Physical organization of a computer

  • What a computer looks like physically:

Physical organization of a computer

  • Categories of the computer components:

Logical (functional) organization of a computer

  • What a computer looks like logically (= by their function):

What a computer looks like from inside

  • When you open the computer case, the inside of the computer looks like this:

What a computer looks like from inside

  • The computer system consists of only 2 (functional) parts:

What a computer looks like from inside

  • The RAM (or Random Access Memory) stores/contains computer programs:

What a computer looks like from inside

  • The CPU (or Central Processing Unit) execute instructions in programs:

Updated logical (functional) organization of a computer

  • What a computer looks like logically (= by their function):

Components of a computer

A computer consists of 4 types of components:

  1. Central Processing Unit (= CPU) = "brain" of a computer
  2. Main memory (= RAM) = storage space of a computer

  3. Input devices = devices used to receive data into the computer
  4. Output devices = devices used to output data from the computer

We take a closer look at the computer (main) memory component next

Computer memory (a.k.a.: Random Access Memory or RAM)

  • The main memory or RAM consists of many memory cells:

  • Each memory cell is uniquely identified by a memory address (which is an integer number)

      • Note: memory addresses always starts at the number zero (0)

  • Each memory cell can store a small number

      • A computer can only store numbers !!!     

Analogy to help you understand a computer memory

  • The main memory or RAM is similar to a collection of mail boxes:

  • Each mail box is uniquely identified by an integer mail box number

      • Imagine that: each mail box contains a (small) slip of paper !!

  • Each memory cell's slip of paper can store a small number

Operations that a computer can perform on the main memory

  • The computer can perform 2 operations on the main memory:

      1. Write operation:   the computer stores a number into one or more memory cells at a specific memory address

      2. Read operation:   the computer retrieves the number from one or more memory cells at a specific memory address

Analogy to help you understand the write and read operations to a computer memory

  • The write operation and the read operation to the computer memory is similar to the store and recall operations of a calculator:

Question:   how can a computer store things (like text) other than numbers ?? --- To be revealed