Why UNIX?

• Operating system code in C is
  easy to read and understand
  easy to change
  easy to port to new machines

• Simple user interface

• Complex programs can be built by combining simpler ones

• Hierarchical file system

• Simple, consistent format for files

• Simple, consistent interface for devices (they look like files)

• Multi-user system with protection and optional sharing

• Multiprocessing

• Programmer's interface is hardware independent

• Harder than some systems to start using
  Easier to become a guru