File Types

File Types

1. Regular files

   • Contains user information.
   • ASCII
     • ASCII files consists of lines of text. Easy to display, print and connect the output of one program to the input of another.
   • Binary
     • They are not ASCII files.
     • executable binary
       • Although technically the file is just a sequence of bytes, the operating system will execute a file only if it has the proper format.
       • header
         • It starts with so-called magic number, identifying the file as executable file.
       • text
       • data
       • relocation bits
         • It loads the text and data of the program into memory and relocate them.
       • symbol table
         • It is used for debugging.
     • archive binary
       • It consists of a collection of library procedures compiled but not linked. Each one is prefaced by a header telling its name, creation date, owner, protection code, and size.

2. Directories

   • System files for maintaining the structure of the file system.

3. Character special files

   • Are related to input/output and used to model serial I/O devices.

4. Block special files

   • Used to model disks.