OS Reviewer - Midterms PDF

MODULE 1 are CREATION, EXECUTION AND LESSON 1: INTRO TO OS TERMINATION of a process - priority: allow more important processes to COMPUTER SYSTEM execute first...

MODULE 1 are CREATION, EXECUTION AND LESSON 1: INTRO TO OS TERMINATION of a process - priority: allow more important processes to COMPUTER SYSTEM execute first than others - hardware & software PROCESS = program execution SOFTWARE - Application software & System Software DEPENDENT PROCESS - may try to share same resources where OPERATING SYSTEM PROCESS SYNCHRONIZATION take place - system software that serves as an intermediary/interface/middleman INDEPENDENT PROCESS between user and hardware - needs a due care to be taken to avoid - primary software installed on a computer overlapping in memory area that manages all the hardware and other - can run on their own but take needs more software on a computer memory to use - a software that communicates with the hardware and which allows to run the 2. MEMORY MANAGEMENT programs, consists of system software, - keep track of WHICH PARTS of a memory or the basic files that your computer needs are currently BEING USED and by WHOM to boot and work MEMORY RESOURCES - a large array of words or bytes, each with - processors (cpu), files, i/o devices, etc. its own address - a repository of quickly accessible data, OS IS A RESOURCE ALLOCATOR shared by the CPU & I/O devices - manage all resources - decide between conflicting requests for Main memory is VOLATILE efficient and fair resource use and suggests - when a computer is turned off, everything solutions stored in RAM will automatically be erased OS IS A CONTROL PROGRAM VIRTUAL MEMORY SYSTEM - controls the execution of programs to - allows your computer to use part of a prevent or avoid errors and improper use of permanent storage device (ex: hard disk) as the computer extra memory OS GOALS 3. FILE MANAGEMENT 1. Execute user programs and make solving - responsible for file and directory user problems, easier creation/deletion 2. Make the computer system convenient to - support of primitive for manipulating files use and directories 3. Use the hardware in an efficient manner - mapping files onto secondary storage - file backup on stable (nonvolatile) storage FUNCTIONS OF AN OPERATING SYSTEM media 1. PROCESS MANAGEMENT FILE - need a certain resources, including CPU - a collection of related information defined time, memory and files, and I/O devices to by its creator accomplish its task - simultaneous execution leads to multiple processes. most basic functionality of an OS FILE SYSTEMS health, keep in track of the time between - provide the conventions for encoding, system responses and services storage, and management of data on a - can aid performance by providing critical storage device such as a hard disk info for troubleshooting issues 4. DEVICE MANAGEMENT (I/O) 7. JOB ACCOUNTING - keeping track of all the devices connected - keep track of the time and resources used to a system by various jobs and users; statistics - designates a program responsible for - maintains track of how much time and every device known as I/O controller resources are consumed by different tasks - decides which process gets access to a and users, and this data can be used to certain device and for how long measure RESOURCE UTILIZATION for - allocates devices in an effective and specific user or group of users efficient way - deallocates devices when they are no 8. ERROR DETECTING AIDS longer required - constantly monitors the system in order to discover faults and prevent a computer DEVICE CONTROLLERS system from failing - components on the motherboard (or on - provides protection of dumps, traces, error expansion cards) that act as an interface messages, and other debugging and error between CPU and the actual device detecting aids - this provides a certain message or warning DEVICE DRIVERS on your screen before performing certain - are the os software components that tasks like deletion, etc. interact with the devices controllers 9. COORDINATION BETWEEN OTHER INTERRUPT CONTROLLER SOFTWARE AND USERS - handles the task of receiving interrupt - coordination and assignment of compilers, requests and prioritizes them to be interpreters, assemblers and other software forwarded to the process to the various users of the computer systems 5. SECURITY & PROTECTION - uses password protection (ex: face recog, INTERPRETER PIN, etc.) to protect user data and similar Input → Interpreter → Output other techniques - prevents unauthorized access to programs COMPILER and user data by assigning access right Source Code → Compiler → Machine Code permission to files and directories → Output - owners of info stored in a multiuser or networked computer system may want to LESSON 2: HISTORY OF OPERATING control use of that info, CONCURRENT SYSTEM PROCESSES should not interfere with each other History of