Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

COMP30023 > Definitions > Flashcards

Definitions Flashcards

(94 cards)

Start Studying
1
Q

Foreground processes

A

Those that interact with and perform work for users

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Multiprogramming

A

The way the CPU rapidly switches between processes to give the illusion they are happening parallel to each other (pseudoparallelism)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Process

A

Instance of executing program

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Program

A

Collection of instructions that perform a task when executed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Time-sharing

A

Multiprogramming with simultaneous terminal access to the machine by several users

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Daemons

A

Processes that stay in the background to handle background activity (eg. Email)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Architecture

A

Set of rules and methods that describe functionality, organisation and implementation of computer systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Embedded Systems

A

Dedicated systems within a larger mechanical or electrical system. These may not have a kernel mode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Interpreted Systems

A

Systems that use interpretation, not hardware, to separate components (eg. Java-based operating systems)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

System Call

A

Programmatic way in which a computer program requests a service from the kernel of the operating system it is executed on

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Abstraction

A

Concealing complex ideas and systems with a simpler one that the user or programmer interacts with

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Multiplexing

A

Sharing of resources

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Program Counter

A

Memory address of next instruction to be fetched

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Stack Pointer

A

Points to top of current stack in memory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Register

A

A quickly accessible location available to a CPU

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

PSW

A

Program status word.
Contains condition code bits which are set by comparison instructions.
Plays important role in I/O.
User progs can generally read entire thing but can only write parts.
A bit in the PSW controls whether CPU is in user or kernel mode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pipeline CPU

A

Executing one instruction, while decoding the next instruction, while fetching the next instruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Superscalar CPU

A

Multiple execution units are present. Multiple instructions are fetched and decoded at once, then stored in a holding buffer until the relevant execution unit is free.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Redirection

A

When output from terminally is redirected from terminal to a file (func > file)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Batch Job

A

Totally automated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Multicore Processor

A

Has multiple CPUs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Process Group

A

A process and all of its descendants in UNIX form a process group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Handle (token)

A

A token given to a parent process in Windows, allowing it to control a child. Can be given to other processes to allow them to control each other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Multithreading

