Table 6-5 Peripheral I/O Parameter Block Layout Relative ~ Addrgss ~ CQQtent 999(H) ---------------------------------------------------------- [ Device Number (low byte)] 991(H) ---------------------------------------------------------- [ Device Number (high byte)] 992(H) ---------------------------------------------------------- [ Command (low byte)] 993(H) ---------------------------------------------------------- [ Command (high byte)] 994(H) ---------------------------------------------------------- [ Result (low byte)] 99S(H) ---------------------------------------------------------- [ Result (high byte)] 996(H) ---------------------------------------------------------- [ Device Result (Status byte 1)] 997(H) ---------------------------------------------------------- [ Device Result (Status byte 2)] 99S(H) ---------------------------------------------------------- [ Device Result (Status byte 3)] 999(H) ---------------------------------------------------------- [ Device Result (Status byte 4)] 99A(H) ---------------------------------------------------------- [ DMA Segment (low byte) ] ggB(H) ---------------------------------------------------------- [ DMA Segment (high byte)] 9gC(H) ---------------------------------------------------------- [ DMA Offset (low byte)] 99D(H) ---------------------------------------------------------- [ DMA Offset (high byte)] 9gE(H) ---------------------------------------------------------- [ Cylinder (low byte)] 99F(H) ---------------------------------------------------------- [ Cylinder (high byte)] glg(H) ---------------------------------------------------------- [ Drive Number] gll(H) ---------------------------------------------------------- [ Head Number ] gl2(H) ---------------------------------------------------------- [ Beginning Sector Number ] 913(H) ---------------------------------------------------------- [ Sector Count Number ] g14(H) ---------------------------------------------------------- [ Sector length ] 9lS(H) ---------------------------------------------------------- [ Retries] g16(H) ---------------------------------------------------------- Total Block Size = 22 (dec) bytes Refer to Disk I/O Parameter Block Definition 6-16