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   Ðåôåðàò: Ñåòåâûå ÎÑ

Ðåôåðàò: Ñåòåâûå ÎÑ

1.    Ââåäåíèå                                                                                                                            3

1.1            ÎÑ êàê ðàñøèðåííàÿ ìàøèíà                                                                                                                               3

1.2            ÎÑ êàê ñèñòåìà óïðàâëåíèÿ ðåñóðñàìè                                                                                                             3

2.    Êëàññèôèêàöèÿ ÎÑ                                                                                                      4

2.1            Îñîáåííîñòè àëãîðèòìîâ óïðàâëåíèÿ ðåñóðñàìè                                                                                          4

2.1.1.            Ïîääåðæêà ìíîãîçàäà÷íîñòè.                                                                                                                       4

2.1.2.            Ïîääåðæêà ìíîãîïîëüçîâàòåëüñêîãî ðåæèìà.                                                                                       4

2.1.3.            Âûòåñíÿþùàÿ è íåâûòåñíÿþùàÿ ìíîãîçàäà÷íîñòü.                                                                           4

2.1.4.            Ïîääåðæêà ìíîãîíèòåâîñòè.                                                                                                                         4

2.1.5.            Ìíîãîïðîöåññîðíàÿ îáðàáîòêà.                                                                                                                  5

2.2            Îñîáåííîñòè àïïàðàòíûõ ïëàòôîðì                                                                                                                  5

2.3            Îñîáåííîñòè îáëàñòåé èñïîëüçîâàíèÿ                                                                                                               6

2.4            Îñîáåííîñòè ìåòîäîâ ïîñòðîåíèÿ                                                                                                                        6

3.    Ñåòåâûå îïåðàöèîííûå ñèñòåìû                                                                  8

3.1            Ñòðóêòóðà ñåòåâîé îïåðàöèîííîé ñèñòåìû                                                                                                     8

3.2            Îäíîðàíãîâûå ñåòåâûå ÎÑ è ÎÑ ñ âûäåëåííûìè ñåðâåðàìè                                                                  10

3.3            ÎÑ äëÿ ðàáî÷èõ ãðóïï è ÎÑ äëÿ ñåòåé ìàñøòàáà ïðåäïðèÿòèÿ                                                             11

4.    Ïðîöåññû è íèòè â ðàñïðåäåëåííûõ ñèñòåìàõ                                 14

4.1            Ïîíÿòèå "íèòü"                                                                                                                                                         14

4.2            Ðàçëè÷íûå ñïîñîáû îðãàíèçàöèè âû÷èñëèòåëüíîãî ïðîöåññà ñ èñïîëüçîâàíèåì íèòåé            14

4.3            Âîïðîñû ðåàëèçàöèè íèòåé                                                                                                                                  16

4.4            Íèòè è RPC                                                                                                                                                                 16

5.    Ñîâðåìåííûå êîíöåïöèè è òåõíîëîãèè ïðîåêòèðîâàíèÿ îïåðàöèîííûõ ñèñòåì                                                                                                                                      17

5.1            Òðåáîâàíèÿ, ïðåäúÿâëÿåìûå ê ÎÑ 90-õ ãîäîâ                                                                                               17

5.1.1.            Ðàñøèðÿåìîñòü                                                                                                                                                 17

5.1.2.            Ïåðåíîñèìîñòü                                                                                                                                                 18

5.1.3.            Ñîâìåñòèìîñòü                                                                                                                                                 19

5.1.4.            Áåçîïàñíîñòü                                                                                                                                                     19

6.    Îïåðàöèîííûå ñèñòåìû ðàçëè÷íûõ ôèðì ïðîèçâîäèòåëåé ïðîãðàììíîãî îáåñïå÷åíèÿ                                                                                                                       21

6.1            Ñåìåéñòâî îïåðàöèîííûõ ñèñòåì UNIX                                                                                                          21

6.2            Ìèêðîÿäðî Mach                                                                                                                                                      23

6.2.1.            Èñòîðèÿ Mach                                                                                                                                                    24

