Introduction to Computer Architecture

Computer Instructions

Computer instructions are written in binary, also known as machine code. Computer hardware operates on a series of these binary instructions through pulsating power signals that signify either OFF or ON based on the binary digits 0 and 1 respectively.

Binary Numbering System

The binary numbering system is built on a base of 2. Every time we reach a power of 2, we add another digit. The decimal system works the same way, just with 10.

Counting to 10 in binary:

Decimal    Binary
   0         0
   1         1
   2         10
   3         11
   4         100
   5         101
   6         110
   7         111
   8         1000
   9         1001
  10         1010

Least and Most Significant Bits (LSBs and MSBs)

The Least Significant Bit (LSB) is the farthest right digit in a binary number while the Most Significant Bit (MSB) is the leftmost digit. 0 is an acceptable value for both the MSB and the LSB.

8675309 expressed in Binary:

  100001000101111111101101
  ^                      ^
 MSB                    LSB

Binary Data

Binary data is any set of expressions that result in a response set of only two answers.

Binary Data Examples:
  - TRUE or FALSE
  - ON or OFF
  - 0 or 1
  - LEFT or RIGHT

Non-Binary Data Examples:
  - TRUE/FALSE/MAYBE
  - LEFT/RIGHT/CENTER
  - Ages of coworkers

Main Functions of a Computer

There are four main functions of a computer that make user interaction possible:

Input
Processing
Memory
Output

- Input is data we give to our computers through interactions
- Processing is comprised of the translation of input and the instructions given for output
- Memory is used to store either temporary or permanent information
- Output is the information that gets returned by the computer