Specifications

INTERFACE COMMANDS
7 – 44
The block count consists of the number of sectors to be transferred as a block and is programmed by the Set Multiple
Mode command, which must be executed prior to the Write Multiple command. When the Write Multiple command is
issued, the Sector Count register contains the number of sectors requested — not the number of blocks or the block count.
If the number of sectors is not evenly divisible by the block count, as many full blocks as possible are transferred, followed
by a final, partial block transfer. This final, partial block transfer is for N sectors, where N = (sector count) modulo (block
count)
The Write Multiple operation will be rejected with an Aborted Command error if attempted:
1. Before the Set Multiple Mode command has been executed, or
2. When Write Multiple commands are disabled.
All disk errors encountered during Write Multiple commands report after the attempted disk write of the block or partial
block in which the error occurred.
The write operation ends with the sector in error, even if it was in the middle of a block. When an error occurs,
subsequent blocks are not transferred. When DRQ is set at the beginning of each full and partial block, interrupts are
generated.
Write DMA
Multi-word DMA
Identical to the Write Sector(s) command, except that:
1. The host initializes a slave-DMA channel prior to issuing the command,
2. Data transfers are qualified by DMARQ and are performed by the slave-DMA channel and
3. The drive issues only one interrupt per command to indicate that data transfer has terminated
at status is available.
Any error encountered during Write DMA execution results in the termination of data transfer. The drive
issues an interrupt to indicate that data transfer has terminated and status is available in the error register. The
error posting is the same as that of the Write Sector(s) command.