1.0 What is Operating System?Operating System → is a program that acts as an intermediary between the user of computer and the computer hardware.Operating System → is a set of software routines that sits between the application program and hardware. *routines: perform key support functions such as accepting and carrying out user commands, communicating with peripheral devices, load a program, copy a file and create a directoryOperating System → acts like an interface between the user and computer hardware.Operating System → is a tool to facilitate efficient operation of computer systemMELJUN CORTES
FOUR COMPONENTS OF COMPUTER SYSTEM1. Hardware –> provides the basic computing resources. (CPU, Memory, I/O Devices)2. Application Program –> define the ways in which these resources are used to solve the computing problems of the users. (Compilers, database system, games & business programs)3. Users –> the one who solve problems in many different application programs. (People and machines)4. Operating System –> control coordinates the use of hardware among the various application programs for varioususers. -> provides environment with other programs to do useful work. -> allocates resources requested by specific programs users to operate computer system fairly and efficiently.
Computer components Hardware Software People ware Data ware
GOALS OF OPERATING SYSTEM To make computer system convenient to use To use the computer hardware efficientlyFUNCTIONS / SERVICES OF OPERATING SYSTEM As a Service Provider As a Resource Manager
OS as a Resource Manager Keeps tracks of its resources. Allocate and de-allocate resources It enforces policies in the user and with the acquisition of resources.
OS as a Service Provider Acts as a resource manager File manager Input/output modules manager Accounting Recovery and archiving Error detection and correction Execute and manipulate files
Operating System as a Service Provider:1. Resource Manager * Program execution The operating system is responsible for the following activities in connection with process management: the creation and deletion of both user and system processes the suspension and resumption of processes the provision of mechanisms for processes synchronization the provision of mechanisms for process communication the provision of mechanisms for deadlock handling
Operating System as a Service Provider:2. I/O Manager * involve a file and I/O devices3. File Manager a. Manipulation of Data b. Execution of Data c. Recovery & Archiving4. Protection & Security *protection involves ensuring that all access to system resources is controlled, security eventually a password which everyuser having to authenticate himself to the system.5. Accounting * To keep track the resources and what kind of computer resources.6. Error Detection & Handling *operating system needs constantly be aware of possible errors.
OS Major Components Memory manager Processor manager Device manager File manager Job scheduler
Criteria to measure OS effectiveness Cost Reliability Throughput Response time Turn around time Ease of use security
CRITERIA TO MEASURE THE EFFECTIVENESS OF THE OS1. Throughput --> the amount of work going on a computer system --> measure of work is the number of processes that are completed per unit time.2. Turnaround Time --> is the sum of the periods spent waiting to get into memory waiting in the ready queue, executing on the CPU, and doing I/O. --> elapsed time from the job submission up to job completion.3. Waiting Time --> is the sum of the periods spent waiting in the ready queue.4. Response Time --> the amount of time it takes to start responding, but not the the time that it takes to output that response.5. Availability --> the measures of system accessibility6. Cost 8. Reliability7. Ease of Use 9. Security
HISTORY OF OPERATING SYSTEM0th Generation – 1945 1955 - No OS at all, machines is controlled hard-wired (Punch card). - No existence of O.S only encoding - No protection - Black Box Concept (Human Operators) *Encoding – programming techniques that binary bit is presentedthrough voltages.1st Generation – During 1950’s, simple operating system weredeveloped that allowed programs to be submitted in sequence andstored. - Batch Processing / Batch Oriented Processing. - Age of Vacuum Tubes
HISTORY OF OPERATING SYSTEM2nd Generation – During 1960’s Multi-using was developed. - Age of Transistors *Multi-using: - To store several programs in memory simultaneously - Share computer resources3rd Generation – Mid 1960, Multiprocessing,Multiprogramming, Time-Sharing, Real-time processing &Virtual memory were introduced. - Aged of Integrated Circuits*Virtual Memory – the ability of OS to expand the memoryof computer systems.
HISTORY OF OPERATING SYSTEM 4th Generation – the period of Networking System & Distributed O.S that provide networking & communication function. - Open system were introduced - Interoperability & other network standard - Massive memory was develop (expansion)*Open System 1. Portability –> a system that can be applied in any kind of computer environment 2. Availability –> source-code licenses in short notice 3. Scalability –> the code can be transferable and resizable 4. Interoperability –> a system that allow sharing of files and applications.
HISTORY OF OPERATING SYSTEM 5thGeneration – Multimode system (1980’s) Provide higher resolution Speech synthesizers & Recognition Computer Vision Allow intelligent machines & Open System *Multimode System – connotes multi- processing & multiprogramming
TYPES OF OPERATING SYSTEMS Single Programmed OS / Single Job Stream Allows execution of program one at a time. One program active Batched OS allowed automatic job sequencing by a resident operating system and improved the overall utilization of the computer. The computer no longer had to wait for human operation.
