Introduction to Computer Hardware

Computer and Information Technology

• Information technology is a collective term used to describe the use of a computer to process and display data.
• A computer needs two components to function – the hardware and the software.
• Hardware is a collective term used to describe the physical parts of the computer.
• Software is the collective term used to describe the programs and applications that run on the hardware, and are responsible for processing data.
• The hardware allows for data input and output, while software allows for data processing.
• The most basic software needed for a computer to become functional is called the operating system (OS). The OS provides an interface that allows OS-dependent software called programs to interact with the hardware and process data.

Basic Computer Hardware

Binary System

• The computer uses the binary system to store data.
• This binary system uses only 2 digits – 1 and 0 – to store data.
• The binary system also allows for the conversion of a decimal number like 379 into a binary using this simple procedure:

Decimal Number	379	189	94	47	23	11	5	2	1
Divided by 2	189	94	47	23	11	5	2	1	0
Remainder	1	1	0	1	1	1	1	0	1

• The binary of 379 is read from right-to-left, and it is thus: 101111011. This binary is a 9-bit number, and it can be converted back to its decimal equivalent using this simple procedure:

Binary Number	1	0	1	1	1	1	0	1	1
Power of 2 (starting from the right)	8	7	6	5	4	3	2	1	0
Product/Value	256	0	64	32	16	8	0	2	1

• Now, add the numbers in the product/value row as 256+64+32+16+8+2+1=379.
• A binary digit can either be a 1 or a 0, and it is called a bit.
• An 8-bit number is called a byte (B). A kilobyte (kB) has 1024B while a megabyte (MB) has (1024X1024)B or 1048576B or 1024kB. A gigabyte (GB) has 1024MB, while a Terabyte (TB) has 1024GB.

Processor

• The CPU or processor is the component that executes instructions that allows for data processing. Therefore, without the processor, the computer cannot be described as a computing device.
• The number of instructions the processor executes per second is the processing power of the CPU and it is measured in Hertz.
• The CPU can have multiple cores, with each core being an independent processor that is connected to other processors.
• Normally, the CPU executes a sequence of instructions stored in the RAM.
• Any sequence of instructions that can be executed by a CPU is called a program.
• The four basic instructions that any CPU must execute are: fetch, decode, execute, and writeback.

Expansion Card

• An internal expansion card is any device that can be plugged into the expansion slot of the motherboard (informally called MoBo). It is also called a plug-in card.
• The internal expansion card that allows for audio signals to be processed by the computer is called the audio card or sound card. It allows for input of audio signals for processing, as well as outputs the processed audio signals. For this reason, it is described as an input-output (or I/O) device.
• The plug-in card that allows for accelerated rendering of graphics, video processing, and accelerated decoding of video codecs is called a video card or more popularly, graphics card.

Computer Peripherals

Video Display Interface

• There are different types of video display interface in the PC that allows a display device e.g a monitor or TV to be connected to the video source (such as a video card) in the PC.
• The main types of video display interfaces are:
  • Digital Video Interface (DVI): It can come as a single link or dual link connector. The single link has 18 pins and a blade, and it supports a resolution of 1920×1200. The dual-link DVI has 24 pins and a blade, and supports a resolution of 2560X1600. If it can only transmit digital signals, then it is called DVI-D, but if it can transmit both analog and digital signals, then it is called an integrated DVI or DVI-I. DVI-I has 4 pins – 2 above the blade, and 2 below it – for relaying analog signals. DVI-D does not have these 4 pins.
  • High Definition Media Interface (HDMI) – It is designed to carry digital video and audio signals from the video source to a high-definition display device.
  • Video Graphics Array (VGA) – It is a 15-pin connector port that does not carry audio signals.
  • Component Video – Used to transmit analog video signals. Like VGA, it cannot carry audio signals. Also, its video signals are split into 3 component channels (color coded as red, green, and blue). This connector is normally used to connect a DVD player to a television or monitor.
  • Composite Video – It transmits analog video signals. Like the component video, it cannot carry audio signals. Unlike component video, the video signal is not split into channels. Its connector is color coded as yellow.

Audio Interface

• The phono jack is used to transmit analog audio signals to a headphone or speaker. It is also called an audio jack, jack plug, or headphone jack.
• It comes in 2 sizes:
  • 3.5millimeter or 1/8-inch jack – The 3.5mm phono jack is the most common type, and it supports stereo audio.
  • 6.35mm or 1/4-inch – Usually used in professional audio equipment such as audio recorders or electronic guitars.
• The XLR connector is a 3-pin connector used in professional equipment.
• RCA audio connectors allow for the transmission of analog stereo audio signals to an amplifier or audio receiver.
• The Toslink connector, also called S/PDIF (Sony/Philips Digital Interface) optical audio connector, is used to carry digital audio signals. It uses fiber optic cable to transmit digital audio data.

