File Descriptors, Processes and Pipes, oh my!

For a more in-depth understanding of how processes and files work at the system level:

Read Chapter 0 of “xv6: a simple, Unix-like teaching operating system”

The xv6 operating system was developed at MIT for their operating systems engineering class. Chapter 0 of the documentation provides a really nice overview of what is going on at the system level when you run a command, redirect input/output, etc.

Self Study

1. This reading provides some insight about what is going on at the system layer when we start a program from the command line, redirect standard I/O, etc. Run a couple commands you are familiar with and think about what is going on at the system level when you run each one.

2. What is the relationship between the C standard I/O library calls such as fputc, fgetc, fputs, etc. and the system calls read and write?

3. What is the relationship between the FILE type defined by the C standard libraries, and file descriptors. What does the fileno library call do?