2. Thursday 8 th October, 2015 Information Technology Fundamentals of Hardware & Software

3. At the end of this lesson you will be able to: Explain functions of RAM and ROM Classify differences between RAM and ROM.

4. Fundamentals of Hardware & Software At the end of this lesson you will be able to: Identify units of storage Convert bytes to Kilobytes, KB, Megabytes, MB and Gigabytes, GB

5. Fundamentals of Hardware & Software The Digital Computer (Bits and Bytes, Episode 1) https://www.youtube.com/watch?v=AdF2 uk-EscE

6. Fundamentals of Hardware & Software

7. Primary Storage There are two types of main memory or primary storage:- Random Access Memory, RAM ROM, Read Only Memory

8. Random Access Memory, RAM Functions of RAM:- The data in RAM can be read (retrieved) or written (stored) It stores data that can be accessed directly by the processor Holds temporary instructions or volatile data needed to complete tasks Holds data during and after processing Contents are modified by programs

9. Read Only Memory, ROM Functions of ROM:- The data in ROM cannot be changed, therefore it can only be read (retrieved). Stores all programs and data when turned off. It is non-volatile. Contains many complex functions such as start up operating instructions Contents of ROM are usually programmed by manufacturer

10. Comparison between RAM and ROM chips RAMROM Read, Write Volatile, Non- Volatile Contents

11. Comparison between RAM and Rom RAMROM Read, WriteRead and WriteRead Volatile, Non- Volatile VolatileNon-Volatile Contents Contents can be modified Contents cannot be modified

12. Data Types and Their Representations Communicator Data Type/Storage Humans Letters Humans Numbers Humans Words

13. Communicator Data Type/Storage Computer Bits Computer Bytes Computer Words

14. Data Types and Their Representations Bit – Bit is a combination of the words Binary Digit. Generally in computers, information is stored in the form of electrical pulses or signals. They are of two states, ‘On’ or ‘Off’ and are represented by 1 and 0, Binary Digits, respectively.

15. Data Types and Their Representations Bit Pattern – The sequence in which Bits are placed to represent a character. An example is 10110101 2 = 181 10

16. Data Types and Their Representations Byte – A Byte is comprised of 8 bits and is used to represent a character such as A letter e.g. A, B, or Y A digit e.g. 1,2 or 4 A special symbol e.g. @, (, ), $

17. Data Types and Their Representations Word – A Word is the number of bits that can be processed at any one time.

18. Data Types and Their Representations Wordsize or Word Length – The number of bits that a computer can process or store as a unit. For example some PCs have been labelled as 32-bit or 64-bit machines according to their wordsize. This means that a 32-bit machine can process 32- bits in a less than a millionth of a second.

19. Data Types and Their Representations Conversion of Bits to Bytes and Bytes to KB, MB, GB and TB 8 bits = 1 Byte 1024 Bytes = 1 KB (KiloByte) 1024 KB = 1 MB (MegaByte) 1024 MB = 1 GB (GigaByte) 1024 GB = 1TB (TeraByte)

20. Data Types and Their Representations

22. Evaluation 1. How is a bit different from a byte? 2. Which two digits are associated with bits? 3. Convert the following:- a. 100 KB = Bytes b. 1.52 TB = MB c. 4.541GB = KB d. 35600 KB = MB

23. Evaluation 4. How is a bit different from a byte? 5. Which two digits are associated with bits? 6. Convert the following:- a. 100 KB = Bytes b. 1.52 TB = MB c. 4.541GB = KB d. 35600 KB = MB

24. Evaluation 1. How is a bit different from a byte? Ans. - Byte has 8 bits, therefore it is larger. 2. Which two digits are associated with bits? 1, 0 3. Convert the following:- a. 100 KB = 102400 Bytes b. 1.52 TB = 1593835.25 MB c. 4.541GB = 4761583.616KB d. 35600 KB = 34.765625 MB

25. Data Types and Their Representations Recap:- Today we learnt Explain functions of RAM and ROM Classify differences between RAM and ROM Identify units of storage Convert bytes to Kilobytes, KB, Megabytes, MB and Gigabytes, GB

26. Thank you for being a great class and have a good afternoon! Please check google drive for today’s lesson.