CSCI3510 Principles of Operating Systems: System Calls

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What happens when a process running a user program in user mode needs a system service?

It executes a special procedure call within the user program.

It executes a trap instruction to transfer control to the operating system. (correct)

It bypasses the operating system and accesses the service directly.

It switches to kernel mode automatically.

What is the mechanism used by a process to request a system service?

Trap instruction (correct)

Kernel execution

Direct memory access

User-level function call

In the context of system calls, what role does the operating system play?

Transfers control to another user program upon request.

Executes the user program directly without any intervention.

Provides direct access to all system services from user programs.

Determines the requested service, carries out the request, and returns control to the calling process. (correct)

What is the purpose of a trap instruction in the context of system calls?

To transfer control from user mode to kernel mode. Signup and view all the answers

How do C programs invoke system calls for requesting services?

<code>By calling a library procedure with the same name as the system call</code>. Signup and view all the answers

What is the significance of return codes in system calls?

<code>Return codes indicate the success or failure of a system call operation</code>. Signup and view all the answers

What is the purpose of system calls in an operating system?

To allow user-level programs to interact with the operating system's kernel Signup and view all the answers

In the context of system calls, what is the role of the operating system's kernel?

To perform the requested service and return the result to the calling program Signup and view all the answers

Which of the following is a typical service provided by system calls in operating systems?

File I/O operations Signup and view all the answers

What role do system calls play in maintaining the security and stability of an operating system?

They provide a secure means for user-level programs to request services Signup and view all the answers

When a user-level program makes a system call, how does the operating system's kernel respond?

By performing the requested service and returning the result to the program Signup and view all the answers

Which programming language is commonly used to make system calls in user-level programs?

C Signup and view all the answers

What keeps track of the number of directory entries pointing to a file in UNIX?

i-node field Signup and view all the answers

In a monolithic system, what is responsible for invoking the requested service procedure?

Main program Signup and view all the answers

What type of hypervisor is a practical type 2 hypervisor?

Pure type 2 hypervisor Signup and view all the answers

Which OS structure involves separate user programs interacting with server programs over a network?

Client-server model Signup and view all the answers

What is removed from the disk if UNIX detects no entries to the file?

Entire file system Signup and view all the answers

What is the primary metric prefixes figure illustration in Tanenbaum's book referred to as?

Principal Metric Prefixes Signup and view all the answers