Midterm Terms

Question 1

Process Control Block

Answer 1

data package that contains register contetns, values of all variables, state of any I/O, pointers to all open files, any interruptes, the program in memory, the program counter

Question 2

Time quanta

Answer 2

The period of time a process is allowed to run uninterrupted

Question 3

Context Switching

Answer 3

The switching of the CPU from one process to another

Question 4

Turn Around Time

Answer 4

Completion time - arrival time

Question 5

Multilevel queue

Answer 5

A scheduling algorithm that gives preference to short jobs, I/O processes, and separates processe sinto categories based on the need of the processor

Question 6

Deadlock

Answer 6

A problem occuring when resources for Job A to occur are competing with Job B. B cannot start until A finishes.

Question 7

Preemptive multitasking

Answer 7

A multitasking method that shares processing time with all running programs.

Question 8

Process/Resource diagram

Answer 8

R1, P1, R2, P2, R3, P3

Question 9

Recovery Algorithm

Answer 9

Identify the victim process, the one with the lowest priority and pull the process out of the key so its resources are available

Question 10

Volume

Answer 10

A single accessible storage area with a single file system

Question 11

Volume descriptor

Answer 11

Describes the characteristics of the file system information present on a given CD-ROM or volume.

Question 12

Master File Directory

Answer 12

An essential data structure on any ITS file system, one level of directories instead of hierarchial.

Question 13

Block

Answer 13

A portion of allocated memory.

Question 14

Single User System

Answer 14

Only one program can be run at a time.

Question 15

Fixed Partitions

Answer 15

The OS has a job scheduler. It keeps track of incoming jobs and which partitions are free, and if there is enough space for a program to fit.

Question 16

Dynamic partitions

Answer 16

Good at assigning space for initialprograms, but suffer from external fragmentation over time

Question 17

Relocatable Dynamic Partitions

Answer 17

Dynamic partitions that the operating system can move around to free up space for a new process in the queue.

Question 18

Kernel

Answer 18

Responsible for resource allocation, low-level hardware interfaces, security.

Question 19

Compaction

Answer 19

Moves all the allocated blocks to one end of memory (defragmentation)

Question 20

Page

Answer 20

Small, fixed sized blocks of virtual memory.

Question 21

Page Frame

Answer 21

Just like a page but in physical memory, not logical memory

Question 22

Demand Paging

Answer 22

A page is not loaded until it is referenced by a process

Question 23

Program Counter

Answer 23

A processor register that indicates where a computer is in its program sequence

Question 24

Page Fault

Answer 24

Occurs when the kernel needs a page, finds it doesn’t exist in physical memory because it has been paged-out, and re-reads it in from disk

Question 25

Page Replacement Policy

Answer 25

The steps carried out by the operating system when a page fault occurs

Question 26

Segment

Answer 26

Are user defined logical modules in a program.

Question 27

Segmentation Fault

Answer 27

An error in which a running Unix program attempts to access memory not allocated to it and terminates with a segmentation violation error and usually a core dump.

Question 28

Pipe

Answer 28

A form of redirection to send the output of one program to another program for further processing

Question 29

Symbolic Link

Answer 29

A file that links to another file.

Question 30

External Fragmentation

Answer 30

When free memory is separated into small blocks and is interspersed by allocated memory

Question 31

Internal Fragmentation

Answer 31

A partition is split to hold more jobs

Question 32

Memory Map Table

Answer 32

Keeps track of which page frames are free.

Question 33

Process

Answer 33

An instance of a program in execution

Question 34

Process scheduling algorithms

Answer 34

FIFO, Shortest Job First, Priority, Round Robin, Multilevel queue

Question 35

Redirection

Answer 35

In Unix, to send output from a process to a different file or device.

Question 36

Round Robin

Answer 36

Process scheduling algorithm

Question 37

Virtual Memory

Answer 37

Using a disk as an extension of RAM

Question 38

CPU Bound Processes (in multilevel queues)

Answer 38

When the time for a task to complete is determined principally by the speed of the CPU

Question 39

I/O Bound Processes

Answer 39

When the time it takes to complete a computation is determined principally by the period spent waiting for I/O operations to be completed.