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Unit 2: Evolution & Architecture Kaplan University 1 Unit 2: Reading & Assignments APA Format Chapter 1: Computer System Hardware Chapter 2: Operating System Overview ◦ ◦ ◦ ◦ ◦ Architecture Evolution of Operating Systems Microsoft Windows Unix & BSD Linux Kaplan University 2 Textbook Reading ◦ Chapter 1 The Memory Hierarchy I/O Communication Techniques ◦ Chapter 2 The Evolution of Operating Systems 2 Discussion Questions Written Essay (due Tuesday, November 1) Kaplan University 3 Read the article on DMA (Direct Memory Access). DMA is a common feature in today's computing technology. Explain the communication process of DMA and what devices may potentially use it. Kaplan University 4 Write a four-page essay, in APA format, on the evolution of operating systems. Your paper should address the different types of operating systems. It should focus mainly on Windows and Linux, should address I/O communication techniques focusing on interrupts and DMA and should briefly describe memory hierarchy. In addition please provide a summation of which operating system you believe could apply to your current business needs. PS: the OS you are researching and explaining is to be used for heavy database functions. No Abstract or Table of Contents Required Kaplan University 5 Paper length is 4 pages and demonstrates student understands the subjects examined (5 points) Address OS Evolution as it relates to: Serial processing, multitasking, time-sharing systems, interrupts, scheduling and resource management, and the concept of process (15 points) Analyzed I/0 Communication Techniques: Interrupts and DMA (15 points) Summarized Memory Hierarchy (15 points) Kaplan University 6 Kaplan University 7 All assignments must have: ◦ ◦ ◦ ◦ ◦ ◦ ◦ ◦ ◦ ◦ Title Page 1 inch margins (top, bottom, sides) Double spaced content References page (if cited or used for paper) Meet minimum page counts (not including title, TOC or refs) Font – 12 point, Times Roman or Arial Headings to separate the sections Use spelling and grammar check BEFORE submitting paper. NO need for abstracts in these papers Table of Contents (for final project only) Quote any direct word for word citations (and include page numbers). Any direct quotes NOT properly cited is considered plagiarism by Kaplan University & will be reported! (Read about plagiarism in “Academic Success”) 3 strikes and you are out… ◦ One Warning – Rewrite paper or receive zero ◦ Strike 1 – Zero on Paper ◦ Strike 2 – Fail Class ◦ Strike 3 – Expulsion from the University Used in body of the paper to direct the readers to specific sources on the reference page. Placed at the end of the information which came from that particular source. Do not use a full web address as your citation! For summary and paraphrase citations in APA, an in-text citation is generally the last name of the author and the year of publication (Fudge, 2007). For quote citations, you also need to include the page or paragraph number: for example, (Smith, 2007, p. 32) or (Jones, 2005, para. 2). Reference Page is last page(s) of document. List of sources you used in preparation of the paper Allows the readers of your paper the ability to look up the information you provided Generally, you need to look for an author, the title on the top of the webpage or article, the providing company, a date, and a little more. If it is a website, you must also provide the date you looked at it. A web address by itself is never enough! Book – one author Calfee, R. C., & Valencia, R. R. (1991). APA guide to preparing manuscripts for journal publication. Washington, DC: American Psychological Association. Author’s last name, First name initial, Middle initial if available (Year of Publication). Book title: Subtitle also starts with a capital letter (edition, if applicable). City of publication: Publisher (year of publication), pages. Article From an Online Periodical Bernstein, M. (2002). 10 tips on writing the living Web. A List Apart: For People Who Make Websites, 149. Retrieved from http://www.alistapart.com/ articles/writeliving Author, A. A., & Author, B. B. (Date of publication). Title of article. Title of Online Periodical, volume number(issue number if available). Retrieved from http://www.someaddress.com/full/url/ Web Page Angeli, E. & Brizee, A. (2010, May 5). General format. Retrieved from http://owl.english.purdue.edu/owl Author, A. A., & Author, B. B. (Date of publication). Title of document. Retrieved from http://Web address Source: http://owl.english.purdue.edu/owl/resource/560/01 Computer System Overview Kaplan University 15 Question: Why do we need to understand computer system hardware? What does an “operating system” have to do with hardware inside the machine? Kaplan University 16 4 structural elements of a computer ◦ Processor Controls the operation of the computer and performs its data processing functions (CPU) ◦ Main Memory Stores data and programs & is volatile ◦ I/O Modules Move data between the computer & external environment ◦ System Bus Provides communication among processors, main memory and I/O modules Kaplan University 17 Processor has set of registers with memory faster than main memory Processor registers functions: ◦ User-Visible registers Location where variables are assigned & held ◦ Control & Status registers Controls operation of processor Processor fetches instructions from memory (one at a time) and executes each instruction. Kaplan University 18 Volatile memory is erased when computer is shut down Different than disk memory that saved information even after computer is shut down Three characteristics of memory: ◦ Faster access time, greater cost per bit ◦ Greater capacity, smaller cost per bit ◦ Greater capacity, slower access speed Kaplan University 19 I/O stands for Input/Output Modules Modules move data from computer to external environment (disks, communications equipment & terminals) 3 Techniques for I/0 Operations (pp. 33-36) ◦ Programmed I/O ◦ Interrupt-driven I/0 ◦ Direct Memory Access (DMA) ** DQ1 Kaplan University 20 “The I/O module performs the requested action and then sets the appropriate bits in the I/O status register, but takes no further action to alert the processor” (Stallings, 2009, p. 33) The processor must “periodically check the status of the I/O module until it find that the operation is complete” (Stallings, 2009, p. 33). Kaplan University 21 Processor issues an I/O command and then does something else. I/O Module interrupts the processor to request service when it is ready. Why is this type of I/O more effective? Kaplan University 22 DMA = Direct Memory Access Performed by separate module on bus or can be incorporate into I/O module How is DMA different from interrupt-drive I/O? Kaplan University 23 Set of wires that carries signals from one component to another Provides communication among processors, main memory, and I/O modules. Kaplan University 24 25 Kaplan University 26 Operating Systems Kaplan University 27 Questions • How would you define “operating system”? • Why do we need one? • What is your current operating system on your computer? Kaplan University 28 Textbook definition (p. 51) “An OS is a program that controls the execution of application programs and acts as an interface between applications and the computer hardware” Objectives of OS ◦ Convenience ◦ Efficiency ◦ Ability to Evolve Kaplan University 29 Program Development ◦ Utility programs supplied with OS such as debuggers and editors Program Execution ◦ Steps performed to execute a program Access to I/O Devices ◦ Each I/O device has it own instructions ◦ OS provides uniform interface to connect to devices Kaplan University 30 Controlled Access to Files ◦ OS understands nature of I/O device (tape drive, CD drive, disk drive) ◦ OS understands the structure of the data System Access ◦ Controls access to system as whole Error Detection & Response Accounting (usage statistics) Kaplan University 31 OS functions in same way as computer software OS often gives up control and depends on processor to allow it to regain control. Kernel ◦ Contains most frequently used functions in OS Kaplan University 32 Why does an operating system need to evolve? Kaplan University 33 Hardware upgrades New types of hardware New services Bug fixes Kaplan University 34 Serial Processing ◦ Users have to schedule computer time ◦ Jobs took time to setup (punch cards, load tapes) Simple Batch Systems ◦ User submits program to monitor ◦ Monitor schedules program and return results to user ◦ Example languages: FORTRAIN Kaplan University 35 1940s – 1950s Computers ◦ No Operating System ◦ Programmers interacted directly with hardware ◦ Computer ran by display lights, toggle switches, input device & printer ◦ Serial Processing ◦ 2 Main Problems Scheduling Setup Time Kaplan University 36 1960s Computer ◦ Simple Batch Processing ◦ IBM, GM ◦ User submits jobs on punch cards or tape to a computer operator ◦ Computer operator “batches” jobs sequentially ◦ Batch is placed on monitor (input device) ◦ When done, program branches back to monitor and next job is started. Kaplan University 37 http://www.nasaimages.org/luna/servlet/detail/nas aNAS~5~5~22813~127165:IBM-Electronic-DataProcessing-Mach Kaplan University 38 Multiprogrammed Batch Systems ◦ Simple batch systems I/O devices were slow compared to processor ◦ Needed a way to allow computers to multitask to eliminate inefficiency Time-Sharing Systems ◦ Processor time is used by multiple users ◦ Terminals and central computer Kaplan University 39 5 major theoretical advances to make modern Operating System 1. 2. 3. 4. 5. Processes Memory Management Information Protection & Security Scheduling & Resource Management System Structure We will cover these 5 topics from Weeks 4-9. Kaplan University 40 Latest OS design features ◦ Microkernal architecture Only essential features assigned to kernel such as address spaces, interprocess communications, & basic scheduling ◦ Multithreading Process executing an application is divided into threads that can run concurrently ◦ Symmetric multiprocessing Computer hardware architecture improvement ◦ Distributing operating systems ◦ Object-oriented code Kaplan University 41 Microsoft Windows Traditional UNIX Systems ◦ From DOS 1.0 (August 1981) to Windows 7 (2009) ◦ Developed by Bell Labs in 1970 Modern UNIX Systems Linux ◦ System V Release 4 (SVR4) ◦ Berkeley Software Distribution (BSD) ◦ Sun Solaris 10 ◦ Started as UNIX variant by Linus Torvalds in 1991 Kaplan University 42 Complete timeline of DOS & Windows at http://bravotech.us/info/msos-timeline.htm Features ◦ ◦ ◦ ◦ Single-User Multitasking (starting with Windows 2000) Architecture Diagram (Textbook – p. 83) Modular architecture Kernel-mode components Executive Kernel Hardware Abstraction Layer Device Drivers Windowing & graphics system Kaplan University 43 Started at Bell Labs in 1970 Rewrote UNIX in programming language C Disadvantages ◦ ◦ ◦ ◦ Runs on single processor Lacks ability to protect data Kernel not designed to be extensible Few facilities for code reuse Kaplan University 44 Modern UNIX Kernel ◦ ◦ ◦ ◦ ◦ ◦ Exec switch Vnode/vfs interface Scheduler framework Streams Block device switch Virtual Memory Framework BSD ◦ FreeBSD ◦ Mac OS X based on FreeBSD 5.0 & Mach 3.0 microkernel Kaplan University 45 Started in 1991 as a UNIX variant Created by Linus Torvalds Features ◦ Open source (i.e., “free”) ◦ Monolithic kernel ◦ Structured as a collection of modules that can be loaded on demand Modules can be linked Modules can be stacked Comparison chart of Windows vs Linux (p. 95) Kaplan University 46 http://distrowatch.com/dwres.php?resource=major Kaplan University 47 Pam Van Hook ◦ Email: [email protected] Office Hours: Thursday Sunday via AIM: 7-8 pm ET 10–11 pm ET [email protected] Kaplan University 48