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section A:
System interface
A.B. System variables
All
system
kernel variables have been collected into a memory area
of
their own.
This area is placed in the
11
common memory" area,
on the MZ-
3500,
it
begins
at 0FF00H.
The data contained there can be read
and
written.
To access system variables,
system call 49 should be used, as
the base address of the variables' area is implementation dependent.
The table below has five columns,
the first of which denotes the offset
of a certain variable relative to the area base address,
the second the
variable name.
Colunm three specifies whether the variable has the same
meaning as the corresponding CP/M plus variable.
Column four
specifies
whether the variable may be altered by the user, or it is
11
read-only".
Offset
Name
CP/M
Alter
Function
-------
-------
-------------------------------------~
00'H-04H
no
- reserved
-
05H
EOSVERS
yes
yes
EOS
version
number for function
12.
Can be changed by function
72.
06H-09H
USERFLG
yes
yes
four bytes free for user applicatiops.
0AH-0FH
no
- :reserved
-
10'H-11H
RETCODE
yes
yes
Program return code for function 108.
12H-17H
no
-
reserved -
1BH-19H
FILENR
no
no
The number stored in this variable is
used by $SPOOL and
$00
to create
uni-
que
file names for temporary
files.
It
is incremented by 1 after each ge-
neration of a temp file. The file name
generated will be "SYSnnnnn.$$$".
1AH
CWIDTH
yes
yes
Characters per screen line.
Not
used
by EOS.
1BH
no
- reserved
1CH
CLENGTH
yes
yes
Number
of screen lines.
Not used
by
EOS.
1DH
TABS TOP
no
yes
current
Tab stop.
This value can
by
changed by use of function 74.
lEH-lFH
no
-
reserved -
EOS System manual
Daeumling
&
Zimmermann
Page 19
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