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- 1What is operating System?An operating provides an enviroment within which a program can be excuted.
- 2List Operating system Services?1. UI
2. Program Execution
3. Program execution.
4. I/O Devices
5. File Manipulation
6. Communications
7. Error Detection - 3what is user interface?Almost all operating systems offer user interfaces. They can take several forms such as UI, CLI, GUI
- 4what is program excution.the system must be able to load a program into memory, anhd to run that program. Its also must be able to end it normally or abnormally.
- 5What is I/O operation?Some progras may require I/O. such as fies and I/O devices, For specific devices, special functions are desired, such as reading from a network file. for protection and safety, users cannot control i/O Directly, so the system must provide the means to do so.
- 6File system manipultaion?programs neet to read and wrie to files, they also need to create, delete and search by name. system also must provide permissions management to prevent and allow some users from accessing files based on file ownership.
- 7communications?there are many circumstances in which process may need to share information with each other. the process mnay communicate with process within the same system or with processes in other systems. communication within the same system between processes may take place by sharing a section of the memory and communcation outside the system, may take place by sending packets of messages in a predifenied format over the network.
- 8Error detection?the system must be able to catch error and fix correctly. errors may occur in cpu and memory. or user trying to access a restricted file. correction might involve halting the system and terminating a process.
- 9Resource allocation?the system must be able to allocate resource accorsingly between multiple pro0cesses running, such as memory alloocation, storage, ram , cpu.
- 10accounting?the system must keep track of users and track the resouces usage. might be used for billing and other puposes
- 11what is a system call?A system call provided an iterface to the services made available by the opearting system. when a computer program requests for services, the OS responds by making a series of system calls to the kernel to satisfy the request. it is writted in high level languages such as C, C++
- 12whats API's role in a system call?A system call is a method for computer programs to request services from the operating sytems kernel. it is a method of iteracting with the operating system via computer programs. The system program interface, connects the operating system functions to the operating systems. it acts a s a link between the operating system and processes, allowing user-level programs to request for services. programs can only access the Kernel, only through the API. such as Win32 for windows.
- 13what happens in a system call?the system program requests for a system service by making a system call for the corresponding system call function in its soruce code. The os associates an unque number for each system calls and mantains a system call table indexed by these numbers. The system call interface locates the system call number corresponding the requested function and passes it to the os kernel. the os kernel excutes the system call on behalf of the system program and returns the status of the system call with any return va;ues using the system call interface. the system program recieves the status of the system call along with any return values and continues wxecution based on the result.
the caller needs to know nothing about how a system call is implemented but just needs to obey the API and understand what will the OS do as a result call - 14types of system calls?1. -r9
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- May Operating systems Fichas sobre Sin título, creado por Murad Hussain el 28/04/2023.
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- Murad Hussain
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