TYPES OF OPERATING SYSTEMS Batched OS The common input devices were card readers & tape drivers. The common output devices were line printers & card punches. Console: a terminal that consists of switches A batch system was introduced to collect a batch of jobs before processing them and printing out results. A batch system consists of three stages—job collection, job processing, and printing out results. All three stages can occur concurrently Multi-programmed OS jobs are kept in memory at one time having several programs running concurrently in the computer.
TYPES OF OPERATING SYSTEMS Time-sharing/Multi-tasking/Multi-using Logical extension of multi-programming. Time shared OS: allows many users to share the computer simultaneously. Uses CPU scheduling. Having several users running in the computer system. Real-time OS Type of OS that is designed for a particular task through the use of sensors. Sensors bring data to the computer. Real system is defined, fixed and time constraint.
TYPES OF OPERATING SYSTEMS2 FLAVORS OF REAL TIME SYSTEM: Hard real-time system – guarantees that critical task is completed on time. A hard real-time system is often used as a control device in a dedicated application. A hard real-time operating system has well defined, fixed time constraints. Processing must be done within the defined constraints, or the system will fail. Soft real-time system – a critical real-time task get s priority over other task, and retains that priority until it completes. Soft real-time systems have less stringent timing constraints, and do not support deadline scheduling.
TYPES OF OPERATING SYSTEMS APPLICATION OF REAL-TIME SYSTEM Satellite Communication Robotics Home Appliances Controllers Nuclear weapon system Scientific Experiment System Industrial Control System Automatic-Fuel-Engine-Injection System Imaging/X-rays
TYPES OF OPERATING SYSTEMS Distributed OS / Network OS Network Operating System is an OS that provide features such as file sharing (WIN NT) across the network, which includes a communication scheme that allows different processes on different computers to exchange messages. A distributed system is a collection of processors that do not share memory or a clock. Instead, each processor has its own local memory, and the processors communicate with one another through various communication lines, such as high-speed buses or telephone lines. A distributed system provides the user with access to the various resources located at remote sites.
TYPES OF OPERATING SYSTEMS Distributed OS / Network OS Distributed OS is a less autonomous environment. The processors in a distributed system may vary in size and function. They may include small microprocessors, workstations, minicomputers, and large general-purpose computer systems.VARIETY Of REASONS FOR BUILDING DISTRIBUTED SYSTMEMS: Resource Sharing . If a number of different sites are connected to one another, then a user at one site may be able to use the resources available at another.
TYPES OF OPERATING SYSTEMS Distributed OS / Network OS Computation Speedup . If a particular computation can be partitioned into a number of sub computations that can run concurrently, then a distributed system may allow us to distribute the computation among the various sites - to run that computation concurrently. Reliability . If one site fails in a distributed system, the remaining sites can potentially continue operating. If the system is composed of a number of large autonomous installations, the failure of one of them should not affect the rest.
TYPES OF OPERATING SYSTEMS Distributed OS / Network OS Communication . There are many instances in which programs needs to exchange data with one another on one system. Example: Users may initiate file transfers or communicate with one another via electronic mail. A user can send mail to another user at the same site or at a different site. Personal Computer OS - Personal computer systems are microcomputers that are considerably smaller and less expensive than are mainframe systems. Operating system for these computers have benefited from the development of operating systems for mainframes in several ways.
QUIZTest 1: Identification1. It controls and coordinates the use of hardware among the various application program for various users.2. A program that runs at all times on the computer3. It is the ability of Operating System to expand the memory of computer system.4. A program used for loading at power-up or during the rebooting process. Typically stored in ROM or EPROM, generally known as firmware5. It allows execution of programmed one at a time.6. It provides higher resolution and speech recognition.7. Guarantees that the critical task is complete on time.8. A software-generated interrupt caused either by an error or a user request.9. A type of Operating System having several programs running concurrently in the computer.10. A terminal that composed of switches
11. A request to the operating system to allow user to wait for I/O completion.12. It contains entry for each I/O device indicating its type, address, and state.13. It is used for high-speed I/O devices able to transmit information at close to memory speeds.14. An extension of main memory that provides large nonvolatile storage capacity.15. It determines the logical interaction between the device and the computer.16. A principle of copying information into faster storage system; main memory can be viewed as a last cache for secondary storage17. A logical extension in which CPU switches jobs so frequently that users can interact with each job while it is running, creating interactive computing.18. It allows execution of processes not completely in memory19. A program in execution20. It specifies location of next instruction to execute.
Test 2: Matching Type COLUMN A COLUMN B1. Herman Holleriths a. Operating System2. Batched Os b. Console3. Virtual Memory c. Distributed and Networked OS4. 2nd Generation d. 4th Generation5. I/O Manager e. Invoker of commands6. User f. Automatic Job Sequencing7. Routines g. System Software8. Operating System h. 3rd Generation9. Application Program i. Used to solve the computing problem10. WinNT j. Games k. Punch card machine l. Batched processing m. File and I/O devices n. Multi-using o. Build communication
COMPUTATION : (20 points)Assuming the computer system has the following setup :If there are 28 instructions, determine the following :a.) %Eff of CPU c.) CR Time e.) CPU Time in msb.) %Eff of CR d.) LP Time