IBM 1130 User Manual page 497

Section
Subsections Page
65
10
I
30 04
If you place an L in column 14 of the / / XEQ
card, the Core Load Builder will print a core map
showing which subprograms,
if
any, are in which
SOCAL overlay, and the size of each overlay. (See
Figure 65.5 for such a map.)
3000 r
2500
t-
2000
t-
1500 t-
1000
f-
500
t-
o
Step 1
Overlay Level 0
T
Overlay
3
Net Gain
Non-Disk
-'-
I/O
Overlay
2
Non-Disk
I/O
Step 2
Overlay Level 1
~f
Overlay
Net Gain
Step 3.
Overlay Level 2
3
--
-'~r----
---,
1
I I
I 1 1
1 I I
I
Unused
1
1
Unused
Overlay
Unused
1
2 1
I
Overlay
I I
1
2
1
I
I
I
I
I
1""--1
I
r - - -
Overlay
Overlay Overlay Overlay
1 1 1
3
Arithmetic
Flipper Flipper
Figure 65.1. Core storage layout at each overlay level
Possible Improvements to the SOCAL Scheme
Figure 65.1 illustrates, to a rough scale, the layout
of the SOCAL area at each overlay level. One fact
is apparent: overlay 2 is much larger than either
overlay 1 or overlay 3, and is, in fact, larger than
the two combined. Since the SOCAL area must be at
least as large as the largest of the three overlays,
a certain amount of core storage is unused in some
circumstances.
On the basis of this fact, there are two techniques
that may be used to make the standard SOCAL sys-
tem more effective:
Reduce the size of the largest SOCAL overlay.
Since LOCALs, discussed later, take precedence
over SOCA.Ls, you have a means to remove sub-
programs from the SOCAL area and to force them
into the LOCAL area. Naturally, you would do this
only to subprograms in the largest overlay, usually
the non-disk I/O package.
Because one LOCAL cannot call another LOCAL,
you must be somewhat careful here. For example,
you cannot LOCALize both the 1132 subroutine and
a subroutine that calls it. One or the other may be
LOCAL, not both.
If you are sure such a situation does not exist,
you can make the following subroutines LOCAL:
Approximate
Name Required for
Size in Words
CARDZ
1442 Card Read Punch 160
PNCHZ 1442-5 Card Punch 70
READZ 2501 Card Reader 60
TYPEZ Console Printer 60
WRTYZ
Console Keyboard and 90
Printer
PRNTZ
1132 Printer 190
PRNZ 1403 Printer 190
PAPTZ Paper Tape Units 225
(If
you accidentally do make one LOCAL call
another LOCAL, the LOADER will call it to your
attention with an error message. )
Each of these routines, if made LOCAL, releases
as much core storage as the size of the routine.
It
is unlikely, however, that you can reduce overlay 2
to the same size as the other two overlays unless
you LOCALize the entire 1150-word Format Inter-
preter (SFIO).