A

A single process having multiple threads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Lightweight Process
This another name for thread
26
Thread
(aka thread of execution or lightweight process) Sequential execution stream within process These are used by CPU.
27
Cache
Collection of heavily accessed pages in main memory for easy access
28
FSM
Finite state machine. Machine exists in a finite state that can altered by external events. Allows efficiency with a single thread.
29
Nonblocking System Call
Returns almost immediately. Lengthy calls will give output later in the form of an event, message or signal
30
Thread Table
Each thread has its own thread table, containing properties unique to the thread. When a thread is moved to ready or to blocked, the information required to restart the thread is stored here
31
Process Table
Data structure maintained by the OS to facilitate context switching and scheduling,
32
Context Switching
Switching of CPU from one thread or process to another
33
Process Control Block
One entry within a process table. Contains information required to restart program if moved to blocked or ready states. This includes program counter, stack pointer, memory allocation and status of open files, accounting and scheduling info
34
Interrupt Vector
Address of interrupt handler Area of memory with replacements for SP, PSW and PC. Essentially table of functions or function pointers to deal with interrupts. There's a function corresponding to each task we want to deal with
35
IVT
Interrupt vector table. Associates interrupt handlers (ISR/interrupt service routine) with interrupt requests in a table of interrupt vectors
36
Interrupt
Alerts processor of higher priority process that requires immediate CPU attention These have different priorities
37
Upcall
A call from a lower-level subsystem (kernel) to a higher-level subsystem (user)
38
Jacket
(aka wrapper) Code placed around a system call to determine if it will read or block, before the call is made (prevent blocking in user-level threads)
39
Page Fault
If program calls or jumps to an instruction that is not in main memory, a page fault occurs. OS will go get instruction from disk
40
Popup Thread
When a message arrives, the system creates a new thread to handle it. This thread is a popup thread.
41
IPC
Interprocess Communication. The communication between processes.
42
Reentrant
Reentrant procedures can be entered again before a return from the first call to the procedure has been returned from
43
Race Conditions
Situations with two or more processes reading or writing to the same shared data where final result depends on who runs at what time
44
Mutual Exclusion
Ensuring that if one process is using a shared data file, no other process can access it at that time
45
Critical Region
(aka critical section) Part of program where shared memory is accessed (shared being by multiple processes)
46
Busy Waiting
Continually testing a variable until some value appears (eg. this isn't needed in definition - this is for understanding while (True): while (var != value): loop )
47
Spin Lock
A lock that uses busy waiting
48
Priority Inversion Problem
In the case of achieving mutual exclusion, priority inversion problem is when a low priority process is in the critical region and a high priority process wants to enter. The preference should be given to the high priority task, but it must wait for low priority to finish.
49
Atomic Action
An action all completed at once. It cannot be interrupted. Either it all happens or it doesn't happen at all. In synchronisation, a test-and-set atomic instruction prevents accesses to the word/value between the read and write
50
Binary Semaphore
A semaphore initialised to 1 and used by 2 or more processes to ensure only one can enter critical region at given time
51
Mutex
Variable that can be in one of two states: locked or unlocked
52
Deadlock
Two processes that both end up and remain blocked forever
53
Monitor
Collection of procedures, variables and data structures that are grouped together. Only one process can be active in a monitor at any instant.
54
Condition Variable
Used for blocking in monitors. These variables wait for a condition to become true
55
Message Passing
Method of IPC that uses 2 primitives, send and receive (system calls)
56
Starvation
When processes continually do work but make no progress
57
Compute-Bound Processes
Those that spend most of their time computing (rather than waiting)
58
I/O-Bound Processes
Those that spend most of their time waiting for I/O (rather than computing)
59
Non Preemptive Scheduling Algorithm
Picks up process to run and lets it run until it blocks or voluntarily releases CPU
60
Preemptive Scheduling Algorithm
Allows process to run for a set amount of time. That is, clock interrupt occurs at end of given time interval and CPU control is given back to scheduler
61
Throughput
Number of jobs per hour that system completes
62
Turnaround Time
Statistically average time from the | moment that a batch job is submitted until the moment it is completed. How long user has to wait for output.
63
Degree of Multiprogramming
This occurs in a 3-level scheduling algorithm. It is how many processes are to be stored in memory.
64
Quantum
Designated time interval
65
Aging
Estimating the next value in a series by taking the weighted average of the current measured value and the previous estimate (a=1/2 is good)
66
Main memory
RAM
67
Memory manager
Part of OS that manages (part of) memory hierarchy
68
ROM
Read only memory
69
BIOS
Basic input output system
70
Memory Compaction
When swapping creates holes in memory, processes can be moved up or down to create consecutive holes that join together to form one big hole.
71
Overlay
Little pieces that a program has been split into
72
Virtual address space
Combination of virtual addresses
73
MMU
(memory management unit) Maps virtual memory pages onto physical memory page frames
74
Page frames
The units in physical memory that correspond to pages in virtual memory
75
Page table
Data structure used by virtual memory to store mapping between virtual and physical addresses
76
Volatile
Storage that only maintains its data while computer is powered
77
TLB
(translation lookaside buffers aka associative memory) Small hardware device for mapping virtual addresses to physical addresses
78
Principle of locality
Page replacement algorithms rely on the future following trends of the past. There are two types of locality: spatial and temporal
79
Spatial locality
If a location was recently referenced, locations NEAR it are likely to be referenced soon
80
Temporal locality
If a location was recently referenced, it is likely to be referenced again soon
81
inode
(information node) contains all information kernel has about a file except its name
82
ACL
(access control list or access matrix)
83
Access matrix
(aka ACL or access control list)
84
Link
Each reference to the same inode (file) from more than one directory entry is called a link
85
Symbolic link
(symlink) Special kind of file that contains filename
86
File descriptor
Small integer
87
Network
Interconnected or intersecting configuration or system of components
88
Internet
network of networks
89
Packet
chunk of data
90
Confidentiality
only sender and intended receiver should understand contents of message
91
Authentication
sender and receiver want to confirm identity of each other
92
Message integrity
the sender and receiver want to ensure that message is not altered without detection
93
Access and availability
services must be accessible and available to users
94
IPL
Interrupt priority level - how important interrupt is

COMP30023 (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions