Theory Flashcards
1
Q
Define the term operating system. [1]
A
A set of programs through which a computer manages/controls its own resources
2
Q
Outline the function of the ALU. [1]
A
Part of a processor that performs arithmetic and logical operations
3
Q
Outline the relationship between binary and hexadecimal. [2]
A
Binary is base 2, whereas hexadecimal is base 16;
Each hexadecimal digit can be represented by a group of 4 binary digits;
4
Q
Describe the characteristics of a stack. [2]
A
Data structure;
Which can only be accessed at one end/LIFO (last in first out);
5
Q
Identify two applications of a stack in computing. [2]
A
Translations of one programming language to another;
Used in calculations;
6
Q
State three advantages of using sub-programs while solving programming problems. [3]
A
A large program can be broken into smaller pieces;
A sub-program could be written independently;
Easier maintenance;
7
Q
What does the MOD function do?
A
Basically just finds the remainder.
8
Q
Static vs Dynamic [2]
A
Fixed size for static, and only has one data type;
Dynamic structure can change in size, and the data type isn’t fixed;
9
Q
How does post-order traverse?
A
Put the apple on the right of the node;
10
Q
What are stacks, linked lists and queues? (static or dynamic?)
A
Dynamic;
11
Q
Why is dynamic structure good?
A
Make memory allocation more efficient, by only using as much as is necessary, while also allowing the programmer to design more flexible algorithms, where the size of a data structure is not known before runtime.
12
Q
What is the role of the MDR? [2]
A
Holds the content of the memory;
Which is to be transferred from the memory to the other CPU components;
13
Q
What is the importance of Memory Management function? [3]
A
Allocates and deallocates memory;
Allowing more programs to run concurrently;
Provides memory protection;
14
Q
Define recursion [1]
A
A function/algorithm that calls itself;
15
Q
Describe the characteristics of a queue [2]
A
FIFO;
Items can only be added to one end and removed from the other end;
16
Q
Explain the benefits of Binary Search Trees (BST’s) compared to a stack when finding specific item;
A
The data in a binary search tree is ordered;
Each element in a stack has to be checked;
Which for large data sets will be ineffeicient;
17
Q
Explain the purpose of cache memory [3]
A
Cache memory is a small-sized type of volatile computer memory;
that provides high-speed data access to a processor;
and stores frequently used computer programs, applications and data;
18
Q
Applications of stacks [2]
A
Evaluating arithmetic expressions;
Parsing;
19
Q
Outline the function of an OS in managing primary memory [2]
A
The operating system (OS) makes sure that each running program always has enough memory for its data;
The OS assigns memory to programs by freeing up space in the computer’s memory;
20
Q
Outline the need for a translation process from high level language to machine code [2]
A
So that the computer can excecute the program;
As the computer only understands machine code;
21
Q
What is an xor gate? (own understanding)
A
An XOR gate is the same as an or gate, just with the exception that 1 and 1 is 0, not 1.
22
Q
Identify 3 operating management techniques.
A
Multitasking;
Virtual memory;
Interrupt;
Paging;
23
Q
Application of queues;
A
Playlist queue;
Super market queue;
Print queue;
24
Q
What is a child node?
A
A child node is a node that has up to two links to other nodes and has only one parent node.
25
What are the steps of traversing using post order tree traversal?
Start from the root node;
If the root is null, return immediately;
Traverse left subtree;
Traverse right subtree;
Visit root;
26
What are the steps of traversing using in order tree traversal?
Start from the root node;
If the root is null, return immediately;
Traverse the left subtree;
Visit the root node;
Traverse the right subtree;
27
What are the steps of traversing using pre-order tree traversal?
Start from the root node;
If the root is null, return immediately;
Visit the root node;
Traverse the left subtree;
Traverse the right subtree;
28
What are the differences between primary storage and secondary storage?
Primary Storage is volatile, cache memory or some other specialized hardware to store data as the computer is on;
Primary storage stores data that is currently in use;
29
What is the difference between bubble and selection sort algorithms?
