Computer Hardware, Software, and Emerging Technologies Detailed Notes
1.2.2 Internal memory
Random Access Memory (RAM):
Volatile, temporary memory where data is stored when running applications.
Data can be written to and read from RAM.
Contents are lost when power is turned off.
Read-Only Memory (ROM):
Non-volatile memory used to store permanent information, like configuration data.
Data can only be read from ROM, not altered.
Information is retained even when power is off.
Stores BIOS (Basic Input and Output System)
Boot File (BIOS):
ROM contains code known as the boot file or BIOS (basic input/output system).
This code instructs the computer on what to do when it starts up.
BIOS Function:
When the computer is turned on, BIOS performs a hardware check to ensure all devices are present and functional.
Then, it loads the operating system into RAM.
CMOS:
BIOS stores the date, time, and system configuration in a non-volatile chip called CMOS (complementary metal oxide semiconductor).
CMOS is usually battery-powered.
Table 1.2: RAM vs. ROM
RAM:
Temporary memory.
Volatile.
Data can be written to and read from.
Stores data, files, programs, and parts of the operating system in use.
Size can be increased to improve computer speed.
ROM:
Permanent memory.
Non-volatile.
Read-only; data cannot be altered.
Stores BIOS and data needed at startup.
1.2.1 CPU
Central Processing Unit (CPU):
Interprets and executes commands from computer hardware and software.
Located on the computer motherboard.
Microprocessor:
Modern CPUs are now microprocessors, single integrated circuits found in PCs and other devices (e.g., engine management systems in cars).
CPU Components:
Control Unit: Controls input and output devices.
Arithmetic and Logic Unit (ALU): Performs calculations and makes logical decisions.
Registers: Small memory locations.
Graphical user interface (GUI)
Graphical User Interface (GUI):
Allows users to interact with a computer (or device) using pictures or symbols (icons) instead of typing commands.
WIMP:
GUIs often use WIMP (windows icons menu and pointing device), developed for PCs.
A mouse controls a cursor, and icons are selected to open/run windows.
Window Manager:
A window manager handles the interaction between windows, applications, and the window system.
Post-WIMP interaction:
Touch screen devices use post-WIMP interaction, like pinching and rotating.
1.2 Main components of computer systems
Computer System Components:
Hardware and software.
Input devices, output devices, and secondary storage.
Table 1.1: Examples of devices
Input Devices: Keyboard, mouse, camera, microphone, sensor, scanner.
Output Devices: Monitor, printer, speakers, projector, plotter.
Secondary Storage Devices: Hard disk drive, solid-state drive, pen drive.
Internal Hardware Components:
Central Processing Unit (CPU) on the motherboard.
Internal hard disk drive or solid-state drive.
Random Access Memory (RAM).
Read-Only Memory (ROM).
1.3.1 User interfaces
User Interface Types:
Command Line Interface (CLI)
Graphical User Interface (GUI)
Dialogue-based User Interface
Gesture-based User Interface
Command Line Interface (CLI):
Requires the user to type in instructions to choose options from menus, open software, etc.
The user has to learn commands just to carry out basic operations.
Advantage: direct communication with the computer, not limited to pre-determined options.
Example (Windows):
%windir%\explorer.exe C:\Users\YourName\Desktop
1.4 Types of computer
1.4.1 Desktop computers
Desktop usually refers to a general-purpose computer that is made up of separate monitor, keyboard, mouse and processor unit.
It is distinguished from, for example, a laptop computer by the fact that it is made up of a number of separate components, which makes them not very portable.
Advantages of desktop computers over laptop computers
Spare parts and connections tend to be standardised, which usually results in Lower costs.
Desktop computers are easier, and less expensive, to upgrade or expand.
The desktop tends to have a better specification (for example, faster processor) for a given price (often due to size and construction constraints in laptops).
Power consumption is not critical because 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 or stolen.
