Systemd

Outcome Understand why PID 1 (“mommy process”) owns every orphan on the box Recall the SysV init flow & its pain points Know what systemd bundles and why nerds argue about it PID 1 — the mommy process Starts first in the kernel’s user-space hand-off → gets PID 1 Every other process is its child, grandchild, or further down the tree If a parent dies, PID 1 adopts the orphan so its exit status can be reaped (prevents zombies) Zombie = process finished execution but still holds a slot in the table; init uses wait() to clean it up SysV init (a.k.a. Sys5 or “classic init”) ...