How Computers Store Data

1. How Computers Store Data

2. TERMS • discrete data • continuous data, • bi-stable device, • number system, • binary number system, • denary number system • human-readable data • machine –readable data • natural numbers • whole numbers, integers • real numbers, magnitude • base, number, digit

3. QUIZ • Classify each set of data as discrete or continuous. • 1) The number of suitcases lost by an airline. • 2) The height of corn plants. • 3) The number of ears of corn produced. • 4) The number of green M&M's in a bag. • 5) The time it takes for a car battery to die. • 6) The production of tomatoes by weight.

4. QUIZ ANSWERS • 1) Discrete. The number of suitcases lost must be a whole number. • 2) Continuous. The height of corn plants can take on infinitely many values (any decimal is possible). • 3) Discrete. The number of ears of corn must be a whole number. • 4) Discrete. The number of green M&M's must be a whole number. • 5) Continuous. The amount of time can take on infinitely many values (any decimal is possible). • 6) Continuous. The weight of the tomatoes can take on infinitely many values (any decimal is possible).

5. Why do computers store data? • For processing • Temporarily • using Random Access Memory (RAM) • For later use • permanently or semi-permanently • using secondary storage devices and media Computers do not store data the way we see it, but in the form of binary digits

6. Why binary digits? • The computer is an electronic device • The computer is a digital device • Electronic • the computer uses electricity to work • Digital • the use of binary digits to store data

7. The computer’s memory • The computer’s memory is made up of tiny two-state electronic devices called bi-stable devices. • A bi-stable devicecan exist in only one of two possible states i.e. on or off. • Bi-stable devices respond to the presence or absence of an electric current: • Absence of an electric current - off state • Presence of an electric current - on state

8. Binary digits and data • Binary digITS (BITS) • 1  ON • 0  OFF • This is why data is stored in the form of binary digits (bits) • Input data is converted to binary digits in order to be processed and stored

9. Binary digits and data (cont’d) • Information for the user is converted from binary digits into human-readable form • Every character on the keyboard can be represented internally using a combination of 8 bits or 1 byte • The computer uses various representation schemes to convert data to binary form

10. Numeration/number system: any notation for the representation of numbers • human-readable format is a representation of data or information that can be naturally read by humans • Machine readable format-

11. Homework • Logon to IT for CSEC • Read and take notes on pages 55 – 56

12. Homework (cont’d) • All ___________ that is _________ into a computer system must be _________ temporarily in ________________. The computer’s ___________ is made up of ___________________ which can exist in only one of _______ possible __________. As a result, the _________________ one and zero are used to represent the ________ and __________ states respectively. ___________ data is therefore _____________ to its binary __________________ in order to be _______________ and ____________. It is then _____________ from ______________ back to its original form in order to be ___________ to the user.Fill in the blanks in the above paragraph using the words given in the list below. Remember that a word may be used more than once.Main memory, data, representation, memory, stored, bistable devices, converted, states, output, two, binary digits, input, on, processed, off, binary.