Topics Paging Virtual Memory File Systems I/O Devices Operating - - PDF document

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Operating Systems

Final Exam Review

Topics

• Paging
• Virtual Memory
• File Systems
• I/O Devices
• Project 3: Macro Shell

Fill in the Page Table

Page 0 Page 1 Page 2 Page 3 1 2 3 Page Table Logical Memory Page 1 Page 3 Physical Memory Page 0 Page 2 1 2 3 4 5 6 7

Fill in the Page Table: Answer

Page 0 Page 1 Page 2 Page 3 1 4 3 7 1 2 3 Page Table Logical Memory Page 1 Page 3 Physical Memory Page 0 Page 2 1 2 3 4 5 6 7

Draw Arrows

Page 0 Page 1 Page 2 Page 3 01 11 00 10 00 01 10 11 Page Table Logical Memory 000 001 010 011 100 101 110 111 Physical Memory 000 001 010 011 100 101 110 111 1 1 1 Page Offset Frame

Draw Arrows: Answer

Page 0 Page 1 Page 2 Page 3 01 11 00 10 00 01 10 11 Page Table Logical Memory 000 001 010 011 100 101 110 111 Physical Memory 000 001 010 011 100 101 110 111 1 1 1 Page Offset Frame

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Virtual Memory

• Page faults

– What is a page fault? – What happens during a page fault?

• Page replacement algorithms

– What is Belady’s anomaly? – How does the OPT algorithm work? – How does LRU work? – What are some LRU approximations?

Virtual Memory

• Thrashing

– What is thrashing? – What is a working set?

• Paging tradeoffs

– How does the page size affect performance?

File Systems

• Concepts

– What is the file system abstraction (user view)?

• Implementation

– Files

+ What is some of the info required to store a file? + What is an I-node? An linked-list w/index (FAT)?

– Directories

+ How are directories stored? + What information does a directory have?

File Systems

• Storing files (aliases)

– What is a soft-link? A hard-link? Difference?

• Disk management

– How do you keep track of free blocks? – What do you do with bad blocks? – What is a partition?

I/O Devices

• Hardware

– What is DMA? – What are some IO device types?

• Software

– What is an interrupt handler? – How does it work?

I/O Devices

• Disks

– What is the performance based on? – What is the “Elevator” algorithm?

• Clocks

– How does a clock work?

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Project 3: Macro Shell

• Sockets

– What is a socket?

• Connection setup

– How do you connect?

• Send and receive

– How do send and receive interact?

Project 3: Macro Shell

• Server

– What does the socket code look like? – What is a concurrent server? (Project 4) – What is a non-concurrent server? (Project 3) – What possible errors might the server see?

• Client

– What does the socket code look like? – What possible errors might the client see?