Internet access can be more stable because a desktop computer is more likely to have a wired internet connection (the user will always have the same data transfer rate); however, due to their portability, laptop computers usually use wireless internet connectivity where the signal can be very variable (giving variable data transfer rate).
Disadvantages of desktop computers
The most obvious is that they are not particularly portable because they are made up of separate components.
They tend to be more complicated because all the components need to be hooked up by wiring, which also clutters up the desk space.
Because they are not particularly portable, it is necessary to copy files on, for example, a memory stick, when you want to do some work elsewhere (for example, doing office work at home); although cloud storage has diminished this disadvantage recently, it still may not be possible to save sensitive data files on the cloud.
The main uses of desktop computers include:
office and business work (word processing, spreadsheets, finance software and databases being the main use)
educational use (using interactive software to teach or learn from)
use as a gaming device (for example, games such as chess, crossword puzzles, fantasy games, and so on)
general entertainment (for example, live or 'catch-up' streaming of television programmes).
1.4.2 Mobile computers
Mobile computers, by their very name, suggest a group of computers which are considerably more portable than desktop computers.
Such computers fall into four categories:
Laptop computers
smartphones
tablets
phablets.
1.3 Operating systems
Operating Systems (OS):
Enable computer systems to function and allow user communication.
Typical OS Tasks:
Control input, output, and backing storage devices.
Supervise loading, running, and storage of applications.
Handle errors in applications.
Maintain system security.
Maintain a computer log.
Allow communication between the user and the computer (user interface).
Dialogue-based and gesture-based interfaces
Gesture-based interfaces:
Rotating a finger clockwise near the radio will increase the sound volume (rotating the finger anti-clockwise will reduce the sound volume)
opening the thumb and next finger will change the track being listened to (for example, in a playlist)
moving the foot under the rear bumper of the car automatically opens the boot lid
moving a hand near a window switch automatically opens a window.
Dialogue-based and gesture-based interfaces - advantages and disadvantages:
Dialogue-based
Advantages:
no need for a driver to take their hands off the steering wheel
in a home, very useful for people with disabilities, because many tasks can be carried out by the spoken word only
possible to use as a security feature, because voice recognition could be used to identify a person
Disadvantages:
still unreliable, with many commands not being recognised or needing to be repeated several times (especially if there is background noise)
can be quite complex to set up
user needs to know which commands can be used
Gesture-based
Advantages:
replaces mechanical input devices
no physical contact required
very natural interface for a human operator
no training needed to interface with the computer
Disadvantages:
possible for unintentional movement to be picked up
only works fairly near to the camera or sensor (maximum of 1.5 metres)
may only accept a limited number of movements (for example, it may take several attempts to find out exactly what finger movements are recognised)
Removable Backing storage
Advantage of removable backing storage:
it can be used as a backup in case of data loss or corruption
Data from the main HDD or SSD can be copied onto another device (such as a pen drive or portable HDD) and then stored in a separate location.
If the original data on the HDD/SSD has been lost or corrupted, it can be restored from the backup device.
Examples of removable storage include external hard disk drives (HDD), external solid-state drive (SSD) and Blu-ray discs.
Table 1.4 summarizes the differences between backing storage and internal memory.
Internal memory
RAM contents are lost when computer is powered down; ROM contents are readable only.
RAM and ROM are much smaller memories than backing storage.
Data access time on RAM and ROM is extremely fast.
Much more expensive per byte than backing storage devices.
RAM and ROM are fixed inside the computer (internal memories].
RAM and ROM can be read directly by the CPU.
Backing storage
Backing storage devices hold their contents permanently, even when powered down.
Have considerably larger capacity to store data than RAM or ROM.
Has much slower data access time than RAM and ROM.
Is much cheaper per byte than RAM or ROM.
Backing storage can either be fixed (external or internal) or it can be removable.
Before data on a backing storage device can be read by the CPU, it must first be moved into RAM; this means backing storage is not directly addressable by the CPU.
