Questions

Compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony and released in 1982. 

These are actually made to replace floppy disks that were used to store files and programs from the computer.

The format was originally developed to store and play only sound recordings but was later adapted for storage of data (CD-ROM).ese CD's uses Laser technology.

The one word substitute for "a person who is always dissatisfied" is malcontent.

Normal Gas welding use oxygen-acetylene.

Depending on what materials you are welding, there are some more options that might be used.

For example - MIG/TIG use Argon, MAG use an argon-something mix.