Computer Hardware Components

Computer Hardware Components

• A computer system uses hardware and software to process data into information.
• Hardware includes the processor, storage, and I/O devices.
• Software includes application and system software.

Inside a Computer Case

• System unit/chassis refers to the case that contains and protects the motherboard, hard disk drive, memory, and other hardware components.
• Located inside: video card, sound card, processor, power supply and fan, heat sink and fan, memory module, integrated sound ports and circuitry, and battery

Motherboard Components

• Northbridge (with heatsink)
• Southbridge
• PCI Slot (x5)
• AGP Slot
• IDE Connector (x2)
• DRAM Memory Slot (x2)
• 20-pin ATX Power Connector
• CMOS Backup Battery
• CPU Fan and Heatsink Mounting Points
• CPU Socket
• Connectors For Integrated Peripherals includes: PS/2 Keyboard and Mouse, Serial Port, Parallel Port, USB (x6), Ethernet, Audio (x3)

Computer Connectors and Ports

• USB (Universal Serial Bus) is a multiuse port for connecting devices such as keyboards, mice, printers, and external storage for data transfer and charging.
• Storage/Disk ports like SATA or M.2 are used for connecting internal and external storage devices, allowing data storage and retrieval.
• Network/Communications ports include Ethernet or Wi-Fi for connecting to networks, enabling internet access and data exchange between devices.
• Audio connectors, such as 3.5mm jacks and optical ports are used for audio input and output, connecting headphones, speakers, and microphones.
• Video ports include HDMI, DisplayPort, or VGA for transmitting video signals to displays such as monitors and projectors.
• Power connectors include AC power sockets or DC power jacks used for supplying electricity to devices and charging batteries.

Inside the Case

• The motherboard/system board is the main circuit board of the computer.
• Many electronic components, such as the processor and memory, are attached or built into it.
• The central processing unit (CPU)/processor is considered the "brain" of the computer.
• It is a silicon chip that fits into the motherboard's CPU socket, covered by a heatsink and fan.
• The chipset controls communication between the CPU, memory, storage, and other peripherals, determining the number of high-speed components the motherboard can support.
• Random access memory (RAM)/main memory temporarily stores data whenever the computer performs operations. RAM contents disappear when the computer is turned off.
• The hard disk drive provides long-term storage that holds data even when the computer is turned off.
• Some laptops use a solid-state drive.
• The power supply unit/laptop AC adapter converts outlet electricity to the power the computer can use.
• Different motherboards and computers require different wattages on the power supply. Desktop computers have built-in fans to keep the power supply cool.
• Most motherboards have built-in video, sound, and network capabilities. Motherboards can have expansion slots to add various types of expansion cards or adapter cards:
• Bluetooth adapter enables Bluetooth connectivity
• MIDI connects to musical instruments
• Modem connects to transmission media
• Network provides network connections, such as an Ethernet port
• Sound connects to speakers or a microphone
• USB connects to high-speed USB ports
• Video usually have a GPU (graphics processing unit) to enhance computer graphics capabilities

Key Internal Connections

• Peripheral Component Interconnect (PCI) is the input/output pathway that connects the CPU to peripheral devices via expansion slots.
• Serial Advanced Technology Attachment (SATA) is a computer bus interface used to connect drive disk controllers or host bus adapters with mass storage devices.
• The Complementary Metal Oxide Semiconductor (CMOS) battery is responsible for keeping all information intact to prevent reconfiguration when the PC is powered off.

Processors

• A processor interprets and carries out basic instructions that operate a computer.
• On large computer systems (mainframes/supercomputers), processor functions extend over separate chips and multiple circuit boards.
• On personal computers, all processor functions are usually on a single chip (microprocessor).
• A processor core contains the circuitry to execute instructions; the operating system views each core as a separate processor.
• A multicore processor is a single chip with two or more processor cores.
• The Control Unit directs and coordinates operations in the computer, interpreting each instruction and initiating the appropriate action and instructions stored in the memory.
• The Arithmetic Logic Unit performs arithmetic and logic operations.
• Arithmetic operations include addition, subtraction, multiplication, and division.
• Logic operations include comparison operations.

Machine Cycle

• For every instruction, a processor repeats a set of four basic operations, comprising a machine cycle:
• Fetching obtains a program instruction or data item from memory.
• Decoding translates the instruction into signals the computer can execute.
• Executing carries out the commands.
• Storing writes the results back to the memory.

Processor Components

• A processor contains small, high-speed storage called registers that temporarily hold data and instructions.
• Registers include those for storing the location from where the instruction was fetched, an instruction while the control unit decodes it, data while the ALU calculates it, and the results of a calculation.
• The processor relies on a small quartz crystal circuit called the system clock to control the timing of computer operations.
• The system clock generates regular electronic pulses/ticks.
• Each tick is equivalent to a clock cycle.
• Today's processors are superscalar, executing more than one instruction per clock cycle.
• The pace of the system clock, called the clock speed, is measured by the number of ticks per second. Current processors can reach clock speeds in the gigahertz (billions of cycles per second) range. The faster the clock speed, the more instructions the processor can execute per second.

Computer Memory

• Memory consists of electronic components that store instructions waiting to be executed, data needed by those instructions, and the results of processing.
• Three basic categories of items are stored in memory including the operating system, applications, and data being processed.
• Each byte of data stored in memory is identified by a memory address and the memory size is commonly measured in gigabytes (GB).

Types of Memory

• Internal (Primary)
• RAM
• ROM
• External (Secondary)
• Magnetic Storage
• Optical Storage
• Flash Storage

Internal Memory

• Also known as main memory.

Random Access Memory (RAM)

• Read from and written to by the processor.
• Volatile, losing its contents when power is removed.

Read Only Memory (ROM)

• Nonvolatile, its contents are not lost when power is removed.
• ROM chips, called firmware, contain permanently written data or instructions, like start-up instructions.

SRAM vs DRAM

• SRAM (Static Random Access Memory) uses transistor.
• It is faster
• It requires no need to refresh to maintain data
• Static Random Access Memory is used in Registers and cache.
• In comparison to Dynamic RAM (DRAM), it requires a separate capacitor to store each bit of data.
• This means DRAM is slower and needs periodic refreshing to maintain data
• All in all, DRAM is an economical option used in Main memory.

Static RAM (SRAM)

• Registers are small, high-speed storage locations that temporarily hold data and instructions inside the processor.
• Cache is high-speed storage that stores frequently used instructions and data, with larger capacity than registers.
• L1 cache is built directly on the processor chip and has a very small capacity
• L2 cache is slightly slower than L1 cache but of larger capacity. Advanced transfer cache (ATC) is faster L2 cache built directly on the processor chip.
• L3 cache is on the motherboard, separate from L2 cache and exists only on computers that use ATC L2 cache.
• A processor searches memory in this order: L1 cache, L2 cache, L3 cache (if it exists), then RAM. Delay is greater with each level of memory it searches. If the instruction or data is not found in primary memory, it must search in secondary storage with a much slower speed.

Measuring Memory Access Time

• Memory Access Time is the amount of time it takes the processor to read data or instructions from memory.
• Millisecond (ms) : one-thousandth of a second
• Microsecond (µs) : one-millionth of a second
• Nanosecond (ns) : one-billionth of a second
• Picosecond (ps): one-trillionth of a second

Dynamic RAM (DRAM)

• SDRAM (Synchronous DRAM) is synchronized to the system clock and much faster than DRAM.
• DDR SDRAM (Double Data Rate SDRAM) transfers data twice for each clock cycle and is faster than SDRAM.
• DDR2 is the second generation of DDR and faster than DDR.
• DDR3 is the third generation of DDR, designed for computers with multi-core processors, and faster than DDR2.
• DDR4 is the fourth generation of DDR, faster than DDR3
• RDRAM (Rambus DRAM) is much faster than SDRAM.
• RAM chips usually reside on a memory module on memory slots
• The memory module has
  • Single Inline Memory Module (SIMM) with pins connect together to form a single set of contacts
  • Dual Inline Memory Module (DIMM) with pins that do not connect and form two sets of contracts

ROM (Read-Only Memory)

• Programmable ROM (PROM) is one-time programmable and programmable by a user using an external programming device.
• Erasable PROM (EPROM) is reusable and its content can be erased using UV light, programmable by external programming device.
• Electrically Erasable PROM (EEPROM) clears entire blocks with a single operation and can be programmable in-place without removing it from the circuit board.

External Memory (Secondary Storage)

• A storage device is the hardware that records or retrieves items to/from storage media.
• Storage Access Time measures the amount of time it takes a storage device to locate an item on a storage medium.
• The transfer rate is the speed with which data and instructions are transferred to/from a storage device; measured in KBps (kilobytes per second), MBps (megabytes per second), or GBps (gigabytes per second).

Storage Types

• Items waiting to be interpreted are stored in Memory (most RAM)
• Operating system, applications, user data, and information are stored in SSDs
• Photos, music, and videos stored on Hard Disks
• Digital photos or files are stored on USB Flash Drives and Memory Cards
• Software, movies, and music is stored on Optical Discs

Hard Disk Drives

• A hard disk is a storage device which has one or circular platters that use magnetic particles to store data and instructions

Solid-state Drive (SSD)

• A flash memory storage device with processor to manage its storage.
• SSDs have advantages of a higher storage capacity, faster access time (80x faster), and transfer rates, quieter operation, lighter weight, less power consumption and longer life.
• SSDs have a disadvantage of data recovery being more difficult and costly per gigabyte.

Flash Memory

• A type of nonvolatile memory that can be erased electronically and rewritten and has solid-state media.
• The lack of moving parts makes flash memory more durable and shock-resistant compared to magnetic disks or optical disks.

Optical Discs

• A storage medium made of metal, plastic, and lacquer that is written and read by a laser.
• USB flash drives are flash memory storage devices that plug into a USB port on a computer or mobile device.
• A Memory card is a removable flash memory storage device that is inserted into a slot in a computer, mobile device, or card reader/writer.

Storage Solutions

• Enterprise storage refers to high-capacity storage solutions for businesses to manage, store, and protect large volumes of data. This includes Network-attached storage (NAS), Storage area networks (SAN), and cloud storage. Enterprise storage is optimized for performance, scalability, and reliability. It often includes advanced features like data redundancy, backup and recovery options, and security measures. Network Attached Storage is a file-level storage solution that connects to a network. It is typically used in for small to medium businesses for easy file sharing.

SAN and Cloud Solutions

• Storage Area Network is a block-level storage solution that connects servers to a dedicated storage network
• Cloud storage is an online storage solution that allows businesses and individuals to store data on remote servers, available via the Internet.
• A cloud storage is usually managed and maintained by cloud service providers like Amazon Web Services, Microsoft Azure, and Google Cloud.
• Cloud storage offers flexibility, scalability, and cost-efficiency by allowing users to pay only for the storage they need, and scale up or down based on requirements. Data can be accessed from anywhere, which make it a great option for businesses with remote workforces or global operations.