Advanced Operating System- Introduction
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The document outlines a syllabus for an advanced operating systems class at MIT, covering various topics such as process synchronization, deadlocks, and distributed operating systems. It discusses the evolution of operating systems from serial processing to multiprogramming and time-sharing systems, along with their functionalities and user types. Additionally, it highlights design considerations and functional requirements for managing processes, memory, and file systems.
Advanced Operating System- Introduction
- 1. Debasis Das
- 2. Syllabus Process synchronization Process Deadlocks Distributed operating System Distributed OS Implementation Multiprocessor Systems Performance, co-processors, RISC & Dataflow Analytic modeling Security & Protection MIT CS704D Advanced OS Class of 2011
- 3. Recommended Books Operating Systems Concepts & designs – Milan Milenkovic, Tata McGraw Hill Operating System- H M Dietel, Pearson Advanced concepts in Operating Systems – Mukesh Singhal, Niranjan Shivaratri, Tata McGraw Hill MIT CS704D Advanced OS Class of 2011
- 4. Additional Books Distributed operating Systems Concepts & Design – Pradeep K Sinha Distributed Operating Systems- Andrew S Tanenbaum, Tata McGraw Hill Modern Operating Systems – Andrew S Tanenbaum, Pearson Operating System principles=Abraham Silberschanz, Peter B Galvin, Greg Gagne, Wiley Asia MIT CS704D Advanced OS Class of 2011
- 5. MIT CS704D Advanced OS Class of 2011
- 6. Evolution of OS Serial processing: Take one job, complete the execution, print out results, take the next job Batch processing: Take a batch of jobs, process them Multiprogramming: Manage program execution as programs come in. Multiple ones may be in execution. MIT CS704D Advanced OS Class of 2011
- 7. MIT CS704D Advanced OS Class of 2011 Program Execution Program Development Edit Compile Execute
- 8. Serial processing Theoretically at least, I can program everything to process a program from start to finish Use of input/ Output devices : punched cards, paper tapes (late fifties) Add I/O routine Loader, linker, librarian formed the rudimentary OS MIT CS704D Advanced OS Class of 2011
- 9. Batch processing Automate sequencing Some housekeeping, like mounting of tapes required to be done manually. Batch several programs on a single tape, housekeeping required only once Phasing = place similar programs in one batch Load Fortran compiler only once for a batch of Fortran programs Need for a Job Control language (JCL) MIT CS704D Advanced OS Class of 2011
- 10. JCL Job beginning and end markers Loading of program Compiling and execution of the program Commands to define resource requirements such as execution time, memory requirements A batch monitor (memory resident part of the batch operating system) would read, interpret and execute these commands MIT CS704D Advanced OS Class of 2011
- 11. Improvements Through the Batch OS Increased system resources utilization, throughput by reducing the idle time between programs Program development is not helped much Turn around times were long Debug was offline and difficult to do from memory dump MIT CS704D Advanced OS Class of 2011
- 12. Further Changes Program execution becoming quite fast, slow I/O times started becoming noticeable Overlapping of I/O with batch operations were the need of the hour DMA channels, peripheral controllers and even dedicate I/O controllers started appearing SPOOL, read/write to disk files MIT CS704D Advanced OS Class of 2011
- 13. MIT CS704D Advanced OS Class of 2011 Typical program Compute I/O Compute I/O Possible speed up Compute I/O Compute I/O Compute I/O Compute I/O Degree of multiprogramming= number of programs competing for resources Higher the degree of multiprogramming, higher the resource utilization
- 14. Example of Multiprogramming Time shared systems ; program, data stored on secondary storage Users provide the job control commands interactively; compile, run and so on Debug is easier with a separate debug system in the OS Program development is helped by interactive edit, compile, debug etc. MIT CS704D Advanced OS Class of 2011
- 15. MIT CS704D Advanced OS Class of 2011
- 16. Types of Operating Systems Studied Batch OS Multiprogramming OS Time sharing systems Real time systems A combination OS MIT CS704D Advanced OS Class of 2011
- 17. Aspects of Operating Systems Compared Processor scheduling Memory management I/O management File management MIT CS704D Advanced OS Class of 2011
- 18. Batch Operating System Program, data, system commands submitted together Very little interaction with users, practically none Better resource utilization Long turn around Difficult debug Programs with long execution times are well suited; e.g payroll, forecasting, statistical analysis etc. Scheduling is first come first served Memory management is simple No time critical I/O management required Rudimentary file system may be present MIT CS704D Advanced OS Class of 2011
- 19. Multiprogramming operating Systems System throughput and resource utilization can be improved Supports two or more active processes, code and data of which needs to be in memory Hardware and/or software memory protection required Supports multiple users, user authentication, per user accounting of resource usage needed Multi access system Multi processor system MIT CS704D Advanced OS Class of 2011
- 20. Time-Sharing Systems Multi programming, multi user system Program development environment, Computer aided design, text processing systems Good terminal response time required Time sliced, round robin scheduling Memory management must provide protection. Data sharing also may be needed I/O management must preserve system integrity & good performance MIT CS704D Advanced OS Class of 2011
- 21. Real-time Systems Events external to the computer must be processed Quick even-response required Industrial control, flight control, telephone switching May be necessary to process thousands of interrupts w/o missing one User convenience and resource utilization is on secondary significance Priority based scheduling of unique processes connected to the event It is also preemptive All processes are memory resident, processes do not die, low movements of programs between main and secondary memories Time critical device management is critical, I/O management, interrupt management MIT CS704D Advanced OS Class of 2011
