) In LBA mode, this register contains LBA bits 8-15 (Low), 16-23 (High). (L = 1) H This indicates the head number of the sector to be transferred. (L = 0) In LBA mode, this register contains LBA bits 24-27. (L = 1) R This indicates the retry bit. This bit is ignored. Deskstar 7K80 Hard Disk Drive Specification 161