IGCSE ICT: 1 Types and components of a computer system

applets and apps

- Apps (short for Applications) - refers to the type of software that runs on mobile phones or tablets. - are usually downloaded from an 'Apps Store' and range from games to sophisticated software such as phone banking. Common examples include: • video and music streaming • GPS (global positioning systems which, together with satellite navigation, help you find your way to a chosen location) • camera facility (taking photos and storing/manipulating the images taken).

Hard Disk Drives and Solid Disk Drives

- HDDs are magnetic in nature and are one of the main methods for storing data, files (text, photos and music) and most of the system and application software. - More modern computers (and all tablets) use newer storage systems that make use of SSD technology and are replacing HDD in many cases. - Their function is the same as HDD.

RAM

- Random access memory - is an internal chip where data is temporarily stored when running applications. - memory can be written to and read from. - Since its contents are lost when power to the computer is turned off; is often referred to as a volatile or temporary memory. - stores the data, files or part of the operating system currently in use.

ROM

- Read Only Memory - is a memory used to store information that needs to be permanent. - is often used to contain, for example, configuration data for a computer system. - chips cannot be altered and can only be read from - One of the main advantages is that the information stored on the ROM chip is not lost even when power is turned off to the computer. - are often referred to as non-volatile memories.

photo-editing software

- allows a user to manipulate digital photographs stored on a computer: • change brightness, • change contrast, • alter colour saturation or • remove 'red eye'. - also allow for very complex manipulation of photos: • change the features of a face, • combine photos, • alter images to give interesting effects etc. - allow a photographer to remove unwanted items and generally 'touch up' a photo to make it as perfect as possible.

video-editing software

- allows a user to manipulate videos to produce an edited video. - enables the addition of titles, colour correction and altering/adding sound to the original video. It includes: • rearranging, adding and/or removing sections of video clips and/or audio clips • applying colour correction, filters and other video enhancements • creating transitions between clips in the video footage.

graphics manipulation software

- allows bitmap and vector images to be changed. - Bitmap images are made up of pixels that contain information about image brightness and colour. - Bitmap graphics editors can change the pixels to produce a different image. - Vector graphic editors operate in a different way and don't use pixels. - This type of software manipulates lines, curves and text to alter the stored image as required. - The type of editing software used depends on the format of the original image.

Video card

- allows the computer to send graphical information to a video display device such as a monitor, television or projector. - usually connects to the motherboard Usually made up of: • a processing unit • memory unit (usually RAM) • a cooling mechanism (often in the form of a heat sink since these cards generate much heat) • connections to a display unit (monitor, television or projector).

Sound card

- an integrated circuit board that provides a computer with the ability to produce sounds. - sounds can be heard by the user either through speakers or headphones. - allow a user to record sound input from a microphone connected to the computer, and to manipulate sounds stored on a disk. Use two basic methods to translate digital data into analogue signals (needed for speakers): • FM synthesis mimics: different musical instruments according to built-in formulas • Wavetable synthesis: relies on recordings of actual instruments to produce sound.

utilities programs

- are software that has been designed to carry out specific tasks on a computer. - are programs that help to manage, maintain and control computer resources. Examples include: • antivirus • anti-spyware • backup of files • disk repair • file management • security • screensavers • disk defragmenter

linkers / link editors

- is a computer program that takes one or more object files produced by a compiler and combines them into a single program that can be run on a computer. - e.g. many programming languages allow programmers to write modules separately. - This simplifies the programming task since it allows the program to be broken up into small, more manageable sub-tasks. - However, at some point, it will be necessary to put all the modules together to form the final program. - This is where the linker comes in

compilers

- is a computer program that translates a program written in a high-level language (HLL) into machine code (code that is understood by the computer) so that it can be directly used by a computer to perform a required task. - The original program is called the source code - The code after compilation is called the object code - Once a program is compiled, the machine code can be used again and again to perform the same task without recompilation. Examples of high-level languages: Java, Python, Visual Basic, Fortran, C++ and Algol.

