memory

Memory Philipp Koehn 9 September 2019 Philipp Koehn Computer - PowerPoint PPT Presentation

Memory Philipp Koehn 9 September 2019 Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019 D-Type Level-Triggered Latch 1 DATA AND Q NOR NOT CLOCK Q NOR AND Philipp Koehn Computer Systems Fundamental: Memory 9


  1. Memory Philipp Koehn 9 September 2019 Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  2. D-Type Level-Triggered Latch 1 DATA AND Q NOR NOT CLOCK Q NOR AND Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  3. Slightly Modified 2 DATA IN AND NOR NOT WRITE DATA OUT NOR AND Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  4. Operations 3 • Circuit latches on one bit of memory and keeps it around • Truth table Data-In Write Data-Out 0 1 0 1 1 1 X 0 Data • Can write 1 bit and read content Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  5. 4 multi-bit storage Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  6. 1 Bit Memory 5 DATA IN AND NOR NOT WRITE DATA OUT NOR AND Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  7. 8 Bit Memory 6 DATA IN WRITE DI W DI W DI W DI W DI W DI W DI W DI W DO DO DO DO DO DO DO DO DATA OUT Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  8. Output Selector 7 • 8 Bit Latch contains 8 bits • Now: only read 1 bit at a time • Select the bit with an address • Input: address • Output: bit value Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  9. Output Selector 8 DATA IN WRITE DI W DI W DI W DI W DI W DI W DI W DI W DO DO DO DO DO DO DO DO 8-Bit Selector ADDRESS OUT Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  10. Output Selector 9 • Truth table Address Output A2 A1 A0 OUT 0 0 0 D 0 0 0 1 D 1 0 1 0 D 2 0 1 1 D 3 1 0 0 D 4 1 0 1 D 5 1 1 0 D 6 1 1 1 D 7 • What Boolean operation returns the correct value for address 000? (NOT A2) AND (NOT A1) AND (NOT A0) AND D0 Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  11. Output Selector 10 • Full Boolean formula ( (NOT A2) AND (NOT A1) AND (NOT A0) AND D0 ) OR ( (NOT A2) AND (NOT A1) AND A0 AND D1 ) OR ( (NOT A2) AND A1 AND (NOT A0) AND D2 ) OR ( (NOT A2) AND A1 AND A0 AND D3 ) OR ( A2 AND (NOT A1) AND (NOT A0) AND D4 ) OR ( A2 AND (NOT A1) AND A0 AND D5 ) OR ( A2 AND A1 AND (NOT A0) AND D6 ) OR ( A2 AND A1 AND A0 AND D7 ) Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  12. Output Selector 11 D0 AND D1 AND D2 AND D3 AND DATA OUT OR D4 AND D5 AND D6 AND D7 AND A0 A1 A2 Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  13. Input Decoder 12 • 8 Bit Latch allows 8 bits to be written at the same time • Now: only write 1 bit at a time • Select the bit with an address • Input – address – write flag – data bit Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  14. Input Decoder 13 WRITE 3-to-8 Decoder ADDRESS DATA IN DI W DI W DI W DI W DI W DI W DI W DI W DO DO DO DO DO DO DO DO DATA OUT Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  15. Input Decoder 14 • Truth table Address Output A2 A1 A0 W7 W6 W5 W4 W3 W2 W1 W0 0 0 0 0 0 0 0 0 0 0 WRITE 0 0 1 0 0 0 0 0 0 WRITE 0 0 1 0 0 0 0 0 0 WRITE 0 0 0 1 1 0 0 0 0 WRITE 0 0 0 1 0 0 0 0 0 WRITE 0 0 0 0 1 0 1 0 0 WRITE 0 0 0 0 0 1 1 0 0 WRITE 0 0 0 0 0 0 1 1 1 WRITE 0 0 0 0 0 0 0 • What Boolean operation returns the correct value for output W0? (NOT A2) AND (NOT A1) AND (NOT A0) AND WRITE Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  16. Input Decoder 15 WRITE W0 AND W1 AND W2 AND W3 AND W4 AND W5 AND W6 AND W7 AND A0 A1 A2 Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  17. 8 Bit RAM 16 WRITE 3-to-8 Decoder ADDRESS DATA IN DI W DI W DI W DI W DI W DI W DI W DI W DO DO DO DO DO DO DO DO 8-Bit Selector DATA OUT Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  18. 8 Bit RAM 17 • 8 Bit Random Access Memory (RAM) • Input – address DI W A – write flag – data bit 8x1 Bit RAM • Output DO – data bit Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  19. 8x2 Bit RAM 18 • 8x1 bit RAM allows read/write of 1 bit at a time • What if we want to read/write 2 bits at a time? (and ultimately 8 bits (1 byte) and more) ⇒ Arrange them together Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  20. 8x2 Bit RAM 19 DATA-IN0 WRT ADDR DATA-IN1 DI W A DI W A 8x1 Bit RAM 8x1 Bit RAM DO DO DATA-OUT0 DATA-OUT1 Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  21. 8x2 Bit RAM 20 DI W A 8x2 Bit RAM DO Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  22. 8x2 Bit RAM 21 2 3 DI W A 8x2 Bit RAM DO 2 Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  23. 64 KB RAM 22 16 8 DI W A 64Kx8 Bit RAM DO 8 • 64KB = 65,536 bytes • 16 bit address space ( 2 16 = 65536 ) • Common memory size in the 1980s: we will use it with 6502 assembly Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  24. Control Panel 23 Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  25. Memories 24 Early 1980s: 64 KB RAM, 16 bit address space Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

  26. Bigger Memories 25 • Early 1980s: 16 bit address space, up to 64 KB • 1990s: 32-bit address space, up to 4 GB • Today: 64-bit address space, up to 16 EB (exa-byte) • Actually supported by Intel/AMD 64-bit processors – 52 bits for physical memory: 4 peta-byte – 48 bits for virtual memory: 256 tera-byte • Actually existing RAM: my lab biggest RAM machine: 768 GB (doubles every ∼ 2 years) Philipp Koehn Computer Systems Fundamental: Memory 9 September 2019

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