Chpt 1: How do computers work?

• Processor registers


  Extremely fast but small data storage spaces that are used directly by the ALU and control unit
• Random access memory (RAM) or main memory


  Where data and instructions are stored temporarily (volatile) so that they can be quickly accessed by the processor when needed
• External memory storage or secondary storage

  Where large amounts of data are stored, such as in a hard disk or hard drive
• Computer architecture


  How a computer is designed and built to function, including how the parts of the computer are designed, organised and connected
• Modern computers evolved from machines designed for doing calculations, so for most computers today, data is represented as numbers
• Mechanical computers used a completely different computer architecture from the computers we are familiar with today
• Bit


  Binary digit which can take on the value of either 0 or 1
• Byte


  Binary number made up of eight bits
• In the past, units of data such as "kilobyte", "megabyte" and "gigabyte" were based on powers of 1,024 (or 210) instead of the standard powers of 1,000 used in the International System of Units (SI)
• Arithmetic logic unit (ALU)


  Part of the processor that processes data by performing basic mathematical and logical operations
• Control unit


  Part of the processor that follows instructions and decides when data should be stored, received or transmitted by different parts of the computer
• Software


  Set of instructions to perform specific tasks on a computer
• Address


  Number that is used to locate a byte in memory
• Volatile


  Lost when the power supply is interrupted
• Hard disk (or hard drive)


  Secondary storage where data is stored on rigid rotating disks coated with a magnetic material
• Address bus


  Bus that is used to specify memory address information
• Input (computer architecture)


  Data or instructions that the computer receives for processing
• Input device


  Hardware device that allows users to enter data and instructions into a computer
• Uninterruptible power supply (UPS)


  Device that provides enough emergency power for a computer to properly shut down in case of a power failure
• Internet Protocol (IP) address


  Sequence of bytes used to identify a computer/device on the Internet
• Magnetic

  • Large capacity(TB), cheaper than both other two
  • Slower than solid-state, easily damaged and break over time
• Optical

  • Large capacity(GB)
  • Non-rewritable, lower capacity than Magnetic, Vulnerable to fingerprints & scratches
• Solid-state

  • Fastest, not vulnerable to fingerprints & scratches & drop, no noise, portable
  • Most expensive
• Read Only Memory (ROM): Computer memory that cannot be written or erased once it has been programmed.
• Random Access Memory (RAM): A type of computer memory that can be accessed quickly by the CPU.