Gesture-based interfaces
Gesture-based interfaces rely on human interaction by the moving of hands, head or even the feet.
Gesture recognition allows humans to interface with a computer in a more natural fashion without the need for any mechanical devices.
This type of interface uses techniques known as computer vision and image processing.
For example, using our car example again, the following gestures can be used to carry out certain functions:
rotating a finger clockwise near the radio will increase the sound volume (rotating the finger anti-clockwise will reduce the sound volume)
opening the thumb and next finger will change the track being listened to (for example, in a playlist)
moving the foot under the rear bumper of the car automatically opens the boot lid
Laptop computers
Laptop computers also have disadvantages when compared to desktop computers:
Because they are easily portable, they are also easier to steal!
They have limited battery life so the user may need to carry a heavy power adaptor.
The keyboards and pointing devices can sometimes be more awkward to use.
It is not always possible to upgrade them, for instance by adding more RAM.
The main uses of laptop computers include:
office and business work (word processing, spreadsheets, finance software and databases being the main use)
educational use (using interactive software to teach or learn from)
used as a gaming device (for example, games such as chess, crossword puzzles, fantasy games, and so on)
general entertainment (for example, live or 'catch-up' streaming of television programmes)
used in control and monitoring (because they can be operated anywhere using their internal battery, it is possible to use laptops to gather data directly from the environment - for example, they can be plugged into a gas boiler during maintenance to monitor its performance).
Smartphones
Smartphones allow normal phone calls to be made, but also have an operating system (such as iOS, Android or Windows) allowing them to run a number of computer applications (known as apps or applets).
They allow users to send/receive emails, use a number of apps, use a camera feature (to take photos or videos), MP3/4 players (for music and videos), and so on.
Smartphones communicate with the internet either by using Wi-Fi hot spots or by using 3G/4G/5G mobile phone networks.
Some of the typical features of smartphones include:
high-definition, anti-glare displays
front- and back-facing cameras (which are used to take photos, videos or act as a webcam when doing video calls over the internet)
lower weight and longer battery life than laptops
use Bluetooth for connection to printers and other devices
make use of flash (solid state) memory and cloud storage facilities to back up and synchronise (often just referred to as 'sync') data sources
they use a number of sensors to carry out the following functions:
proximity sensors to detect if the device is close to, for example the ear, which allows it to block unintended 'touches'
accelerometers, which detect movement and orientation of the device (for example, move the display from portrait to landscape to view videos, or allow it to be used as a 'steering wheel' in-car racing games)
can use sophisticated speech recognitions systems (such as Siri) to enable the user to ask the device to look for things (such as search the address book).
Smartphones - New generation
The new generation of smartphones are becoming even thinner and lighter, because they make use of OLED (organic light emitting diode) touch screens.
Future smartphones will also use OLED touch screens that are coated with a crystalline layer that allows the phones to be partially solar powered; this allows them to use Li-Fi (similar to Wi-Fi, except communication uses visible light rather than radio waves).
Communication using Li-Fi is considerably faster than with Wi-Fi (much higher data transfer rate); it is also more secure (by stopping internet 'piggybacking').
The Li-Fi system can also be used during aeroplane flights because it does not use radio waves and therefore does not interfere with flight control systems.
Advantages of smartphones:
They are very small in size and lightweight - therefore they are very easy to carry and have on your person at all times (this is more difficult with laptops because they are much bulkier and much heavier).
You can use them to make phone calls, but also connect to the internet while on the move.
Because they use Wi-Fi and mobile phone networks they can be used almost anywhere (this is not the case with laptops or desktops; although tablets also use the same technology).
They have apps which make use of sensor data provided by the smartphone, for instance location data for maps - this can provide services that are not available on desktops or laptops.
They have a reasonable battery life compared to laptops.
Disadvantages of smartphones:
The small screens and keyboards make pages difficult to read.
