Introduction to Operating Systems

1. Introduction to Operating Systems M.C. Juan Carlos Olivares Rojas Operating Systems jolivares@uvaq.edu.mx February, 2009

2. Outline • Operating Systems History • Basic Concept about OS • OS Architecture • Monolitic • By Layers • Microkernel • Others • OS Virtualization • OS Installation (Solaris, Windows 7, Linux, FreeBSD, MacOSX).

3. Operating System Description What’s an Operating System? • It’s a software which control a computer, It acts like a Human-Machine Interface. It manages all the resources (hardware and software) of a Computer System. • What’s a System? • It’s a set of elements which are interrelated for achiving a common objective.

4. Introduction

5. Operating Systems • The objective of an Operating System is the operation of a Computer. • It’s the computer principal software which execute when the computer is turned on. • Does a calculator have an Operating System? Why?

6. Introduction Bank Systems Reservation Web Browser Application programs Compilers Editors Command Interpreter System programs OPERATING SYSTEM Machine Language Hardware Microprogramming Physical Devices

7. Operating Systems • The Operating System development is influented by technological development. The Operating System premisses (objective function) are: • Minimize the effort (human-machine frontier). • Maximize the computer resources performance

8. Operating Systems • The principal resources managed by an Operating System are: • Process, Tasks, Applications (Process Management) • Devices, Peripherals (I/O Management) • Memory (Memory Management) • Data (File System)

9. Operating Systems

10. Operating Systems • The esential part of an Operating System is the Kernel. • An Operating System is executed in supervisor mode of the microprocessor (it can access all microprocessor functions). • The programs are executed in user mode.

11. Operating Systems • The Operating Systems actions depends of the applications that run on it. • It’s no the same resource administration for a monouser system than multiuser system, or process administration in a multitask system than time-sharing system. • Operating Systems are totally dependent of computer architectures.

12. Operating Systems • This is the reason why Operating Systems such as Windows can not be executed over Power PC Architectures, because it´s linked an x86 Intel Architecture. • Recently 64 bits microprocessor are becoming popular, for this reason is necesary and special operating Systems for the correct resources utilization.

13. Operating Systems • Actually Operating System supports multitasking and concurrence in native form on multiprocessor or multicore processors. • For the good use of resources, Operating Systems need to use politics and control mechanism. An Operating System has to plan, control, drive and execute all the system operations.

14. Operating Systems • The programs can access directly to some function in superivor mode throught a System Call. • An operating System has an interface to users and other interface to programms (programmers). • In UNIX this distnction doesn’t exist.

15. Operating Systems • As well hardware and software are not mutually exclussive (they are a binom). Operating System are in the middle of this resources. • Actually the trend is construct operating Systems for Emedded Devices such as: ATM, watchs, PDAs, cell phones, electrodoméstics, etc.

16. Operating Systems • Another Operating Systems which are growing are Real-Time OS. • Examples of Operating Systems are: DOS, Windows, Unix, Linux, Mac OS X, among others.

17. Operating Systems History • Quiz1 • What was the firt OS for 32 Bits PCs? • When was Linux OS appear? • What was the first important OS constructed enterily in high level programming language? • What is the most recent Linux Version?

18. Operating System History • In the begining Turing created the machine… • The Operating System History comes hand in hand with hardware and software evolution. • The computer paradigms have changed with the pass of the times, for instance de 1950‐1970 decade the concept of “one computer many users” appears.

19. Operating Systems History • In1980‐1990 decade the computer paradigm shifted to “one computer one user”. • Finally in this decade, the paradigm shift to “one user many computers”.

20. Operating Systems • In the Generation 0 (1940’s) and First Generation (1950’s) the Operating System doesn’t exist, reason why users have to configure the circuits for operating the machine. • The second generation (1960’s) appears the first OS which principal fuction was to act like a extended machine.

21. Operating System History • All the OS was constructed in assembler language, reason why it was totally dependant of the machine. • The OS only can manipulate some peripherals. The batch processing was used to improve the resources use. • In Third Generation (1970’s) OS was more complex because they used concepts such as multiprogramming and time-sharing.

