Understanding Computer Basics: Hardware & Types

Computer Basics

• A computer is an electronic device used to process data.
• Computers store, retrieve, and process data based on a given set of instructions or a program.

Types of Computers

• Personal computers (PCs) include laptops and desktop computers
• Handheld devices include smart phones
• Personal computer (PC) generally refers to any small computer.
• A standard desktop PC consists of a casing/box, monitor, keyboard, and mouse.
• A laptop is a portable computer that can be carried in a small bag or case.
• Laptop computers are powered by batteries.
• Laptops have similar computing capabilities to desktop computers
• Cell phones are handheld computers that have advanced features and capabilities.
• Mainframe computers are powerful and used for large tasks at high speeds.
• Mainframe computers are used by organizations like banks and postal services for business operations.
• Mainframe computers are expensive and require large spaces.

Hardware vs Software

• Hardware refers to the physical components of a computer, such as the processor, memory, keyboard, and monitor.
• Software is a set of instructions that enables the computer to function.
• Software can be categorized into operating systems and applications.
• Software is stored on the hard disk or a portable storage device, such as a CD-ROM, and loaded into the computer's RAM to be processed by the CPU.

Von Neumann Computer Architecture

• The Central Processing Unit (CPU) contains the control unit and the arithmetic/logic unit.

Main Parts of a PC

• Keyboards, monitors, mice, and speakers, mainboard (motherboard) are the basic components
• A Modem, Case/Box, Central Processing Unit (CPU), Memory (RAM), Hard disk drive (HDD), CD-ROM Drive, Wireless connectivity chips are also main parts of a PC
• Keyboards input information.
• Keyboards have multiple characters and special-function keys (buttons).
• QWERTY keyboards are a common keyboard layout.
• A mouse helps control the computer to select menu options, drag and drop items, etc.
• Types of computer mice include ball (obsolete) and optical.
• Computer mice can be wired or wireless.
• Monitors display information from the computer.
• Monitors vary in size.
• Picture quality on monitors is described by resolution and number of pixels.
• A system case/box is a plastic or metal enclosure for essential computer parts like the CPU, Motherboard, HDD, and CD drive.
• Printers output text, pictures, and documents.
• Types of printers include inkjet and laser printers.
• Touch screens are special monitors which are used not only to display information but also to take input.
• Graphic tablets are touch-sensitive and use a stylus (digital pen) for drawing or writing.
• Scanners convert printed papers into digital files.
• CD/DVD/BluRay drives read/store information on optical disks.
• A modem converts digital data from a computer into analogue signals for network transmission, and vice versa.
• Modems can be internal or external.
• Ports on a computer are places to connect external devices.
• Serial ports connect external devices and transfer data in a single (serial) stream.
• Parallel ports connect external devices and transfer data in multiple (parallel) streams.
• Universal Serial Bus (USB) ports are the most common serial port to connect external devices and have no pins
• Network (Ethernet) ports connect the PC to networks

Central Processing Unit (CPU)

• CPU is the central computation unit (brain) of the computer.
• The CPU performs data processing and calculations.
• Popular CPU manufacturers include Intel and AMD.
• Computer speed is measured in GHz, and the CPU determines how fast the computer will run.
• A 3 GHz CPU is faster than a 1 GHz CPU.
• The CPU is also referred to as the Processor.
• The CPU consists of arithmetic and logic unit (ALU), control unit, registers, cache memory, and a clock.
• The ALU contains functional units to perform arithmetic/logic operations for data processing.
• The Control Unit manages the flow of data processing based on program instructions.
• Registers are the smallest storage unit and they process small pieces of data within the CPU.
• Cache memory is a fast, small memory, and acts as a buffer between processor and RAM.
• The clock is a measure of CPU's processing speed, cycles per second in Hertz (Hz).

Memory

• Memory stores program data temporarily during processing.
• Random Access Memory (RAM) stores and retrieves data.
• Data in RAM is lost when the power is off (volatile).
• The Hard Disk Drive (HDD) stores data permanently.
• HDDs can be external or internal.
• Data on HDDs is retained when the power is off (non-volatile).
• Random Access Memory (RAM) is the main 'working' memory used by the processor.
• RAM stores data or programs temporarily.
• When a program is in use, the program's data is loaded into RAM.
• RAM is called Volatile Memory since all data will be lost when the computer is turned off.
• RAM size affects computer performance.
• Dynamic Random Access Memory (DRAM) stores a program; needs to be refreshed periodically (dynamic).
• "Random Access" means memory access takes the same amount of time no matter what portion of the memory is being read.
• Cache memory resides inside the processor and it is used as a buffer between the CPU and RAM.
• Cache memory is a Static Random Access Memory (SRAM) which is faster than DRAM but has less capacity.
• SRAM and DRAM are two layers of the memory hierarchy.
• ROM is a special memory type that holds software needed by the computer system
• Information in ROM can only be read (no write)
• ROM retains information even after powered off (non-volatile)
• The ROM-BIOS chip, containing read-only software, is an example of ROM that starts the computer
• Network cards and video cards also contain ROM chips.
• The HDD can be divided into many parts (drives).
• Each section is represented by a character, e.g. (drive E:).
• System files are usually located in drive C

iPad Components

• iPad contains an LCD display, front camera, microphone, headphone jack, metal frame and display cover
• The logic board contains the processor and the memory, wireless communication chip (Wi-Fi, Bluetooth, and FM tuner), gyroscope and accelerometer, Li-ion cells, and speaker assemble

Computer Storage

• The smallest unit of computer storage/memory is the Bit.
• A bit is either 1 or 0 (binary number)
• 1 Byte equals 8 bits
• 1000 Bytes can also be written as 1KB - kilobyte (KB) = 10^3 Bytes - megabyte (MB) = 10^6 Bytes - gigabyte (GB) = 10^9 Bytes - terabyte (TB) = 10^12 Bytes - petabyte (PB) = 10^15 Bytes - exabyte (EB) = 10^18 Bytes - zettabyte (ZB) = 10^21 Bytes
• Memory sticks/flash memory are portable and plug directly into the computer
• Memory sticks are fast and store large amounts of data
• Memory sticks use the Electrically Erasable Programmable Read only memory (EEPROM) technology in read/write data.
• Websites provide facilities to save data on the Internet called online (cloud) file storage
• Online (cloud) file storage helps to store and access data anywhere and anytime.
• Types of online (cloud) file storage
  • Software as a Service (SaaS): such as google apps, Webex meetings, dropbox
  • Platform as a service (PaaS): helps to develop applications such as Microsoft Azure
  • Infrastructure as a Service (IaaS): provides hardware resources (e.g., processing, memory) such as Amazon Web Services (AWS)

Factors Affecting Computer Performance

• Computer performance is evaluated using CPU speed, RAM size, and Hard disk capacity.

Information and Communication Technology (ICT)

• ICT is the integration of information and telecommunication technologies to facilitate information exchange.
• Examples of ICT technologies include cellular networks (e.g., 4G, 5G), Internet of Things (IoT), and Robotics.