Computer-Assisted Music  
 
Computer-Assisted Music (or CAM) is music generated or composed with the aid of computers. It  has its roots from the electronic music.
 
The first use of the Computer-Assisted Music was in the techno music at the end of the 20th century where some composers made music only with computers thanks to plugins (electronics synthesizers) and effects (like vocoders or modulation effects).
Subsequently, Lejaren Hiller (the Illiac Suite) used a computer in the 1950s to compose works for a philharmonic orchestra.
 
Nowadays, modern computers and web technology such as MIDI and mp3 take a large place in the music industry. Lot’s of producers used computers to compose, manipulate, play or perform their music .
 
There is some softwares to make music on your computer. The most famous are Cubase or Logic Studio on Macintosh. I used to work on Acid Pro (for PC) and a famous one : Fruity Loops Studio.  
There are two big classes of softwares : sequencers and samplers.
 
The samplers as Fruity Loops include many instruments with which you can use to write a melody.
I explain.
You’ve got a virtual keyboard in a window and you can associate any virtual instruments with a note and a rythm. When you think that your melody is finished, you can compress the sound to make a sample which can be used with another software. And you do it again with another instrument to make different ambiances.
The sequencers, like Cubase or Acid Pro, are used to make the final music. You can add the melodies you made with Fruity Loops for example and repeat the sample and associate it with other samples. You also can settle the beat per menute or add acoustic instruments or voices. Nowadays we can download more samples or effects from the web.