The Pib is the ID badge for each user. It tells the system all the internal administrative information it needs to track, such as what account the user is in, what kind of permissions are allowed, and how much time has been used.
Some of the D3 commands display PIB status bytes, which are described below:
Pib Major Byte (XX…)
| 0 | Sleeping | Page Fault | Echo not Enabled | I/O Bound | Outputting | Inputting | Active | |
| 1 | Activatible | Full Duplex | Comatose | |||||
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Pib Minor Byte (…XX)
| 0 | Sleeping | Page Fault | Echo not Enabled | Debug Attention Codes | ||||
| 1 | In Vir. Debugger | XOFF in effect | Typeahead enabled | XON/XOF supported | Debug Attention Codes | |||
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
3Fxx = Sleeping
5Fxx = Page Fault (Waiting for Disk I/O
7Bxx = Terminal is outputting
FBxx = Terminal is outputting
FDxx = Terminal is inputting
7Fxx = Active, or Ready to Go
FFxx = Active, or Ready to Go
Pibs need additional space to store information about the processes it is running, and a place to store the process data and variables. This area is called the Process Control Block (PCB).