OS is linked with the history and development of various generations of 6. CONTROL OVER SYSTEM computer systems PERFORMANCE - record delays between request for a CHARLES BABBAGE (English service and response from the system Mathematician) - monitors the overall health of the system - he designed the first true digital computer in order to optimize performance - Father of Digital Computer - to get through picture of the system’s ANALYTICAL ENGINE II the operator loads the program which reads - computer’s mechanical design that was the first job from the tape and runs it. The slow and unreliable output is now written onto the 2nd tape, after each job finished, the OS GENERATION OF OPERATING SYSTEM automatically reads the next job from the tape and output tape will be inserted into 1ST GENERATION (1940’s to early 1950’s) IBM 1401 for printing. - Computers were introduced back in the 1940s but it was made WITHOUT an OS. 1955 - All programming was done in ABSOLUTE - TRANSISTORS were introduced MACHINE LANGUAGE, often wiring up - FORTRAN MONITOR SYSTEM as the first PLUG BOARDS to control the machine’s OS, was introduced in computers & used a basic functions high level language - OS were not necessary because the purpose of computer at that time was just 3RD GENERATION (1965-1980) to perform simple mathematical - System of Multiprogramming calculations - Growth of Mini Computers - First gen (1945-1955), technology was used - Creation of the 1st version of UNIX as VACUUM TUBES still WITHOUT OS, and - technology was INTEGRATED CIRCUITS, used machine language = BINARY WITH OS, using a HIGH LEVEL language LANGUAGE (1965-1967) 2ND GENERATION (1955-1965) MULTIPROGRAMMING (SYSTEM) - technology was TRANSISTORS, WITH OS, - a computer program will be able to used ASSEMBLY and HIGH LEVEL language perform multiple jobs at the same time - features of the computers are using - developed by OS designers in late 1960’s transistors as their MAIN ELECTRONIC COMPONENT DEC PDP-1 (1961) - COBOL & FORTRAN are some of the high - a mini computer that only had 4k of 18-bit level languages, that was introduced words but $120,000 per machine (which was towards the end of this generation less than 5% of the price of a 7094) and it was sold like hotcakes. GMOS - first OS by General Motors in the early INTEGRATED CIRCUITS 1950’s - basis of the computers on this generation - used to run single IBM (International - are single component containing number Business Machines) mainframe computers of transistors that was invented by Robert - it performs in large computer rooms and Noyce and Jack Kilby in 1956-1959 1958-1959 handled by pro operators - ex: PDP-8, PDP-11, ICL 2900, IBM 360, IBM 370, etc. SINGLE-STREAM BATCH SYSTEMS Programmers would construct programs on 4TH GENERATION (1980-PRESENT) a piece of paper then it will be punched on - personal computers are largely popular cards and will be brought to the operator. It - NETWORK OS and DISTRIBUTED OS will be handed to the operator until the input is done and given to the programmer MS-DOS (Microsoft Disk Operating again, after. The data accumulated was System) submitted into groups. - OS made by IBM (while they were creating a new PC) and Bill Gates that was first Batch system works on MAGNETIC TAPES called DOS in the 1980’s that are mounted on a TAPE DRIVE, then GUI (Graphical User Interface) switches over to the next task - uses icons, menus, windows for easier - it can be a single user or different users access and user-friendly by Doug Engelbart - ex: Multics, Unix, etc. of Stanford Research Institute - it was adapted by Steve Jobs (co-inventor QUANTUM of Apple computer) and Apple Macintosh - the time that each task gets executed hugely succeeded; it was cheap and user friendly because of GUI ADVANTAGES: - Each task gets an equal opportunity LESSON 3: TYPES OF OS - Fewer chances of duplication of software - CPU idle time can be reduced 1. BATCH OPERATING SYSTEM - users doesn’t directly interact with the DISADVANTAGES: computer - Reliability problem - user prepares the job in an offline device - One must have to take care of the security (punch cards) and gives it to the operator and integrity of user - the operator then groups them (with the - Data communication problems same requirement or similar jobs) into batches 4. MULTIPROCESSOR OPERATING - ex: IBM’s MVS SYSTEM (Parallel OS/Tightly Coupled OS) - have more than one processor in close ADVANTAGES: communication, sharing the computer bus, - Processors of the batch systems know how clock and sometimes memory and long the job would be when it is in queue peripheral devices - Multiple users can share the batch systems - executed multiple jobs at the same time - The idle time for this is very less and makes the processing faster - It’s easy to manage large work repeatedly - supports large physical address space and in batch systems larger virtual address space - if one