Advantages and disadvantages of Unix

Last revision August 2, 2004


  • Full multitasking with protected memory. Multiple users can run multiple programs each at the same time without interfering with each other or crashing the system.
  • Very efficient virtual memory, so many programs can run with a modest amount of physical memory.
  • Access controls and security. All users must be authenticated by a valid account and password to use the system at all. All files are owned by particular accounts. The owner can decide whether others have read or write access to his files.
  • A rich set of small commands and utilities that do specific tasks well -- not cluttered up with lots of special options. Unix is a well-stocked toolbox, not a giant do-it-all Swiss Army Knife.
  • Ability to string commands and utilities together in unlimited ways to accomplish more complicated tasks -- not limited to preconfigured combinations or menus, as in personal computer systems.
  • A powerfully unified file system. Everything is a file: data, programs, and all physical devices. Entire file system appears as a single large tree of nested directories, regardless of how many different physical devices (disks) are included.
  • A lean kernel that does the basics for you but doesn't get in the way when you try to do the unusual.
  • Available on a wide variety of machines - the most truly portable operating system.
  • Optimized for program development, and thus for the unusual circumstances that are the rule in research.


  • The traditional command line shell interface is user hostile -- designed for the programmer, not the casual user.
  • Commands often have cryptic names and give very little response to tell the user what they are doing. Much use of special keyboard characters - little typos have unexpected results.
  • To use Unix well, you need to understand some of the main design features. Its power comes from knowing how to make commands and programs interact with each other, not just from treating each as a fixed black box.
  • Richness of utilities (over 400 standard ones) often overwhelms novices. Documentation is short on examples and tutorials to help you figure out how to use the many tools provided to accomplish various kinds of tasks.
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