6.2.2.            Öåëè Mach                                                                                                                                                          24

6.2.3.            Îñíîâíûå êîíöåïöèè Mach                                                                                                                        24

6.2.4.            Ñåðâåð Mach BSD UNIX                                                                                                                                 25

6.3            Ñåòåâûå ïðîäóêòû ôèðìû Novell                                                                                                                       26

6.3.1.            Èñòîðèÿ è âåðñèè ñåòåâîé ÎÑ NetWare                                                                                                   26

6.3.2.            Âåðñèÿ NetWare 4.1                                                                                                                                         27

6.4            Ñåìåéñòâî ñåòåâûõ ÎÑ êîìïàíèè Microsoft                                                                                                  29

6.4.1.            Ñåòåâûå ïðîäóêòû Microsoft                                                                                                                       29

6.4.2.            Windows NT 4.0                                                                                                                                                 30

6.4.3.            Îáëàñòè èñïîëüçîâàíèÿ Windows NT                                                                                                      30

6.4.4.            Êîíöåïöèè Windows NT                                                                                                                                31

6.4.5.            Ñîâìåñòèìîñòü Windows NT ñ NetWare                                                                                                   41

6.5            Îïåðàöèîííàÿ ñèñòåìà OS/2                                                                                                                                42

6.5.1.            Èñòîðèÿ ðàçâèòèÿ OS/2 è åå ìåñòî íà ðûíêå                                                                                         42

6.5.2.            Áèòâà Microsoft - IBM íà ðûíêå íàñòîëüíûõ ÎÑ                                                                                42

6.5.3.            OS/2 - ïîñòåïåííûå óëó÷øåíèÿ                                                                                                                  43

7.    Çàêëþ÷åíèå                                                                                                                    44

Ñïèñîê ëèòåðàòóðû                                                                                                        46

ïðèëîæåíèå                                                                                                                          47


1.   Ââåäåíèå

Îïåðàöèîííàÿ ñèñòåìà â íàèáîëüøåé ñòåïåíè îïðåäåëÿåò îáëèê âñåé âû÷èñëèòåëüíîé ñèñòåìû â öåëîì. Íåñìîòðÿ íà ýòî, ïîëüçîâàòåëè, àêòèâíî èñïîëüçóþùèå âû÷èñëèòåëüíóþ òåõíèêó, çà÷àñòóþ èñïûòûâàþò çàòðóäíåíèÿ ïðè ïîïûòêå äàòü îïðåäåëåíèå îïåðàöèîííîé ñèñòåìå. ×àñòè÷íî ýòî ñâÿçàíî ñ òåì, ÷òî ÎÑ âûïîëíÿåò äâå ïî ñóùåñòâó ìàëî ñâÿçàííûå ôóíêöèè: îáåñïå÷åíèå ïîëüçîâàòåëþ-ïðîãðàììèñòó óäîáñòâ ïîñðåäñòâîì ïðåäîñòàâëåíèÿ äëÿ íåãî ðàñøèðåííîé ìàøèíû è ïîâûøåíèå ýôôåêòèâíîñòè èñïîëüçîâàíèÿ êîìïüþòåðà ïóòåì ðàöèîíàëüíîãî óïðàâëåíèÿ åãî ðåñóðñàìè.

