CSE 131 Chapter Notes - Chapter 1: Include Directive, Network Layer, Exokernel
Document Summary
Trap instruction: switches from user mode to kernel mode. Processes memory divided into 3 segments in unix have their. Between the data and stack is a gap of unused address space. Entire os runs as a single program in kernel mode. The os is written as a collection of procedures, linked together in a single large executable binary program. Each procedure in the system is free to call any other one. Pros: being able to call any procedure is very efficient. Cons: thousands of procedures without restriction is difficult to understand, a crash in any procedure with take down the entire os, no information hiding. Main program that invokes the requested service procedure. A set of service procedures that carry out the system calls. A set of utility procedures that help the service procedures. Organize the operating system as a hierarchy of layers. Allocated space for processes in main memory and drum.
