IBM IC35L020 Hard Drive Specifications - Page 135

15.9 Initialize Device Parameters (91h) 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 Cylinder Low Cylinder High Device/Head 1 - 1 D H H H H Command 1 0 0 1 0 0 0 1 Command Block Input Registers Register 7 6 5 4 3 2 1 0 Data Error Sector Count Sector Number Cylinder Low Cylinder High Device/Head Status see below Error Register 76543210 CRC UNC 0 IDN 0 ABT T0N AMN 00000V00 Status Register 7 6 5 4 3 2 10 BSY RDY DF DSC DRQ COR IDX ERR 0 V 0 - - 0 -V Figure 87. Initialize Device Parameters Command (91h) The Initialize Device Parameters command enables the host to set the number of sectors per track and the number of heads minus 1 per cylinder. Words 54-58 in Identify Device Information reflect these parameters. The parameters remain in effect until following events: O Another Initialize Device Parameters command is received. O The device is powered off. O Soft reset/Hard reset has occurred and the Set Feature option of CCh is set instead of 66h. Output parameters to the device Sector Count The number of sectors per track. Zero does not mean there are 256 sectors per track, but that there are no sectors per track. H The number of heads minus 1 per cylinder. The minimum is 0 and the maximum is 15. Note: The following conditions need to be satisfied to avoid invalid number of cylinders beyond FFFFh. O (Total number of user addressable sectors)/((Sector Count)*(H+1)) < = FFFFh O The total number of user addressable sectors is described in Identify Device command. Deskstar 60 GXP Hard disk drive specification 121