IBM 709 General Information Manual page 22

System Used
Time Taken
00 ---
709 system
100 seconds
ri-l--
7090 system
20 seconds
Figure 41. Time Comparison for Each Trajectory
the initial components of its velocity, an initial alti-
tude, and the initial angle.
The position of the object is identified by its co-
ordinates with respect to fixed axes passing through
the launching point.
Factors in this problem are:
1,100 time steps per trajectory.
1,000 operations per time step.
1,100,000 operations per trajectory.
The time comparisons for each computer are ap-
proximate and are shown in Figure 41.
Electron Density
The third application is in the field of fundamental
research (Figure 42). The electrons surrounding two
nitrogen atoms which form a nitrogen molecule) are
treated as a degenerate Fermi-Dirac gas. Such treat-
ment results in a partial differential equation called
the Thomas-Fermi-Dirac or "statistical field" equa-
tion.
The computer calculates solutions to this equation
and thereby determines the density of electrons in the
molecule and the energy of the molecule. The
Thomas-Fermi-Dirac equation is replaced by a differ-
ence system over a network of points. The network
consists of the intersections of 60 quasi-Iemniscates
Figure 42. Electron Density
[ "1"
P~;I
..... ,..".,
r
:W 800 years
Desk co
I
cu
I
ator
4000 weeks
IBM 701 system
2
hours
IBM 709 system
25 minutes
:Ii :
IBM 7090 system
5 minutes
Figure 43. Time Comparison of Computer Systems. Electron
Density Problem
with 15 curves at right angles to them. The following
procedures are used to solve the problem:
900 simultaneous non-linear equations.
80 iterations per solution.
900,000 operations per iteration.
72,000,000 operations per solution.
This application graphically points out one of the
problems that could not be solved without the use of
high-speed computers. Again, the time comparisons
are approximate. Note the great range of times. The
span of 800 years required with a pencil and paper is
reduced to five minutes by the
IBM
7090 Data Process-
ing System (Figure 43) .
Average execution speeds for both fixed and float-
ing-point arithmetic operations (including the time
needed to take a word from or put a word into core
storage) is shown in Figure 44.
The use of transistors in the 7090 system provides
a saving in electrical power and air conditioning re-
quirements. The reduction of electrical power may
be as great as seventy percent of the 709 requirements.
The nodular unit design of the 7090 makes it pos-
sible to place units side by side and thus minimize
space requirements. As much as fifty percent of the
709 system space requirements may be saved.
Central Processing Unit 21