What’s in the box? Overview of Essential ConceptsWhat is a computer?Slide 3Slide 4Slide 5Slide 6Simple operations … … but complex tasksSlide 8Slide 9Slide 10Slide 11Some concepts (details) coming laterSlide 13The limitation of computersHow to Solve a ProblemCan and Cannot DoSlide 17Slide 18Hardware: Basic ComponentsCOMPUTER SystemSlide 21COMPUTER SYSTEM (from Vendor):Speed and storage capacityTime vs FrequencyNext ClassCOMP 4—Power Tools for the Mind 1What's in the box?What’s in the box? Overview of Essential Concepts What we’ll cover for this topic:•What is a computer?•What are its limitations?•Logical vs. physical structure of computers•Some important digressions•A little about speed and capacityCOMP 4—Power Tools for the Mind 2What's in the box?•How was a “computer” defined before 1940s...?•Agricultural tools => Industrial tools => Mind tools•Intelligence Amplifier, rather than Artificial Intelligence–Software: stored knowledge–“I’m deeply committed to the belief that a MIND plus a machine can do MORE than either a mind or machine alone on HARD problems.”…………………………Fred Brooks•Power toolWhat is a computer?COMP 4—Power Tools for the Mind 3What's in the box?•A concept manipulator–But it only manipulates form, not meaning.•A symbol-processing machine–The universal language of computers: symbols.–IT DOESN’T CARE !•A transformation machine–An abstract machine used to transform data into useful information.DATA& INSTRUCTIONSININFOOUTCOMPUTERTransformationIn the “box”COMP 4—Power Tools for the Mind 4What's in the box?COMPUTERChecks for availabilityof fundsATM MACHINE• Account info• PIN• Withdrawal• Here’s your moneyor• Get realCOMPUTERLooks up price instore databasePOS TERMINALItem Bar code #Bananas$1.49/lb!COMP 4—Power Tools for the Mind 5What's in the box?• Gross Income• Federal WithholdingCOMPUTERIRS• Refund!or• You owe $$and/or• Audit!Think of some tool and tell it to a neighbor (not a computerized tool)..Device that:–Accepts input–Processes data–Stores data–Produces outputIs that all it does?What makes a computerdifferent?PROGRAMMABILITY !!!COMP 4—Power Tools for the Mind 6What's in the box?Important digression!•Computers must be able to REPRESENT various kinds of information that people care about.•Computers must be able to TRANSFORM information (meaningful inputs to meaningful outputs).But…•Computer hardware usually supports only very basic data types and transformations.–E.g.: most hardware supports the addition of two integer (whole number) values:35Adder8COMP 4—Power Tools for the Mind 7What's in the box?LIKE COOKING!Ingredients (flour, eggs, water, baking powder)Hot and delicious pancakesSimple operations … … but complex tasksCOMP 4—Power Tools for the Mind 8What's in the box?Simple tasks:–Crack egg–Mix–Pour–FlipMaking Pancakes (recipe):1. Crack egg2. Pour (egg into bowl)3. Pour (flour into bowl)4. Pour (water into bowl)5. Pour (baking powder into bowl)6. Mix7. Pour (mixture into hot frying pan)8. Flip9. Repeat step 8 until doneSimple operations … … but complex tasksCOMP 4—Power Tools for the Mind 9What's in the box?FIRST BIG QUESTION•How can hardware that can perform only a few really basic operations (like a simple addition) do more complex operations (transformations)?ANSWER? They are PROGRAMMABLEFor example: our simple hardware supports whole numbers and a simple ADD.–So how can it multiply? What is multiplication?–Once the multiplication operation is defined, then it, too, can be used to define yet other operations.COMP 4—Power Tools for the Mind 10What's in the box?•How can hardware that can represent only whole number values be used to represent more complex data values (real numbers; negative numbers; characters; sounds…)?ANSWER? New data types can be defined similarly.For example: I can speak faster than you can write.–So what can you do to improve the speed of your note-taking? –Instead of FOR YOU…?4Uasap0 1–Instead of as soon as possible…?–Instead of true or false…?SECOND BIG QUESTIONCOMP 4—Power Tools for the Mind 11What's in the box?•As long as the meaning is understood, the exact representation is not important.•The rules people define for transforming data depend on the representations that we choose for the data.=> that’s computer science in a nutshell•Most concepts underlying computer operation are not new and are reasonably straightforward.•Complexity lies in the details. We’ll look at some of them this semester.COMP 4—Power Tools for the Mind 12What's in the box?Some concepts (details) coming later•Representing data/information–Will show how many common types of data are represented using the simpler data types available in computers.•Memory/storage systems–Will discuss where information is stored in a computer and why.•Computer architecture–Will explain in more detail how transformations are done in a computer and how software extends the computer hardware’s basic functionality.COMP 4—Power Tools for the Mind 13What's in the box?Some concepts (details) coming later•Why is the operating system important?–Will explain how physical devices, such as the processor and the mouse, are coordinated.•Programming–Will explain the concept of architecture-independent programming languages.•Telecommunications concepts–Explain how computers communicate with each other over networks.COMP 4—Power Tools for the Mind 14What's in the box?The limitation of computers•Can a computer, by itself:–Cure cancer?–Save the whales?–Eliminate starvation?–Prevent crime?•Computers only FOLLOW instructions provided by people. Computers cannot solve problems by themselves.•Computers are only TOOLS.COMP 4—Power Tools for the Mind 15What's in the box?How to Solve a Problem•To solve a problem, one must first:–UNDERSTAND the problem–MODEL the problem–DEVELOP an IDEA for solving the problem.•Computers cannot do these things for us, but they sure can help us to develop ideas and understanding faster.COMP 4—Power Tools for the Mind 16What's in the box?Can and Cannot Do•A computer –cannot cure cancer; but it can be used to analyze the behavior of cancer and its reactions to various therapies.–cannot save the whales, but it can be used to track migration patterns, which will help us