This page is about Hardware, something everyone has come in contact with for sure.
Hardware is the tangible, physical parts of a computer which input, process, output and store data. From mobile phones, to processors, to hard disks, all hardware requires software in order to function.
Hardware affects how IT systems are used and in some cases a system may be inaccessible to disabled users without specialist hardware (e.g. braille keyboards for blind and partially sighted people).
Types of Computer
Supercomputers - The largest, fastest, most powerful and most expensive computers available. 1000s of Gb of primary storage, and terabytes of secondary storage. They used for very complex calculations such as advanced scientific research such as gene sequencing, analysing climate change, and analysing the effects of nuclear explosions.
Mainframes - Very powerful computers that share some features with supercomputers, however unlike supercomputers they are not designed for very complex calculations but rather a high throughput of data in a short time. For example, airline reservation management, or banking. Uptime is critical with these systems and as such they usually feature redundant failover systems that take over if a Mainframe has downtime.
Desktops - Prices have fallen for desktop computers over the year as the convenience of laptops has meant more people opt to buy laptops instead. Desktops are usually more comfortable to use over time and promote good posture and ergonomics with an adjustable screen, with mouse and keyboard at a good height. Desktops are easier to maintain and upgrade individual components over time because the case is more accessible. This can however increase e-waste with discarded obsolete pieces of hardware.
Laptops - Laptops are portable devices originally designed as convenient workstations with Internet access, but have since become entertainment hubs and even gaming devices for many as hardware specs and affordability have improved (Moore's Law). A major concern for laptops is how to ensure that the device stays cool when using it, with many having fan vents to help with this, many modern laptops use mobile standard processors that draw less power meaning that they stay cooler, battery lasts longer, and devices can be thinner.
Netbooks/Chromebooks - Laptops with lower specifications and designed for maximum portability. Essentially dependant on a connection to the Internet in order to use Web Services such as Google Docs or Microsoft Onedrive. Usually a slow processor, minimal RAM and low storage. Some higher end Chromebooks have started to appear with better specs and touch screens such as Google's Pixelbook range.
Smartphones - Smartphones have more features than the name 'phone' suggests. They now more often than not include a good specification of camera on the front and back. the ability to record and play video, sound, and manipulate images. Apple's App Store, and Google's Play store provide smartphone users with the ability to download and run applications (commonly shortened to 'Apps'). As mobile data speeds have increased (4G+ etc...) so has the complexity of the apps available. Using content from the 'Cloud' allows devices to display content without storing the content locally on the device. A good example of one of these services is Netflix which allows users to stream video content to their mobile devices or desktop for a subscription fee. The software distribution model is now heavily moved towards a subscription based approach (Office 365, iCloud, Onedrive etc...).
Think of how technical developments have contributed to the development of smartphones with these capabilities. Try to list as many as you can...
Embedded Systems - Embedded systems are specialised computer systems that are hidden within another device. Examples include washing machine systems that control wash cycles and water efficiency, traffic lights to synchronise the lights and anti-lock breaking systems in car engine management systems. Embedded systems are usually made for one specific task, and as such they need to be very reliable as they run for very long periods without being restarted. They are often real-time systems meaning that they must provide immediate output.
Keyboards - Most of the keyboards you'l encounter have the QWERTY layout which dates back to typewriters from the 1870s. It has changed very little since then. There are alternatives such as the DVORAK keyboards which use a different layout with commonly paired letters in such a way that it's supposed to increase typing speed. Some variations of QWERTY also exist with a small number of keys swapped around.
Concept Keyboards - Each key is programmed to do a custom function. An example of this is in a fast food restaurant, there might be a button to choose 'large burger with fries meal'. They are used in areas with fast input is important.
Mice - Standard pointing device on most desktop computers with a point and click interface. Many have a scroll wheel in the middle to help move through documents and websites, and some even have custom buttons on the side which can be programmed to perform certain functions such as opening applications.