Motherboard

- is a printed circuit board found in all computers. - allows the processor and other computer hardware to function and communicate with each other. - One of the major functions is to act as a kind of 'hub' that other computer devices connect to. - A typical motherboard consists of a sheet of non-conductive material, such as hard plastic. - Thin layers of copper or aluminium are printed onto this sheet. - These form the circuits between the various components. - it also contains several sockets and slots to connect the other components.

control and measuring software

- is designed to allow a computer or microprocessor to interface with sensors so that it is possible to: • measure physical quantities in the real world (such as temperatures) • control applications (such as a chemical process) by comparing sensor data with stored data and sending out signals to alter process parameters (for example, open a valve to add acid and change the pH).

operating systems

- is software running in the background of a computer system. - It manages many of the basic functions. - Without the OS, most computers would be very user-unfriendly and the majority of users would find it almost impossible to work with computers on a day-to-day basis. Operating systems allow: • input/output operations • users to communicate with the computer (for example, windows) • error handling to take place • the loading and running of programs to occur • managing of security (for example, user accounts, log on passwords).

device drivers

- is the name given to software that enables one or more hardware devices to communicate with the computer's operating system. - Without them, a hardware device (e.g., a printer) would be unable to work with the computer. Examples of drivers: printers, memory sticks, mouse, CD drivers, etc

word processing

- is used to manipulate text documents, such as an essay or a report. - Text is entered using a keyboard and the software provides tools for copying, deleting and various types of formatting. Some of the functions include: • creating, editing, saving and manipulating text • copy and paste functions • spell checkers and thesaurus • import photos/images into a structured page format • translation into other languages

spread sheet

- is used to organise and manipulate numerical data (in the form of integer, real, date, etc). - Numbers are organised on a grid of lettered columns and numbered rows. - The grid itself is made up of cells, and each cell is identified using a unique combination of columns and rows (for example, B6). Some of the functions include: • use of formulas to carry out calculations • ability to produce graphs • ability to do modelling and 'what if' calculations.

database management systems

- is used to organise, manipulate and analyse data. -A typical database is made up of one or more tables. - Tables consist of rows and columns. - Each row is called a 'record' - Each column is called a 'field'. - This provides the basic structure for the organisation of the data within the database. Some of the functions include: • ability to carry out queries on database data and produce a report (dbms) • add, delete and modify data in a table.

describe how robotics are having an impact on everyday life

1. has been around for many years, mostly in the manufacturing industry. They are used in car factories to weld car bodies, spray body panels and fit items such as windscreens. No human intervention is required. 2. The military have used drones in reconnaissance missions for a number of years 3. Civilian uses a) surveying the landscape in 3-D for use with GPS, investigating weather phenomena (i.e. flying into hurricanes or other weather conditions that would be dangerous for manned surveillance) b) search and rescue/fire fighting in natural disasters. > All of these are currently under evaluation and many more applications could evolve over the coming years. 4. Another application is the use of robots in surgical procedures. a) It allows surgeons to perform complex procedures with more precision, flexibility and control than standard surgical techniques. b) With this technique, surgeons use robotics equipped with a camera arm and several interactive mechanical arms - these have joints that work like a human's wrist.

describe how artificial intelligence biometrics are having an impact on everyday life

> AI biometrics overcomes this problem by using dynamic profiling - the system learns by using AI about a person's fingerprints on every scan a) This means a person doesn't have to worry about getting their finger in exactly the right place every time on the scanner. b) The system learns from the different alignments so it is still able to match the fingerprints to those stored on a database. > New systems use AI to learn from scanning a number of faces and can pick out these soft biometric features. a) This means the system can still recognise faces and cross-reference these attributes with corresponding images stored on the database.

Describe operating systems which contain a Graphical User Interface (GUI)

> For example, a whole CLI code would be replaced by a single icon - simply selecting this icon would automatically execute all of the steps in CLI. > they use various technologies and devices to provide the user interface. > One of the most common is WIMP, which was developed for use on personal computers (PCs)

describe how quantum cryptography are having an impact on everyday life

> There are many methods of cryptography in existence but all of them have a limited life as computers become faster and faster at number crunching. > A consequence of this is that, over the next few years, a hacker is increasingly likely to decipher encrypted messages unless computer designers can further strengthen security systems.

Describe operating systems which contain a Command Line Interface (CLI)

> are often a number of commands that need to be typed in, for example, to save or load a file. >This means the user has to learn a number of commands just to carry out basic operations. > Having to key in these commands every time an operation has to be carried out is also slow. > the advantage of CLI is that the user is in direct communication with the computer and is not restricted to a number of predetermined options.

describe how quantum cryptography works

> is based on the use of photons (light) and their physical quantum properties to produce a virtually unbreakable cryptography system > This helps protect the security of data being transmitted over fibre-optic cables. > The technology relies on the fact that photons oscillate in various directions and produce a sequence of random bits (0s and 1s) across the optical network. > It is based on the laws of physics rather than mathematics (which is how current cryptography methods work).

Describe the characteristics of a personal/desktop computer and its uses, both as a standalone and networked computer

> refers to a general-purpose computer that is made up of a separate monitor, keyboard, mouse and processor unit.

What is the common problem that facial recognition systems face?