22. Operating Systems • Unix was the first OS constructed in a High-Level Language (C Languaje) with only the critical part (I/O) in assembler. • In the Fourth Generation (1980’s) appears the first extremely-used OS in PCs: DOS and Windows. Reason why OS was more complex and more easy to use.

23. Operating System History • Since 1990 the computer network utilization (overall Internet) and multimedia in OS was extended in such way than today are present in any OS. • Activity: in personal Way write a essay with the three most important Linux commandments, describe why this three point are important for you

24. Introduction IBSYS IOCS 55 60 65 70 75 80 85 90 95 00 03 CTSS DOS/360 OS/360 MULTICS CP/CM5 RSX-11M UNIX TSO RT-11 CP/M UNIXV.7 VMS 1.0 DOS/VDSE MVS/370 VM/370 4.1BSD XENIX MS-DOS 1.0 SYSTEM III DR/DOS SUN OS 4.2BSD VS MVS/XA VM/XA SYSTEM V AIX OS/2 POSIX MACH WIN 3.0 OSF/1 4.3BSD VMS 5.4 WIN 3.1 AIX/370 SYSTEM V.4 VS/ESA MVS/ES VM/ESA AIX/ESA SOLARIS 2 LINUX 4.4BSD WIN NT WIN 9X VMS 7.3 WIN 2000 LINUX 2.6 WIN XP SOLARIS 10 WIN Server 2003

25. Windows and Linux Evolution 1970 1980 1990 2000 VMS v1.0 NT 4.0 Server 2003 Windows XP Windows 2000 Windows NT 3.1 1970 1980 1990 2000 v2.0 v2.6 v2.2 v2.3 v2.4 Linux v1.0 UNIX V6 UNIX público Nacimiento de UNIX

26. Operating System Basic Concepts ACTIVITY: • The principal aspects of an Operating Systems are: process, file, shell and system calls. • In pairs, explain with practical exercises how we can note this concept in a OS. • Develops a Rubric with your own metrics (5 or more) and evaluate the follow OS: Linux, Windows 6.0, Solaris 10, Mac OS X 10.5

27. OS Basic Concepts • Process is a program in execution. • File: basic unit of persistent storage information • Shell: a part in an OS which functions like an interface (front end) between programms and user with OS (back end). This term generally is focused in Command Line Interfaces (CLI).

28. OS Basic Concepts • System Call: is the way in how programs can acess to supervisor mode instructions of microprocessor throught kernel. • It’s important don’t confuse the call system and command terms; for instance, kill is a command (calling by usuers) which let to send signals to process; and kill() is system call (calling by a programm) which do the same.

29. OS Structure • Operating Systems have evolutioned in its internal form trying to achive its performance. • All OS have a process which fuction is load the OS and the Applications, this process is called Loader. For instance, Linux have loader like LILO (Linux LOader) and Grub. • The loader use a boostrap to expand the OS.

30. OS Structure • All OS have a core process called Kernel, it has the basic routines of an OS. • Some OS use the microkernel concept, this have the function to coordinate to the other parts of an OS such as : I/O Devices, Process, Memory and File Systems. • The structure of and OS could be different but in most of the time are very similar because some OS use Open Standards.

31. OS Architecture • The first structure for an OS was Monolithic Structure. This doesn´t have any real structure, this is the reason why OS is only one big process called Kernel. • Other well-know structure for OS is client-server model in where OS have server process management each one of system resources and kernel functions in base a one client making request to servers.

32. Monolithic Architecture App App User Mode Kernel Mode System Services OS Procedures Hardware

33. OS Architecture • This Client-Server function has to let OS portability to another architectures such as distrubted architectures, where each service could be localizate in diferent remote machines. • Other Architecture was Ring Architecture, where OS is structured in concentric circles called Rings. Each Ring has a well-defined structure.

34. OS Architecture • The most used Architecture in OS is Layer Architecture, where Layers are divided in diferente levels like Ring Architectures. Inside each layer can exist two o more levels. Layers can interact with higher an lower levels thus in the same level.

