Operating Systems (process, storage, memory & device management)

Question 1

system call (concept)

Answer 1

system calls offer an interface to access OS services

Question 2

Windows’ & Linuxs’ API

Answer 2

UNIX: POSIX; Win = Win32

Question 3

CPU burst (concept)

Answer 3

the time a process actually spends computing (using the CPU)

Question 4

process scheduling algorithms

Answer 4

FCFS (First Come First Served); Shortest-Job-First; Priority-Scheduling

Question 5

process (definition)

Answer 5

1) program & dynamically-allocated memory

2) stack, instruction pointer & registers

Question 6

multi-threading (concept)

Answer 6

in a multithreaded process on a single processor, the processor can switch execution resources between threads, resulting in concurrent execution.

Question 7

thread (definition)

Answer 7

‘context of execution’ –> stack/memory/registers a process needs to resume at (e.g. reading a book, put it down, specify a page, paragraph & letter)

Question 8

what are the main functions of an operating system?

Answer 8

 Resource sharing
 Task co-operation
 Scheduling
A layer of abstraction between hardware and software

Question 9

list sub-systems that form part of the operating system?

Answer 9

memory, process, device and storage management

Question 10

pre-emptive multi-tasking

Answer 10

time slots allocated to processes

Question 11

co-operative multi-tasking

Answer 11

process hands control over once finished

Question 12

a system has the following parameters:
    virtual address space = 1Tb
    page size = 4Mb
    physical memory = 4Gb
determine the number of page entries required.

Answer 12

1Tb = 40 bits required to address
4Mb = 22 bits required to address
Therefore, 40-22 = 18, therefore 2^18 page table entries required