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H. CHECKING FEATURES
The question of whether or not to include built-in checking
features in a general purpose computing system is still a rather
debatable issue. It is usually possible to check the results
by prograimning techniques. A well designed system can proceed
for many hours without a malfunction. If this is the case, it
is entirely possible that the installation of a checking system
can do more harm than good since the checking feature can mal-
function and cause an alarm or stoppage when machine malfunction
has not occurred. For example, the second unit of twin arithmetic
units can malfunction, the comparer of a redundancy checker can
malfunction, or a forbidden pulse combination decoder can mal-
function, all yielding false indications of a machine malfunction.
Approximately 25 of the 84. computing systems described in this
report do not have any kind of a built-in checking system. The
only types of checks open to the operators of these systems is
a visual or test check on print-out, a complete or partial re-
calculation of the results, a programmed check or a marginal
checking system to determine the reliability of the equipment.
The remaining 59 computing systems of the 84. reported utilize
some form of built-in check. A redundancy or duplication check
on storage and magnetic recording is used on 8 systems. A twin
arithmetic unit performing calculations simultaneously is utilized
in 5 computing systems. Some type of overflow or exceed capacity
is used on 10 of the 84 systems and an odd-even check is used on
17 systems. Various kinds of transfer checks are used on 5 of
TABLE X
NUMBER OF TUBE TYPES IN VARIOUS COMPUTING SYSTEMS
NUMBER SYSTEM NUMBER SYSTEM
------ ------ ------ ------
40 WHIRLWIND-I 6 MAGNEFILE-B
38 UNI-SCI (ERA l103A) 6 MANIAC-II
35 IBM-7O1 6 TIM-II
34 SEAC 5 ELECOM-50
29 SWAC 5 IAS
21 UNI-SCI (ERA 1105) 5 FER MARK-I
20 ILLIAC 5 PEGASUS
20 NORC 5 PENNSTAC
19 EDVAC 5 ORDFIAC
18 UNI-SCI (ERA 1101) 5 WEDILOG
16 ENIAC 5 FLAC
15 NCR-CRC-102D 4. ALWAC-III
15 UNIVAC 4 CALDIC
15 UNIVAC-II 4 IBM-CPC
14 DATATRON 4 IBM-604.
12 NCR-CRC-102A 4 MAGNEFILE-D
12 ORDVAC 4 MONROBOT-IlI
12 RAYDAC 4 NAREC
12 RCA BIZMAC 4 TECHNITROL- 180
10 IBM- 702 3 BENDIX-G15
10 IBM- 705 3 CYCLE
10 MIDAC 3 LOG
10 UDEC-I 3 MODAC-14014
9 MELLON INST DIG 3 MODAC-1410
8 BUR-El0l 3 NCR-303
8 JOHNNIAC 3 OLIVETTI-GBM
7 BAR-COL DEC DIG 3 READIX
7 IBM-607 3 WISC
7 IBM-650 2 FER MARK-Il
7 LGP-30 2 OARAC
7 MANIAC
6 ADEC
6 BENDIX- D12
6 ELECOM- 100
6 HAL RAY BROWN
95% 1 Type MANIAC-Il
90% 1 Type DYSEAC
Over 85% 1 Type ELECOM- 125FP
95% 2 Types ELECOM-125
95% 2 Types ELECOM-120A
TABLE XI
CRYSTAL DIODE QUANTITIES IN VARIOUS C0MPUTING SYSTEMS
QUANTITY SYSTEM QUANTITY SYSTEM
------- ------ ------- ------
62,897 RCA BIZYAC 4,500 ELECOM-120A
50,000 NORC 4,400 READIX
50,000 TECHNITR0L -180 5,700 SWAC
25,500 DYSEAC 5,565 HUGHES AAC MOD-III
20,000 MIDAC 5,500 DATATRON
20,000 NAREC 5,000 BENDIX-G15
18,000 FLAC 5,000 UNI-SCI (ERA-1102)
18,000 RAYDAC 5,000 FER MARK-Il
18,000 UNIVAC 5,000 MODAC-1410
18,000 UNIVAC-II 2,600 LOG
17,000 IBM-702 2,585 UNI-SCI (ERA 1101)
15,159 SEAC 2,200 BENDIX D-12
