• A fork() in the road : r/programming
• A fork() in the road - Microsoft Research

Where is the cursor stored for a file?

• every time there's system call open(), a new entry is generated for the open file table.
• if process forks, both the parent and child share a pointer to the same open file entry, and therefore their cursors will be the same.

Assignment 2: The Unix v6 Filesystem

• to write a program in C(not in C++) that can read from a 1970s-era Unix version 6 filesystem.

  • the test data you are reading from are literally bit-for-bit representations of a Unix v6 disk.

• writing code in for different files

  • inode.c
  • file.c
  • directory.c
  • pathname.c

• since it's in C, you'll have to rely on arrays of structs, and low-level data manipulation, as you don't have access to any C++ standard template library classes.

• must formulate your questions to be conceptual enough

More on Multiprocessing

• waitpid can be used to temporarily block one process util a child until a child process exit.
  • pid_t waitpid(pid_t pid, int *status, int options);
  • pid specifies the wait set
  • *status supplies the address of an integer where termination information can be placed(or we can pass in Null if we don't care for the information)
  • options is a collection of bitwise-or'ed flags. for the time being, we'll just go with 0 as the required parameter value, which means that waitpid should only return when a process in the supplied wait set exists.
  • return value is the pid of the child that exited, or -1 if waitpid was called and there were no child processes in the supplied wait set.