Types of Computers

• The Microcomputer is a computer that uses a microprocessor. It is also called a personal computer (PC) and it comes in the following forms:
  • Desktop PC – A microcomputer designed for modular builds and maximization of computing power and storage space in a consumer-grade PC case. It comes in a computer case with installed internal hardware. This fully kitted case is called a console. This console is ready to be attached to a basic output peripheral for video display (the monitor) as well as basic input peripherals – keyboard and mouse. Informally, PC is used to refer to microcomputers that run on Windows or Linux OS, while those that run on MacOS are simply called Macs.
  • All-in-one (AIO) Desktop PC – It is a desktop PC whose video display and internal hardware are integrated into a single unit. It only comes with basic input peripherals, with some models featuring a touchscreen. It does not afford the freedom of customization that a standard desktop PC offers.
  • Laptop – It is a portable PC whose monitor is hinged onto a console unit that has a keyboard, trackpad, buttons, and internal hardware. The trackpad and buttons replace the mouse. The screen size ranges from 12 inches to 17 inches.
  • Netbook – Similar in design to a laptop but it is smaller in size, and has less computing power and smaller storage space. The screen size is usually 10 inches. Google has built a Netbook that runs on ChromeOS and is designed to sync with its cloud service, and this netbook is called a Chromebook. ChromeOS is a linux-based OS built around the Chrome web browser, with storage usually provided by Google Drive, hence requiring the netbook to be connected to the internet in order to be used.
  • Tablet – It is basically a netbook whose display and internal hardware are integrated into a single unit, with the keyboard and mouse being replaced by the touchscreen, It can be described as the AIO version of a Netbook. If the tablet can be connected to a detachable keyboard, then it is called a hybrid PC. This is because a tablet connected to a detachable keyboard operates like a laptop.

• The mainframe computer is a large computer that operates at very high speeds that can never be achieved by even the most powerful microcomputer. Also, it allows for a large number of peripherals to be connected to it. It also has a very large memory capacity. It is usually used for bulk data processing.
• The supercomputer has hundreds of thousands or even millions of microprocessors and operates at an astronomically high processing speed. It occupies a large room or hall that needs to be air-conditioned. It also needs a high-speed optical network to support the networking of its different components. The Blue Gene supercomputer built by IBM has 250,000 CPUs and operates at 200 trillion operations-per-second.

Understanding Hardware Specifications

• There are 5 main questions that one should ask before acquiring a PC, and they are:
  1. Does the PC need to be portable?
  2. Will the PC be used for:
     • Playing games?
     • Editing videos and photos?
     • Playing multimedia files and viewing photos?
     • Typing documents, creating presentations, and making spreadsheets?
     • Browsing the internet and engaging in video chats?
• Answers to these aforementioned questions allow one to estimate the acceptable processor speed, required RAM capacity, and storage space, as well as determine if a dedicated graphics card will be needed or not, and if it will be needed, what should its minimum requirements be.

Internet

• Internet is provided to the consumer by an internet service provider (ISP), which is usually a telecommunication company.
• The ISP can offer cabled internet through 3 types of connections:
  • Digital Subscriber Line (DSL): It uses a telephone line that is connected to a DSL filter. The DSL filter is then connected to a cabled DSL modem router. Both the DSL filter and accompanying DSL modem router are provided by the ISP. In a DSL connection, the upload speed is slower than the download speed.
  • Fiber Optic: The fiber optic cables run to the telephone cabinet where it connects to the vDSL (very high-speed DSL) copper cables to reach the house. This is called Fiber to the Cabinet (FttC). In some cases, the fiber cable runs to the house, and a fiber modem is provided. This setup is called Fiber to the Premises (FttP) network architecture.
  • Cable: It uses a coaxial cable that is usually provided by the provider of cable television (TV) services. A splitter is used to separate the internet signals from the video signals. This splitter allows the coaxial cable to be connected to both the TV decoder and a cable modem.
• The ISP can also offer cableless internet through the following types of wireless connections:
  • Satellite: It uses satellite dishes and its internet speed is slower than that of cabled connections. Reception is also affected by the weather.
  • 3G/4G: It uses the (phone) cellular network and requires a SIM card to be inserted into a USB modem for it to work. Internet speed is lower than speeds offered by cabled internet connections.

