Fundamental 2 Lec#03 Shugofa Hassani Session Objective • To understand different types of operating system • To distinguish between types of operating system Types of operating systems • Single- and multi-user operating system • Single tasking / Batch operating system • Multi programing operating system • Multi-tasking operating system / Time-sharing operating system • Embedded operating system • Distributed operating system • Network operating System • Real Time operating System • Mobile operating System Single- and multi-user • Single user operating system allows one user to interact with system like desktop operating system , in reverse the multi user operating system system allows to several users to interact with the system in the same time like server operating system . Single- Tasking / Batch Operating system • A single-tasking system allows only one program in one time such as batch operating system . • In a batch operating system user do not interacted with the computer directly , each user prepared his job on offline device like punch card and submit to computer operator . • Job with similar needs batch together and run as group , the required time for executing of a batch do not considered. • The second batch executed when the first one completed , CPU goes to idle until completing the first batch . Multitasking / Time sharing operating system. • A multi-tasking (Time sharing) operating system can operate more than one program such as Windows operating system . Multi-tasking may be divided into two types. 1. Preemptive multitasking 2. Cooperative multitasking Con.. Preemptive multitasking : • Preemptive multitasking use schedule for each process to decide how long to allocate to any one task before giving another task a turn to use the operating system. • The act of taking control of the operating system from one task and giving it to another task is called preempting. • OS such as Solaris, Linux and Amiga operating systems are preemptive multitasking. Con.. Cooperative multitasking: • Cooperative multitasking run process at the same time that enables two or more programs to cooperatively share the processing time and resources of the host processor. • The example is Microsoft Windows operating system used cooperative multi-tasking. Time-sharing / Multitasking • Time-sharing is a technique which enables many people, located at various terminals, to use a particular computer system at the same time. Example in university . • In this system, it also allows multiple users for distribution of processor time, mass storage, printing, and other resources. • In time-sharing system the processor's time is which is shared among multiple users at the same time is know as time-sharing. Con.. • Multiple jobs are executed by the CPU by switching between them , if N users are present, then each user can get a time quantum. When the user submits the command, the response time is in few seconds at most. • The operating system uses CPU scheduling and multiprogramming to provide each user with a small portion of a time • The big disadvantages of time sharing systems is that it consumes much resources so it need special operating systems. Switching between tasks becomes sometimes sophisticated as there are lot of users and applications running which may hang up the system Different between multiprogramming and multi tasking ? Embedded • These Operating Systems are manufactured which can be used in embedded computer systems. • They are made to run on small machines such as PDAs . They are capable to run with a restricted number of resources. • Windows CE and Minix 3 are embedded operating systems Note: PDA (Personal Digital Assistant) small portable computer which provides tools for everyday office tasks (Computers) . Distributed operating system • A distributed operating system manages a group of distinct computers and makes them seem to be a single computer. • Distributed systems use multiple central processors to serve multiple users. Data processing jobs are distributed among the processors accordingly. • The processors communicate with one another through various communication lines (such as high-speed buses or telephone lines). The OS manages the communications between the processors. Con.. • Processors in a distributed system may vary in size and function. These processors are referred as sites, nodes, computers, and so on. • With resource sharing facility, a user at one site may be able to use the resources available at another. • If one site fails in a distributed system, the remaining sites can potentially continue operating. Network operating System • A Network Operating System runs on a server and provides the server the capability to manage data, users, groups, security, applications, and other networking functions. • The primary purpose of the network operating system is to allow shared file and printer access among multiple computers in a network, typically a local area network (LAN), a private network or to other networks. • Examples of network operating systems include Microsoft Windows Server 2003, Microsoft Windows Server 2008, UNIX, Linux, Mac OS X, Novell NetWare, and BSD What is Different between network and distributed system? Real time operating system • In real time systems, Operating Systems intended to serve real time application which process data as it comes without buffering Daley . • The Operating system must guarantee response to events within fixed periods of time to ensure correct performance. • Used in robots , air traffic control system, weapon system...etc , There is two type of real time operating system 1- Hard Real Time OS (delay is impossible) , 2- Soft real time OS (delay is a bit possible) . Mobile operating system • Android – which is Linux based around 90% used • Symbian- Nokia company • Ios – Apple company • Blackberry - which is the most secure operating system. Desktop operating system • Microsoft Windows around 82.74%. • Mac OS by Apple Inc. is in second place (13.23%), • varieties of Linux are collectively in third place (1.57%) Exercise #3 Find the correct answer 1- OS that runs on a server Distributed OS , Time sharing , Embedded, Network 2- OS manages the communications between the processors Distributed OS , Time sharing , Embedded, Network 3- OS which enable users from various terminals, to use a Distributed OS , Time sharing , Embedded, Network particular computer system at the same time 4-operating system manages a group of distinct computers Distributed OS , Time sharing , Embedded, Network 5- Operating Systems are manufactured which can be used in Distributed OS , Time sharing , Embedded, Network embedded computer systems 6- Operating Systems that process data as it comes without Distributed OS , Time sharing , Real Time, Network buffering Daley 7- the processor's time is shared among multiple users at the Distributed OS , Time sharing , Embedded, Network same time . 8- operating system can operate more than one program Multitasking OS , Time sharing , Embedded, Network 9- They are made to run on small machines such as PDAs Distributed OS , Time sharing , Embedded, Network 10 - operating system to allow shared file and printer access Distributed OS , Time sharing , Embedded, Network among multiple computers in a network. Assignment # 3 1- What is Thread? a- Difference between Process and Thread b- Types of Thread Kernel Level Threads User Level Threads Thank You! .