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CrOnIc-KiLlA

Quote:

Originally posted by Sum Yung Guy

PROBLEMS (If does not be in the registrations asociativos) : · In the direct Correspondence: there are three accesses to memory, would delay three times more than a normal access, therefore the correspondence is utilized combined. This direct correspondence can be found with: · If the segmento S does not be in the real memory, an interruption of the Operating System is produced, which has to catch that segmento and to enter it together with its Board of Pages to be able to continue. · If once loaded it so happens that the page requested does not be in the real memory, another interruption is produced, with what goes to the secondary storage, charges it in a framework of page, and already there is the value of p. · That upon arriving to that page, tries to write upon that direction, but only is reading/execution (bits of protection), with what gives an irretrievable error of the Operating System. The segmentación paginada utilizes also the correspondence asociativa, being the boards that needs in memory. Compartición: Also the boards of pages are shared that cause another. The objective of the virtual and real systems of storage, is the to enable the multiprogramación, the difference is that in the real storage is necessary that a process be totally loaded in memory to be able to be executed, to the opponent that in the virtual storage. TECHNICAL FOR THE BY MEMORY VIRTUAL ADMINISTRATION. 1. PAGINACIÓN BY DEMAND: 1º it is arranged of a memory. 2º Enlarges the level of multiprogramación enlarging the productivity. 3º The Entrance/Exit of the program will not be in its totality, but in part, some page, for which accelerate the operations of AND/S. This it provides advantages to the user and to the system. In almost all the systems is utilized the paginación by demand, but can also be utilized: · The segmentación paginada. · The Paginación. · The segmentación (by demand). à This himself does not be used to employing because the algoritmos for transferencias of segmentos are a great deal more complicated than the of pages, by being the segmentos of variant length. The Paginación by Demand consists of adding him to the paginación the exchanges of paginas through a paginador. · The exchange is carried out through pages. · What operations one must carry out to solve a failure of page when a program requests a page to execute it: The Operating System: 1. It locates the page to enter. 2. It transfers the page to the free framework. 3. It brings up to date the Board of Correspondences. 4. It finishes the operation of AND/S. In this way, can begin to execute a program including without having no page in memory. · When there is solapamiento total or partial of blocks: If we move data from TO to B, and itself machacan the intial data from TO, and then a failure of page occurs, no longer the problem can be fixed. There is 2 solutions: · to Have a microcódigo to see if a failure of page is produced, and thus to be assured that herself is not produced. · To Place all the block fountain in a temporary registration, and if a failure of page is produced and one must repeat the operation, the original block by the temporary one is substituted, to be able reiniciar the operation. The Time of Access to Memory (TAM), if there is not failures of page, would be the same as the Effective Time of Access, but is not thus: if p is the probability that a failure of page be produced, should be found this among 0 and 1 (really very near 0), so that the performance of this technical be the adequate one. TPF will be the Page Failure Time: Effective time Access = (1 - p) TAM + (p x TFP) FAILURES OF PAGE. 1. To attend to the failure of page: N Interruption: Guard the data of the processor, to occupy it with another process. N The type of interruption determines it the Operating System. N Is legal that page that requests, by the bits of protection. 2. It agrees to the HD (secondary storage) : N Locates that page in the secondary storage. (The following failure of page is put to the queue). N Operation of AND/S: is consumed the Time of Posicionamiento, Latencia and of Transferencia (of the HD). 3. It follows the execution: N Notifies that already the page to memory has been carried (Interruption). · It Returns to keep the information of the processor. · Permit the updating of the Board of Correspondences. · The Planificador short-term elects the process that should be followed executing. Ej: TPF: 100-200ns HD:

I take it you are bored, no?