It is more difficult and slower when typing things in (laptops and desktops have much bigger screens and much larger keyboards).
Web browsing and photography can quickly drain the battery.
Memory size in most phones is not very large when compared to laptops and desktops - although it is comparable with tablets (however, the latest generation smartphones come with 1 TiB memories).
Not all website features are compatible with smartphone operating systems.
Because of their small size, it is much easier to lose a smartphone or for it to be stolen compared to laptops or desktops.
The data transfer rate using mobile phone networks can be slower than with Wi-Fi - this makes streaming of video or music, for example, less than satisfactory at times.
1.1.3 Analogue and digital data
Computers can only understand data which is in a binary format (that is, a base 2 number system where only the values 0 and 1 can be used).
This is often referred to as digital data (because it can only have discrete, discontinuous values).
Analogue data is physical data that changes smoothly from one value to the next, and not in discrete steps as with digital data.
If analogue data is being sent to a computer, it must first be converted into digital data; this is done by hardware known as an analogue to digital converter (ADC).
If the computer is controlling a device (such as a motor) then the digital output from the computer needs to be converted into analogue form. This is done by a digital to analogue converter (DAC).
1.2.4 Backing storage
The main memories in a computer are RAM and ROM.
However, to permanently store large amounts of data it is necessary to use backing storage.
This normally takes the form of the internal hard disk drive (HDD) or solid-state drive (SSD).
This is the computer's main internal storage where the applications software, disk operating system and files (for example, text, photo or music) are stored.
A key feature of a backing store is that it must store data permanently - that is, it must be non-volatile.
Unlike RAM and ROM, backing storage is not directly addressable (that is, it cannot be read directly by the CPU).
The data access time for RAM and ROM is much shorter than it is for backing storage.
Backing storage is considerably larger than RAM because it is considerably less expensive per byte.
Who would use each type of interface?
CLI: 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.
GUI: the end-user who does not have to (or does not need to) have any great knowledge of how the computer works; a person who uses the computer to run software, play games or store/manipulate photographs, for example.
Dialogue-based user interfaces
Dialogue-based user interfaces use the human voice to give commands to a computer system.
An example of its use is in some luxury modern cars, where voice activation is used to control devices such as the in-car entertainment system or satellite navigation system.
By speaking certain commends, such as 'Hey BMW, drive me to the nearest airport', the system allows natural speech to enable the driver to intuitively interact with the car.
The satellite navigation system will automatically direct the driver to their chosen destination (in this case, the nearest airport).
This type of interface could also be used in the home; by using voice commands, it is possible to switch on/off lights, operate electronic equipment and so on.
In recent years, devices such as Amazon Alexa, Google Now, Apple Siri and Microsoft Cortana have all been developed to interact with a human by recognising verbal commands.
These devices act as a personal assistant.
Laptop computers advantages
Laptop computers do have advantages when compared to desktop computers:
The most obvious advantage is their portability; they can be taken anywhere because 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 (only one single cord is used).
They take up much less room on a desk, so they can be used anywhere (for example, in a café).
Their portability allows them to take full advantage of Wi-Fi features.
Because they are portable, they can link into any multimedia system.
Tablets advantages and disadvantages
Advantages of tablets compared to laptops:
very fast to switch on (no time delay waiting for the operating 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 do not need any other input devices
can use several apps as standard (such as built-in camera, MP3/4 players and so on)
not much 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 of tablets compared to laptops:
tend to be rather expensive when compared to laptops (but this will probably change with time as they become more common)
they often have limited memory or storage when compared to a laptop (although some of the latest devices have 1 TiB memory capacity)
if 3G/4G/5G mobile phone networks are used, they can be expensive to run if the internet is being accessed frequently
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 'application atore'; this lack of 'drag and drop' facility can prove to be irritating to users
laptops tend to support more types of file format than tablets and are also better equipped to run different types of software.