Bubble sort swaps adjacent items;
Selection sort finds the next smallest (each time it checks);
30
What is the difference between non-binary and binary trees?
A node on a non-binary tree can have as many subtrees as it wants, however, a node on a binary tree can only have 2.
31
Describe the steps needed to calculate the sum of all numbers held in a circular linked list.
Initialize a variable sum 0;
Loop from beginning to the end, until all nodes get traversed;
Add current number to the total sum;
End when the end node is pointing to the header;
32
Compare the use of arrays and linked lists.
Arrays are fixed in size, while linked lists can expand and contract their size;
Elements are stored consecutively in arrays, whereas in linked lists it is stored randomly;
33
Outline the role of the data bus.
Data bus transfers data from from-to CPU to be processed ;
Address bus carries address of memory storage to be written;
34
What is the purpose of cache memory?
Is used to save time in accessing RAM;
35
Compare the uses of static and dynamic data structures [3]
Static data structures have a predetermined number of elements, whereas in dynamic structure the does not have to be defined in advance;
Static data structures has limited size, the amount of memory available is the only limit in dynamic structures;
In static data structure, elements can be directly accessed. Whereas in a dynamic data structure elements have to be accessed sequentially which takes longer;
36
Define the term bit [1]
Bit is a binary digit, and the smallest unit of data. Can be 0 or 1.
37
Outline the role of an address and data bus [2]
Data bus is a physical connection to transport data from-to CPU to be processed;
Address bus is a physical connection to transport an address of memory storage where data (transported in the data bus) should be read/written;
38
Describe how a system uses paging [3]
memory management method that uses secondary memory to increase the amount of
primary memory;
transfers data blocks of the same size (“pages”);
from secondary storage to main storage when they are required;
and returns them to secondary storage when they are not;
39
State the part of the CPU that performs the decoding [1]
The CU;
40
Outline the function of the MAR [2]
Stores the address of the next instruction to be fetched;
To be written/read to RAM;
41
Describe the steps involved in using the bubble sort algorithm as a way to sort an array [4]
Loops through array;
Comparing each pair of adjacent item;
Swaps if required (if in wrong order);
Ends until there is no more swapping required;
42
Describe one difference between queues and stacks [2]
Queue is a first-in-first-out (FIFO) data structure;
and stack is last-in-first-out (LIFO) data structure;
43
Why is hexadecimal used in computing? [1]
Hexadecimal numbers are used for shorter representation of data because a
(modern) byte can be represented exactly by two hexadecimal digits;
Hexadecimal numbers are used for shorter representation of data, because
computers store and handle binary digits, and four binary digits make one
hexadecimal digit;
44
Outline what is virtual memory [1]
Virtual memory is a memory management capability of an OS;
that (uses hardware and software to) allow a computer to compensate for physical memory shortages by temporarily transferring data from random access memory (RAM) to disk storage;
45
What are the collection functions?
addItem( data ) = add data item to the collection
.resetNext() = start at the beginning
.hasNext() → tells whether there is another item in the list
.getNext() → retrieves a data item from the collection
.isEmpty() → check whether collection is empty
46
Identify three characteristics of a collection [3]
Collection is a container of discrete values;
Collections have a set of methods that define operations performed on an element;
Which reduces programming effort;
47
Difference between LAN (Local Area Network) and WAN (Wide Area Network) [2]
WAN covers a much larger area (national or international)/ LAN covers a smaller area (such as a site or building);
LAN is more secure since WAN has a larger distance to cover, thus increasing the risk of something happening to the data;
48
State three operating system management techniques. [3]
Virtual memory;
Scheduling;
Piling;
Paging;
49
Outline the steps needed for a binary search [4]
Find/calculate the midpoint/median value between HI and LOW;
If the array value at midpoint equals the search value; then the search value
is found;
lf search value is greater than the array value at midpoint, set the midpoint as a new LOW
and repeat the process - if search value is less than the array value at midpoint, set midpoint
as anew HI;
Repeat until search value is found;
50
Define an embedded system [2]
An embedded system is a system which performs a specific function;
For a larger system for which it is part of;
51
What are characteristics of PAN (Personal Area Network)?
