The memory-test is started a few seconds after the machine is turned on.
The test will display the amount of user-memory (RAM) available,
then continues with the boot (startup) process.
If you press any key (except <Shift>, <Alternate>, <Control> or <Caps-Lock>) during the test, the memory test will be cancelled and the computer will continue with booting (starting up), loading AUTO programs, ACCessories etc.
(you may find it useful however to wait a few seconds before quitting the test
to allow the hard disk to spin up and get ready).