A human being is still able to recognise a face even if the person has grown facial hair, now wears glasses or has aged. However, Computerised facial-recognition systems are confused by such soft biometric changes.

Describe the advantages and disadvantages of operating systems which contain a GUI

Advantages • the user doesn't need to learn any commands • it is more user-friendly; icons are used to represent applications • a pointing device (such as a mouse) is used to click on an icon to launch the application - this is simpler than typing in commands Disadvantages • uses up considerably more computer memory than a CLI interface • the user is limited to the icons provided on the screen • needs an operating system, such as Windows, to operate, which uses up considerable memory

Describe the advantages and disadvantages of operating systems which contain a CLI

Advantages • the user is in direct communication with the computer • the user is not restricted to a number of predetermined options • it is possible to alter computer configuration settings Disadvantages • the user needs to learn a number of commands to carry out basic operations • all commands need to be typed in, which takes time and can be error prone • each command must be typed in using the correct format, spelling, and so on • more difficult to edit once commands entered

Describe the advantages and disadvantages of a laptop computer (vs. desktop computers)

Advantages ● portability; they can be taken anywhere since the monitor, pointing device, keyboard, processor and backing store units are all together in one single unit ● because everything is in one single unit, there are no trailing wires, etc. ● they can take full advantage of Wi-Fi ● can link into any multimedia system. Disadvantages ● since they are easily portable, they are also easier to steal ● they have limited battery life, so the user may need to carry a heavy adaptor ● the keyboards and pointing devices can sometimes be awkward to use.

Describe the advantages and disadvantages of a personal/desktop computer (vs. a laptop)

Advantages ● spare parts and connections tend to be standardised, which usually results in lower costs ● the desktop tends to have a better specification (for example, a faster processor) for a given price (often due to size and construction constraints in laptops) ● power consumption is not critical since they usually plug straight into a wall socket and the larger casings allow a better dissipation of any heat build-up ● because they are usually fixed in one location, there is less likelihood of them being damaged Disadvantages ● not portable ● they tend to be more complicated since all the components (for example, keyboard, mouse) need to be carried round with you clutters up the desk space.

Describe advantages and disadvantages of a tablet computer (vs. laptops)

Advantages ● very fast to switch on (no time delay waiting for the 'windows' system to load up) ● fully portable - they are so lightweight that they can be carried anywhere ● touch-screen technology means they are simple to use and don't need any other input devices ● can use several Apps as standard (such as built-in camera, MP3/4 players and so on) ● don't generate any heat - they use solid state technology ● battery life of a tablet is a lot longer ● when the power button is pressed it goes into standby but remains connected to the internet, so the user still hears alerts when emails or other 'events' are received. Disadvantages ● they often have limited memory or storage ● they can be expensive to run if the internet is being accessed frequently via 3G/4G/5G mobile phone networks ● typing on a touch screen can be slow and error prone compared to a standard keyboard ● transferring of files often has to be done through an 'Apps store'; the lack of a 'drag and drop' facility can prove irritating for users ● laptops tend to support more types of file format than tablets, and are also better equipped to run different types of software.

Define secondary/backing storage

Backing storage also known as secondary storage is the name for all external hard drives, portable flash drives, CDs, and DVDs that can be attached to a computer. Because secondary storage technology is not always connected to the computer, it is commonly used for backing up data. Backing storage is usually non-volatile, so it is generally used to store data for a long time.

Define input devices

Devices which allow a user to input data into a computer, tablet or phone e.g. keyboard, scanner, mouse, touch screen

Define output devices

Devices which send or display data from a computer, tablet or phone e.g. printer, speakers, screen

describe how 3D and holographic imaging are having an impact on everyday life

Holograms have the following applications: ● engineering design (CAD) ● architecture (ability to rotate design through 360 degrees) ● simulations ● medical imaging (see inside organs in 3-D - links into tomography, which is the same technology behind 3-D printers) ● cinema (special effects) ● gaming (special effects) ● advertising ● holographic televisions (expected by around 2025, these should give a full 3-D experience without the need for special glasses) ● holographic computer memories (a new type of optical storage - a crystal the size of a sugar cube can hold up to 1 TB of data) ● optical computers (these will operate at speeds that are trillions of times faster than current technology computers).

Describe the differences between input and output devices

Input devices allow a user to input data into a computer, tablet or phone whereas output devices send or display data from a computer, tablet or phone

Describe a microprocessor including its role

It is a single integrated circuit which is at the heart of most PCs and is also found in many household devices and equipment where some control or monitoring is needed (for example, the engine management system in a car).

Describe the features of a microprocessor/CPU

It is made up of: • a Control Unit, which controls the input and output devices • an arithmetic and logic unit (ALU), which carries out calculations and makes logical decisions • and the immediate access store (RAM).

