Memory, process management, threading concurrency week 2 pos 355.pptx

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MEMOERY AND PROCESS MANAGEMENT, THREADING AND CONCURRENCY FRANKLIN UGWU POS 355 ROBERT O’CONNOR 10/03/2016
MEMORY MANAGEMENT o WINDOWS : WINDOWS ARE DEVELOPED IN A LONG SERIES OF OPERATING SYSTEMS STARTING WITH MSDOS o THE DATA STRUCTURES USED BY WINDOWS NT ARE INSTEAD OF A LINKED LIST THE WINDOWS NT SYSTEM KEEPS IT IN A TREE FORM o EACH NODE OF THE TREE IS CALLED VIRTUAL ADDRESS DESCRIPTORS (VAD). o EACH VAD DENOTES A RANGE OF ADDRESS WHICH HAS THE SAME PROTECTION PARAMETERS AND COMMIT STATE INFORMATION o THE TREE IS ALSO BALANCED WHICH MEANS THAT DEPTH OF THE TREE IS KEPT AT A MINIMUM.
MEMORY MANAGEMENT o WINDOWS USES CLUSTERED DEMAND PAGING FOR FETCHING PAGES, AND THE CLOCK ALGORITHM FOR THE PAGE REPLACEMENT. o THE KERNEL RECEIVES 5 KINDS OF PAGE FAULTS THE PAGE REFERENCED IS NOT COMMITTED. A PROTECTION VIOLATION HAS OCCURRED. A SHARED PAGE HAS BEEN WRITTEN. THE STACK NEEDS TO GROW. THE PAGE REFERENCED IS COMMITTED BUT NOT CURRENTLY MAPPED IN
MEMORY MANAGEMENT o LINUX : LINUX HAS BEEN DEVELOPED BY HACKERS ORIGINALLY FOUNDED BY LINUX TORVALDS. o LINUX IMPLEMENTS THE VIRTUAL MEMORY DATA STRUCTURE IN A SIMILAR MANNER TO UNIX. o IT MAINTAINS A LINKED LIST OF VM AREA STRUCTURES. o THESE ARE STRUCTURES WHICH REPRESENT CONTINUOUS MEMORY AREAS WHICH HAVE THE SAME PROTECTION PARAMETERS. o THIS LIST IS SEARCHED WHENEVER A PAGE IS TO BE FOUND THAT CONSISTS A PARTICULAR LOCATION.
MEMORY MANAGEMENT o THE STRUCTURE ALSO RECORDS THE RANGE OF ADDRESS IT IS MAPPING

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