Chapter 1: Our Digital Planet

• The computer is a versatile tool.

ex: compute taxes, deploy missile

• All computers take in information ca;;ed input and give out info called output.


• Hardware: the physical part


• Software the instructions that tell the software what to do.


• 1939: Konrad Zuse-first digital computer


• 1943: First electronic digital computer called Colossus by mathematician Alan Turing.


• 1939: Professor John Atanasoff developed possibly the first electronic digital computer, the Atanasoff-Berry Computer(ABC)


• 1944: Professor Howard Aiken developed the Mark I, by a one million dollar grant from IBM.


• John Mauchly and J. Presper Eckert helped the U.S effort in World War II by constructing a machine to calculate trajectory tables for new guns.


• After the war, John Mauchly and J. Presper Eckert started a private company called Sperry and created UNIVAC I, the first general-purose commercial computer.


• Vacum Tubes- were used in early computers


• ENIAC Electronical Numerical Integrator Computer


• Transistors replaced vacuum tubes starting in 1956


• By the mid-1960 transistors were replaced by integrated circuits.


• Integrated circuits brought:


• Increased reliability


• Smaller size


• Higher speed


• Higher effciency


• Lower cost


• 1971: The first microprocessor was invented by Intel engineers


• THe personal computer


• Desktop Computers


• Embedded Computers- perform specific tasks


• Special purpose computers


• controling the temperature and humidity


• Monitoring your heart rate


• Monitoring your house security system


• The program is etched on silicon so it cannot be altered . This is called firmware.


• Personal Computers


• PCs serve a single user at a time.


• Common applications include:


• word processing


• Workstations: high-end desktoop computers with massive computing power used for high-end interactive applications.


• Portable Computers: machines that are not tied to the desktop


• Notebooks-laptops


• Handheld Computers-PDA


• Servers: Computers designed to provide software and other resources to other computers over a network.


• Mainframes:


• Used by large organizations, such banks and airlines, for big computing jobs.


• Communicate with mainframe through terminals


• Multiple communications at one time through process of timesharing.


• Supercomputers: For power users who need access to the fastest, most powerful computers made.


• The Emergance of Networks


• Connect devices together.


• 1960s: Internet developed with backing of the U.S goverment.


• The Internet Explosion- Pver a billion people with Internet acceses by the end of 2005.


• Electronic mail- email


• World Wide Web


• Led the Internet's tranformation from a text-only environment into a multimedia


• Web Browsers: Programs that serve as navigable wilndows into the Web.
• explorer, firefox. chrome


• Hypertext links: millions of Web pages tied together created by different authors.


• Internet varied activities:


• eBay-international transactions


• Real-time multiplayer games


• In history we have had:


• Agricultural Age


• Industrial Age


• Now we are in the Information Age- people earn a living now by working with words, numbers, and ideas
• Social and Ethical issues
• personal privacy
• high-tech crime and keeping data secure
• defining and protecting intellectual property
• The threat of automation and the dehumanization of work
• The abuse of info as a tool of political and economic power
• The emergence of bio-digital technology
• The dangers of dependence on complex technology
• Bio-digital examples:
• Micro-chipping pets
• Prosthetic limbs
• Virtual Surgery
• Brain fused with PC chip
  

Chapter 4 Continued

Web Applications

• Web applications fall into several categories
• Some simple Web applications perform simple data-processing tasks that could also be performed by traditional programs running on stand-alone PCs. Ex: Blogs
• Most Web applications take advantage of the Web’s connectivity.
• Many Web applications leverage the Web’s strength as a huge repository of information.
• Some Web applications support online business transactions.
• News-oriented Web applications provide up-to-the-minute reports on a myriad of subjects.
• Other Web applications support a more traditional form of information broadcasting.
• Web applications take advantage of web connectivity