processor fails, the other processor DISADVANTAGES: should retrieve the interrupted process state - Computer operators should be well known so the process can continue with batch systems - interprocess communication mechanism is - Batch systems are hard to debug provided and implemented in hardware - It’s something costly - The other jobs will have to wait for an 5. DISTRIBUTED OPERATING SYSTEM unknown time if any job fails (Loosely Coupled Systems) - various autonomous interconnected 2. MULTIPROGRAMMING OPERATING computers communicate with each other SYSTEM using a shared network - used to execute more than 1 jobs - independent systems have their own simultaneously by a single processor memory unit & CPU - increases CPU utilization by organizing - ex: Locus, DYSEAC jobs so that CPU has always one job to execute 6. NETWORK OPERATING SYSTEM - uses the mechanism of job scheduling and (Tightly Coupled Systems) CPU scheduling - it runs on a server and provide capability to manage data, users, groups, security, 3. TIME-SHARING OPERATING SYSTEM apps and other networking functions - each task is given some time to execute so all tasks work smoothly (MULTITASKING SYSTEMS), and after the interval is over, OS  - allows shared access to files, printers, and use of smaller versions of MS Word, Excel, other networking functions over a small and Outlook private network - ex: MS Windows Server 2003/2008/2012, PALM OS UNIX, Linux, MacOS X, Novell NetWare, and - standard OS for Palm-brand PDAs as well BSD, etc. as other proprietary handheld devices CLIENT COMPUTERS SYMBIAN - “other” computers arc - found in smart cell phones from Nokia and - each computer that is connected to a Sony Ericsson network server must be running client software that is designed to request a OPERATING SYSTEM CLASSES specific request (CATEGORIES) ADVANTAGES: DESKTOP CLASS OPERATING SYSTEM - Highly stable centralized servers - Security concerns are handled through PLATFORM servers - the hardware required to run particular OS - New technologies and hardware up-gradiation are easily integrated into the INTEL PLATFORM (IBM-COMPATIBLE system - Windows - UNIX - Server access is possible remotely from - DOS - Linux different locations and types of systems MACINTOSH PLATFORM DISADVANTAGES: - Mac OS - Servers are costly - User has to depend on a central location IPAD & IPHONE PLATFORM for most operations - IOS - Maintenance and updates are required regularly MS-DOS - a Single User Single Tasking OS 7. REAL-TIME OPERATING SYSTEM - no built-in support for networking and - serve real time systems users had to manually install drivers - time interval (response time) required to anytime they added a hardware component process and respond to input is very small - supports only 16-bit programs, command - used when there are time requirements line user that are very strict like MISSILE SYSTEMS, AIR TRAFFIC CONTROL SYSTEMS, ROBOTS, WHY DOS IS STILL IN USE? etc. - Size and Simplicity. Doesn’t require much memory for the system and docs doesn’t 8. EMBEDDED OPERATING SYSTEMS require a powerful computer - one that is built into the circuitry of an electronic device MICROSOFT WINDOWS - now found in automobiles, barcode - its graphical OS is designed for Intel scanners, cellphones, medical equipments, platform desktop and notebook computers and personal digital assistants - best known, greatest selection of apps Ex: Windows XP Embedded available (Windows 7, 8, 8.1 & 10) WINDOWS CE.NET MAC OS - supports wireless communications, - user-friendly, runs on Mac hardware, many multimedia and web browsing. Also allows apps available (Sierra, High Sierra, Mojave, Catalina & Big Sur Version XI (Nov 2020) ANDROID - popular OS for smartphones and tablets LINUX that is based on Linux Kernel, developed by - open source, cross platform OS that runs Google on desktops, notebooks, tablets and - Android 11 (released on Sept. 2020) smartphones - Linus (Linus Torvalds) + UNIX = Linux - users are free to modify the code, improve and redistribute it - developers are not allowed to charge money for the Linux kernel (main part of OS) but can charge money for distributions (distros) GOOGLE CHROME OPERATING SYSTEM - popular thin client OS THIN CLIENT - a computer with minimal hardware, designed for a specific task - ex: thin web client is for using the internet SERVER OPERATING SYSTEMS WINDOWS SERVER - familiar GUI interface for those experienced with Windows UNIX - very mature server capabilities, time tested, large user community, stable LINUX - free, customizable, many free services and utilities available TABLET & PHONE OPERATING SYSTEM/ MOBILE OS SYSTEM-ON-CHIP (SoC) - comes preinstalled on a chip on a portable device such as a smartphone - iOS for iPad & iPhone AND Android for variety of tablets & phones - Apple App Store AND Google Play Store IOS (iPhone and iPad) - created by Apple - latest is iOS 14 on Sept. 16, 2024