OS

1
OS Operating System??????

• ???
• ???

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Outline

• ???????
• ?????????
• ?????????
• ??????
• ??????

3
????????
???

• A basis for application programs
• ???????????
• An intermediary between users and Hardware
• ????????????
• Can boot and Run at all time
• ????,?????????
• The stuff shipped by vendors as an OS
• ?! ??????,???????OS.

?????
4
??????????

• ??
• 1. ?? 2. ????? 3. throughput(??)
• ????
• 1. ???? 2. ???????.?
• ?????
• ???? ?? ??????????
• ??? ?? ?????????????????????
• PDA ?? ??????
• ????? ?????????

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??????

• Batch System(??)?????
• Ex. ???
• Multiprogrammed System(??)?????
• Ex. ???????B??????????
• Time-Sharing System(??)??????????
• Ex. Ptt ?????? 5000?
• Real-Time System(??)
• Hard real-time ???????
• Ex. ????
• Soft real-time ????
• Ex. ??demo

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???????
????
????
I/ O interrupt(??)

• ????
• I/ O interrupt(??)
• timer interrupt (????)
• system call (trap)(????)

• scheduling (????)
• ???? ??

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??????????

• ????(interrupt)
• 1. ??????
• Ex. ??????????
• 2. ?????
• gt ?????????process??
• ????(trap)
• 1. ???????????????
• why? ?????????
• 2. ??????
• Ex. ??0?????????.?

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???????

• ?????????? ??????
• lt??gt
• 1. CPU ?????
• 2.??????
• 3.I/O????
• ??????
• 1.CPU??CPU??,????????CPU???????
• 2.???????????????????,???????????
• 3.I/O???????????,?????????,?????????(system
  call),???????????

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???? multiprogramming(??)

• ??
• preemptive(???)???????????
• nonpreemptive(????)????????????I/O?,??????
• ??
• 1. ???????????????,???????
• 2. ????????,???I/O?,?CPU???????,?????CPU?I/O?????
  ???,????
• ??
• ?????????????? (context switch overhead)

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???? Process Thread

• ????????,?????
• ??
• Process????????????
• Thread????????(a basic unit of CPU utilization)
• ?????
• ??process????? 1????thread,???????????,????proces
  s??thread????????process????,??????????,??????????
  ?

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???? CPU??

• 1. FCFS (first come first serve) ???????
• 2. SJF (shortest job first) ?????????
• 3. Priority Scheduling ??????
• 4. Round-Robin Scheduling ??????
• 5. Multilevel Queue Scheduling ???????
• 6. Multilevel Feedback Queue Scheduling ?????????

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1. FCFS(???????)

• ????
• Convoy effect(????)
• gt??SJF??

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2. ????????? (SJF)

• ????????????!!

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3.??????(Priority Scheduling)

• priority????????????!!

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4. ?????????

• ???????,???????????,????????????
• ??
• 1. ???????queue?????????????,??????queue??????
• 2.????????,????????,???????,?????????????queue???
  ?
• ??
• 1. ??SJF???,?????????,??????????????
• 2. ?????queue??????????????.???,???????

Ex.
????? 8 ms????????
????? 16 ms????????
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Deadlock(??)

• ????,???? gt ???????
• ?CPU? gt ??????????????????
• ?????????
• 1. ????????????????????
• 2. ????????,????????
• 3. ??????????
• 4.???? ?????? P0, P1, , Pn, P0
  ????????,???????????????????

??B
??A
A
B
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???????

• 1. ?????
• ??????????????
• 2. ?????
• ???????,?????
• 3. ?????
• ?????????,???

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????? ???????

• Deadlock prevention
• ??
• ??????,??????????????????????
• Deadlock avoidance
• ??
• 1. ????????????,???????????????,???????????
• 2.???????? gt ?????????,???????????????????????,?
  ?????????,?????????????
• ?????????

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Spooling (Simultaneous Peripheral Operation
On-Line)

• Spooling ????????I/O??buffering(??)?????
• ??????????????,?????????
• 1. ???(?CPU?)
• 2. ????,???????????
• ??CPU????????????????????,?????????,??,CPU???????
  ,?????????,????,?????????????????,?CPU????????????
  ??????

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DMA (Direct Memory Access)

• ?I/O????????,??????CPU?????
• gt ?I/O?????????memory?,?????????,???????
• ?????device?CPU?memory??????

???
CPU
??
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??OS?? Windows 2000

• ??
• windows 2000????????
• 1. Professional 2. Server
• 3. Advanced Server 4. Datacenter Server
• ????98 ? NT4.0???,?????????
• ??
• ??
• ???(extensible)??????,????,???MS-DOS?POSIX?OS/2??
  ?
• ???(portable)?????hardware,???????
• ???(security)????,???,??????????????windows???
• ???? ?CPU ????? ???????? NTFS file system

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??OS?? Linux

• ??
• Linux ????Linus Torvalds ? 1991
  ?????????,?Linux????????,????????free
  software,??????,Linux?? ????????????,??????????,
  ?????????
• ?UNIX????,??Linux?RedHat?Slackware?Debian
  ??????????
• ??
• ????
• ?????UNIX??,????????????,???????
• ??????????????,????????????????(Ex. ????)

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Reference

• http//www.mis.kyit.edu.tw/learn/classnote/OS/
• http//www.ascc.net/course/BCC/slide3.html
• ltOperating Systems Conceptsgt Abrahan Silberschatz
  and James L. Peterson