Understanding Computer Hardware

• Computer hardware consists of the physical components of a computer system
• Hardware refers to the electrical parts and devices making up a computer

Basic Hardware Categories

• Input devices send data to the computer's processor or memory
• Processors fetch, decode, and execute data to turn it into information
• Memory holds the data and instructions needed by the CPU
• Output devices display information and results
• Secondary storage devices store data and information for later use

Computer System Hardware

• Computer systems consist of hardware components like keyboards, mice, monitors, printers, speakers, and the CPU
• Data flows between input devices, the CPU, memory (RAM), and output devices via the Basic Input/Output System (BIOS)

Processing and Processing Hardware

• Processing is procedure that transforms raw data into useful information
• The processor and main memory are processing hardware
• The processor, or CPU, interprets and executes instructions
• The basic function of a CPU is to fetch, decode, and execute instructions held in ROM or RAM

Processor

• The processor interprets and executes instructions and is also called the microprocessor
• A computer's processor is considered its brain
• Faster processor speeds result in faster instruction execution

CPU Operations

• A central processing unit (CPU) executes instructions of a computer program and performs arithmetic, logical, input/output operations
• Microprocessors provide temporary storage for addresses and data
• Microprocessors perform arithmetic and logic operations
• Microprocessors control and schedule all operations

Examples of Processors

• Intel CPUs: Celeron, Pentium III, Pentium 4 (500 MHz – 3.0 GHz)
• Apple/Motorola CPUs: Power G3, G4 (500 MHz – 700 MHz)
• AMD CPUs: K6, K7, Duron, Athlon (500 MHz - 1.5 GHz)

Memory

• Memory refers to the physical devices used to store programs (sequences of instructions), data, text, images, and videos
• Computer memory is the storage space where data to be processed and instructions required for processing are stored
• Memory has three types: cache, primary, and secondary

Cache Memory

• Cache is smaller and faster, storing copies of frequently used data from main memory (RAM)
• Cache acts as a buffer between the CPU and Memory
• Cache holds parts of programs used most often by the CPU
• Computer microprocessors can access cache memory more quickly than regular RAM

Primary Memory (Main Memory)

• Primary Memory has two subcategories: ROM and RAM
• ROM (Read only memory) stores the boot program and information enabling the computer to start up and recognize its hardware
• ROM permanently stores data even when the computer is off and is non-volatile

Read Only Memory (ROM)

• A major function of the BIOS is to identify the boot device (CD-ROM, floppy disk, or hard disk) and transfer the operating system code to RAM
• ROM contains information about the computer's hardware devices
• ROM is faster than secondary memory

Random Access Memory (RAM)

• The area in a computer in which data is stored for quick access by the processor (CPU)
• Data held in RAM is erased when the computer is reset or powered off
• RAM is also called read/write or auxiliary memory
• Computers cannot run without primary memory (RAM/ROM)

(RAM)

• RAM is lost if the computer is turned off

Input Devices

• Input devices are hardware used to enter data into a computer via encoding such as keyboard entry, scanners, or pointing devices like a mouse
• Input hardware converts data into a form that a computer can understand and use

Input Device Examples

• Camera
• Mouse
• Microphone
• Touch tablet
• Keyboard
• Flatbed scanner

Output Devices

• Output devices use display/produce the result of computer's processing of data
• Output provides usable information to the user
• Information presented in a variety of forms depends on the output device

Output Device Examples

• Monitor
• Speakers
• Laser printer
• Multimedia projector

Input & Output devices

• Headphones
• Touchscreen
• Laser Printer

Storage devices

• Data storage devices record (store) information and data
• Hardware storing data for future use are storage devices
• Storage devices found inside or outside the computer system
• Different kinds of storage devices exist

Storage Device Examples

• Magnetic Hard disk/External hard drive/Memory cards
• Optical CD-ROM, DVD (Digital Versatile Disk.)

Hard Disk

• A hard disk is a mass storage device for software applications and data files.
• Hard disks provide a semi-permanent place for data, and possess high capacities
• Hard disks range in size from 80GB to 1TB or 1 PB
• Companies and corporations commonly use Peta Bytes or Zeta Bytes of storage space

CD-ROMs (COMPACT DISC READ ONLY MEMORY)

• Optical storage devices
• CD-ROM’s read and write data, using lasers
• CD-ROMs can store up to 650MB to 700MB of data

CD-R and CD-RW

• CD-R (CD-Recordable) discs record can not be rewritten.
• CD-RW allows erase and rewrite without loss of space

DVD and rewritable DVD

• DVD (Digital Versatile Disc) optical discs share same overall dimensions of a CD with higher capacities
• DVD+RW allow data storage and digital video recording onto 4.7 GB
• Rewritable DVD are still in infancy