Owner`s manual
Appendix
3.'
EMS
Technz'cal
Reference
Applications
programmers
writing
software
for
the
EMS
mode
on
the
RAM
3000 Deluxe should
refer
to
the
Lo-
tus/Intel/Microsoft (LIM) specification, Version
3.20,
re-
leased
September
1985.
Use
of
this
document
will facilitate
portability
to
all EMS-compatible
expanded
memory
cards.
A3.1
Expanded Memory Definition
Expanded
memory
is a
bank
switching
technique
that
in-
creases
the
memory
capacity
of
the
PC
up
to
eight
megabytes beyond
the
present DOS
memory
addressing
range
of
OK-640K
(OOOOOH-9FFFFH).
A 64KB window
(called a
page frame) is located between
the
640K
and
%OK
(AOOOOH-EFFFFH) reserved
area
boundaries.
The
page
frame
is divided
into
four contiguous 16KB pages.
The
EMS
mode
on
the
RAM
3000 Deluxe is divided
into
128
16KB
blocks,
totaling
two megabytes. By sending
commands
to
the
control
circuitry
on
the
RAM
3000 Deluxe,
the
EMM.SYS
expanded
memory
manager
can
map
anyone
of
these blocks
into
any
of
the
four pages.
Refer
to
the
Lotus/Intel/Microsoft (LIM)
Expanded
Memory Specifi-
cation
(Version
3.20),
September
1985
if you need a
more
de-
tailed
explanation
of
expanded memory.
72