IBM DTCA-24090 Hard Drive Specifications - Page 127
Read Multiple
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12.14 Read Multiple (C4h) Command Block Output Registers Register 76543210 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 1L1DHHHH Command 11000100 Command Block Input Registers Register 76543210 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 HHHH Status ...See Below... Error Register 76543210 CRC UNC 0 IDN 0 ABT T0N AMN 0V0V0V0V Status Register 76543210 BSY RDY DF DSC DRQ COR IDX ERR 0V0V 0 V Figure 74. Read Multiple Command (C4h) The Read Multiple command reads one or more sectors of data from disk media, then transfers the data from the device to the host. The sectors are transferred through the Data Register 16 bits at a time. Command execution is identical to the Read Sectors command except that an interrupt is generated for each block (as defined by the Set Multiple command) instead of for each sector. Output Parameters To The Device Sector Count The number of continuous sectors to be transferred. If zero is specified, then 256 sectors will be transferred. Sector Number The sector number of the first sector to be transferred. ( L = 0 ) In LBA mode, this register contains LBA bits 0 - 7. ( L = 1 ) Cylinder High/Low The cylinder number of the first sector to be transferred. ( L = 0 ) In LBA mode, this register contains LBA bits 8 - 15 (Low), 16 - 23 (High). ( L = 1 ) H The head number of the first sector to be transferred. ( L = 0 ) In LBA mode, this register contains LBA bits 24 - 27. ( L = 1 ) Command Descriptions 119