Trackballs - A pointing device with a large revolvable ball that when moved, controls the pointer on the screen. They don't need to be moved around a surface like a mouse so can be used when space is tight.
Touch pads - Touch pads or track pads have become the most common input type on laptops. A user moves the pointer on screen by dragging their finger across the touch pad. Most also allow pressing anywhere on the touch pad to act as a mouse click, and many now support multi-touch gestures such as moving 2 fingers apart or closer together to zoom in or out.
Touch screens - Where users can interact with content on screen by touching it directly. iPads have made touch screens commonplace, and you can also find non-multi touch screens on things like ATMs in banks.
Microphones - An input device that allows sound data to be captured and entered into a computer. Most computers have microphones installed by default. Voice recognition input systems such as Cortana in Microsoft and Siri for Apple devices allow users to interact with their devices just through speech. Voice recognition software can also be used to dictate the text in word processed documents for example. Voice recognition is built in to Mac OS and Windows to also help users with disabilities.
Game controllers (joysticks/gamepads) - Used by gameplayers to control the action in games. Some modern controllers also support motion detection as input, such as the Nintendo Wii.
Barcode scanners - Uses a laser to shine onto a barcode label. The amount of dark lines and spacing between the lines determines the amount of reflected light. This is then interpreted as a number by the barcode scanner. Mainly used to identify products in shops.
Magnetic Stripe Readers - Bank cards, credit cards, hotel cards feature a magnetic stripe. The magnetic stripe stores a small amount of data which is identified by Magnetic Stripe Readers. Although quite secure, it is possible to buy strip writers to alter data on cards and produce counterfeit or cloned cards.
Smart Cards - Plastic credit card style cards that have higher storage capacity and an embedded processor. The processor is powered on by inserting the card into or over a smart card reader. Commonly used for paywave banking systems. Travel cards such as Oyster Cards in London or EZ-Link in Singapore also use this technology.
OMR - A fast way of reading the responses for multiple choice papers. Uses reflected light to determine if a box has been coloured in or not then adds up the results.
MICR - Uses ink with iron particles in it to make it magnetic. MICR text is written in a spacial way to make it readable by humans but the amount of iron used in each character allows the computer to read them. Used on the bottom of bank cheques.
Scanners - Digitises a piece of paper and saves it as an image files such as a JPEG or PNG. The resolution of scans is measured in Dots Per Inch (DPI). Some scanners come with OCR (Optical Character Recognition) to convert scanned text back into computer based text.
Sensors - These are used to measure something from the physical world such as temperature or light. Data is collected in analogue format as it is continuous data so it needs to be converted to digital so the computer can interpret it. This happens via an ADC (Analogue to Digital Converter). Sensor are useful to collect data without any need for human presence, such as weather analysis or in dangerous situations like studying volcano temperatures or other planets.
Digital Cameras - These have replaced physical film role cameras over the years. The data can be entered straight into a computer as the image or video is captured in digital format.
Web cams - A low resolution camera used to conduct video conferences normally.
Radio tags - These emit high frequency radio signals over a large distance. Often used to track animals in areas where there are endangered species. They can also be used alongside GPS to locate animals.
RFID - Once considered a long term replacement for barcodes, they use an RFID tag and an RFID reader to identify and read items. RFID has greater storage capacity than a barcode and does not require line of sight to function. Currently being used in passports to store biometric information and allow automated gates in various airports around the world.
Screens - To output the visual interface of a computer system to a user. CRTs (Cathode Ray Tube) are the old big deep monitors that were on every desktop. LCD monitors have replaced almost all of those now. Liquid Crystal Displays are cheaper, thinner, lighter and higher quality resolution than CRT displays. Projectors can be used to shine visual data on larger surfaces, and combined with touch screens can be used as interactive whiteboards in classrooms.
