source: thinkgeek

1. source: http://thinkgeek.com

2. It’s All (just) Bits 1) Numbers are bits 2) Text is bits 3) Formatted text is bits 4) Pictures are bits 5) Sounds are bits Paradigm Shift?

3. 2 1 Bits can be operated on! Example: adding two bits decimal binary 0+0 = 0 = 0 0 0+1 = 1 = 0 1 1+0 = 1 = 0 1 1+1 = 2 = 1 0 addends sum built using http://logic.ly by Josh Tynjala

4. It’s All (just) Bits 1) Numbers are bits 2) Text is bits 3) Formatted text is bits 4) Pictures are bits 5) Sounds are bits 6) Programs (instructions on how to operate on bits) are also bits!

5. multiplexer: chooses 1 bit out of 2using bits! data bits 0 1 selector bit output bit

6. data bits output: equal to top data bit if selector is 0 equal to bottom data bit if selector is 1 selectorbit built using http://logic.ly by Josh Tynjala

7. R1 R2 R3 R4 R5 R6 R7 R8 Computer Architecture in 1 Slide • A program is a sequence of instructions • Both data and program sit in memory (RAM) • At the heart of your computer is a processor, which simply executes instructions in order, one at a time • A processor has a few registersfor storing intermediate results (like scratch paper) • There are only a few possible instructions and a few registers; anything more complex is built up from there

8. Example Instructions 1. R1  100 2. R2  9 3. R3  R1+R2 4. R8  218 5. R6  R8/2 Instructions can be encoded as bits:need a code for each operation (e.g., +=1, =2, /=3)write down the operation code, the values,and the register numbers 100 218 109 109 9 R1 R2 R3 R4 R5 R6 R7 R8

9. … 149 150 151 152 153 154 155 156 157 158 159 … v o n n e u m a n n Memory • But we have lots of data; it doesn’t all fit into the few registers. It sits in memory. • Big idea: address it. … … (lots of) memory

10. R1 R2 R3 R4 R5 R6 R7 R8 Memory How to choose a value by location? • But we have lots of data; it doesn’t all fit into the few registers. It sits in memory. • Big idea: address it. load into R1 the value in memory at address 153 … 149 150 151 152 153 154 155 156 157 158 159 … … 118 111 110 32 110 101 117 109 97 110 110 … (lots of) memory 110

11. multiplexer: chooses 1 bit out of 2 data bits 0 1 selector bit output bit

12. choosing 1 bit out of 4 Set selectors to: 00 0 0

13. choosing 1 bit out of 4 Set selectors to: 01 (bottom to top) 1 0

14. choosing 1 bit out of 4 Set selectors to: 10 (bottom to top) 0 1

15. choosing 1 bit out of 4 Set selectors to: 11 (bottom to top) 1 1

16. choosing 1 bit out of 8 000 001 010 011 100 101 110 111 Addresses:

17. choosing 1 bit out of 8 000 001 010 011 100 101 110 111 Addresses: 1 1 0

18. How many layers of multiplexers?

19. R1 R2 R3 R4 R5 R6 R7 R8 Program using memory 1. load into R1 the value in memory at address 153 2. R1  R1  32 … 149 150 151 152 153 154 155 156 157 158 159 … … 118 111 110 32 110 101 117 109 97 110 110 … (more layers of multiplexers) 110

20. R1 R2 R3 R4 R5 R6 R7 R8 Program using memory 1. load into R1 the value in memory at address 153 2. R1  R1  32 3. store the value in R1 into memory at address 153 … 149 150 151 152 153 154 155 156 157 158 159 … … 118 111 110 32 110 101 117 109 97 110 110 … 78

21. R1 R2 R3 R4 R5 R6 R7 R8 Program using memory 1. load into R1 the value in memory at address 153 2. R1  R1  32 3. store the value in R1 into memory at address 153 … 149 150 151 152 153 154 155 156 157 158 159 … 78 … 118 111 110 32 110 101 117 109 97 110 110 … demultiplexers 78

22. R1 R2 R3 R4 R5 R6 R7 R8 Program using memory 1. load into R1 the value in memory at address 153 2. R1  R1  32 3. store the value in R1 into memory at address 153 … 149 150 151 152 153 154 155 156 157 158 159 … N v o n 110 e u m a n n … … 78

23. Dilbert by Scott Adams, May 8 2005

24. It’s All (just) Bits SO WHAT? 1) Numbers are bits 2) Text is bits 3) Formatted text is bits 4) Pictures are bits 5) Sound is bits 6) Programs (instructions on how to operate on bits) are also bits!