35. Layer Architecture OS Application Program Application Program Application Program User Mode Kernel Mode System Service File System I/O and Memory Management System Process Management Hardware

36. Microkernel Architecture Client Application Memory Server Network Server Process Server File Server Display Server User Mode Kernel Mode Microkernel Request Response Hardware

37. Windows NT High-Level Architecture User’s Application DLL Subsystem Environment Subsystems Services and System Process Windows POSIX OS/2 Windows User Mode Kernel Mode Executive Windows User/GDI Device Driver Device Handler Kernel Hardware Abstraction Layer (HAL)

38. Windows NT Architecture Control Management Service LSASS SvcHost.Exe Task Manager WinMgt.Exe Explorer WinLogon SpoolSv.Exe User Applications Services.Exe User Mode DLLs Subsystem Kernel Mode Envinroments Subsystem Procesos del Sistema Services Applications Windows OS/2 Session Handler POSIX Windows DLLs System Thread NTDLL.DLL System Dispatch System (Kernel Mode Interfaceel) Windows USER, GDI I/O Manager File System Cache Object Handler Plug and Play Manager Energy Manager Security Reference Monitor Virtua Memory Process and Threads Configuration Manager (Registry) Local Process Call File System and Device Drivers Grpahical Manager Kernel Interfaces de Hardware(buses, Dispositivos de E/S , interrupcciones, intervalos de temporizadores, DMA, control de memoria cache , etc.) Hardware Abstraction Layer (HAL)

39. Windows NT Architecture • Kernel and Executive are located at ntoskrnl.exe program • Inside Executive are located File, Memory and Process Manager. • Device Handler are located in files with *.sys management.

40. Windows NT Architecture • Wndows Handler is located windowsk.sys file • HAL is located at hal.dll • Most of Windows Code is writed in C, some of this component are developed at C++. One of the trends is writing legacy modules in C++ • Operating System such Windows Vista has more than 20 millions of line of codes.

41. Windows NT Architecture Core OS components: NTOSKRNL.EXE Executive and kernel HAL.DLL Hardware abstraction layer NTDLL.DLL Internal Support Systems Fundamentales System Process: SMSS.EXE Service Management Process WINLOGON.EXE System Authentication Process SERVICES.EXE Control Services Process LSASS.EXE Local Security Authority Subsystem Windows Subsystem: CSRSS.EXE* Windows Process Subsystem WIN32K.SYS USER and GDI Components KERNEL32/USER32/GDI32.DLL Windows subsystem DLLs

42. WoW64 • Win32 over Win64 is the Windows Subsytem which Execute Win32 applications in 64-bits environments in transparent mode. • Other diferences implie in the word length of data and addressing memory of an OS. • HOMEWORK: Writing a Research Document where compares Windows NT Architecture with Linux 2.6.

43. WoW64 32-bit EXE, DLLs 32-bit ntdll.dll Wow64cpu.dll Wow64win.dll Wow64.dll 64-bit ntdll.dll Modo Usuario Win32k.sys Ejecutivo Modo Kernel

44. Homework • Show High-Level Linux Architecture and Explain it (40%) • Show the diferences beetwen each module and explain how it works. Detail all the modules which only exist in Linux or Windows (60%). • Section not present (-10%). Without References 0 is the grade.

45. OS Virtualization • Virtualization isn’t a new concept. I was originated in 1970s by IBM in its OS VM/360. • The “virtual” term means “a thing with simulated existence Abstraction. • Every Problem in Computing Science can be solved by adding an indirection layer.

46. OS Virtualization • In Computing a lot of things are virtual: • Virtual Reality • VLAN (Virtual LAN) • VNC (Virtual NetworkComputing) • VPN (Virtual PrivateNetwork) • Virtual Memory • Virtual Storage • JVM (Java Virtual Machine) • ….

47. OS Virtualization • Actual Problems in OS: • Security (viruses) • Legacy Software • Performance • Incompatibility between applications in diferent OS • All these problems can be solved through Virtualization. • Virtualization is another OS Architecture using and special core element called Exokernel.

48. OS Virtualization • Aproximately only 10% of time a computer is working. • “Virtualization = Freedom. One server can be the work of many” • Around 20% (in 2006 10%) of server are virtualized.

49. OS Virtualization

50. OS Virtualization • Some virtualization tools are: • Bochs and QEMU (emulation) • VMWARE, Virtual PC, Virtual Box, Parallels Workstation (Completed Virtualization) • Xen andUser-ModeLinux (UML) paravirtualization • Linux V-Server and OpenVZvirtualización (OS Virtualized)