15,000 WHIRLWIND-I 2,200 ELECOM-l00
12,900 IBM-705 2,000 ELECOM-50
12,800 IBM-701 1,600 TIM-Il
10,000 PEGASUS 1,500 ALEC
9,500 UNI-SCI (ERA l103A) 1,500 MELLON INST DIG
8,500 NCR-CRC-102D 1,260 BUR-ElOl
8,000 NCR-CRC-102A 1,200 BAR-COL DEC DIG
8,000 EDVAC 1,200 LGP-30
7,200 ENIAC 1,000 CALDIC
7,000 OARAC 1,000 FER MARK-I
6,500 NCR-SOS 1,000 MODAC-14014
6,000 ORDFIAC 500 MANIAC
6,000 PENNSTAC 450 OLIVETTI-GBM
6,000 UNI-SCI (ERA 1103) 580 MANIAC-Il
5,500 ELECOM-125FP 550 WISC
5,000 ALWAC-III 240 MAGNEFILE-D
5,000 ELECOM-125 200 JOHNNIAC
5,000 UDEC-I 200 WEDILOG
5,000 WHITESAC 100 MONROBOT-IlI
4,600 IBM-650 80 ORDVAC
40 MAGNEFILE-B
5 IAS
TABLE XII
TRANSISTOR QUANTITIES IN VARIOUS COMPUTING SYSTEMS
QUANTITY SYSTEM
-------- ------
500 approx. UNIVAC-Il
100 RCA BIZMAC
Model Stage IBM- 608
the systems. Approximately 9 systems established a checking
system by detecting pulse combinations which are not supposed to
occur in the process of computation. The various names that
have been applied to this type of check are forbidden pulse
combination, unused order (instruction), unallowable order digit,
improper operation code, improper command, false code, forbidden
digit, non-existent code, and unused code. There is a distinction
to be made between the terms order, instruction, and command.
These preferred definitions are given in the glossary of computer
terminology. The following table shows the approximate distri-
bution of checking methods in the systems described in this
report.
TYPE OF BUILT IN CHECK NO. OF SYSTEMS UTILIZING CHECK
---------------------- ------------------------------
Redundancy 8
Twin Arithmetic Unit 5
Overflow or Exceed Capacity 10
Odd-Even-Parity 17
Forbidden Pulse Combination 9
Transfer 5
Miscellaneous 8
No built-in Check 25
I. PHYSICAL FACTORS
Important aspects of computing systems are the physical factors
of power, space and weight.
Power requirements may very well dictate the physical location
of a large computing system within a building, particularly when
the power required is in excess of 50 KM. For most systems,
however, the power is brought to the most favorable computer
location from the point of view of personnel accessability for
operation and servicing. Table XIII shows the power requirement
of various domestic digital computing systems. The air condition-
er power requirements are not included in these figures.
An interesting figure might be the relation between the number
of tubes utilized in a computing system and the power requirement.
In order to determine whether or not a consistent tube to power
ratio could be established, the ratio was computed for the forty
computing systems for which the data was available. Discounting
5 systems in which the tube to power ratio exceeds 150 tubes/kilowatt
and the one system in which the ratio is less than 50 tubes/kilowatt,
it may be said that for the vast majority of computing systems the
tube-power ratio lies between 50 and 150 tubes per kilowatt. The
exact average ratio of the forty systems reporting this datum is
110 tubes per kilowatt. Miniaturization of tubes and the use of
diodes and transistors will reduce this figure considerably.