Speakers - From earphones, to multi speaker systems. As part of entertainment systems or as part of an information feedback system such as an announcement in a train station. Sounds such as beeps can also be used where appropriate to help draw a user's attention.
Printers - Used to produce hard copies of documents or files. The speed of a printer is measured by pages per minute (PPM) and the quality in Dots Per Inch (DPI). Laser printers produce higher qulity images than inkjet printers but are more expensive. Laser printers output around 40PPM.
Microprocessors - The Central Processing Unit or CPU (or microprocessor) performs or executes all instructions and tasks of a computer. Instructions (from software) are loaded from secondary storage into RAM (random access memory) and then the processor executes each instruction one by one. The speed of the processor determines how quickly the instructions are carried out.
Clock Speed - The speed which a processor executes instructions. Measured in GHz (Gigahertz) or perhaps in the future, in THz (Terahertz)
Multicore processors - A processor with multiple cores meaning it has more cores to run individual process threads, which boosts performance. Current affordable processors are octa-core processors (8 cores).
Motherboards - A motherboard connects all parts of the system together, from the processor to the RAM to the hard disks or any additional expansion cards such as sound cards or graphics cards. They also house ports such as USB, or audio, or display (such as VGA or HDMI).
Primary Storage (connected directly to the processor (such as RAM) - High speed electronic memory that can be accessed directly by the processor.
Random Access Memory (RAM) - Temporary (volatile) storage for programs and data that are being used at a given moment. When a program or file is needed, it is first loaded from the hard disk (secondary storage) into RAM. The processor then fetches the instructions and data from the RAM, executes them, then saves the results back to the RAM (which then may be transferred to secondary storage - e.g. if a file is saved). RAM is lost when your computer is turned off. RAM only needs a few GB of storage to function compared to secondary storage which may need to store all programs and data even when they're not being used.
Read Only Memory (ROM) - BIOS - A type of primary storage whose contents can't be changed once written. An example of ROM is the BIOS (basic input output system) which stores instructions on how a computer can boot up. IT locates the secondary storage devices (hard disks) then loads the operating system (such as Windows or Mac OS) into RAM to begin.
Secondary Storage - These store all programs and data on a computer system whether they are being used or not. They remain even when a computer is turned off. Slower and cheaper than primary storage.
Magnetic Tapes - Used a lot in the 1980s but not popular these days other than in manual backup for servers. They are sequential so must be wound forwards or backwards in order to locate data.
Magnetic Disks (internal and external) - Most common hard disk. They have disk platters that spin up to 10,000rpm inside a solid case. A read/write head moved back and forth over the disk to magnetically charge areas to store data. High capacity, high speed but quite fragile. External hard disks often use flash storage or Solid state Drives so that they don't lose data if dropped.
Optical Storage - CDs DVDs Blu-ray - Read and store data using lasers. Small areas in the disks reflect light differently to represent a 0 or 1 which is binary and read by the computer. CDs store around 750Mb of data, while DVDs store around 4.7GB. Blu-Rays can store around 50GB on a dual layer Blu-ray. (Blu-rays are called as such as they use blue lasers).
Flash memory (USB disks, SD cards) - Stores data using electronic logic gates. They have no moving parts and therefore are more durable, use less power, and offer faster access speeds.
Storing Data (Bits and Bytes)
ASCII - American Standard Code for Information Interchange. Coding scheme to represent the English alphabet. Each byte of data represents a single character. (8 bits in a byte)
Unicode - Modern coding scheme where up to 4 bytes can represent one character. 231 characters can be represented for languages such as Hebrew or Arabic. Windows, Mac OS and Linux all use Unicode as their character representation standard (so they can easily support multiple languages).
Plain Text - ASCII and Unicode are both plain text. They don't contain any formatting information such as font or colour.
Ports and Connectors - Various are used to connect input, output, storage and network devices. Using standard ports promotes interoperability between systems and devices. Examples include HDMI for graphics, USB for data, Ethernet for networks.