CERN LIBRARIES, GENEVA CERN/SPC/220 28 February, 1966 CM-P00095068 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH SCIENTIFIC POLICY COMMITTEE Thirty-eighth Meeting 8 March, 1966 EXTENSIONS TO THE CERN COMPUTING FACILITIES by Dr. M.G.N. Hine The attached paper contains a review of CERN's needs from its central computing facilities, both in the near future and as far as 1969-1970. It describes possible ways in which these needs might be met within the budget forecasts, and suggests an optimum way to proceed. The scientific policy is to be discussed at the Scientific Policy Committee meeting on 8th March. If the policy line is cleared at that meeting, the Finance Committee could start discussion of the contractual implications at its meeting on 10th March. The Finance Committee would not be pressed to give final decisions at that meeting about contract adjudications, but those decisions will be needed in the near future. 66/348/5 CERN/SPC/220 EXTENSIONS TO THE CERN COMPUTING FACILITIES 1. Introduction The need to continue the development of computing facilities at CERN in order to keep pace with the rapidly growing use of com• puting and digital techniques in high-energy physics has been ex• plained on several occasions to the Scientific Policy Committee and the Finance Committee, and money has been reserved in the future budget forecasts for this purpose. A review of our needs has been made recently in the light of a year's experience of use of the CDC 6600 and associated equipment, and this paper describes the conclusions and the policy we propose to follow. An internal tech• nical report (DD/CO/66/I) is annexed, giving details of the future needs, the performance of the 6600, the possible ways of development and their financial implications. 2. History A major study of CERN's computing needs was made in 1963 by the European Committee and its working party, who reported that CERN should provide for a great increase in ordinary computing load over the period 1965-1969, allowing for the use of complicated on-line applications involving large programmes such as HPD and spark chamber experiments, and in addition should develop a system of remote operating consoles, whereby individual users could test and run programmes much more easily than with conventional input/output media. The report recommended the purchase of a CDC 6600 central computer, with a set of peripheral computers to pre-treat raw experi• mental data, and the addition at some time of extra storage capacity to cope with the problem of time-sharing with large programmes and many users. As a result, the CDC 6600 was purchased and installed at CERN early in 1965, and preparations for these various uses were pushed ahead, including the study of the extensions required when on-line uses became common. Programming systems and equipment were studied, and offers were requested from manufacturers for an input/ output processor and for some means of extending the central memory of the 6600 (see Annex, section 4). Meanwhile, the problem of getting the 6600 into regular use had been much worse than expected, both because of the long delays by CDC in supplying software and because of machine unreliability, which ultimately required a complete overhaul and the retuning of the cen• tral processor in November. Since then, the machine has been working 66/348/5 CERN/SPC/220 Page 2 better and a more efficient operating system has been developed, which should give a speed of-5-6 7090s with HPD in operation at the same time. As a result of these delays, there is a backlog of work, par• ticularly of film to be measured on HPD and Luciole, which will take several months to be run off, even when the new time-sharing system, SIPROS, is in full use. In broad terms, wo can say that we.have lost some six months in bringing HPD and other devices into production, and it will be a difficult job to regain this lost time. Since November, we have also been using a 32 K CDC 3400 (about equivalent to a 7090) lent to us by the firm, and we propose continuing with it until we can make other arrangements for a reserve computer as described in the last section of this paper. This experience has led us to make a complete review of the policy outlined above, including a re-estimate of the future needs of the various users. For comparison with other laboratories' programmes, wo may recall that Berkeley have just taken delivery of their 6600, and Brookhaven's is due to be installed shortly. Argonne have cancelled their arrangement for an IBM 360/92 and have ordered instead a CDC 6800 for delivery in two years' time. Berkeley will soon also have installed a CDC 6411 to increase the input/output capacity of their 6600, and have an option to buy an extended core store next year. 3. Review of Policy 3.1 Needs In 1963 the computing load at CERN was estimated to grow from the capacity of 1 IBM 7090 at the end of 1964 to between 10 and 15 7090s by the end of 1968. The detailed bases of these estimates have been reviewed very recently (see Annex, section 2), and the con• clusions are very similar, predicting a load of 8 7090s in mid 1967 and 13 7090s by mid 1968. A large fraction of this load will be provided by on-line devices, either measuring film, or collecting experimental data on the PS, and the size of many of the programmes involved will vary between 40 000 and 70 000 words. At about this time the data rates from on-line experiments could increase still further if a largo data-collecting set-up involving wire chambers or fast hodoscopes were built as part of the improvements programme. Such a project would probably have to include as an integral part a medium-sized computer for data collection and at least partial treatment of the information. For a work load of this kind, with large programmes and real time uses, it is unlikely that the 6600 as it now stands can have a capacity of more than 10 7090s, even with further develop• ments in compilers and operating systems. To reach the ultimate computing speed of the machine, and to be able to store enough pro• grammes in an accessible form to run several on-line devices and to 66/348/5 CERN/SPC/220 Page 3 begin the use of a multi-access console system, it will be necessary, as foreseen broadly in the 1963 studies, tc add some half a million words of fast-access storage to the 6600 system, and to provide an input/output processor to assemble and edit data on its way to and from the 6600. The review of needs, and also our practical experience with the 6600, raised two points - the desirability of having extra capacity in the form of a reserve computer, and the amount of time needed for system development work and testing time for now on-line equipment - which were not given sufficient weight in the 1963 studies. At that time, the need for a medium-sized computer was considered, and rejected on the grounds that it could only add a small extra capacity, and that it would not be useful in adding flexibility of operation when a time-sharing system was operating on the 6600. The poor reliability of the 6600 in the past year, and the difficulty in diagnosis and cure of faults or in installation and testing of improvements (which is intrinsic to any of the new genera• tion of very large and complicated machines), illustrate how important it is that the overall computer facility at CERN should have "fail safe" characteristics, and that therefore the 6600 should be backed up by some independent computer capacity to take care at least of urgent short-term work in case the main machine is out of action, and, possibly, to handle some parts of the production load if circumstances warrant. Further, although the need to do systems development work at CERN, for the on-line applications and a console system for example, was recognized in 1963, it was then hoped that the initial performance of the 6600 would be good enough - as it would have been if CDC had lived up to their promises on software - to provide easily spare time in 1965-1967 to do this work. Secause of the backlog of work which has built up over the past few months, and the delays in introducing a programming system adequate for our needs, this spare time will not be available. An independent reserve computer would enable development work to be continued, possibly on the second machine, possibly by off• loading the 6600 to some extent, as the 3400 has done over the past three months. Thus, to the previous requirements of adding extra storage and input/output processing to the present system, we must add the need for some independent computing capacity to act as a reserve in case the 6600 is out of action and to provide extra time for develop• ment work, or to reduce the 6600 load for certain types of work. 66/348/5 CERN/SPC/220 Page 4 3.2 Possible Solutions Various ways to satisfy these requirements individually are described in the Annex (section 4), Two possibilities for the storage and input/output development emerged from the consideration of manufacturers' replies to our request for tenders for this system, viz.
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