An Overview of the Linux Operating System Group Members: Chad Dalton Robert Grey Jonathan Mencher Andrew Serene Greg Tumolo

Overview of Presentation: History and General Description Basic Features of the Early OS Process Description and Management Thread Description and Management Memory Management The File System

Linux History Linux began as an effort by Linus Torvalis to replicate the minix operating system for free Evolved into an open source project supported and developed by users across the internet Ported to several processors including Alpha, Sun SPARC, Motorola, and the Apple PowerPC Major companies have evolved distributions

Main Features of the OS Multi User, Multi Tasking OS Process Oriented with Multi-Threading Offers X Windows graphical interface Extremely Internet Oriented

The Early Kernel and Basic Services True Microkernel Architecture Basic Kernel Services Process and Thread Management Module Loading Initialization of OS Basic OS Services Command Prompt Compiler Access to Hardware Virtual Memory File System

Process Description and Management Description of Processes task_struct Controls process table Creates processes Process Table Structure 2 links to previous and next Process State Running, Waiting, Stopped and Zombie Process Security Process has privileges of parent

Thread Description and Management Description of Threads First used in version 1.3.56 User Level Less overhead Cause starvation Kernel Level Require mode changes Preferred in Linux Allow for SMP in Linux Thread Classification

Memory Management Paging scheme is utilized in Linux Block scheduling Aging variable mem_map_t and mm_struct mem_map_t -> physical memory mm_struct -> virtual memory

The File System Linux File System History EXT EXT2 VFS – Virtual File Syste Supports many file systems including msdos, smb, iso9660, sysv, hpfs, etc. Inode is a basic component File systems are “mounted” in Linux Possible to mount over existing directory Original Structure is returned after “unmounting”