Phablet
Some of the latest smartphones have been designed as a hybrid between a tablet and a smartphone; these are referred to as a phablet.
They have much larger screens than a smartphone but are smaller than a tablet.
All the features of a smartphone (described earlier) also apply to phablets together with the typical features of a tablet.
1.5 Emerging technologies
1.5.1 Impact of emerging technologies
There are many definitions of artificial intelligence (AI).
Essentially, AI is a machine or application which carries out a task that requires some degree of intelligence.
For example:
the use of language
recognising a person's face
the ability to operate machinery, such as a car, aeroplane, train, and so on
analysing data to predict the outcome of a future event, for example weather forecasting.
AI duplicates human tasks
AI duplicates human tasks which require decision-making and problem-solving skills.
Eventually, many tasks presently done by humans will be replaced by robots or computers, which could lead to unemployment.
However, the positive side includes improvements in safety and quality of services and products.
Whenever AI is mentioned, people usually think of science fiction fantasies and think of robots. The science fiction writer Isaac Asimov even went as far as producing his three laws of robotics:
robots may not injure a human through action or inaction
robots must obey order given by humans without question
a robot must protect itself unless it conflicts with the two laws above.
Many science fiction movies continue to fuel people's imagination with slightly sinister interactions between humans and machines.
However, AI goes way beyond robotics and covers many areas, such as those shown in Figures 1.15-1.11
Negative impacts of Al
All of the above examples give a very favourable view of the effect of AI on our everyday lives.
However, in any balanced argument, we should also consider the drawbacks of the new technology:
could lead to many job losses in a number of areas (although it is true to say that new technical jobs would also be created); many jobs could be lost in manufacturing, but other roles are likely to be affected (such as bus, taxi, lorry and train drivers)
dependency on technology and the inability to carry out tasks done by robots, for example, could be an issue in the future
loss of skills - even now, skills from previous generations have been lost as humans have been replaced by machines and software applications.
Extended reality
Extended reality (XR) refers to real and virtual combined environments, and is a 'catch all' term for all immersive technologies.
The three most common examples at the moment are:
augmented reality (AR)
virtual reality (VR)
mixed reality (MR).
All these immersive technologies extend the reality we experience by either blending the virtual and real worlds or by creating a fully immersive experience.
Augmented reality (AR)
The features of augmented reality include:
allow the user to experience the relationship between digital (virtual) and physical (real) worlds
virtual information and objects are overlaid onto real-world situations
the real world is enhanced with digital details, such as images, text and animation
the user can experience the AR world through special goggles or via smartphone/phablet screens
the user is not isolated from the real world and is still able to interact and see what is going on in front of them
examples include the Pokémon GO game which overlays digital creatures onto real-world situations.
Future impact augmented reality
In the future, augmented reality will have an impact on all the following areas:
safety and rescue operations (for example, it is possible to provide 3D images of an area where a rescue mission is to take place, giving the team the opportunity to interact with the environment and try out rescue procedures before doing the real thing)
entertainment (for example, AR takes users into a virtual environment where it is possible to interact with the characters; imagine the characters of your favourite film interacting with you at home)
shopping and retail (this is one of the big areas - for example, using your smartphone camera you can try out make-up and see how it looks on you before buying it, or you can experience a virtual tour of a new car where you can 'sit' in the interior and try out the driving experience before buying the car)
Laptop (or notebook)
Laptop (or notebook) refers to a type of computer where the monitor, keyboard, pointing device and processor are all together in one single unit.
This makes them extremely portable.
Key features you would expect to find in a laptop:
lightweight (to aid portability)
Low power consumption (and also long battery life)
low heat output (cooling is very important).
Tablets
Tablets are becoming an increasingly used type of mobile computer.
They work in a similar way to a smartphone.
Tablets use touch screen technology and do not have a conventional keyboard.
The keyboard is virtual; that is, it is part of the touch screen and keys are activated by simply touching them with a finger or a stylus.
