process-table

tags: os process scheduler is_child_of: process

Process table

A process table is a data structure used by scheduler to store process information and state.

It has process information entries, also known as process control block. This process control block contains information about:

1. Process management
   1. Registers
   2. Program counter
   3. Program status word
   4. Process id
   5. Stack
   6. Process group
   7. Signals
   8. and so on.
2. Memory management
   1. Pointer to text segment
   2. Pointer to data segment
   3. Pointer to stack segment
3. File management
   1. File descriptors
   2. Root directory
   3. Working directory
   4. User ID
   5. Group ID

Bonus: /proc directory in Linux machine, we can see information stored about each process in user program space. Commands such as ps uses this information to show the process. However, ps also uses information from process table residing in kernel memory.