TABLE XIII
APPROXIMATE POWER REQUIREMENT OF COMPUTING SYSTEMS
KW SYSTEM KW SYSTEM
-- ------ -- ------
174 ENIAC 12 PEGASUS
168 NORC 11 IBM- 607
105 WHIRLWIND-I 10 CALDIC
100 UNIVAC 10 WISC
80 IBM-701 10 NCR- CRC-102D
80 UNIVAC-II 8 NCR-CRC-102A
75 IBM-702 7 BENDIX-D12
69 IBM- 705 7 IBM- CPC
55 IBM-704 7 FLAC
50 EDVAC 7 ELECOM-120A
50 ORACLE 7 ELECOM-125
50 TECH-180 7 ELECOM-125FP
45 LOG 6 READIX
45 UNI-SCI (ERA 1103A) 6 IBM-6014
41 UNI-SCI (ERA 1103) 5 HAL RAY BROWN
40 ALEC 5 ALWAC-III
35 JOHNNIAC 5 MINIAC
35 MANIAC 5 ORDFIAC
35 ORDVAC 5 MONROBOT-V
35 UDEC-lI 5 WHITESAC
30 FERRANTI MARK-lI 4 MODAC-1410
30 SWAC 3 CIRCLE
30 RAYDAC 3 MELLON INST-DIG
30 UDEC-I 3 BENDIX-G15
28 lAS 3 ELECOM-100
26 FERRANTI MARK-I 3 MODAC-404
25 MANIAC-II 3 NCR-SOS
25 MIDAC 3 OLIVETTI-GBM
25 NAREC 2 BUR-El0l
25 OARAC 2 MONROBOT-III
22 UNT-SCI (ERA 1102) 2 WEDILOG
19 ILLIAC 2 BAR-COL DEC DIG
15 PENI'TSTAC 2 ELECOM- 50
15 SEAC 2 IBM- 608
15 U141-SCI (ERA 1101) 2 ELECOM-50
12 DYSEAC 1 HUGHES AAC MOD-III
1 LGP-30
1 MAGNEFILE-D
1 MAGNEFILE-B
1 TIM-II
Included in the figure is all of the power dissipated in associated
circuitry, lost in transformers and otherwise radiated.
The problem of space requirements has been solved in so many
ways it is impossible to determine a consistent relation between
space requirement and any other factor. Similar large computing
complexes have been installed in areas ranging from a corner of a
basement to an entire floor of a large building. The pictorial
coverage of computing systems and the space requirements discussed
under Physical Factors gives a rough approximation of the space
requirements of the computing systems described in this report.
The dimensions of various components of unitized systems are
important when considering clearance in rooms, passages, doorways
and elevators.
Air conditioning requirements vary considerably from system
to system. Air conditioners may utilize water to absorb the
heat from circulated air, use a secondary loop of air, to force
the heated air to the outside, or utilize an outdoor evaporator.
The smaller systems circulate room air and depend on the ambient
temperature to cool the system. Almost 100% of the power required
by the system is dissipated in the form of heat and must be removed.
Practically every computing system from the desk size to the
largest must be operated in air-conditioned room. The large
systems usually require separate heat removal facilities. Crystal
diodes and transistors are particularly temperature sensitive. In
many systems humidity and dust control within the machine are
necessary in order to maintain satisfactory operation.
The factor of weight can be important when the floor loading
for distributed and concentrated loads is within the loading
range of the equipment under consideration. Many systems may
require reinforcement or specially constructed buildings or wings.
Many items of peripheral equipment cause concentrated loads in
excess of maximum permissable concentrated loadings on some
structures. Vibration and shock caused by some equipment such
as tabulators and card punches can cause troubles in other compo-
nents. Shock and vibration absorbing media are required in such
cases. In unitized construction, the weight of a single unit is
a factor in transportation and installation.
J. PRODUCTION RECORD
In almost any new and rapidly changing field there will be
many instances in which one model of a large piece of equipment
will be built. This is the normal result of the usual course
of events, namely, a feasability study, a research effort, a
development effort and a prototype construction. Mass production
can only occur when the rapid evolution of new concepts ceases
and the best characteristics have been obtained that the properties
and limitations of materials will permit. Of the 614 systems on
which production records were reported, 35 were single model
systems. In many cases, a second model will never be built,
since the ideas incorporated into the single system have long
been outmoded. Some manufacturers have built a single system
with the intention of production in quantity. This single
model is in current operation and several may be on order. Of
the 814 systems described in this report, some of the very large
commercial and business type machines have as many as 22 in
current
operation. Some of the very large systems exist in the form of
1 engineering prototype with over 100 on order.
Delivery time varies from six months for a small desk size
system to 56 months for the large sprawling computer complexes.
Reference to the production records of the computing systems
described in this report will yield some concept of the avail-
ability and prevalence of various systems.
K. COST
Perhaps the most elusive and intricate item considered in the
systems descriptions of this report is the question of initial
cost, blandly described as "approximate cost of basic system
Manufacturers are quite naturally quoting current prices for
their respective systems. Research and development may be ab-
sorbed by the first few models or spread out over many. The one
of a kind" system usually includes all research, development,
construction, overhead and sub-contracting costs. The question
of what is included under "basic systems" is immediately brought
to mind. The basic system includes an input device, the controls,
the storage system, the arithmetic unit, and the output device.