Wireless Fidelity (WiFi)

• WiFi uses a wireless local area network (LAN) to broadcast the internet using 2 bands of radio frequencies – 2.4 gigahertz (2.4GHz) and 5 GHz.
• A WiFi modem provides internet to the Wireless LAN, which is usually password-protected.
• The name assigned to the wireless LAN is described as its service set identifier (SSID).
• If the wireless LAN can use both broadcast bands, then it is called a dual-band wireless LAN, while if it can only use 2.4Ghz or 5Ghz, then it is called a single-band wireless LAN.
• To extend the range of WiFi coverage provided by a WiFi router or modem, a piece of equipment called a WiFi repeater or WiFi extender is used.
• The current wireless standard that is used in wireless networks is the IEEE 802.11 standard. It has four versions:
  • IEEE 802.11b – It provides internet at a maximum DTR of 11 Mbps using the 2.4GHz band.
  • IEEE 802.11g – It provides internet at a maximum DTR of 54 Mbps using the 2.4Ghz band.
  • IEEE 802.11n – It provides internet at a maximum DTR of 300 Mbps using both the 2.4Ghz and 5GHz bands. It is also called the Wireless N standard.
  • IEEE 802.11ac – It provides internet at a maximum DTR of 1 Gbps using the 5GHz band. It is also called Gigabit WiFi.
• Bytes and Bits are different, with 1 Byte (B) being equal to 8 bits (b). Therefore, 1 MegaByte (MB) is equal to 8×1 megabits or 8 Mb.
• Security for the wireless LAN is provided using 2 standards of the wireless protected area (WPA) protocols: WPA and WPA2.
• Implementation of WPA uses PreShared Key (PSK) that relies on Temporal Key Integrity Protocol (TKIP) for encryption. WPA is also called WPA Personal.
• In WPA2, encryption is implemented using the Advanced Encryption Standard (AES).

Computer Network

• If 2 computers are connected together, then a computer network has been established.
• There are 3 types of computer networks:
  • Local Area Network (LAN): The computers in the network are inside a single building and are connected together using a single switch. The LAN usually uses a single router, and it can have a file server.
  • Metropolitan Area Network (MAN): It is an interconnection of LANs serving a specific locality, like a city, or LANs used by a single institution such as a university. In the university, the LAN of each campus is interconnected with LANs from other campuses so as to create a MAN.
  • Wide Area Network (WAN): It is used to connect computers, LANs, and MANs in different areas of a nation. Also, if an organization has branches in different cities across the world, the LAN of each branch can be connected to LANs of other branches so as to create a WAN.
• If the computers in the network serve the same role, then the network is designated as a peer-to-peer network.
• If one computer holds data and resources that can be accessed and used by other computers, then this computer is called a server, and the computers that connect to it to access and use its resources and data are called clients. The network formed is called a client-server network.
• In the network, a switch allows computers to pass data to each other.
• A wireless network distributed over land and using radio base stations (RBSs) is called a cellular (or mobile) network. The area covered by an RBS is called a cell, and as one moves from one cell to another, one is switched automatically across the RBSs, and this is termed roaming. Each RBS in the network is assigned a unique transmission frequency.
• A wireless technology that allows for data transfer across short distances using a very narrow frequency range of 2.4Ghz to 2.485Ghz is called Bluetooth. The computing devices connected together using Bluetooth form a personal area network (PAN).
• The cloud was initially used as a metaphor for the internet but later came to represent the hardware infrastructure that hosts applications and provides storage space that can be accessed via the internet.
• Access and usage of cloud resources within a client-server network configuration is called cloud computing. The 3 main types of cloud computing are:
  • Software-as-a-Service (SaaS) – The server hosts the software that can be accessed and used by client computers.
  • Platform-as-a-Service (PaaS) – The server provides a hardware and software layer where one can build and develop an application, and thereafter deploys this application. The building, development, and deployment of this application are done via a client computer.
  • Infrastructure-as-a-Service (IaaS) – The server hardware, including server computer and network hardware, are provided for one to install an OS and use the resultant server resources. Server hardware is accessed through the internet. IaaS allows one to create multiple PaaS.

Computer Software

• Software is a computer program that takes user input, processes it according to its set of (programmed) algorithms, and then outputs the results for the user to use.
• An application is software designed to run on a desktop PC.
• An app is a scaled-down version of an application that is designed to be used on a computing device with a touchscreen. Compared to an application, an app has a smaller size, less functionality, and lower system requirements.
• The operating system (OS) is the system software that manages all PC resources – both software and hardware resources.
• The data created on a PC is saved as a file, which can be an image file, audio file, or document file.
• An image file and a document file are 2 different types of files, and to differentiate between different file types, 3-or-4 letter extensions called file extensions are used. Therefore, the image file can be image.jpg or image.jpeg, while the document file can be document.rtf or document.docx.
• If the file is saved on the PC that created it, then it is saved in local storage. The local storage can be an internal hard disk drive (HDD) or solid-state disk (SSD).
• File extensions allow for the organization and grouping of files.
• Files with the same file extension can be grouped together and moved into the same folder.

CREDITS FOR ALL PHOTOS USED IN THIS POST CAN BE FOUND ON THE CREDITS PAGE.