Computer Fundamentals And Operating System Concepts PDF

Computer Fundamentals And Operating System Concepts Sunbeam Infotech www.sunbeaminfo.com Operating Systems and Computer Fundamentals Module introduction CCAT point of view: - Operating Systems: 9 Questions - Computer Fundamentals + Networking: 10 Questions Refer...

Computer Fundamentals And Operating System Concepts Sunbeam Infotech www.sunbeaminfo.com Operating Systems and Computer Fundamentals Module introduction CCAT point of view: - Operating Systems: 9 Questions - Computer Fundamentals + Networking: 10 Questions Reference Book: - Operating System Concepts - Galvin Sunbeam Infotech www.sunbeaminfo.com Operating Systems and Computer Fundamentals Practice Exam : - Quiz : 4 quiz exam OS ( 10 Question ) - Quiz : 1 quiz exam Computer Fundamentals ( 10 Question ) - Module End Quiz Exam ( 20 Question ) Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts  Introduction: - o Why there is need of an OS? o What is an OS? o Booting process in brief o Functions of an OS Computer Fundamentals: o Major Components : Processor, Memory Devices & IO Devices. o Memory Technologies and its characteristics o IO Techniques Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts UNIX System Architecture Design o Major subsystem of an UNIX system: File subsystem & Process Control subsystem. o System Calls & its categories o Dual Mode Operation Process Management o What is Process & PCB? o States of the process o Process life cycle o CPU scheduling & CPU scheduling algorithms o Inter Process Communication: Shared Memory Model & Message Passing Model o Processor architecture (CF) Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Process Management o Process Synchronization/Co-ordination o Deadlocks & deadlock handling methods Memory Management o Memory types (CF) o Swapping o Memory Allocation Methods o Internal Fragmentation & External Fragmentation Segmentation o Paging o Virtual Memory Management Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts File Management o What is file? o What is file system & file system structure? o Disk structure (CF) o Disk space allocation methods o Disk scheduling algorithms o Computer structure (CF) o Interrupts (CF) o Direct Memory Access (CF) o Input-Output (CF) o System calls Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Q. Why there is a need of an OS? - Computer is a machine/hardware does different tasks efficiently & accurately. - Basic functions of computer : 1. Data Storage : Memory Devices 2. Data Processing : CPU/Processor 3. Data Movement : I/O Devices 4. Control - As any user cannot communicates/interacts directly with computer hardware to do different tasks, and hence there is need of some interface between user and hardware. Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Diagram :OS Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Q. What is an Operating System? o An OS is a system software (i.e. collection of system programs) which acts as an interface between user and hardware. o An OS also acts as an interface between programs and hardware. o An OS allocates resources like main memory, CPU time, i/o devices access etc... to all running programs, hence it is also called as a resource allocator. o An OS controls an execution of all programs and it also controls hardware devices which are connected to the computer system and hence it is also called as a control program. Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts o An OS manages limited available resources among all running programs, hence it is also called as a resource manager. From End User: An OS is a software (i.e. collection of programs) comes either in CD/DVD, has following main components: 1. Kernel: It is a core program/part of an OS which runs continuously into the main memory does basic minimal functionalities of it. e.g. Linux: vmlinuz, Windows: ntoskrnl.exe 2. Utility Software's: e.g. disk manager, windows firewall, anti-virus software etc... 3. Application Software's: e.g. Google chrome, shell, notepad, MS office etc... Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Q. What is a Software? o Software is a collection of programs. Q. What is a Program? o Program is a finite set of instructions written in any programming language (either low level or high level programming language) given to the machine to do specific task.  3 types of programs are there: 1. "user programs": programs defined by the programmer user/developers e.g. main.c, hello.java, addition.cpp etc.... 2. "application programs": programs which comes with an OS/can be installed later e.g. MS Office, Notepad, Compiler, IDE's, Google Chrome, Mozilla Firefox, Calculator, Games etc.... 3. "System Programs": programs which are inbuilt in an OS/part of an OS. e.g. Kernel, Loader, Scheduler, Memory Manager etc... Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Functions of an OS: Basic minimal functionalities/Kernel functionalities: 1. Process Management 2. Memory Management 3. Hardware Abstraction 4. CPU Scheduling 5. File & IO Management Extra utility functionalities/optional: 6. Protection & Security 7. User Interfacing 8. Networking Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts What is an IDE (Integrated Software Development) ? o It is an application software i.e. collection of tools/application programs like source code editor, pre-processor, compiler, linker, debugger etc... required for faster software development. e.g. VS code editor, MS Visual Studio, Net beans, Android Studio, Turbo C etc.... 1. "Editor": it is an application program used to write a source code. Source Code – Program written in any programming language. e.g. notepad, vi editor, gedit etc... 2. "Pre-processor": it is an application program gets executes before compilation and does two jobs - it executes all pre-processor directives and removes all comments from the source code. e.g. cpp 3. "Compiler": it is an application program which converts high level programming language code into low level programming language code i.e. human understandable language code into the machine understandable language code. e.g. gcc, tc, visual c etc... Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts 4. "Assembler": it is an application program which converts assembly language code into machine language code/object code. e.g. masm, tasm etc... 5. "Linker": it is an application program which links object file/s in a program with precompiled object modules of library functions exists in a lib folder and creates final single executable file. e.g. ld: link editor in Linux. Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Booting Process  Terminologies : Bootstrap Program It loads OS kernel into main memory Each OS has Its own Bootstrap program. Located in first sector of bootable storage device. Bootable Device Storage device whose first sector (512 bytes) contains a special program “Bootstap Program “. Usually it is device that stores OS installation setup; E.g. Bootable CD/DVD ,Bootable Pendrive. Bootloader When multiple OS are installed on single computer, at the beginning one program asks end user about which OS boot. This task perform by bootloader program. Bootloader program bootstrap program of selected OS. Located in second sector of bootable storage device. Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts BIOS/Firmwaer Firmware is a program/set of a program loaded into base ROM of motherboard. It is developed by Manufacturer of motherboard. The firmware developed for PC (by IBM) is named as BIOS : Basic Input Output System BIOS Contain POST/BIST Bootstrap loader Information utility Bootable Device preference/settings Basic/Minimal device driver. POST/BIST POST - Power ON Self Test BIST - Built In Self Test Send signal to all peripheral(e.g. keyboard , mouse, monitor…)and test if they are functioning well. Located in Base ROM(Part of Firmware) Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Bootstrap Loader : Finds the bootable device in the computer and start it’s Bootloader. It check all devices in a order given in BIOS and start the first found bootable device. Located in Base ROM (Part of Firmware). Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts oUNIX Operating System: o UNIX : UNICS – Uniplexed Information & Computing Services/System. o UNIX was developed at AT&T Bell Labs in US, in the decade of 1970’s by Ken Thompson, Denies Ritchie and team. o It was first run on a machine DEC-PDP-7 (Digital Equipment Corporation Programmable Data Processing-7). o UNIX is the first multi-user, multi-programming & multi-tasking operating system. o UNIX was specially designed for developers by developers o System architecture design of UNIX is followed by all modern OS’s like Windows, Linux, MAC OS X, Android etc..., and hence UNIX is referred as mother of all modern operating systems. Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts o Kernel acts as an interface between programs and hardware. o Operating System has subsystems like System Call Interface Block, File Subsystem Block, Process Control Subsystem Block (which contains IPC, Memory Management & CPU Scheduling), Device Driver, Hardware Control/Hardware Abstraction Layer. o There are two major subsystems: 1. Process Control Subsystem 2. File Subsystem o In UNIX, whatever is that can be stored is considered as a file and whatever is active is referred as a process. o File has space & Process has life. Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts o From UNIX point of view all devices are considered as a file o In UNIX, devices are categorizes into two categories: 1. Character Devices: Devices from which data gets transferred character by character character special device file e.g. keyboard, mouse, printer, monitor etc... 2. Block Devices: Devices from which data gets transferred block by block  block special device file e.g. all storage devices. o Device Driver : It is a program/set of programs enable one or more hardware devices to communicate with the computer’s operating system. o Hardware Control Layer/Block does communication with control logic block i.e. controller of a hardware. Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Dual Mode Operation: System runs in two modes: 1. System Mode 2. User Mode 1. System Mode: o When the CPU executes system defined code instructions, system runs in a system mode. o System mode is also referred as kernel mode/monitor mode/supervisor mode / privileged mode. 2. User Mode: o When the CPU executes user defined code instructions, system runs in a user mode. o User mode is also referred as non - privileged mode. o Throughout execution, the CPU keeps switch between kernel mode and user mode Sunbeam Infotech www.sunbeaminfo.com Operating Systems Concepts Dual Mode Operation: oThroughout an execution of any program, the CPU keeps switches in between kernel mode and user mode and hence system runs in two modes, it is referred as dual mode operation. oTo differentiate between user mode and kernel mode one bit is there onto the CPU which is maintained by an OS, called as mode bit, by which the CPU identifies weather currently executing instruction is of either system defined code instruction/s or user defined code instruction/s. oIn Kernel mode value of mode bit = 0, whereas oIn User mode value of mode bit = 1. Sunbeam Infotech www.sunbeaminfo.com Operating Systems and Computer Fundamentals System Calls: are the functions defined in a C, C++ & Assembly languages, which provides interface of services made available by the kernel for the user (programmer user). - If programmers want to use kernel services in their programs, it can be called directly through system calls or indirectly through set of libary functions provided by that programming language. - There are 6 categories of system calls: 1. Process Control System Calls: e.g. fork(), _exit(), wait() etc... 1. fork() : To create new processes 2. _exit() : To exit processes 3. wait() : To hold/wait processes 2. File Operations System Calls: e.g. open(), read(), write(), close() etc... 1. open() : 2. read() : 3. write() : 4. close() : Sunbeam Infotech www.sunbeaminfo.com Operating Systems and Computer Fundamentals 3. Device Control System Calls: e.g. open(), read(), write(), ioctl() etc... 4. Accounting Information System Calls: e.g. getpid(), getppid(), stat() etc... 1. getpid() : To get Process ID 2. getppid() : To get Parent Process ID 3. stat() : To get File Information 5. Protection & Security System Calls: e.g. chmod(), chown() etc.. 1. chmod() : Change user mode / permission 2. chown() : get file owner info 6. Inter Process Communication System Calls: e.g. pipe(), signal(), msgget() etc... Sunbeam Infotech www.sunbeaminfo.com Operating Systems and Computer Fundamentals 1. CUI/CLI : Command User Interface/Command Line Interface - By using this kind of interface user can interacts with an OS by means entering commands onto the terminal/command line in a text format. - e.g. In Windows name of the program which provide CUI => cmd.exe - command prompt In Linux name of an application program which provides CUI => shell/terminal - In MSDOS name of the program which provides CUI => command.com (Microsoft Disk Operating System). 2. GUI : Graphical User Interface - by using this kind of interface user can interacts with an OS by means making an events like click on buttons, left click/right click/double click, menu bar, menu list etc..... - - Windows = User friendly GUI. - e.g. In Windows name of an application program which provides GUI => explorer.exe - In Linux name of an application program which provides GUI => GNOME/KDE (GNU Network Object Model Environment / Common Desktop Environment). Sunbeam Infotech www.sunbeaminfo.com  Thank you! Kiran Jaybhave email – [email protected] Sunbeam Infotech www.sunbeaminfo.com