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Operating System
Operating System
• Is a program designed to run other programs on a computer. A computer’s operating system manage both software and hardware resources.
OS Conceptual view
Function of Operating Systems
User Interface
• User interface control how you enter data and instruction and how information is displayed on the screen.
User Interface
1. Command Line Interface (CLI)
User Interface
1. Command Line Interface (CLI)It involves the computer responding to
commands typed by the operator. This type of interface has the drawback that requires the operator to remember a range of different commands and is not ideal for novice users.
User Interface
2. Menu Driven Interface
User Interface
2. Menu Driven InterfaceUser do not need to memorize keywords such as copy, paste and syntax. On screen, menu driven interface provide menu as mean for entering command
Example: ATMs
User Interface
• Graphical User Interface
User Interface
• Graphical User InterfaceUser friendly. It interact with visual image such as button and icon and sometimes also referred to as WIMP because they use Windows, Icons, Menus and Pointers
Different Interfaces of OS
• Command Line Interface (DOS)– User have to
memorize all the syntax to issue command
– Take a long time to learn
• Graphic User Interface– User friendly – Easy to use and
doesn’t require the users to memorize all the syntax to issues command
Types of Operating System
• Real-Time Operating System (RTOS)– Is a multitasking operating system that aims
at executing real applications.– It must be able to process data as it comes
in, typically without buffering delays.
Types of Operating System
• Real-Time Operating System (RTOS)Example:High-Definition Television
receiver and display. It needs to read a digital signal, decode it and display it as the data comes in.
Types of Operating System
• Multi-user– Is an OS that allows multiple users to
access a computer system at the same time.
Types of Operating System
• Multi-userExample:
Unix server – where multiple remote users have access(such as via Secure shell) to the Unix shell prompt at the same time.
Types of Operating System
• Multi-tasking vs. single-tasking– A multi-tasking operating system allows
more than one program to be running at the same time
– A single-tasking system has only one running program
Types of Operating System
• Multi-tasking Types1. Pre-emptive
• the operating system slices the CPU time and dedicates one slot to each of the programs.
Example: Solaris, Linux, 32-bit versions of both Windows NT and Win9x
Types of Operating System
• Multi-tasking Types2. Co-operative
• Cooperative multitasking is achieved by relying on each process to give time to the other processes in a defined manner.
Example: AmigaOS, 16-bit versions of Microsoft Windows
Types of Operating System
• Distributed– manages a group of independent computers
and makes them appear to be a single computer.
– When computers in a group work in cooperation, they make a distributed system.
Types of Operating System
• TemplatedIn an o/s, distributed and cloud computing
context,templating refers to creating a single virtual machine image as a guest operating system
Types of Operating System
• Embedded– are designed to be used in
embedded computer systems. – They are designed to operate on small
machines like PDAs with less autonomy. – Example: ATMs, cellphones, printers,
thermostats, calculators
• All user software needs to go through the operating system in order to use any of the hardware, whether it be as simple as a mouse or keyboard or as complex as an Internet component.
OS Components
Examples of Operating System
• Unix and Unix-like operating systems
Examples of Operating System
• Unix and Unix-like operating systems– Unix-like systems run on a wide variety of
computer architectures. They are used heavily for servers in business, as well as workstations in academic and engineering environments.
Examples of Operating System
• BSD and its descendants
Examples of Operating System
• BSD and its descendants-These operating systems are most commonly found on webservers
Examples of Operating System
• OS X– (formerly "Mac OS X") is a line of
open core graphical operating systems developed, marketed, and sold by Apple Inc.,
Examples of Operating System
• OS X
Examples of Operating System
• Linux and GNU
Examples of Operating System
• Linux and GNU– is a Unix-like operating system that was
developed without any actual Unix code, unlike BSD and its variants. GNU/Linux can be used on a wide range of devices from supercomputers to wristwatches.
Examples of Operating System
• Google Chromium OS– Chromium is an operating system based on
the Linux kernel and designed by Google.
Example of Operating System
• Microsoft Windows– Microsoft Windows is a family of proprietary
operating systems designed by Microsoft Corporation and primarily targeted to Intel architecture based computers
Examples of Operating System
• Other– AmigaOS; OS/2 from IBM and Microsoft;
Mac OS, the non-Unix precursor to Apple's Mac OS X; BeOS; XTS-300; RISC OS; MorphOS; Haiku;BareMetal and FreeMint.
OS Components
• The components of an operating system all exist in order to make the different parts of a computer work together
OS Components
• Kernel
OS Components
• Kernel- the kernel provides the most basic level of control over all of the computer's hardware devices. It manages memory access for programs in the RAM
OS Components
• Program execution– provides an interface between an
application program and the computer hardware
OS Components
• Interrupts– are central to operating systems, as they
provide an efficient way for the operating system to interact with and react to its environment.
OS Components
• Modes
OS Components
• Modes
Types: 1. Supervisor Mode- operating system's kernel
for low level tasks that need unrestricted access to hardware
OS Components
• Modes
Types: 2. Protected Mode
and can only use hardware by communicating with the kernel
OS Components
• Memory management– This ensures that a program does not
interfere with memory already in use by another program.
OS Components
• Virtual memory– memory managem
ent technique that is implemented using both hardware and software
– It maps memory addresses used by a program, called virtual addresses, into physical addresses in computer memory.
OS Components
• Multitasking– refers to the running of multiple independent
computer programs on the same computer; giving the appearance that it is performing the tasks at the same time.
OS Components
• Disk access and file systems– Access to data stored on disks is a central
feature of all operating systems.
OS Components
• Disk access and file systems– Access to data
stored on disks is a central feature of all operating systems.
OS Components
• Device drivers– is a specific type of computer software
developed to allow interaction with hardware devices.
OS Components
• Networking– This means that computers running
dissimilar operating systems can participate in a common network for sharing resources such as computing, files, printers, and scanners using either wired or wireless connections.
OS Components
• Security– The operating system must be capable of
distinguishing between requests which should be allowed to be processed, and others which should not be processed.
-- "privileged" and "non-privileged"
OS Statistics (2014)
Desktop Operating System Market Share
Common Types of OS
• Linux• Unix• Windows• Mac OS
Common Types of OS
• Linux is a free and open-source operating system developed by Linus Torvalds and friends and was first announced by Linus in a post he made August 25, 1991.
• The Linux kernel runs on numerous different platforms including the Intel and Alpha platform and is available under the GNU General Public License.
Common Types of OS
• Unix or UNIX (not an acronym) A term coined by Brian Kernighan– is an operating system that was developed
by some of the members of the MULTICS team at the Bell Laboratories starting in the late 1960's, many of who also helped create the C programming language.
Common Types of OS
• Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The original operating system was first introduced in 1984 as being integral to the original Macintosh, and referred to as the "System".
Common Types of OS
• Microsoft Windows or Windows is a superfamily of graphical operating systems developed, marketed, and sold by Microsoft. It consists of several families of operating systems, each of which cater to a certain sector of the computing industry.
http://en.wikipedia.org/wiki/Operating_systemhttp://www.netmarketshare.com/operating-system-market-sharehttp://www.computerhope.com