Writing data and stopping data writing
Applications use the open(), write(),
and close() calls to work with the z/VM monitor stream.
Before an application can write monitor records, it must
issue open() to open the device driver. Then, the
application must issue write() calls to start or
stop the collection of monitor data and to write any monitor records
to buffers that CP can access.
When the application has finished
writing monitor data, it must issue close() to close
the device driver.