Nonproductive Time That Can Be Reduced By Hardware Changes; Additional Core Storage; Additional Disk Drives - IBM 1130 User Manual

Nonproductive Time that Can Be Reduced by Hard-
ware Changes
By definition, three items fall into this category:
1. DISK seek, to get from one data record to
the next
2. DISK seek, to get from data area to overlay
area, and vice versa
3. DISK read to read overlay
All three items are necessary, but unproductive as
far as you are concerned. Note that item 1 is re-
quired whenever you are using data files, item 3
whenever you are using overlays (SOCALs, LOCALs,
and/or LINKs), and item 2 whenever you have both
overlays and data files.
The time requirements of all three are difficult
to determine, so an exact analysis will not be
attempted, as with the card readers, punches, etc.
There are two hardware changes that will reduce
these times:
1. More core storage, which will probably
eliminate overlays, and therefore items 2 and 3.
2. More disk drives, which will allow a re-
distribution of files and overlays, and reduce items
1 and 2.
Section Subsections
Page
90 30
I
30 01
Additional Core Storage
Asside from programmer convenience, the main
advantage in adding more core storage is its probable
effect on performance, or run time.
If
you can
execute your programs without any overlays, they
can be expected to run at some "top" speed,
governed mainly by the amount of productive work
you want done.
Additional Disk Drives
Unlike core storage, which will probably be aug-
mented to improve performance, additional disk
drives are likely to be considered primarily to
increase capability -- the capability to copy disks,
the additional storage gained, etc. In many cases,
however, the move from a single to a multiple disk
1130 system may be accompanied by a gain in
throughput or performance. This will be true only
if you plan your system so that the LOCAL/SOCAL
overlays are on a cartridge other than the one on
which the data files reside.
The location (cartridge
ill
number) of the data
files is specified on the *FILES card. The LOCAL/
SOCAL overlays are either (1) in Working Storage,
if the program is executed immediately after
compilation, or (2) with the mainline program (in
UA or FX), if the program has been stored in core
image format.
If
they are in Working Storage, the
Monitor should be informed, with the JOB card, to
use the Working Storage on a disk cartridge other
than the data file cartridge. If they are with the
mainline program (in UA or FX), you should make
sure the core load is stored on a cartridge other
than the data file cartridge.