All conversion equipment such as card-to-printed page (tabulators)
card-to-tape, tape-to-card etc. are considered peripheral equip-
ment, and both the quantity and type is dependent upon specific
system application. These are not included in the cost or price
of the basic system. In order to determine the cost of a given
system, refer to the system description. Table XIV shows the
approximate relative cost of various computing systems. For the
systems reported upon, cost figures range from $17,000 to $2,500,000.
More recent systems currently under development, may cost 5 to 6
million dollars.
The methods of computing system or component acquisition
include direct purchase at a fixed price, direct purchase on a
cost plus fixed fee basis, continuous rental, and rental with
a part of the rental applicable toward purchase. Most forms of
rental include servicing. Direct purchase can include a service
contract. Rental rates are of the order of 5 per cent of the
direct purchase price per month.
Table XIV does show the nominal price one may expect to pay
for a basic system. For many systems one might add 20 or 50 per
cent for required peripheral equipment. Most prices include
installation but not shipping costs. Some of the figures reflect
prices which are not current and have not taken into account general
price rises during the past several years. Some figures include
initial service or some type of warranty. The figures quoted are
only for general consideration and not for ordering purposes.
Indeed, many systems are not available, even at the price quoted.
One might make many studies utilizing the cost figures of
Table XIV and relating them to other features of the systems.
Suppose we assume that all of the systems are balanced, in the
sense that nothing is placed in the computing system in excess,
or is overdesigned. For example, a large system usually has a
correspondingly large storage capacity and an equally costly
arithmetic unit, control unit and input-output system. One might
then speak in terms of the cost per bit of high speed storage
in terms of the cost of the entire system. If a large system
handles payrolls or inventories, and the number of references
or transactions completed per day could be determined, one could
determine total operating costs per day including depreciation
and establish the cost per transaction. In most applications,
however, the cost per unit of calculated output cannot be deter-
mined.
An attempt was wade to discover whether a working figure
could be established by considering the "cost per tube" which
one might apply to other systems with some accuracy. For the
larger systems, the figure is of the order of 200 dollars per
tube and for the smaller systems approximately 100 dollars per
tube. However, a glance at Table XIV and Table IX and some
mental approximation will show that such a figure cannot be
calculated with reasonable accuracy. An attempt to determine
a figure such as "cost per cubic foot" of electronic equipment
would be equally inaccurate.
L. PERSONNEL REQUIREMENTS
Personnel problems have confronted computing system operators
and manufacturers from the very outset in all phases of computer
research, development, manufacture, installation, operation,
improvement and servicing. Various grades of skills are required
in the fields of engineering, physics and mathematics. Each
TABLE XIV
APPROXIMATE COST OF BASIC COMPUTING SYSTEMS
DOLLARS SYSTEM
------- ------
2,500,000 NORO
1,750,000 RAYDAC
1,1400,000 UNI-SCI (ERA-ll02)
1,025,000 UNIVAC-Il
950,000 UNIVAC
895,000 UNI-SCI (ERA-ll03A)
850,000 UNI-SCI (ERA-los)
750,000 ENIAC
600,000 ADEC
500,000 FLAC
500,000 TECH-180
467,000 EDVAC
550,000 LOG
550,000 PER MARK-I
500,000 ILLIAC
250,000 MANIAC
250,000 UDEC-I
225,000 MANIAC-Il
225,000 OBDVAC
206,000 ORDFIAC
200,000 UDEC-Il
180,000 QARAC
150,000 CALDIC
150,000 PEGASUS
140,000 DATATRON
140,000 NCR-303
120,000 MODAC-1410
100,000 ELECOM-125
100,000 PENNSTAC
99,500 NCR- CRC-102D
97,000 ELECOM-120A
89,500 NCR-CRC-102A
86,074 MONROBOT-V
85,000 MINIAC
85,000 MODAC-404
85,000 MDP-MSI- 5014
70,000 CIRCLE
70,000 MAGNETRONIC RES
60,000 ALWAC-III
60,000 ELECOM-125FP
60,000 ELECOM- 100
55,000 BENDIX-D12
55,000 READIX
50,000 MAGNEFILE-D
45,000 BENDIX-G15
52,500 BUR-El0l
50,000 LGP-30
25,000 TIM-II
20,000 MAGNEFILE-B
20,000 WEDILOG
17,000 ELECOM-50
large system has a crew of engineers and technicians for improving
and. servicing and a group of mathematicians and operators for
problem analysis, coding and progra.ziuing. In the very small
systems,
all of these functions may be performed by one or two persons.
