1. CENG334 Introduction to Operating Systems Erol Sahin Dept of Computer Eng. Middle East Technical University Ankara, TURKEY URL: http://kovan.ceng.metu.edu.tr/ceng334 Linux and Overview Topics:

2. 2 Linux May 14, 1991, Finnish student Linus Torvalds releases Linux v 0.01 on the internet small but self-contained kernel for Intel 80386, implementing a small number of UNIX services. run only on 80386 processors impemented processes and protected address spaces fairly basic virtual memory system with no support for memory-mapped files extremely limited device driver support supported Minix file system (Tanenbaum) no networking March 14, 1994, Linux 1.0 networking, included support for TCP/IP networking protocols ext2, an enhanced file system extended virtual memory system to support paging to swap files and memory mapping of files still restricted to Intel X86 platform hardware support extended to floppy disk, Cdrom devices, sourd cards/ IPS (interprocess communication) insluding shared memory, semaphores, and message queues were implemented. Simple support for loadable and unloadable kernel modules.

3. 3 Linux March 1995, Linux kernel 1.2 released. Side note: odd numbered minor version numbers are development kernels such as 1.1 odd numbered minor version numbers are production kernels such as 1.2 The last Intel only kernel much wider hardware support including the PCI hardware bus architecture revised networking June 1996, Linux kernel 2.0 support for multiple architectures Intel, 64-bit Alpha, Motorola 68000 series, Sun SPARC series multi-processr systems memory management code greatly improved unified caching of file-system and data caching extended to networked file system improved TCP/Ip performance Support for internal kernel threads Handling dependencies between kernel modules and automatic loading of modules on demand

4. 4 Linux January 1999, Linux kernel 2.2 port for UltraSPARC Networking improved for better firewallling routing, traffic management kernel level NFS daemon Better and fine-grained signal handling Improved SMP performance Linux kernels 2.4, and 2.6 increased support for SMP journalling file systems enhancements to MM In 2.6, a new process scheduler with O(1) scheduling algorithm was added In 2.6, kernel is now fully preemptive allowing a process to be preempted while it's running in kernel mode.

5. 5 Linux Linux distribution: Linux kernel + Many other components gnu toold, gcc, gdb X windowing system Linux licensing Under GPL (Gnu Public License) cannot be distributed as only in binary form, source code should be included does not prohibit selling of software however, any derivations of GPL code should also be released under GPL

6. 6 MT results Avg: 52.5 Variance: 24.1

7. 7 Looking back You have come a long way in this class !!! Virtual memory Processes and threads Scheduling Locks Mutexes and CVs Race conditions NFS and RAID Deadlock Page replacement TLBs Disk I/O Scheduling Kernel architecture Hardware support Virtual machines