CMD_WRITE/ETD_WRITE - write sectors of data to a disk.

These commands transfer data from a supplied buffer to the track buffer. If the track that contains this sector is already in the track buffer, no disk activity is initiated. If the desired sector is not in the buffer, the track containing that sector is automatically read in. If the data in the current track buffer has been modified, it is written out to the disk before the new track is read in for modification. ETD_WRITE will write the sector label area if iotd_SecLabel is non-NULL.

io_Device

preset by the call to OpenDevice()

io_Unit

preset by the call to OpenDevice()

io_Command

CMD_WRITE or ETD_WRITE

io_Flags

0 or IOF_QUICK

io_Data

pointer to the buffer where the data should be put

io_Length

number of bytes to write, must be a multiple of TD_SECTOR.

io_Offset

byte offset from the start of the disk describing where to write data to, must be a multiple of TD_SECTOR.

iotd_Count

(ETD_WRITE only) maximum allowable change counter value.

iotd_SecLabel

(ETD_WRITE only) NULL or sector label buffer pointer. If provided, the buffer must be a multiple of TD_LABELSIZE.

io_Error

0 for success, or an error code as defined in <devices/trackdisk.h>

Under versions of Kickstart earlier than V36, the io_Data had to point to a buffer in chip memory. This restriction is no longer present as of Kickstart V36 and beyond.

CMD_READ, TD_FORMAT