Atari 400 User Manual page 189

tures both ajoystick and a true trackball mode.
It is available for about $60.
ADDITIONAL MEMORY FOR YOUR
COMPUTER
Once you know the type of programs and the
software format(s) you will be using, you will
need to make sure that your computer has
enough
memory
to hold the program you wish
to load. Recall that your computer comes with a
certain amount of memory already in it mea-
sured in units called K (kilobytes). For example,
most Atari 400 computers come with 16K of
memory, most 800 systems have 48K, and the
1200XL comes with 64K of memory.
When you load larger programs into your com-
puter, such as word processing or data base pro-
grams, the amount of memory needed may be
greater than the amount your computer comes
with. In such a case, you can buy additional
memory for your computer to enable you to use
these types of programs. Extra memory is avail-
able in the form of boards which hold additional
memory chips-the
components that allow the
computer to store information in its memory.
Odd as it may seem, there is little practical differ-
ence between the capabilities of the newer 64K
system and an older 48K system, due to the way
in which the extra memory of the newer models
is utilized. Also, given the large number of older
machines in use, few software producers will
write programs that will work only on 64K sys-
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