Hitachi C4K60 Specifications - Page 126

The WRITE MULTIPLE command is similar to the WRITE SECTORS command, except interrupts are not generated on every sector, but on the transfer of a block which contains the number of sectors defined by the SET MULTIPLE MODE command. The number of sectors defined by the SET MULTIPLE MODE command is transferred without intervening interrupts. DRQ qualification of the transfer is required only at the start of the data block, not on each sector. The SET MULTIPLE MODE command, which must be executed prior to the WRITE MULTIPLE command, sets the block count of sectors to be transferred. When the WRITE MULTIPLE command is issued, the Sector count Register contains the number of sectors (not the number of blocks or the block count) requested. If the number of requested sector is not evenly divisible by the block count, as many full blocks as possible are transferred, followed by a final, partial block transfer. The Partial block transfer shall be for n sectors, where n = residue of {Sector Count / (Sector Count per Block)} Disk errors encountered during WRITE MULTIPLE commands are posted after the attempted disk write of the block or partial block transferred. The write operation ends with the sector in error, regardless of the position in the block. Subsequent blocks are not transferred in the event of an error. Interrupts are generated when DRQ is set at the beginning of transfer of each block, except first block. 7.5.62. Write Multiple EXT [39h] Task File Register 7 6 5 4 3 2 1 0 Command 39h Feature Previous setting XX Current setting XX LBA High Previous setting LBA bit 47 - 40 Current setting LBA bit 23 - 16 LBA Mid Previous setting LBA bit 39 - 32 Current setting LBA bit 15 - 8 LBA Low Previous setting LBA bit 31 - 24 Current setting LBA bit 7 - 0 Sector Count Previous setting Sector Count bit 15 - 8 Current setting Sector Count bit 7 - 0 Device X 1 X DEV X X X X The WRITE MULTIPLE EXT command is similar to the WRITE SECTORS EXT command, except interrupts are not generated on every sector, but on the transfer of a block which contains the number of sectors defined by the SET MULTIPLE MODE command. The number of sectors defined by the SET MULTIPLE MODE command is transferred without intervening interrupts. DRQ qualification of the transfer is required only at the start of the data block, not on each sector. The SET MULTIPLE MODE command, which must be executed prior to the WRITE MULTIPLE EXT command, sets the block count of sectors to be transferred. When the WRITE MULTIPLE EXT command is issued, the Sector count Register contains the number of sectors (not the number of blocks or the block count) requested. If the number of requested sector is not K6610170 Rev.2 Dec 22, 2004 - 126 -