However, it is possible to buy tablet cases which contain a normal-sized keyboard.
Internet access is usually through Wi-Fi or 3G/4G/5G (mobile phone) connectivity.
Like smartphones, tablets are equipped with a series of sensors which include camera, microphone, accelerometer and touch screen.
The typical features of tablets are identical to those of a smartphone (described earlier).
1.1 Hardware and software
1.1.1 Hardware
Hardware is the general term for the physical components that make up a typical computer system.
For example:
keyboard
mouse
camera
input devicemonitor
printer
output deviceplotter
Hardware falls into two categories: internal and external.
The list above are examples of external hardware, which is discussed in detail in Chapter 2.
Internal hardware devices
Figure 1.1 considers the following internal hardware devices:
motherboard
central processing unit (CPU)/processor
random access memory (RAM)
read-only memory (ROM)
graphics card
sound card
network interface card (NIC)
internal storage devices (hard disk drive and solid-state drive).
1.1.2 Software
Software is the general term used for the programs that control the computer system and process data.
The software considered in this book falls into two categories: applications and system.
Applications software provides the services that the user requires to solve a given task.
For example:
word processing
spreadsheet
database (management system)
control and measurement software
apps and applets
video editing
graphics editing
audio editing
computer-aided design (CAD).
System software is the software designed to provide a platform on which all other software can run.
For example:
compilers
linkers
device drivers
operating systems
utilities.
Virtual reality (VR)
The features of virtual reality include:
the ability to take the user out of the real-world environment into a virtual (unreal) digital environment
in contrast to AR, the user is fully immersed in a simulated digital world
users must wear a VR headset or a head-mounted display which allows a 360° view of the virtual world (this 'fools' the brain into believing they are walking on an ocean bed, walking in an alien world or inside a volcano)
this technology can be used to good effect in: medicine (teaching operation procedures), construction, engineering and the military.
Future impact virtual reality
In the future, virtual reality will have an impact on all the following areas:
military applications (for example, training to operate a new tank)
education (for example, looking inside an ancient building as part of a history lesson)
healthcare (for example, as a diagnostic tool to recommend treatment)
entertainment (for example, games where gloves, goggles or helmets are worn to fully immerse players and make it seem very real)
fashion (for example, to do fashion shows before doing the real thing - see the clothes on people, check out the venue and so on)
heritage (for example, allowing users to walk around and close up to monuments like Stonehenge)
business (for example, training courses and role-playing scenarios for staff)
engineering (for example, seeing how new designs like bridges will look in an existing environment)
sport (for example, a golfer trying to improve his swing can use this technology and get feedback to improve his game)
media (for example, interactive special effects in movies)
scientific visualisation (for example, part of a molecular structure in chemistry, or a cell in biology).
1.3 Comparison of input and output devices
Input devices
An input device is any hardware device that allows a user to enter data or instructions into a computer directly.
An input device can send data to another device, but it cannot receive data from another device.
Input devices are necessary for a computer to receive commands from its users and data to process; the devices are under the control of the user or can be direct data entry.
Input devices can be fairly complicated because they have to ensure that the user can interact with the computer correctly.
Output devices
An output device is any hardware device that takes the output data from a computer and puts it into a human-readable format or uses it to control another device.
An output device is capable of receiving data from another device in order to generate an output, but it cannot send data to another device.
Output devices are needed by a computer so it can share the results of its processing with a human; output devices are under the control of the computer.
Output devices are less complex than input devices because they only have to turn computer signals into an output.
Advantages and disadvantages of CLI and GUI interfaces
Command line interface (CLI)
Advantages
The user is in direct communication with the computer.
The user is not restricted to a number of pre-determined 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.
Graphical user interface (GUI)
Advantages
The user does not 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
This type of interface uses up considerably more computer memory than a CLI interface.
The user is limited to the icons provided on the screen.
Needs a more complex operating system, such as Windows, to operate, which can be slower to execute commands.