- 22. Combination Operating Systems Real life is a mix of situations. A university system may need to provide program development needs as well as long simulations Combination of features are thus common A multi user interactive system OS may support batch operation Time shared terminal servers may need to send and accept real time packets MIT CS704D Advanced OS Class of 2011
- 23. Distributed Operating System Independent systems that communicate and collaborate via hardware and software features OS coordinates the interaction and presents a virtual machine feel to users System wide sharing of resources characterizes such OS, remote resources may be shared, computation may be sent to a remote node Global naming, distributed file systems, distribution of computations are required features MIT CS704D Advanced OS Class of 2011
- 24. MIT CS704D Advanced OS Class of 2011
- 25. Types of Users Users who get services from the OS through commands typed at a terminal, or embedded ones in a batch job (Command language users) Users who obtain services through system calls at the run time. Calls that are activated when the program runs through them (System call users) MIT CS704D Advanced OS Class of 2011
- 26. Command Language User’s View System specific Functionality is similar though, syntax varies Typical such functions are log on & house keeping, Program activation and control, file management, status reporting and system management MIT CS704D Advanced OS Class of 2011
- 27. Log On & Housekeeping Typically on multiuser systems Log on and off Password management Setting of some initial configuration; type of terminal, naming of file system devices MIT CS704D Advanced OS Class of 2011
- 28. Program Activation & Control Loading of program, run or abort Quite often just typing the name of the program will run (load and execute) it Scheduling may be available Setting of scheduling priorities also may be available MIT CS704D Advanced OS Class of 2011
- 29. File Management Create, delete, rename, copy files File utilities are available ( comparison etc) Volume maintenance feat5ures MIT CS704D Advanced OS Class of 2011
- 30. Status Reporting Status of user initiated activities, devices assigned and system wide state Status, size and content of print queue etc could be requested by the user Performance stats may be made available These routines that monitor performance are resource hogs, so they may be accessible to a privileged class of users only MIT CS704D Advanced OS Class of 2011
- 31. System management For system managers and maintenance personnel Creation and maintenance of user accounts, resource usage limits, specifying default devices Collecting reports on system performance, behavior Analysis of error and debug MIT CS704D Advanced OS Class of 2011
- 32. System call User’s View System calls through the API (Application programming interface) Provides all the services available through command (except log on/off), finer and more controls More direct control to I/O hardware Program control (run, execute, abort, suspend, resume etc.) Inter program communication and synchronization Resource management ( memory allocation, release, etc.) Device & file management (open & close a device, random access to block structured devices, init and mode selection, etc.) MIT CS704D Advanced OS Class of 2011
- 33. Typical Command Flow #1 Typical command Edit Myfile.txt On CR the low level keyboard driver passes the command to the CLI CLI parses the command and searches for Edit If not in main memory starts a search on disk drive through a disk driver, directory entry tells OS memory requirement Memory managers allocates memory, loads into that space Address maps are updated MIT CS704D Advanced OS Class of 2011
- 34. Typical Command Flow #2 A unique process is created with a PCB Program name, system id, execution priority, pointers to address translation tables, list of allocated resources, etc. Placed into system ready list Scheduler the decides when to start processing the Editor process When started editor issues system calls for opening the files etc. Passes message to user if not found Editor asks if a new file should be created, communicates through standard input and output MIT CS704D Advanced OS Class of 2011
- 35. Typical Command Flow #3 Create “Myfile.txt” through a system call Interacts with user based on edit commands and stores inputs into the file On termination, editor writes pending data in buffers Closes file through system call, issues system call for exit OS check PCB for any open files, closes and terminates the process. Memory and resources are freed, PCB memory freed into the PCB pool MIT CS704D Advanced OS Class of 2011
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- 37. Problems & Approaches in Design & Implementation What are the needs of managing OS objects? (processes, memory, files) The structural view for implementation MIT CS704D Advanced OS Class of 2011
- 38. Functional Requirements#1 Management of processes Created based on user request, implicit or explicit Requires system services, resources Multiple processes can compete for processing resources Exception handling Allocate hardware/software resources, pro6ection, access control, security Inter-process communications, signals and message MIT CS704D Advanced OS Class of 2011
- 39. Functional Requirements#2 Management of memory Specific requirements of processes Dynamic expansion of needs Contiguous or non contiguous allocation of memory Fragmentation , mapping issues (segmentation, paging, virtual memory Isolation of processes for violating other spaces, controlled sharing MIT CS704D Advanced OS Class of 2011
- 40. Functional Requirements#3 File system needs Device independent access Protection & sharing Recovery & restoration Distributed systems Global naming Distributed file system Inter-process communication & synchronization MIT CS704D Advanced OS Class of 2011
- 41. MIT CS704D Advanced OS Class of 2011 Kernel Basic I/O Memory management File system Command language interpreter
- 42. Implementation #2 MIT CS704D Advanced OS Class of 2011 Level Name Objects Typical Operations 5 CLI Environment data Statements in command language 4 File system Files, devices Create, delete, open, close, read, write 3 Memory management Segments, pages Read, write, fetch 2 Basic I/O Data blocks Read, write, allocate, free 1 kernel Process, semaphores Create, destroy, suspend, resume, signal, wait
- 43. Implementation #3 Goals Reliability Ease of maintenance Necessary Modularity Hiding complexity Clean interface between layers MIT CS704D Advanced OS Class of 2011