Acorn Computers Limited PLUS 1, User Manual

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5 Using cartridges
The Plus 1 has two sockets in its upper surface into which a variety of cartridges can be
plugged. These cartridges can provide games, languages, utilities, application programs or other
facilities. Contact your local dealer for a list of cartridges currently available.
Full instructions in the use of these cartridges will be provided with the individual cartridges.
Cartridges should not be installed or removed with the Electron switched on. If you remove or
install a cartridge with the computer turned on, you will need to press BREAK or CTRL
BREAK to restore normal operation.
Games and applications cartridges will usually behave quite differently from language
cartridges, so they are described separately below.
Games and applications: ROM file cartridges
These cartridges are usually designed to load and run the software they contain automatically,
taking over operation of the Electron when it is turned on or after pressing CTRL BREAK, so
that the Electron behaves as a machine dedicated to running that program while the cartridge is
plugged in. To defeat this mechanism, you should press CTRL BREAK, wait about one second,
and then press ESCAPE.
If you have two games/applications cartridges plugged in, the one at the front (nearest the
keyboard) will be the one that 'takes over' the Electron.
The programs and data used by these cartridges are contained in ROMs, accessed by a filing
system similar to the cassette tape filing system you are used to, but much faster and restricted
to reading information only. This is called the ROM filing system.
When you break out of a game, the ROM filing system will be active instead of the cassette
filing system. The commands available are
*CAT, LOAD
and
CHAIN
,
which have identical
functions to their cassette equivalents, but work with the ROM files.
To use the cassette filing system, select it by typing
*TAPE
;
to use the ROM filing system
again, type
*R0M
.