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not necessarily to develop an architecture that matches
the physics but to develop a high degree of parallel pro-
cessing leading to a machine that is approximately 10
times faster than the fastest commercially available
machine.
It appears that specialized architectures embodying
some features of the physics of the problem are unlikely
to be important for astronomical computing in the 1980'
On the other hand, very fast computers may well become
available as a result of work like that being done at
NASA/Ames.
For the same reasons as stated in Recommendation 3 of
Section IV on theoretical computing, mutual benefits
accrue when astronomers are allowed access to nonastro-
nomical computational facilities. - ~ -
mus, any new facili
ties that are developed should be open (consistent with
the objectives of the facility) to use by the astronom-
ical community. For its part, the astronomical community
must remain aware of developments in this area and make
plans for the effective use of such facilities.
APPENDIX 5. A:
THE "CANONICAL " SYSTEM
Earlier sections of this chapter have recommended the
installation of minicomputer-based facilities equivalent
to 30 "canonical" systems.
This Appendix provides some
of the characteristics of the canonical system and expands
on our concepts for the implementation of these systems.
It must be emphasized at the outset that the canonical
system is a concept that is used solely for the purpose
of sizing and costing. Some installations, such as those
used primarily to support image analysis for a small uni-
versity group, may be only one third the size of the
canonical system. Others, such as those at the National
Astronomy Centers, which must support processing and
analysis for a large number of users, may be three or
four times the size of the canonical system. It may well
be that no system exactly matching the canonical system
is installed in the 1980's.
At present, one may purchase, for approximately
$220,000, a system with the following characteristics:
32-bit address space with virtual memory, 1-Mbyte physi-
cal memory, complete floating-point intruction set, 50
Mbytes of disk storage, one tape transport, and a capa-
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city of 1-2 ~FLOPS. On a system primarily used for
theoretical computing, an array processor is extremely
desirable. Systems used primarily for image analysis
will benefit from sophisticated display and hard-copy
peripherals.
Of course, array processors are useful for image analy-
sis, and sophisticated displays are useful for theoreti-
cal computations--if one must choose one or the other,
then theorists will choose the array processor while the
image analyst will select the display. Either of these
two options will bring the purchase price of the system
to about $300,000. We believe that such a system is ade-
quate to support the research of a medium-sized theoreti-
cal or observational research group or department.
Smaller groups can make significant progress with systems
down to the $100,000 level, although the array processor,
sophisticated display, and 32-bit virtual memory archi-
tecture must be dispensed with (the last, only for the
next few years). Larger groups, in which theory and
analysis are to be done on the same machine, may require
large systems with more memory, terminals, and both the
array processor and display devices. Facilities to be
deployed at major observatories and intended for image
processing as well as analysis may be several times the
size of the canonical system depending on the number of
users that must be served.
Our proposed implementation strategy calls for the
funding agencies to provide for the purchase of systems
equivalent to five canonical systems per year, which
allows systems to be replaced every 6 years as they
become obsolete (see below for a discussion of the need
for periodic replacement). A system to be installed at
university should be proposed by astronomers at the uni-
versity and evaluated through a peer-review process that
takes account of the scientific merit of the research
performed by the potential users of the system and the
impact the system will have on this research. A system
to be installed at a National Astronomy Center should be
evaluated in the context of the objectives of the Center,
together with the scientific programs and requirements of
the users and staff of the Center.
In addition to the funds needed to purchase capital
equipment, funds are also needed to provide for the main-
tenance and operation of the systems and basic software
support. These expenses may be met by cost sharing
between the universities and the funding agencies in the
case of university installations but must be wholly
.
a
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included in the operating budgets of the National
Astronomy Centers.
Typical service contracts are in the range of 6-10 per-
cent of the purchase price per year; we have adopted a
figure of 8 percent for our cost estimates. Operations
expenses include consumables such as paper, magnetic tape,
power, and air conditioning. Although these expenses can
amount to several thousand dollars per year, we have ig-
nored them in our cost estimates.
The systems that we are proposing, although relatively
inexpensive, are quite sophisticated.
It is our estimate
that each system will require a minimum level of software
support equivalent to that provided by one full-time soft-
ware person. This support includes installation and main-
tenance of the operating-system software, development of
local system software, development of basic applications
software, adaptation of software developed at other sites,
and assistance to users.
Maintenance and software support can be provided
through several mechanisms. Some groups may wish to keep
their astronomers "doing astronomy" and elect to provide
these functions through a service contract and the full-
time employment of a systems programmer. In this case,
maintenance and software support would appear explicitly
in the budget of the group. At the other extreme, some
groups may elect to provide these services through part-
time involvement of faculty and students. In this case,
maintenance and software support would not appear in the
budget and would seem to be provided free, although in
reality the costs have merely been shifted to another
part of the budget.
We arrive at the following formulas for the steady-
state costs of the systems that we have proposed:
~ _
Cm
where Cc' ~m'
=
i2/T,
NPM,
= NS,
and C~ are the annual costs for
capitaL~equ~pment, -maintenance, and software support,
respectively; N is the number of systems; P is the
purchase price of an average system; T is the system
~ _ _ , _ _ _
lifetime in years; M is the annual service contract cost
as a fraction of the Purchase price; and S is the salary,
benefits, and indirect costs required for a computer
professional. With N = 30, P = $300,000, T = 6 years,
M - 0.08 per year and S = $50,000 per year, the steady-
state annual costs are
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C-
_c
$1.5 million/year,
$0.7 million/year,
$1.5 million/year.
As mentioned above, we expect that the funding agencies
will be responsible for gs and that cost sharing is
appropriate for ~ and ~ . If, for example, 50 percent
cost sharing is achieved, the cost to the funding agencies
would be $2.6 million/year.
We believe that funding of these systems should begin
immediately and build up to this ~steady-state" value in
3 or 4 years (the buildup will not require 6 years because
some systems are already in existence) and should there-
after remain constant in real dollars. Of course, the
computational facilities must be periodically reviewed
and evaluated, and upward or downward adjustments may be
required. However, the concept of a steady level of fund-
ing in real dollars is important, as it provides for con-
tinuous upgrades in the computational capability as new
technology becomes available. Such upgrades will be
necessary to handle the ever-increasing data volume and
the growing complexity of theoretical computations. With
the model that we are recommending, the average computa-
tional capability available to the majority of the astro-
nomical community advances with the state of the art,
remaining approximately 3 years behind the very latest in
new technology. This will be a substantial improvement
over the situation today in which computers of the 1960's
remain the workhorses of several major observatories. A
final advantage of our recommendation is that it provides
the flexibility to accommodate modest changes in research
emphasis, computational requirements, or funding levels.
We are not concentrating our resources in only a few large
facilities. If it should turn out, for example, that we
have erred in the estimates of the needs for theoretical
computation relative to image processing, it will be a
relatively simple task to switch resources from one area
to the other. If we have somewhat underestimated the com-
putational requirements of the community, more facilities
can be acquired for the same level of funding simply by
stretching out the replacement interval.
Representative terms from entire chapter:
cost sharing
