Systems Software◦ Manage and control computer hardware◦ Example: Operating System

Application Software◦ Designed to perform a specific task◦ Example: Word processing, Web Browser,

Accounting software

Provides user interface for computer system

Handles Input and Output System Administration Handles ‘multitasking’

◦ Running anti-virus scan while Web Browsing

Allocates Memory Protection / Security Shares resources (file,

printers, etc.)

Operating system has final control over allocation of resources◦ Memory

What programs and data are in main memory (RAM), virtual memory, cache, etc.

◦ Manages hard disks, printers and other devices◦ Sharing files and other networking issues ◦ Coordinates users and processing tasks◦ Tracks connections to printers and the Internet

Operating Systems◦ Windows

XP Vista Windows 7

◦ Macintosh OS (based on Unix) Tiger Leopard Snow Leopard

◦ Unix Developed at AT&T’s Bell Labs, powerful

◦ Linux Free, Open-Source

Determines how user interacts with computer. Today, mostly graphical.◦ WIMP

Windows Icons Menus Pointers

Do I have the proper hardware?◦ Memory, processor speed, graphic, storage◦ If not, may have purchase upgrades for machine

Bugs in the new operating system?◦ Yes, most software is released with bugs -- so best

wait until service packs (updates) are ready Does it support my drivers?

◦ Updates for newer hardware may not be immediately available

Does it support/run all of my applications? How much does operating system cost?

Performs tasks that the user wishes to perform◦ Word processing, spreadsheets, media players,

Web browsers Program

◦ Detailed sequence of instructions that tells a computer how to perform a task

Suites◦ Collection of applications bundled together◦ Example: Microsoft Office

Enterprise/Business◦ Financial, project management

Media Development◦ Graphic art, Web site development, digital

animation, image editor Engineering

◦ CAD (computer aided design), CAM (Computer Aided Manufacturing)

Educational Software◦ Educate, testing and progress reports

Simulation◦ Research, training or entertainment

Home◦ Personal Finance, Tax prep, Home design

Software Licensing◦ Legal document governing distribution of software

Use one or more copies of software under certain circumstances

◦ Proprietary Software (Commercial) Owned by publisher but is licensed for use by the

end user (Examples: MS Word, Adobe Photoshop) End User License Agreement (EULA)

◦ Open-Source software Development of source code for software that is

made available for public collaboration Non-exclusive ownership to individual who obtains

software legally (example: NVU)

Purchase at retail◦ Brick and mortar stores or online

Site Licensing◦ Purchase copies for an entire organization

Shareware◦ Free, but try out software under limited

circumstances. At end of trial - delete or pay. “Try before you buy.”

Freeware◦ Usually, no obligation to pay for software (private

use versus commercial use)

Used to create programs that control the behavior of a machine◦ C◦ C++◦ Ada◦ Java◦ JavaScript◦ Perl◦ PHP

Depends on hardware and software◦ Software:◦ Traveling salesman example (3 clients) 3! =

3*2*1 HABCH, HACBH, HBACH, HBCAH, HCABH, HCBAH Computational complexity of the study of the

complexity of algorithms. Exponential and factorial complexity problems do not

scale up. That is these algorithms cannot be used in a practical sense on a computer to solve problems if the size of the data is large. The time needed will take too long (example: years).

http://www.cs.uofs.edu/~cil102/cil102.html#

Tests used to compare the performance of computers with different hardware or software combinations.◦ Ex. For product reviews – which one is better?

Base opinion on a benchmark test

In a computer system unit, the power supply converts AC to DC for use by the components

Computers that run single programs and are used in consumer and industrial devices are called Embedded Computer Systems◦ Examples: Automobiles, microwave ovens,

electric toothbrushes, DVD players

8 bit Number---------------------------------------- 0 1 0 0 0 0 1 1---------------------------------------- 27 26 25 24 23 22 21 20

128 64 32 16 8 4 2 1

64 + 2 + 1 = 67

decimal“C”