Integrated Applications and Suites: Software Bundles
Vertical -Market and Custom Software
• Very expensive compared to mass market applications
mass-market applications
• Job-specific software: Medical billings, Library cataloging, Legal reference software, Restaurant management, Single-client software needs

The Hardware-Software Connection
• System software: A class of software that includes the operating system and utility programs, handles these details, and hundreds of other tasks behind the scenes.
System Software:
The Hardware-Software Connection
• Operating system functions:
• Supports multitasking
• Manages virtual memory
• Maintains file system
• Responsible for authentication and authorization

Utility Programs and Device Driver
• Utility programs: Serve as tools for doing system maintenance and repairs that aren’t automatically handled by the operating system.
• Make it easier for users to:
• Copy files between storage devices
• Repair damaged data files
• Translate files so that different programs can read them
• Guard against viruses and other potentially harmful programs (as described in the chapter on computer security and risks)
• Compress files so they take up less disk space
• Perform other important, if unexciting, tasks

• Symantec Norton Utilities is a popular utility package that includes software tools for recovering damaged files, repairing damaged disks, and improving disk performance

Device drivers:

• Small programs that enable I/O devices—keyboard, mouse, printer, and others—to communicate with the computer.

• Included with the operating system or bundled with peripherals

Where the Operating System Lives
• Some computers store their operating system in ROM.
• Others include only part of it in ROM.
• The remainder of the operating system is loaded into memory in a process called booting, which occurs when you turn on the computer.
• Most of the time the operating system works behind the scenes.
• Interacting with the operating system, like interacting with an application, can be intuitive or challenging and it depends on something called the user interface.


The User Interface
The Human–Machine Connection

• User Interface: The interface defines the look and feel of the computing experience from a human point of view.
• Desktop Operating Systems
• MS-DOS ( Microsoft Disk Opening System)is a disk operating system in which the user interacts using characters:
• Letters
• Numbers
• Symbols

• Features include:

• Command-line interface (commands are typed)

• Menu-driven interface (commands are chosen from on-screen lists)

• Graphical User Interfaces (GUI)

• Mac OS was developed by Macintosh in 1984 using GUI.

• Microsoft Windows is now the most popular operating system.
Multiple User Operating Systems: UNIX and Linux
• UNIX was developed at Bell Labs before personal computers were available.
• Linux was created by Linus Torvalds and continues to be a work-in-progress.
• UNIX allows a timesharing computer to communicate with several other computers or terminals at once.
• Linux is free for anyone to use or improve.
• UNIX remains the dominant operating system for Internet servers.
• Some form of UNIX is available for personal computers, workstations, servers, mainframes, and supercomputers.
Hardware and Software Platforms
• Windows Vista
• Windows Server 2003
• Windows XP
• Windows ME
• Microsoft Windows CE
• Mac OS X (10)
• Mac OS 9
• Linux, Sun Solaris, and other UNIX variations

• Cross-platform applications, such as Microsoft Office and Adobe Photoshop, are programs that are available in similar versions for multiple platforms.

• Mac users can buy software emulation programs that:

• Create a simulated Windows machine in the Mac .

• Translate all Windows-related instructions Mac equivalents.



• Future applications may be more tied to networks than to desktop computer platforms.

• Microsoft .NET strategy

• Java, a platform-neutral computer language developed by Sun Microsystems for use on multiplatform networks.

Chapter 4 Questions

1. What is the the difference between authentication and authorization? Give Examples.

• An authentication system is to verify that the user is really who they are. For example, Password Based Authentication that requires the user to know a password.
• An authorization system is how the system decides what the user can do. For example, the difference between a normal user and the superuser on a unix system.
  

2. What does the operating system do?

• It manages the hardware and software resources of the system.
• It provides a good way for applications to deal with hardware without it being required to know the details of the hardware.
  

3. What is the difference between utility programs and device drivers?

A device driver is a small program that tells the operating system how to communicate with a device. A utility program help to control computer resources, such as protecting your computer from viruses.