Types Of Operating Systems PDF

Types of Operating Systems Chapter 2 Angelika S. Balagot Instructor Target Topics Five types/categories of Operating System 1. Batch 2. Interactive 3. Real-time 4. Hybrid 5. Embedded Brief History of Operating Systems Development Types...

Types of Operating Systems Chapter 2 Angelika S. Balagot Instructor Target Topics Five types/categories of Operating System 1. Batch 2. Interactive 3. Real-time 4. Hybrid 5. Embedded Brief History of Operating Systems Development Types of Operating System Operating systems for computers large and small fall into five categories distinguished by response time and how data is entered into the system: batch, interactive, real- time, hybrid, and embedded systems. Types of Operating System Batch System - Batch systems date from the earliest computers, when they relied on stacks of punched cards or reels of magnetic tape for input. - Jobs were entered by assembling the cards into a deck and running the entire deck of cards through a card reader as a group—a batch. - The efficiency of a batch system is measured in throughput—the number of jobs completed in a given amount of time (for example, 550 jobs per hour). Types of Operating System Interactive Systems - Give a faster turnaround than batch systems but are slower than the real- time systems - They were introduced to satisfy the demands of users who needed fast turnaround when debugging their programs. - It required the development of time-sharing software - It provides immediate feedback to the user and response time can be measured in fractions of a second. Types of Operating System Real-time systems - Used in time-critical environments where reliability is key and data must be processed within a strict time limit. - The time limit need not be ultra-fast (though it often is), but system response time must meet the deadline or risk significant consequences. - These systems also need to provide contingencies to fail gracefully—that is, preserve as much of the system’s capabilities and data as possible to facilitate recovery. - Must be 100% responsive, 100% of the time Types of Operating System Two Types of Real-Time Systems - Hard real-time systems risk total system failure if the predicted time deadline is missed. - Soft real-time systems suffer performance degradation, but not total system failure, as a consequence of a missed deadline. Types of Operating System Hybrid Systems - Combination of batch and interactive - Users can access the system and get fast responses - Accepts and runs batch programs in the background when the interactive load is light - It takes advantage of the free time between high-demand usage of the system and low-demand times. - Many large computer systems are hybrids. Types of Operating System Embedded systems - Computers placed inside other products to add features and capabilities. - For example, you find embedded computers in household appliances, automobiles, digital music players, elevators, and pacemakers. Types of Operating System Embedded systems - Each one is designed to perform a set of specific programs, which are not interchangeable among systems. - This permits the designers to make the operating system more efficient and take advantage of the computer’s limited resources, such as memory, to their maximum. History of Operating System Development History of Operating System Development 1940s: first generation - Time when computers are based on vacuum tube technology - No standard operating system software - Typical program included every instruction needed by computer to perform the tasks requested - Poor machine utilization - CPU processed data and performed calculations for fraction of available time - Computers are the size of classrooms - Compilers and Assemblers History of Operating System Development History of Operating System Development 1950s: second generation - Focused on cost effectiveness of the system - Developed to meet the needs of new markets – government and business researchers - Computers were expensive - IBM 360: $200,000 - Two widely adopted improvements - Computer operators were hired to facilitate machine operations - Concept of job scheduling: group together programs with similar requirements - Expensive time lags between CPU and I/O devices History of Operating System Development 1950s: second generation History of Operating System Development 1950s: second generation - Job scheduling introduced the need for control cards, which defined the exact nature of each program and its requirements. - First use of a job control language History of Operating System Development 1950s: second generation History of Operating System Development 1950s: second generation - Speed of I/O increased - Blocking - Buffering - Spooling History of Operating System Development 1960s: third generation - Faster CPUs - Speed still caused problems when they interacted with printers and other I/O devices that ran at slower speeds - The solution was multiprogramming, which introduced the concept of loading many programs at one time and sharing the attention of a single CPU. - The most common mechanism for implementing multiprogramming was the introduction of the concept of the interrupt. History of Operating System Development 1960s: third generation - Active multiprogramming - occurs when the operating system interrupts a job process. - Passive multiprogramming - the operating system didn’t control the interrupts but waited for each job to end an execution sequence. History of Operating System Development 1970s - Main memory physical capacity limitations - Multiprogramming schemes used to increase CPU - Virtual memory developed to solve physical limitation - Database management software - Became a popular tool because it organized data in an integrated manner, minimized redundancy, and simplified updating and access of data. - Programs started using English-like words, modular structures, and standard operations History of Operating System Development 1980s - Cost/performance ratio improvement of computer components - Hardware was more flexible, with logical functions built on easily replaceable circuit boards - Firmware, a word used to indicate that a program is permanently held in read-only memory (ROM) - Multiprocessing (having more than one processor), - More complex languages were designed to coordinate the activities of the multiple processors servicing a single job History of Operating System Development 1990s - The overwhelming demand for Internet capability sparked the proliferation of networking capability - The World Wide Web by Tim Berners-Lee made the Internet accessible by computer users worldwide - Introduced a proliferation of multimedia applications demanding additional power, flexibility, and device compatibility for most operating systems History of Operating System Development History of Operating System Development 2000s - Primary design features support: - Multimedia applications - Internet and Web access - Client/server computing - Computer systems requirements - Increased CPU speed - High-speed network attachments - Increased number and variety of storage devices - Virtualization - Single server supports different operating systems Object-oriented design An important area of research that resulted in substantial efficiencies was that of the system architecture of operating systems. The way their components are programmed and organized, specifically the use of object-oriented design and the reorganization of the operating system’s nucleus, the kernel. Object-oriented design The kernel is the part of the operating system that resides in memory at all times, performs the most essential operating system tasks, and is protected by hardware from user tampering. Early OS vs Object-oriented OS End of Discussion Angelika S. Balagot Instructor