CMD_CLEAR/ETD_CLEAR - mark the track buffer as containing invalid

These commands mark the track buffer as invalid, forcing a reread of the disk on the next operation. ETD_UPDATE or CMD_UPDATE would be used to force data out to the disk before turning the motor off. ETD_CLEAR or CMD_CLEAR are usually used after having locked out the trackdisk.device via the use of the disk resource, when you wish to prevent the track from being updated, or when you wish to force the track to be re-read. ETD_CLEAR or CMD_CLEAR will not do an update, nor will an update command do a clear.

io_Device

preset by the call to OpenDevice()

io_Unit

preset by the call to OpenDevice()

io_Command

CMD_CLEAR or ETD_CLEAR

io_Flags

0 or IOF_QUICK

iotd_Count

(ETD_CLEAR only) maximum allowable change counter value.

io_Error

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

CMD_WRITE, CMD_UPDATE