This paper discusses the implementation of a database buffer manager as a component of a DBMS. The interface between calling components of higher system layers and the buffer manager is described; the principal differ...
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This paper discusses the implementation of a database buffer manager as a component of a DBMS. The interface between calling components of higher system layers and the buffer manager is described; the principal differences between virtual memory paging and database buffer management are outlined; the notion of referencing versus addressing of database pages is introduced; and the concept of fixing pages in the buffer to prevent uncontrolled replacement is *** basic tasks have to be performed by the buffer manager: buffer search, allocation of frames to concurrent transactions, and page replacement. For each of these tasks, implementation alternatives are discussed and illustrated by examples from a performance evaluation project of a CODASYL DBMS.
This paper investigates the implementation of the page fault frequency (PFF) replacement algorithm as the mechanism for selecting and replacing pages of programs loaded into the main memory of a multiprocessing, multi...
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This paper investigates the implementation of the page fault frequency (PFF) replacement algorithm as the mechanism for selecting and replacing pages of programs loaded into the main memory of a multiprocessing, multiprogrammed computer system. The frequency at which an executing program requires a page of virtual memory, the PFF, provides a basis for judging the real memory requirements of the program. Operating difficulties of PFF that reduce its usefulness in a time-shared computer system (Michigan Terminal System) are discussed, and a means of implementing the algorithm is proposed.
Adaptive memory management techniques for multiprogramming operating systems are described. Page replacement during execution and initial page assignment are the factors affecting optimal memory usage. Modifications t...
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Adaptive memory management techniques for multiprogramming operating systems are described. Page replacement during execution and initial page assignment are the factors affecting optimal memory usage. Modifications to a time-shared operating system (Michigan Terminal System) that would allow implementation of the Page Fault Frequency replacement Algorithm are discussed. Additional modifications to this system are suggested that would subordinate job initiation to memory availability.
A general class of adaptive replacement schemes for use in paged memories is developed. One such algorithm, called SIM, is simulated using a probability model that generates memory traces, and the results of the simul...
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The operation of 'folding' a program into the available memory is discussed. Measurements by Brawn et al. and by Nelson on an automatic folding mechanism of simple design, a demand paging unit built at the IBM...
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The operation of 'folding' a program into the available memory is discussed. Measurements by Brawn et al. and by Nelson on an automatic folding mechanism of simple design, a demand paging unit built at the IBM Research Center by Belady, Nelson, O'Neill, and others, permitting its quality to be compared with that of manual folding, are discussed, and it is shown that given some care in use the unit performs satisfactorily under the conditions tested, even though it is operating across a memory-to-storage interface with a very large speed difference. The disadvantages of prefolding, which is required when the folding is manual, are examined, and a number of the important troubles which beset computing today are shown to arise from, or be aggravated by, this source. It is concluded that a folding mechanism will probably become a normal part of most computing systems. [ABSTRACT FROM AUTHOR]
A formal model is presented for paging algorithms under /-order nonstationary assumptions about program behavior. When processing a program under paging in a given memory, a given paging policy generates a certain (ex...
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