The LINUX Operating System By Cathy Thiaw ID # COSC 513Lecturer: M. Anvari SEU‘99 Summer Term

Plan What’s Linux? Linux Features Resource Management Processes Security Comparison with other OS

What’s Linux? an OS initially created by Linus Torvalds (Finland) and a team working over the Internet; developed from MINIX, a small Unix system; An open and free operating system, adaptable to meet individuals needs;

Linux Features Multitasking Virtual memory Shared libraries Multi_users capabilities X-windows systems Run most Unix programs

Linux Features Advanced networking capabilities: LAN or WAN setting, different types of protocols, fast TCP/IP drivers Support for Macintosh, Windows, NT, Novell, OS/2 Server or Client

Resource Management Use of semaphores 1 process at a time can access to some resource The semaphore data structure includes a count of number of processes that wish to use a resource, a waking parameter (number of processes waiting to be woken up), and a wait queue.

Processes on Linux Interprocess-communications: Unix -liked mechanisms of signals, pipes and semaphores, shared memory... Relationships parent / child process Most process has virtual memory

Processes on Linux Max number of processes in the system: 512 State process: –*running –*waiting: interruptible or uninterruptible –-*stopped –*zombie: dead process

Security Security on Linux is comparable with most Unix system Security tools : firewalls, packets filtering, encryption, kerberos… are available Monitoring (logs) and audit of logon activities, resource utilization …available

Comparison with other OS Windows NT BSDI Solaris 7.0

Network Inter-operability Runnable foreign libraries: -Linux2.2: Windows 3.* ‑ 98 Mac (Executor), SCO and some other Intel based SysV's(iBCS) NT4: MAC(Executor),dos, windows 3.1/W32 BSDI: DOS, support for Linux in development Solaris: Macintosh,Windows 3.1

Network and Inter-operability Mountable filesystems Linux 2.2: FAT, FS read-only,HPFS read- only (OS/2), iso9660 (CDROM), minix, NTFS (read-only), HFS (MacOS)… NT4: FAT, NTFS, iso9660 BSDI: iso9660 Solaris: UFS, FAT (dos, windows),UFS, iso9660…

OS Convenience Bug fix and other updates: Linux2.2.: Freely download able NT4: not free BSDI: Some minor, updates/bugfixes can be downloaded freely. Solaris7.0: not free

References nux/index.html ‑ html/node45.h tml e_info.html ‑ HO WTO ‑ 9.html