1.1  ÎÑ êàê ðàñøèðåííàÿ ìàøèíà

Èñïîëüçîâàíèå áîëüøèíñòâà êîìïüþòåðîâ íà óðîâíå ìàøèííîãî ÿçûêà çàòðóäíèòåëüíî, îñîáåííî ýòî êàñàåòñÿ ââîäà-âûâîäà. Íàïðèìåð, äëÿ îðãàíèçàöèè ÷òåíèÿ áëîêà äàííûõ ñ ãèáêîãî äèñêà ïðîãðàììèñò ìîæåò èñïîëüçîâàòü 16 ðàçëè÷íûõ êîìàíä, êàæäàÿ èç êîòîðûõ òðåáóåò 13 ïàðàìåòðîâ, òàêèõ êàê íîìåð áëîêà íà äèñêå, íîìåð ñåêòîðà íà äîðîæêå è ò. ï. Êîãäà âûïîëíåíèå îïåðàöèè ñ äèñêîì çàâåðøàåòñÿ, êîíòðîëëåð âîçâðàùàåò 23 çíà÷åíèÿ, îòðàæàþùèõ íàëè÷èå è òèïû îøèáîê, êîòîðûå, î÷åâèäíî, íàäî àíàëèçèðîâàòü. Äàæå åñëè íå âõîäèòü â êóðñ ðåàëüíûõ ïðîáëåì ïðîãðàììèðîâàíèÿ ââîäà-âûâîäà, ÿñíî, ÷òî ñðåäè ïðîãðàììèñòîâ íàøëîñü áû íå ìíîãî æåëàþùèõ íåïîñðåäñòâåííî çàíèìàòüñÿ ïðîãðàììèðîâàíèåì ýòèõ îïåðàöèé. Ïðè ðàáîòå ñ äèñêîì ïðîãðàììèñòó-ïîëüçîâàòåëþ äîñòàòî÷íî ïðåäñòàâëÿòü åãî â âèäå íåêîòîðîãî íàáîðà ôàéëîâ, êàæäûé èç êîòîðûõ èìååò èìÿ. Ðàáîòà ñ ôàéëîì çàêëþ÷àåòñÿ â åãî îòêðûòèè, âûïîëíåíèè ÷òåíèÿ èëè çàïèñè, à çàòåì â çàêðûòèè ôàéëà. Âîïðîñû ïîäîáíûå òàêèì, êàê ñëåäóåò ëè ïðè çàïèñè èñïîëüçîâàòü óñîâåðøåíñòâîâàííóþ ÷àñòîòíóþ ìîäóëÿöèþ èëè â êàêîì ñîñòîÿíèè ñåé÷àñ íàõîäèòñÿ äâèãàòåëü ìåõàíèçìà ïåðåìåùåíèÿ ñ÷èòûâàþùèõ ãîëîâîê, íå äîëæíû âîëíîâàòü ïîëüçîâàòåëÿ. Ïðîãðàììà, êîòîðàÿ ñêðûâàåò îò ïðîãðàììèñòà âñå ðåàëèè àïïàðàòóðû è ïðåäîñòàâëÿåò âîçìîæíîñòü ïðîñòîãî, óäîáíîãî ïðîñìîòðà óêàçàííûõ ôàéëîâ, ÷òåíèÿ èëè çàïèñè - ýòî, êîíå÷íî, îïåðàöèîííàÿ ñèñòåìà. Òî÷íî òàêæå, êàê ÎÑ îãðàæäàåò ïðîãðàììèñòîâ îò àïïàðàòóðû äèñêîâîãî íàêîïèòåëÿ è ïðåäîñòàâëÿåò åìó ïðîñòîé ôàéëîâûé èíòåðôåéñ, îïåðàöèîííàÿ ñèñòåìà áåðåò íà ñåáÿ âñå ìàëîïðèÿòíûå äåëà, ñâÿçàííûå ñ îáðàáîòêîé ïðåðûâàíèé, óïðàâëåíèåì òàéìåðàìè è îïåðàòèâíîé ïàìÿòüþ, à òàêæå äðóãèå íèçêîóðîâíåâûå ïðîáëåìû.  êàæäîì ñëó÷àå òà àáñòðàêòíàÿ, âîîáðàæàåìàÿ ìàøèíà, ñ êîòîðîé, áëàãîäàðÿ îïåðàöèîííîé ñèñòåìå, òåïåðü ìîæåò èìåòü äåëî ïîëüçîâàòåëü, ãîðàçäî ïðîùå è óäîáíåå â îáðàùåíèè, ÷åì ðåàëüíàÿ àïïàðàòóðà, ëåæàùàÿ â îñíîâå ýòîé àáñòðàêòíîé ìàøèíû.

Ñòðàíèöû: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20


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