Discussion of the required seek time (distance) to complete a disk merge using two units. It is shown that it takes n**2 seek distance in the case of the conventional balanced merge, while it takes only nlogn seek dis...
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Discussion of the required seek time (distance) to complete a disk merge using two units. It is shown that it takes n**2 seek distance in the case of the conventional balanced merge, while it takes only nlogn seek distance in the case of a forecasting merge (where the forecasts are made using the lower and upper keys in each cylinder when the data records are written, predicting the read seek sequence in the next pass). A seek-distance analysis is given for the 2-way case and later extend it to p-way. A cylinder-oriented data-record block is considered. This analysis is also applicable to track-oriented and sector-oriented data records.
Testing new or changed Initial Program Load (IPL) text previously required using an Operating System (OS) Utility Program to place the assembled object deck for IPL on a disk pack, as part of the Utility Program analy...
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Testing new or changed Initial Program Load (IPL) text previously required using an Operating System (OS) Utility Program to place the assembled object deck for IPL on a disk pack, as part of the Utility Program analyze function. Then track 0 of this analyzed pack had to be copied by the utility dump function to an OS SYSRES pack. A quick bypass to this lengthy procedure is provided by loading an IPL object deck directly into core and passing control to it.
The TOP/BOTTOM function is to make a selection based on ordinal numbers in some collating sequence from a set of unordered records (or ordered in some other collating sequence). Traditionally TOP/BOTTOM selection is i...
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The TOP/BOTTOM function is to make a selection based on ordinal numbers in some collating sequence from a set of unordered records (or ordered in some other collating sequence). Traditionally TOP/BOTTOM selection is implemented with SORT followed by truncation. It is shown how significant performance improvements can be made by eliminating records not in the selection at an early stage.
A technique is described for enhancing the optimization of implicitly declared variables using the PL/I Optimizing Compiler. The technique includes a program which is implemented as a Time Sharing Option command proce...
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A technique is described for enhancing the optimization of implicitly declared variables using the PL/I Optimizing Compiler. The technique includes a program which is implemented as a Time Sharing Option command procedure.
Decision tables often exceed the given formats. Tables of this kind have to be decomposed into sub-tables. The problems arising can be solved with the aid of the formal systems described.
Decision tables often exceed the given formats. Tables of this kind have to be decomposed into sub-tables. The problems arising can be solved with the aid of the formal systems described.
It is shown that the various major problems existing in manual maintenance of the programmingsystems in use can be significantly reduced through appropriate guidelines for directed, computer-independent programming a...
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It is shown that the various major problems existing in manual maintenance of the programmingsystems in use can be significantly reduced through appropriate guidelines for directed, computer-independent programming as well as computer-supported maintenance.
作者：
FREDERIC.DHIBM CORP
THOMAS J WATSON RES CTRRES DIVYORKTOWN HEIGHTSNY 10598
Programmers are quite accustomed to describing data they use: where to find it, what devices are involved, the layout of the data, what to do with it after the job is complete, processing techniques employed, and ofte...
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Programmers are quite accustomed to describing data they use: where to find it, what devices are involved, the layout of the data, what to do with it after the job is complete, processing techniques employed, and often a great deal more. The reason data is so described is that, nowadays, programs call upon a great many other programs for assistance. All sorts of common-place functions that the programmer takes for granted are provided by other, already-written programs, that are invoked explicitly or implicitly by what the programmer himself writes. Thus programmers must describe things about their data to be able to use the functions provided.
作者：
BARD, YIBM CORP
DATA PROC DIV SCI CTRTECHNOL SQCAMBRIDGEMA 02138
This paper describes a method for predicting the paging behavior of a program in a virtual memory multiprogramming environment. The effect of overall system activity on the program is summarized in one parameter, the ...
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This paper describes a method for predicting the paging behavior of a program in a virtual memory multiprogramming environment. The effect of overall system activity on the program is summarized in one parameter, the page survival index. The model correlates well with observations taken on programs running under CP-67. The model can be used for paging load prediction, simulator input verification, and evaluation of program rearrangement and sharing.
Introductory principles of program performance in virtual storage have been presented to give a perspective of the virtual environment for systems designers and programmers. It is recognized that the list of guideline...
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Introductory principles of program performance in virtual storage have been presented to give a perspective of the virtual environment for systems designers and programmers. It is recognized that the list of guidelines presented is not comprehensive as many more useful techniques will be developed as experience is gained with virtual storage systems. It is hoped that these program design considerations and the programming guidelines will assist these users in their future virtual storage program development.
The formulation of the closed queuing network model of a multiprogrammingcomputer system is generalized to allow each task to have its own set of facility service rates and I/O device selection probability distributi...
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The formulation of the closed queuing network model of a multiprogrammingcomputer system is generalized to allow each task to have its own set of facility service rates and I/O device selection probability distribution. In the model, processor sharing is assumed for different types of customers. It is shown through a series of investigations that the model reasonably approximates pre-emptive priority dispatching.
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