●●● ●●●● 2.2 User Operating System Interface :::8 ●●●● GUI typically is removed from the system structure, its design is therefore not a direct function of the operating system Many systems now include both CLI and GUI interfaces o Microsoft Windows is GUl with CLI"command"y shelll Apple Mac os X as“Aqua” GUI interface with UNiX kernel underneath and shells available Solaris is cll with optional GuI interfaces( Java Desktop KDE
16 2.2 User Operating System Interface ⚫ GUI typically is removed from the system structure, its design is therefore not a direct function of the operating system ⚫ Many systems now include both CLI and GUI interfaces ⚫ Microsoft Windows is GUI with CLI “command” shell ⚫ Apple Mac OS X as “Aqua” GUI interface with UNIX kernel underneath and shells available ⚫ Solaris is CLI with optional GUI interfaces (Java Desktop, KDE)
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17 2.2 User Operating System Interface
●●● ●●●● 2. Operating-System Structures 9988 ●●●● o 2.1 Operating system Services 2.2 User Operating System Interface ●2.3 System Calls 2. 4 Types of System Calls ·24 System Programs 2.6 Operating System Design and Implementation 2.7 Operating System Structure ●28 Virtual machines 2.9 Operating System Generation 2.10 System Boot
18 2. Operating-System Structures ⚫ 2.1 Operating System Services ⚫ 2.2 User Operating System Interface ⚫ 2.3 System Calls ⚫ 2.4 Types of System Calls ⚫ 2.4 System Programs ⚫ 2.6 Operating System Design and Implementation ⚫ 2.7 Operating System Structure ⚫ 2.8 Virtual Machines ⚫ 2.9 Operating System Generation ⚫ 2.10 System Boot
●●● ●●●● 2.3 System Calls ●●●●● ●●●● ●●●●● ●●●● ● Definition Programming interface to the services provided by the os Typically written in a high-level language(C or C++) o Few low-level routines may need to be written in assembly-language instructions Example o read data from a file and copy them to another file Require a sequence of system call Get the names of files, open the input file and create the output file Error output and terminate program abnormally program to abort Replace the existing file, then read, write and close files
19 2.3 System Calls ⚫ Definition ⚫ Programming interface to the services provided by the OS ⚫ Typically written in a high-level language (C or C++) ⚫ Few low-level routines may need to be written in assembly-language instructions ⚫ Example ⚫ read data from a file and copy them to another file ⚫ Require a sequence of system call ▪ Get the names of files, Open the input file and create the output file ▪ Error output and terminate program abnormally ▪ program to abort ▪ Replace the existing file, then read , write and close files
●●● ●●●● 2. 3 System Calls ●●●●● ●●●● ●●●●● ●●● System call sequence to copy the data of one file to another file o source file destination file Example System Call Sequence Acquire input file name Write prompt to screen Accept input Acquire output file name rite prompt to screen Accept input Open the input file if file doesnt exist, abort Create output file if file exists, abort LOOl p Read from input file Write to output file Until read fails Close output file Write completion message to screen Terminate normally
20 2.3 System Calls System call sequence to copy the data of one file to another file