Model
II
TRSDOS
Memory Requirements
TRSDOS
occupies 6.1 tracks
on
the System diskette
(39
,040 bytes). However,
only a small portion
is
actually
in
memory at
anyone
time. The Supervisor
Program, input/output drivers, and
other
essentials are always in memory.
Auxiliary code
is
loaded
as
needed into an "overlay area".
Memory
addresses 0 through 10239
(XO'-X'27FF)
are reserved for the Oper-
ating System. Certain commands, called "high overlays", also use memory
addresses up
to
X'2FFF' (details provided in the Commands section). User
programs must be located above
X'27FF'; and you may want to locate them
above X'2FFF'
to
allow use
of
the high overlays without loss
of
your program.
DECIMAL
ADDRESS
a
10240
12288
TOP*
32767 or
65535
SYSTEM AREA
USER AREA (SHARED WITH
TRSDOS "HIGH OVERLAY COMMANDS")
USER AREA UNTOUCHED**
BYTRSDOS
MAYBE
RESERVED BY TRSDOS
FOR
SPECIAL PROGRAMMING
Last Memory Address
MEMORY
REQUIREMENTS
OF
TRSDOS
HEX
ADDRESS
X'OOOO'
X'2800'
X'3000'
TOP*
X'7FFF'or
X'FFFF'
Note:
The
term
"user
program" applies to any program which
is
not a part of
TRSDOS.
Therefore BASIC
is
a user program. For memory requirements of
BASIC,
see the BASIC Reference Manual.
"'TOP
is
a memory protect address set by TRSDOS.
IfTRSDOS
is
not protecting
high memory,
then
TOP
is
the same as "Last Memory Address".
**Single-drive
COpy
from one diskette to another, BACKUP and
FORMAT
use
all user memory.
52
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