Reference to the systems descriptions of this report will show
various estimates of manufacturers and operators of what the
personnel requirements are or should be for various systems. The
estimates, in some cases do not reflect the need for personnel
availability for overtime, vacations, illness, and turnover
purposes.
It was intended to obtain the number of full time persons of
various skills required to provide satisfactory operation of the
system. Just as in any application of manpower to machines, it
is necessary to provide sufficient manpower so as to maximize the
benefits of machine utilization. Many installations include multi-
million dollar computer complexes. A large capital investment
must be utilized at maximum efficiency in order to avoid severe
losses. Twenty four hour operation increases the output of the
system when integrated over the life of the system since the life
of a computing system is more of a function of time rather than
of use.
Examination of the personnel requirements section of the
systems descriptions in this report will indicate the approximate
needs for a system of the type described. Information from
operating agencies usually will indicate the actual number of
persons required for operation and servicing. Since improvement
is a continuous function, additional personnel will be required,
including engineers and technicians. Manufacturers tend to esti-
mate the minimum number of personnel required to be in attendance
for various number of shifts of daily operation. Again, these
figures must be used only as a guide.
M. RELIABILITY AND OPERATING EXPERIENCE
The most discussed and most controversial issues in the field
of computing machinery are the questions of reliability, efficiency
and system evaluation. The determination of the reliability of
a system is nearly impossible, almost purely because of a lack of
a common understanding or -interpretation of the definitions of
computer operating terminology. What actually constitutes "good
time" on a computing system? What is "down time", "scheduled
engineering", "useful production and code checking."? An attempt
has been made to provide working definitions of these and other
terms in the Glossary of Computer Engineering and Programming
Terminology in this report. The very crude "Operating Ratio" as
is used in the systems descriptions is defined as the "Good Time"
obtained on the machine divided by the time one actually attempted
to run the system. Here again, the question is where to put the
time lost in scheduled engineering (preventive maintenance), since
technically, one is not attempting to run the system during this
period. Many systems, such as the BRIJ machines, are operated for
167 hours per week. The operating ratio for these would use 167
as the denominator and the number of useful output hours as the
numerator, yielding a much smaller (but perhaps truer) ratio than
TABLE XV
CHRONOLOGICAL ORDER OF
CUSTOMER ACCEPTAMCE OF VARIOUS CONPUTING SYSTEMS
1946 ENIAC
1950 MAY SEAC
1950 WHIRLWIND-I
1951 MAR UNIVAC
1952 IAS
1952 MAR ORDVAC
1952 MAR MANIAC
1952 JUN TELEREGISTER- SPEDDH
1952 JUL MAGNETRONIC RESERVISOR
1952 SEP ILLIAC
1953 MAR LOG
1955 APR OARAC
1953 JUN ORACLE
1955 JUL RAYDAC
1953 AUG MAGNEFILE-D
1953 AUG UNI-SCI (ERA-ll03A)
1953 SEP FLAC
1953 OCT UDEC-II
1955 DEC UDEC-I
1953 DEC MINIAC
1954 FEB MAGNEFILE-B
1954 MAR ELECOM-120A
1954 MAR JOHNNIAC
1954 APR DYSEAC
1954 APR ORDFIAC
1954 JUN ALWAC-XII
1954 JUN CIRCLE
1954 JUL FERRANTI MARK-I
1954 JUL MDP-MSI- 5014
1954 AUG BENDIX-D12
1954 AUG DATATRON
1954 SEP MODAC-4O4
1954 DEC TIM-II
1955 FEB IBM-702
1955 FEB NORC
1955 MAR WHITESAC
1955 PENNBTAC
a system operated on an 8-hour 5-day week shift and using off-time
for servicing. This may yield operating ratios of the order of
.90 to 1.00 and give a false indication of reliability.
The question of how one determines the average error-free
running period is also a difficult one. It may be estimated
or calculated by actual counts of the periods of malfunction-free
operation. It may be the period used as a guide by coders to
prevent losses due to running for extended periods between obtain-
ing output information, particularly where volatile storage media
are being used.
Every large scale, electronic digital computer in the
United States is still in an operating condition. However, many
are probably approaching the age of retirement and replacement.
Constant improvement may have replaced many of the original
components of a system. The next few years will see the retire-
ment of many of the older systems; such retirement may take the
form of salvage of parts or use for educational and training
purposes.
MARTIN H. WEIK
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