What is another name for the CPU ?

Known as the microprocessor.

Systems software

Programs that allow the hardware to run properly and allow the user to communicate with the computer e.g. operating systems

Application software

Programs that allow the user to do specific tasks e.g. spreadsheets

Describe the role of the CPU

The CPU Central processing unit is the part of the computer that interprets and executes the commands from the computer hardware and software.

describe how virtual reality are having an impact on everyday life

The technology is used in 1. training ● in a nuclear reactor where the user can see all the walls, pipes, vessels and valves as if they were inside the reactor, so that they can be trained safely to deal with certain events 2. education ● to explore the inside of a building such as a castle or an ancient building in a history lesson 3. military applications ● training to use a new tank 4. healthcare ● as a diagnostic tool 5. entertainment ● games where gloves, goggles or helmets are worn to give realism to the scenario and even to give images or sound to make it seem very real 6. fashion ● to do fashion shows before doing the real thing to see the clothes on people, check out the venue and so on 7. heritage ● showing monuments such as Stonehenge 8. business ● training courses and role-playing scenarios for staff 9. real estate ● allowing people to 'look around' houses that are for sale 10. engineering ● seeing how new designs will look 11. sport ● a golfer trying to improve their swing can use this technology and get feedback to improve their game 12. media ● special effects in films such as The Matrix 13. scientific visualization ● looking at molecular structures in chemistry

WIMP

Windows; Icons; Menu; Pointing device

Hardware

a general term for the physical components that make up a computer system: the keyboard, mouse, monitor, printer and so on. Hardware can be either external or internal.

Software

a general term for the programs that control the computer system and the processing of electronic data

Who would use a CLI interface?

a programmer, analyst or technician; basically somebody who needs to have direct communication with a computer to develop new software, locate errors and remove them, initiate memory dumps (contents of the computer memory at some moment in time), and so on.

What else does a ROM chip contain?

also contains some coding known as the boot file which tells the computer what to do when it first starts up - called BIOS (basic input/output system). > The BIOS stores the date, time and system configuration in a non-volatile chip called a CMOS (complementary metal oxide semiconductor) (usually battery powered).

Define Graphical User Interface (GUI)

an operating system that allows the user to interact with a computer (or MP3 player, gaming device, mobile phone etc.) using pictures or icons (symbols) rather than having to type in a number of commands WIMP

Define Command Line Interface (CLI)

an operating system that requires a user to type in instructions to choose options from menus, open software and so on.

What are the 2 types of software?

application and system software

3D and holographic imaging

is a technology that allows 3-D images (known as holograms) to be produced. ● a source of laser light ● interference of light ● light diffraction, and ● light intensity recording.

Virtual reality

is an artificial environment created by software. The user makes use of data goggles, sensor suits, data gloves or helmets to get a feeling of reality (that is, the feeling of 'being there').

Cryptography

is the science of making a message unintelligible to any unauthorised user (a hacker). This technique is often referred to as encryption.

What is the common problems that biometric systems face?

many fingerprint identification systems falsely reject a person's fingerprints - when the scanned fingerprints are checked against the database no matches are found

Who would use a GUI interface?

the end-user who doesn't have (or doesn't need) any great knowledge of how the computer works; a person who uses the computer to run software or play games or store/manipulate photographs, for example.

Describe ROM (internal memory)

• is an internal chip where data is temporarily stored when running applications • this memory can be written to and read from. • volatile or temporary memory because its contents are lost when power to the computer is turned off

Describe RAM (internal memory)

• is non-volatile memory used to store information that needs to be permanent (info not lost when power off) • chips cannot be altered and can only be read from

Identify at least 3 types of systems software

● compilers ● linkers ● device drivers ● operating systems ● utilities

Identify at least 3 general tasks for a typical operating system

● control the operation of the input, output and backing storage devices ● supervise loading, running and storage of applications programs ● deal with errors that occur in application programs ● maintain security of the whole computer system ● maintain a computer log (which details computer usage) ● allow communication between the user and the computer system (user interface).

Identify at least 3 external hardware devices

● monitors ● keyboards ● mice ● keyboards ● printers as input and output devices ● external storage devices in general

Identify at least 3 internal hardware devices

● the motherboard ● random access memory (RAM) ● read-only memory (ROM) ● video card ● sound card ● internal storage devices: hard disk drive (HDD) and solid state drive (SSD).

Identify at least 3 types of applications software

● word processing ● spreadsheet ● database management systems ● control software ● measuring software ● applets and apps ● photo-editing software ● video-editing software ● graphics manipulation software