Smallest type of network;
Connected via Bluetooth/wireless;
eg. smartphone to car connection
51
Outline one example of where circular linked list would be used in preference to a linear linked list [2]
A music playlist, that repeats or is on "loop";
The last node points towards the first song.
52
Outline the role of the memory data register in the machine excecute cycle. [2]
Holds a copy of the data from the memory;
To be transferred to other components of the CPU;
53
Benefits of WLAN (in terms of LAN)
Reduces wiring - more safety
Less set up required - less cost
Allows BYOD
54
How does VPN help with security?
Data that passes through a VPN can be encrypted - so any unauthorized access won't understand the data.
Multiple exit nodes - Making it difficult to see where the data started from.
55
Outline the function of a web browser. [2]
Web browser allows users to access information on the WWW;
The web browser fetches the content required from a web server and acts as an interface between the client and the server.
56
Outline applications of queues in computing [2].
Print queue (serving requests on a shared printer);
Handling of interrupts;
CPU task handling;
Buffer for devices like keyboard;
57
Outline one reason for using Unicode to represent data in a computer system. [2]
Because Unicode is a standard for data representation for all languages and characters;
So data can be used through many different systems.
58
Define the term interrupt. [1]
(Hardware) Interrupt is a signal created by some action taken by a hardware device and sent to the CPU to stop its current activity;
59
What is a collection? [2]
A collection is a grouping of a variable number of data items into a single unit;
That needs to be operated upon together;
60
Distinguish between RAM and ROM [2]
RAM is a volatile memory, while ROM is a non-volatile memory;
Data stored in the RAM can be altered whilst the data stored in the ROM can only be read;
61
Outline one advantage of the use of virtual memory [1]
Use of virtual memory allows better CPU and RAM utilization;
Virtual memory can be free;
It uses the potion of a hard drive that the users already have;
62
State two technologies that are required to provide a Virtual Private Network (VPN) [2]
(VPN aware) router (and firewall);
VPN client software;
(VPN) tunnelling (server);
Encryption (Protocol);
63
Identify two factors that may affect the speed of data transmission [2]
Physical distance/Number of devices to be crossed;
Number of network users;
Quality of network equipment;
64
Explain why data compression would be used when data is transmitted [3]
Because compression reduces the size of a file;
Which reduces transmission time;
And can result in significant cost savings;
65
Describe the role of a firewall [2]
A firewall monitors incoming and outgoing traffic;
And filters/blocks traffic coming from unsecured or blacklisted apps;
66
Outline how encryption is used to protect data [2]
Encryption scrambles readable text;
So it is only read by the person who has the decryption key;
67
What is the role of a feedback in a control system? [2]
The output value is continuously compared to the desired value to produce an error value;
The error value is fed to the input;
68
Describe one function of an operating system [2]
Processor management;
The OS decides how much processing time each process has;
69
What is a dedicated operating system?
(not ms answer, but for concept): A dedicated operating system, in the context of computing, refers to an operating system designed and optimized for a specific purpose or type of device. Unlike general-purpose operating systems like Windows, Linux, or macOS, which are designed to run a wide variety of applications on various hardware configurations, a dedicated operating system is tailored to meet the specific requirements of a particular application or device.
70
Characteristics of centralised control system
- Easier to use - it allows control at a central point;
- Controlled by a single processor;
- Centralized systems is easy to physically secure;
- In case of a local failiure, the whole system stops working;
- more cost-efficient for small systems;
71
Characteristics of distributed control system
Controlled by a collection of independent processors;
Easier to modify/upgrade without disturbing other processes;
In case of failure, all other processes continue to work;
Difficult to know which node failed;
72
Outline two disadvantages of recursive methods.
