unit 2: evolution & architecture kaplan university 1

Unit 2: Evolution & Architecture

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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

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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)

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DQ1◦ 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 how it works through the OSI Model.

DQ2◦ Read articles & explain the differences between Quad-

core, dual-core, and single-core processors in your own words. How does a 64-bit processor work compared to the typical 32-bit processor? Give a situation where you would need to use a 64-bit processor versus a 32-bit process in a business environment.

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Write a four-page essay, in APA format, on the evolution of operating systems ◦ include information on processing, multitasking, time-

sharing, interrupts, scheduling, and the concept of process

Your paper should address the different flavors of the Linux operating system, as well as how each unique flavor addresses personal and business needs.  

In addition please provide a summary of which operating system you believe could apply to your current business (or home) needs.

Please include a title page and a references page in addition to the actual content pages required. No abstract or table of contents is required.

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All assignments should have:◦ Title Page◦ 1 inch margins (top, bottom, sides)◦ Table of Contents (for final project)◦ 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

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

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Question:

Why do we need to understand computer system hardware?

What does an “operating system” have to do with hardware inside the machine?

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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

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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.

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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

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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

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Set of wires that carries signals from one component to another

Provides communication among processors, main memory, and I/O modules.

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Operating Systems

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Questions

• How would you define “operating system”?

• Why do we need one?

• What is your current operating system on your computer?

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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

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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

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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)

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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

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Why does an operating system need to evolve?

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Hardware upgrades

New types of hardware

New services

Bug fixes

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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

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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

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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.

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http://www.nasaimages.org/luna/servlet/detail/nasaNAS~5~5~22813~127165:IBM-Electronic-Data-Processing-Mach

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

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5 major theoretical advances to make modern Operating System

1. Processes2. Memory Management3. Information Protection & Security4. Scheduling & Resource Management5. System Structure

We will cover these 5 topics from Weeks 4-9.

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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

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Microsoft Windows◦ From DOS 1.0 (August 1981) to Windows 7

(2009) Traditional UNIX Systems

◦ Developed by Bell Labs in 1970 Modern UNIX Systems

◦ System V Release 4 (SVR4)◦ Berkeley Software Distribution (BSD)◦ Sun Solaris 10

Linux◦ Started as UNIX variant by Linus Torvalds in

1991

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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

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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

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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

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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)

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http://distrowatch.com/dwres.php?resource=major

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Pam Van Hook◦ Email: pvanhook@kaplan.edu

Office Hours: Wednesday 9-10 pm ET Sunday 10-11 pm ET

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