The University of Akron Summit College Business Technology Department Computer Information Systems 2440: 145 Operating Systems Introduction to UNIX/Linux Instructor: Enoch E. Damson

Introduction to UNIX/Linux2 Operating System  The most important program running on a computer  It helps: Store information Process data Use application software Access all hardware attached to a computer Control all the computer’s resources Provide the basis upon which application programs can be used or written

Introduction to UNIX/Linux3 Types of Operating Systems  Different computer systems can have different operating systems  For example: Operating Systems for Desktop PCs  Microsoft Windows  Mac OS  Linux Operating Systems for Server Computers  Microsoft Windows 2000 Server  Microsoft Windows Server 2003  UNIX/Linux  NetWare  Mac OS X Server

Introduction to UNIX/Linux4 Types of Operating Systems…  Other operating systems include: Operating Systems for Mainframes  IBMS’s MVS (Multiple Virtual Storage)  z/OS Operating Systems for Network Servers  Novell NetWare  UNIX/Linux, Windows 2000/XP  Windows Server 2000

Introduction to UNIX/Linux5 Types of Operating Systems…  Other operating systems include: Operating Systems for Cellphones  Google Android  Symbian  Palm OS (HP WebOS)  RIM Blackberry OS  Apple iOS (iPhone)  Windows Mobile

Introduction to UNIX/Linux6 Operating System Components  Some of the components of operating systems include: Application Programming Interface (API) – software designed to communicate with the application software and the user Basic Input/Output System (BIOS) – provides the basic input/output functions to communicate with system devices, such as monitors, keyboard, disks, etc Kernel – the core of the operating system that coordinates operating system functions, such as controlling memory and storage  Communicates with the BIOS, device drivers, and the API to perform these functions and also interface with the resource managers

Introduction to UNIX/Linux7 Operating System Components…  Other operating system components include: Device drivers – programs that take requests from the API via the kernel and translate them into commands to manipulate specific hardware devices, such as disks, keyboards, monitors, printers, etc Resource managers – programs that manage computer memory and central processor use Optional drivers – for other functions and devices, such as sound

Introduction to UNIX/Linux8 Characteristics of Operating Systems  One way to look at a computer and operating systems is to consider them in terms of one or more of the following characteristics: Single-tasking Multi-tasking Time-sharing Batch processing Real-time Multiuser

Introduction to UNIX/Linux9 Single Tasking Systems  Executes only one process at a time  Generally restricted to microcomputers and certain specialized applications

Introduction to UNIX/Linux10 Multi-tasking Systems  Executes more than one program at a time for a user  It can run several programs in the background while users are working on another task in the foreground

Introduction to UNIX/Linux11 Time-sharing System  A central computer system that is used by multiple users and applications simultaneously Mainframe computers typically fall into this category Most of the work is done in batches or batch processes

Introduction to UNIX/Linux12 Batch Processing Systems  Execute programs (batch process) that do not require active user intervention  Normally uses a noninteractive I/O devices such as disks or document scanners for input and returns results to those same devices

Introduction to UNIX/Linux13 Real-time Systems  An operating system that interacts directly with the user and responds in real time (immediately or almost immediately) with required information Windows XP and Mac OS X are examples of these systems

Introduction to UNIX/Linux14 Multi-user Systems  Supports multiple users who are accessing the computer’s and operating systems’ hardware and software facilities Both time-sharing and real-time systems can be multiuser systems

Introduction to UNIX/Linux15 Operating Systems Platforms  The main operating system platforms include: Windows: by Microsoft Corporation Mac OS: by Apple UNIX  Linux  Solaris

Introduction to UNIX/Linux16 The UNIX Operating System  Multiuser, multitasking operating systems with built-in network functions  Can be used on systems functioning as: Dedicated servers in a server-based network Client workstations connected to a server-based network Client/server workstations connected to a peer-to-peer network Standalone workstations not connected to a network  UNIX/Linux are: Multiuser systems – allow many people simultaneous access and share the resources of a server computer Portable – can be used in a variety of computing environments

Introduction to UNIX/Linux17 A Brief History of UNIX/Linux  Developed in the 1970s by a group of inventive scientists at Bell Laboratories. The created an operating system consisting of: Kernel – main program to control the CPU and all other hardware Utilities – a collection of user and system programs Filesystem – a structure for keeping and locating data in files on the hard drive

Introduction to UNIX/Linux18 UNIX Versions  There are two major versions of UNIX: AT&T UNIX version V Berkeley UNIX

Introduction to UNIX/Linux19 Other UNIX Systems  There are several versions of UNIX running on Sun, HP, IBM, etc that are slightly different: Linux Solaris UnixWare

Introduction to UNIX/Linux20 Linux  Linus Torvalds and other Internet accomplices wrote Linux (a UNIX look- alike OS) and made it available for free in its basic form  Versions of Linux include: Ubuntu OpenSolaris Fedora Red Hat OpenSuse Knoppix Debian

Introduction to UNIX/Linux21 Linux Shells  Versions of UNIX shells include: sh – Bourne shell (UNIX 7th Edition) bash – Bourne-again shell (GNU) tcsh – Popular extension of the C shell csh – C shell (BSD) jsh – Job control shell (SVR4) ksh – Korn shell (Bell Labs) rsh – Remote shell (TCP/IP) zsh – Popular extension of the Korn shell

Introduction to UNIX/Linux22 Linux GUI Desktops  Mainstream desktop environments for Unix-like operating systems using the X Window System include: KDE GNOME LXDE Xfce