The command FLUSH forces all of the QL’s temporary buffers attached to the specified channel (default #3) to be emptied into that channel. This will only work on channels attached to files, any other type of channel will return error -15 (bad parameter).
This command is necessary due to the use by QDOS of slave blocks whenever a file is opened. Data can be stored partly in the slave blocks to aid speed and when writing to a file, which will only be written to that file once the channel has been CLOSEd or the slave blocks have become full.
Because of this, there is always a danger that part of the data will be lost if there is a power failure or other accident. FLUSH helps you to avoid this.
FLUSH will not work with Micro Peripherals disk drives. Nor can it be used to flush the Networks.