Recursion can be slow;
If too many recursive calls occur;
73
Outline the need for a translation process from a higher level language to a lower level language [2]
A human-readable form of the program should be translated into machine language code;
Which is the only language computer hardware can understand;
74
Define the term variable [1]
Variables define areas in memory in which values (data) are stored;
75
Explain how increasing the size of the CPU cache improves performance of computer [3]
Commonly used instructions from a program are stored in cache memory to be accessed by the processor (faster access than from RAM)
Increasing the size of the cache memory means that more instructions can be quickly found by the processor;
Thus, program execution is faster.
76
Identify one hardware component in a wireless LAN [1]
(Wireless) Router;
Across points;
(Wireless) Controller;
76
Distinguish between a wired network and a wireless network in terms of reliability of transmission
The reliability of wireless depends on the strength of the wireless signal;
Depends on distance from router,
depends on the topology/shape of the surroundings:
a wireless LAN has slower data transfer;
whilst
Ethernet is more reliable as the strength of the signal does not depend on the
distance from the router/ wired LAN support longer distances;
wired is immune to interference;
there is no issue with the topology/shape of the surrounding;
but the Ethernet cable may be cut/broken, affecting reliability;
76
Explain how data is transmitted by packet switching [4]
Data is organized in specifically formatted units;
All packets contain; data, address of sender, address of the receiver size of the packet, sequence number, control codes, etc.;
Which are routed from source to destination using network switches and routers;
data packets are reassembled at the destination;
77
How does bubble sort algorithms work?
Looping through the array;
Comparing each pair adjacent elements in the array;
Swapping if the one after is less than the before;
Repeating till no swaps left;
77
Identify the components of a node in a binary tree [3]
Two data fields;
Pointer to the left child;
Pointer to the right child;
77
State one technology which is necessary for a VPN [1]
TLS;
SSL 3.0;
IPsec with encryption;
78
What does concurrently mean? (concept)
"concurrently" means doing multiple things at the same time. It's like juggling or multitasking, where different tasks are happening together, not one after the other. So, if you are working on homework while your friend is playing a game, you are both doing things concurrently. It's a way of saying "simultaneously" or "at the same time."
79
What are the purpose of protocols? [2]
Protocols are sets of rules for transmitting data correctly;
To ensure that data is sent from a customer's and received by the receiving computer;
To create a secure transmission of data from the client to the server through the use of the HTTPS;
80
Identify two reasons why consistent grammar and syntax should be essential features of higher level programming language. [2]
Easy to use;
There will be no compilation errors;
There will be no logical errors;
Future development is possible by other programmers;
81
State one method of providing user documentation [1]
Help files;
Online support;
82
Identify two features of a user interface that till allow application programmers to interact more easily with the programming language [2]
GUI;
Toolbars;
Menus;
Predicted text so that typing a class name followed by a full stop will bring up a list of methods;
83
Outline the need for an interpreter or a compiler [2]
Must be translated from a higher level language understandable by humans;
Must be translated into machine code;
For the CPU to execute it;
84
Outline the need for predefined sub-programs and collections [2]
Reusability;
Modularity;
Reliability;
85
Define the term analogue data [2]
Data represented by a continuous variable;
86
Control process (greenhouse example) [5]
Sensor: Converts an inputted physical quantity (temperature, light) into an electrical signal;
Processor: Executes a set of instructions which control the whole process
Transducer: Converts electrical signals into other forms of energy;
Feedback: Input signals is monitored;
And fed back to the processor where they can be used to make decisions whether to change/modify the climate in the greenhouses or not;
87
How to determine the number of names in a circular linked list? [4]
Use a variable (counter) to keep track of nodes;
Use a temporary pointer;
Follow the pointers from the beginning of the list;
Until the pointer to the end of the list is encountered;
88
What is slower accessing? Static or dynamic structures? [1]
In static data structure elements, they can be directly accessed;
In dynamic data structure, access is sequential;
89
Describe one way off-site storage can be used to prevent data loss [2]
Internet backup service could automatically back up (all important) data files;
To a remote server that could be accessed/controlled over the internet;
Copies of all important data files (backup) could be placed on two separate hardware devices;
