Operating system 12 system programs
- 1. Operating System 12 System Programs Prof Neeraj Bhargava Vaibhav Khanna Department of Computer Science School of Engineering and Systems Sciences Maharshi Dayanand Saraswati University Ajmer
- 2. System Programs • A modern computer system has a collection of system programs. • System programs, also known as system utilities, provide a convenient environment for program development and execution. • Some of them are simply user interfaces to system calls; others are considerably more complex. • In the logical computer hierarchy, the lowest level is hardware. Next is the operating system, then the system programs, and finally the application programs.
- 3. System Programs • Provide a convenient environment for program development and execution – Some of them are simply user interfaces to system calls; others are considerably more complex • File management - Create, delete, copy, rename, print, dump, list, and generally manipulate files and directories • Status information – Some ask the system for info - date, time, amount of available memory, disk space, number of users – Others provide detailed performance, logging, and debugging information – Typically, these programs format and print the output to the terminal or other output devices – Some systems implement a registry - used to store and retrieve configuration information
- 4. System Programs (Cont.) • File modification – Text editors to create and modify files – Special commands to search contents of files or perform transformations of the text • Programming-language support - Compilers, assemblers, debuggers and interpreters sometimes provided • Program loading and execution- Absolute loaders, relocatable loaders, linkage editors, and overlay- loaders, debugging systems for higher-level and machine language • Communications - Provide the mechanism for creating virtual connections among processes, users, and computer systems – Allow users to send messages to one another’s screens, browse web pages, send electronic-mail messages, log in remotely, transfer files from one machine to another
- 5. System Programs (Cont.) • Background Services – Launch at boot time • Some for system startup, then terminate • Some from system boot to shutdown – Provide facilities like disk checking, process scheduling, error logging, printing – Run in user context not kernel context – Known as services, subsystems, daemons • Application programs – Don’t pertain to system – Run by users – Not typically considered part of OS – Launched by command line, mouse click, finger poke
- 6. System Program categories • System Programs can be divided into following categories: • File management • Status information • File modification • Programming-language support • Program loading and execution • Communications
- 7. File management. • These programs create, delete, copy, rename, print, dump, list, and generally manipulate files and directories.
- 8. Status information. • Some programs simply ask the system for the date, time, amount of available memory or disk space, number of users, or similar status information.
- 9. File modification. • Several text editors may be available to create and modify the content of files stored on disk or other storage devices. There may also be special commands to search contents of files or perform transformations of the text.
- 10. Programming-language support. • Compilers, assemblers, debuggers, and interpreters for common programming languages (such as C, C++, Java, Visual Basic, and PERL) are often provided to the user with the operating system.
- 11. Program loading and execution. • Once a program is assembled or compiled, it must be loaded into memory to be executed. The system may provide absolute loaders, relocatable loaders, linkage editors, and overlay loaders. Debugging systems for either higher-level languages or machine language are needed as well.
- 12. Communications. • These programs provide the mechanism for creating virtual connections among processes, users, and computer systems. • They allow users to send messages to one another's screens, to browse Web pages, to send electronic-mail messages, to log in remotely, or to transfer files from one machine to another.
- 13. System Utilities • In addition to systems programs, most operating systems are supplied with programs that are useful in solving common problems or performing common operations. • Such applications include browsers word processors, text editor spreadsheets, database systems, compilers, plotting and statistical analysis packages, and games
- 14. Assignment • Explain the concept of System Programs. Briefly describe the System Program categories.