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Segmentation-1

Segmentation-1. Segment variable size block 비교 ) page or page frame  fixed size block variable partition multiprogramming first-fit , best-fit, worst-fit 비교 ) fixed partition multiprogramming. Segmentation -2. Implementation of Segment table. DAT in Segmentation

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Segmentation-1

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  1. Segmentation-1 • Segment • variable size block • 비교) page or page frame  fixed size block • variable partition multiprogramming • first-fit , best-fit, worst-fit • 비교) fixed partition multiprogramming SunMoon University

  2. Segmentation -2 SunMoon University

  3. Implementation of Segment table DAT in Segmentation Virtual Address = ( s, d ) s : segment number in virtual storage d : displacement in that segment dfig 8.18 Sfig 8.23(7.19) dfig 8.19 Segment Table Base Register ( STBR ) SunMoon University

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  7. Direct Mapping in Segmentation(1) Segment Map Table Format (dfig 8.22) residence bit secondary storage address segment length protection bit starting address of that segment SunMoon University

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  9. Direct Mapping in Segmentation(2) Three types of faults 1st : check residence bit missing segment fault 2nd : check displacement <= segment length segment overflow fault 3rd : check access right segment protection fault SunMoon University

  10. Direct Mapping in Segmentation(3) Advantage of segmentation more logical than paging easy to protection and sharing ex.) sharing in a segmentation static int array[10000]; dfig 8.23 (fig 7.21 = Sfig 8.25) SunMoon University

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  13. Direct Mapping in Segmentation(4) Placement first_fit / best_fit / worst_fit Disadvantage external fragmentation same as a dynamic stroage_allocation scheme SunMoon University

  14. Paging and Segmentation Systems(1) Comine Paging and Segmentation each segment : multiples of page size all the pages of a segment need not be in primary stroage at once DAT V.R. = ( s, p, d ) s : segment number p : page number in the segment SunMoon University

  15. Paging and Segmentation Systems(2) d : displacement in the page dfig 8.25 advantages easy to sharing and protection disadvantages diffcult to address mapping SunMoon University

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  17. Paging and Segmentation Systems(3) various kind of fault missing segment fault missing page fault segment overflow fault segment potection fault process table dfig 8.26 SunMoon University

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  19. Memory-Management Unit (MMU) • Hardware device that maps virtual to physical address. • MMU 기법에 의한 변환 • 기준 레지스터를 재배치 레지스터(Relocation Register) 라고 부름 • 기준 레지스터에 들어있는 값은 메모리로 보내질 때마다 모든 주소에 더해짐 • 사용자 프로그램은 논리 주소를 사용하고, 메모리 하드웨어는 논리 주소를 물리 주소로 바꿈 • 실행시간 바인딩 • 사용자 프로그램 • 단지 논리 주소(Logical Addresses)만을 만들어 냄 • 결코, 실제 물리 주소(Physical Addresses)를 보지 못함 SunMoon University

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