Disk processor machines

The above is an example of how direct algorithms may be formulated for methods involving electron correlation. It illustrates that it is not as straightforward to apply direct methods at the correlated level, as at the SCF level. However, the steady increase in CPU performance, and especially the evolution of multi-processor machines, favours direct (and semi-direct where some intermediate results are stored on disk) algorithms. ... 

The use of concurrence or parallelism in chemistry applications is not new. In the 1980s chemistry applications evolved to take advantage of multiple vector registers on vector supercomputers and attached processors by restructuring the software to utilize matrix—vector and matrix—matrix operations. In fact, once the software had been adapted to vector supercomputers, many applications ran faster on serial machines because of improved use of these machines memory hierarchies. The use of asynchronous disk operations (overlapped computation and disk reads or writes) and a few loosely coupled computers and workstations are other concurrency optimizations that were used before the development of current MPP technology. The challenge of the... 

Back in the early days of mainframes, it took a full staff of people working around the clock to keep the machines going. With today s NOSs, servers are able to monitor memory, CPU time, disk space, and peripherals, without a babysitter. Each of these operating systems allows processes to respond in a certain way with the processor. 

The disks are 256 MB (formatted) CDC disks with a transfer rate of 1.2MB per second. Each of the iterative search computers is connected to the IBM 3705 communications processor and to its screen search machine with 9600 bps serial links. 

Hardware the Revolution. Everyone agrees that a revolution is taking place in computer hardware. It is clear that we can, if we choose, have workstations on our desks in the 5-20 MIP range, at today s personal computer prices, in the next few years. Some moderately priced machines achieve the lower end of that scale today. But this revolution is not limited to raw cpu power. It extends to available memory, computer networking, hard disks, specialized processors, etc. 

My secretary edited all the chapters (according to my instructions on a hard copy) on a Wordplex machine using the WPS+ word processor. A Wordplex floppy disk of each chapter was sent for typesetting (with a hard copy indicating problems such as special fonts, umlauts etc.). The floppy disks were re-converted to ASCII and typeset on a Linotron 202. 

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