OS Services

Question 1

IPC

Answer 1

Inter-Process-Communication: Communication between running processes. Anything from pipes, unix sockets and network sockets count as IPC.

Question 2

Kill system call

Answer 2

Send a certain process a signal with a certain code. Can be overwritten when written in c/c++ to do whatever you want.

Question 3

System call parameter passing (3 ways)

Answer 3

1. Using registers.
2. Save the parameter in memory and pass the location using a register.
3. Push onto the stack and have the OS pop from it.

Question 4

System programs

Answer 4

Programs provided by the OS to appeal more to human usage and not have the user use system calls for everything. Includes text editors, programming language support and more.

Question 5

6 Layers of OS

Answer 5

1: Hardware.
2: CPU Scheduling
3: Memory Management.
4: Process Management.
5: I/O Buffer.
6. User Programs.

Question 6

OS Modules

Answer 6

Each core component is separate and can be loaded when needed withing the kernel. The modules communicate through known interfaces.

Question 7

Virtual machine

Answer 7

An OS that thinks it has its own hardware but actually is running through a hypervisor that is emulating the hardware.

Question 8

Hypervisor (2 types)

Answer 8

1. Runs directly on the hardware itself and just manages and forwards the requests of the VMs it is hosting.
2. Runs ontop of another OS, doesn’t directly communicate with the hardware but does so through the OS it is sitting on.