Computer Memory Organization

Main Memory Organization

• A bit is the smallest piece of memory, holding an electrical charge (positive or negative).
• A byte is 8 consecutive bits, having an address in memory, and there are millions or billions of bytes in a computer.

Secondary Storage

• Non-volatile/permanent storage holds data when the program is not running or the computer is turned off.
• Types of secondary storage include:
  • Disk drive (magnetic storage)
  • Optical storage (CD or DVD drive)
  • Flash storage (USB flash drive)

Software Programs

• System software manages the computer hardware and programs, and includes:
  • Operating Systems (control computer operations, manage devices, and allow programs to run)
  • Utility Programs (support programs, e.g. virus scanners, data backup, file compression)
  • Software development tools (used by programmers, e.g. compilers, integrated development environments)

Hardware Components

• Input devices send information to the computer from outside, examples include:
  • Keyboard, mouse, touch screen
  • Microphone, scanner, digital camera, disk drive, CD/DVD drive, USB flash drive
• Output devices send information from the computer to the outside, examples include:
  • Computer screen, printer, speakers, disk drive, CD/DVD recorder, USB flash drive

Central Processing Unit (CPU)

• The CPU is a hardware component that runs programs, comprising:
  • Control Unit (retrieves and decodes program instructions, coordinates computer operations)
  • Arithmetic & Logic Unit (ALU) (performs mathematical operations)

The CPU's Role in Running a Program

• The CPU cycles through:
  • Fetch (get the next program instruction from main memory)
  • Decode (interpret the instruction and generate a signal)
  • Execute (route the signal to the appropriate component to perform an operation)

Main Memory

• Main memory holds both program instructions and data.
• Main memory is volatile (erased when the program terminates or computer is turned off).
• Also known as Random Access Memory (RAM), as the CPU can access data and instructions from any memory location.

Why Program?

• A computer is a programmable machine designed to follow instructions.
• A program/software is a set of instructions that a computer follows to perform a task.
• A programmer is a person who designs, creates, and tests programs for computers.

Programming

• Programming involves both artistry and science:
  • Artistry: organization of tasks, information display, user interaction
  • Science: understanding the language used to write the program, testing, and changing it if needed

Hardware Component Categories

• Main hardware component categories include Central Processing Unit (CPU), Main Memory (RAM), Secondary Storage Devices, Input Devices, and Output Devices.

Input Devices

• Input devices are used to send information to the computer from outside.
• Examples of input devices include keyboard, mouse, touch screen, microphone, scanner, digital camera, disk drive, CD/DVD drive, and USB flash drive.

Output Devices

• Output devices are used to send information from the computer to the outside.
• Examples of output devices include computer screen, printer, speakers, disk drive, CD/DVD recorder, and USB flash drive.

Central Processing Unit (CPU)

• The CPU is a hardware component that runs programs.
• It includes the Control Unit, which retrieves and decodes program instructions and coordinates computer operations.
• It also includes the Arithmetic & Logic Unit (ALU), which performs mathematical operations.

CPU's Role in Running a Program

• The CPU's role in running a program involves a cycle of:
  • Fetch: getting the next program instruction from main memory.
  • Decode: interpreting the instruction and generating a signal.
  • Execute: routing the signal to the appropriate component to perform an operation.

Main Memory

• Main memory holds both program instructions and data.
• It is volatile, meaning it is erased when the program terminates or the computer is turned off.
• It is also called Random Access Memory (RAM) because the CPU can access data and instructions from any memory location.

Secondary Storage

• Secondary storage is non-volatile, meaning it holds data even when the program is not running or when the computer is turned off.
• Examples of secondary storage include disk drives, optical drives (CD or DVD), and flash drives (USB flash drive).

Software

• System software manages the computer hardware and the programs that run on the computer.
• Examples of system software include Operating Systems, Utility Programs, and Software development tools.

Programming

• Programming is both an art and a science.
• The artistry of programming involves the organization of tasks, display of information, and user interaction.
• The science of programming involves understanding the programming language and testing the program.

Hardware Component Categories

• Main hardware component categories include Central Processing Unit (CPU), Main Memory (RAM), Secondary Storage Devices, Input Devices, and Output Devices.

Input Devices

• Input devices are used to send information to the computer from outside.
• Examples of input devices include keyboard, mouse, touch screen, microphone, scanner, digital camera, disk drive, CD/DVD drive, and USB flash drive.

Output Devices

• Output devices are used to send information from the computer to the outside.
• Examples of output devices include computer screen, printer, speakers, disk drive, CD/DVD recorder, and USB flash drive.

Central Processing Unit (CPU)

• The CPU is a hardware component that runs programs.
• It includes the Control Unit, which retrieves and decodes program instructions and coordinates computer operations.
• It also includes the Arithmetic & Logic Unit (ALU), which performs mathematical operations.

CPU's Role in Running a Program

• The CPU's role in running a program involves a cycle of:
  • Fetch: getting the next program instruction from main memory.
  • Decode: interpreting the instruction and generating a signal.
  • Execute: routing the signal to the appropriate component to perform an operation.

Main Memory

• Main memory holds both program instructions and data.
• It is volatile, meaning it is erased when the program terminates or the computer is turned off.
• It is also called Random Access Memory (RAM) because the CPU can access data and instructions from any memory location.

Secondary Storage

• Secondary storage is non-volatile, meaning it holds data even when the program is not running or when the computer is turned off.
• Examples of secondary storage include disk drives, optical drives (CD or DVD), and flash drives (USB flash drive).

Software

• System software manages the computer hardware and the programs that run on the computer.
• Examples of system software include Operating Systems, Utility Programs, and Software development tools.

Programming

• Programming is both an art and a science.
• The artistry of programming involves the organization of tasks, display of information, and user interaction.
• The science of programming involves understanding the programming language and testing the program.