Which are placed in two different physical locations;
A remote file server could be set up;
For uploading all important data files;
90
Explain the purpose of cache memory [3]
Cache memory is a small-sized type of volatile computer memory;
That provides high speed data access to a processor;
And stores frequently used computer programs, applications and data;
91
Why are hexadecimals used frequently in computing? [2]
Hexadecimal numbers are used for shorter representation of data because a byte can be represented exactly by two hexadecimal digits;
Hexadecimal numbers are used for shorter representation of data, because computers store and handle binary digits, and four binary digits make one hexadecimal digit;
92
Explain why abstraction is required in the design of algorithms? [3]
Abstraction allows us to create a general idea of what the problem is and how to solve it;
Through the process of abstraction, a programmer hides all but the relevant data about an object in order to reduce complexity and increase efficiency;
In OOP, abstraction is one of the three central principles (along with encapsulation and inheritance)
93
Outline what is meant by virtual memory? [2]
Virtual memory is a memory management capability of an OS;
That uses hardware and software to allow a computer to compensate for physical memory shortages by temporarily transferring data from the RAM to disk storage;
94
Outline two advantages of a school using a computer network [4]
Communication;
Students/teachers can communicate with people around the world via the internet;
Improved network security;
If the school has its own network, it can monitor network traffic;
95
What is a router? [2]
Router acts a processing unit for information packets;
It duplicates information packets for use during transmission from one network to another;
96
What is NIC (network interface card) [2]
Interface cards determine the infrastructure of a local area network (LAN);
And allow all of the computers to connect to the network;
97
Evaluate the use of trusted media access control (MAC) addresses as one method of network security [4]
Each adapter has a unique label called a MAC address;
Routers uses these addresses to identify computers and can whitelist or black list based on the MAC address;
The disadvantage is that the whitelist should be amended any time a new device is purchased;
The method is useless against hackers who intercept data passing through the network;
98
Explain the role of the operating system in terms of managing the hardware resources [4]
OS controls all the activities of the computer system and acts as an interface between user and hardware;
Thus, the role of OS is
To keep track of who is using which resource;
To grant resource requests;
To allocate time to different programs;
To allocate space for different users, each gets a part of the resource;
99
Explain the steps of the sensors, microprocessors and output transducers (random question, however useful info and structure) [6]
Sensors detect measure (whatever it is);
Sensors continuously take readings and send these readings to the processor;
The processor determines what actions the machine should take next;
Processor controls sensors, valves, and actuators responsible for (whatever it is);
Output transducers are used for turning on and off devices that control the rest of the machine;
such as (whatever it is)
100
State two differences between primary storage and secondary storage [2]
Primary storage holds currently running programs, secondary storage does not;
Primary storage is accessed by a computer's central processing unit (CPU) and secondary storage is not accessed directly by the CPU;
Primary storage has lower access time than secondary storage;
101
Outline what is meant by a sorting algorithm [2]
A sorting algorithm is a method for reorganizing a number of items;
Into a specific order;
102
Outline one difference between a bubble sort algorithm and a selection sort algorithm [2]
Bubble sort swaps adjacent items;
Selection sort finds the next smallest;
Bubble sort can exit easily if the list is sorted.
Selection sort will need to go through the procedure every time.
103
Outline how the last node of a circular list is identified [2]
The last node is identified by its next pointer;
Which is equal to the pointer "head";
104
Describe the steps required to calculate the sum of all the numbers held in a circular linked list;
Initialize (a temporary pointer with the head and) a variable sum with 0 (zero);
Loop from the beginning to the end of the circular linked list / until all the nodes get
traversed);
Add the value (of the data field) (of the current node) to the sum;
Change the temporary pointer so it points the next node of circular linked list;
105
What is the function of the ALU?
Part of the CPU that does all the arithmetic (+/-) and logical
(AND/OR) calculations
106
Functions of the control unit
It handles the loading of new commands into
the CPU and the decoding of these commands.
Also, it directs the data flow and the operation
of the ALU.
107
The three important buses
- Data bus (links RAM to CPU via MDR)
* Control bus (links RAM to CPU via CU)
* Memory bus (links RAM to CPU via MAR)
108
