操作系统完整课件(第二课 操作系统基本概念)L2-Intro-Concepts

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Computer Hardware Review
Structure of a disk drive
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1 Base-Limit & 2 Base Limit Pairs Base Limit Base-Limit
Address 0xFFFFFFFF User program and data Registers when program 1 is running Limit 2 Limit Base User program and d d data Base-2 Limit-1 Li it 1 Base 1 User-1 data User program Limit-1 Base-1 User-2 data Base 2 Base-2 Registers when program 2 is running Limit-2
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How the CPU is interrupted
Current instruction Next instruction 3. t 3 return 1. Interrupt 2. Dispatch to handler Interrupt handler
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Structure of a large Pentium system
Introduction: Main OS Concepts
Instructor: Hengming Zou, Ph.D.
In Pursuit of Absolute Simplicity 求于至简，归于永恒
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Content
Computer hardware review Main operating system concepts – Kernel and User Mode Programs – Processes – Memory – Files – System calls – Shell
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Kernel and User Mode Programs
Functionality Implemented in Kernel – CPU-, memory-, Input/Output managment – Multiprocessor management, diagnosis, test – Parts of file system and of the networking interface Functionality Implemented in User – Compiler, assembler, interpreter, linker/loader – File system management – Telecommunication – Network management – Editors, spreadsheets, user applications
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Processes
Processes, process table, core image Parent and child processes Mutual exclusion and synchronization Inter-process communication Scheduling, signals Deadlock and synchronization
Operating System 0
Operating System
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Computer Hardware Review
Disk drive 3 CPller 2
Disk controller
Steps in starting an I/O device and getting interrupt
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Sys Calls For Miscellaneous Tasks
Call S = chdir(dirname) S = chmod(name, mode) S = kill(pid signal) kill(pid, Seconds = time(&seconds) Description Change the working directory Change a file’s protection bits Send a signal to a process Get the elapsed time since Jan. 1, 1970
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Steps in Making a System Call
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Sys Calls For Process Mgmt
Call pid = fork() pid = waitpid(pid, &statloc, options) s = e ec e(name argv, environp execve(name, arg en ironp exit(status) Description p Create a child process Wait for a child to terminate Replace a process’s core image Terminate process & return status
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Sys Calls For File Mgmt
Call fd = open(file, how, …) s=close(fd) n=read(fd, buffer, nbytes) n=write(fd, buffer, nbytes) position=lseek(fd, offset, whence) s = stat(name &buf) stat(name, Description Open a file for reading or writing Close an open file Read data from a file into a buffer Write data from buffer into a file Move the file pointer Get a file’s status information file s
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Computer Hardware Review
A superscalar CPU
Execute unit Fetch unit Decode unit Holding buffer Fetch unit Decode unit Execute unit Execute unit
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Computer Hardware Review
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Computer Hardware Review
Components of a simple personal computer
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Computer Hardware Review
A five-stage pipeline
Fetch
Decode
Operand fetch
Execution
Write
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Sys Calls For Directory Mgmt
Call S = mkdir(name, mode) S = rmdir(name) S = link(name1 name2) link(name1, S = mount(special, name, flag) S = umount(special) Description Create a new directory Remove an empty directory Create a entry name2 pointing to name1 Mount a file system Unmount a file system
User Process Virtual address Translator ( (MMU) ) Physical address Physical y memory Dynamic Address Translation
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Files
Files, directories, root Path, working directory Protection, rwx bits File descriptor, handle Special files, I/O devices
mia pit tmp t etc t usr root
A sample file hierarchy
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File Mounting
Root floppy
A
B
X
YD
A
B
C
D (a)
C
D (b)
X
YD
Before mounting, – files on floppy are inaccessible After mounting floppy on b, – files on floppy are part of file hierarchy
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Some Win32 API calls
UNIX Fork F k Waitpid Execve Exit Open Close Read Write Lseek L k Stat Win32 CreateProcess C P WaitForSingleObject (none) ExitProcess CreateFile CloseHandle ReadFile WriteFile SetFilePointer S tFil P i t GetFileAttributesEx Description Create a new process C Can wait for a process to exit CreateProcess=fork+execve Terminate execution Create a file or open an existing file Close a file Read data from a file Write data to a file Move th fil pointer M the file i t Get various file attributes