Computer Programs


This post is part 4 (out of 6) in a series of blog posts: 

  1. Computers Today
  2. Where Computers Came From
  3. Computer Hardware
  4. Computer Programs (this blog post)
  5. Why Are There so Many Programming Languages? 
  6. Where Did BASIC Come From?

  

What’s a Computer Program?

A computer program is an application full of instructions/commands that tell the computer how to carry out certain tasks (like a list of chores from your parents, or instructions you’re given on how to make a half-caf vanilla soy latte in a job at a coffeehouse). Computer programming is the act of writing these instructions.

A computer program includes instructions for every detail! Because of this heavy requirement for details, a new job position was created called a Program Manager (PM), to create the specifications for these computer programs. Computers only understand machine language. The alphabets of this language contain only two letters: 0 and 1. For example, on one type of computer, the instruction “10110110 00000000 10111011” commands the computer to read the number from memory address 187 and store it in one of its working memory areas. The first computer programs ever written, a long time ago, were actually entered into to the computer as 0s and 1s by flipping some switches on the computer’s front panel.

Because this process was so tedious and full of errors, people invented the assembly language to make the programmer’s job easier. For example, instead of typing 01001001, they’ll type ADD, and instead of typing 01111110 they’ll type JMP. A computer program written in assembly language for one computer could look like this:

movl $1, %eax

movl $0, %ebx

...

A specific computer program, called assembler, would then read the assembly code program and convert it to the 1s and 0s used by that computer.

Although assembly language was much easier to work with than machine language (the 1s and 0s), it was still not the best solution. Machine language and assembly language are low-level languages.

Ultimately, computer scientists invented high-level languages. These languages are a lot like English, but they’re much easier to understand and learn (tell that to your English teacher). Each of these languages is made up of a set of keywords and some rules of grammar that instruct you how to use these keywords. Take this side quest to learn about compilers: Small Basic Compiler.

 

Next, continue reading the 5th part in this series (or start with Part 1 if you skipped it): 

  1. Computers Today
  2. Where Computers Came From
  3. Computer Hardware 
  4. Computer Programs (this blog post)
  5. Why Are There so Many Programming Languages? 
  6. Where Did BASIC Come From?

       

Have a good buy! The best buy ever!!!

   - Ninja Ed & Majed Marji

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