Memory 9278 9279 9280 9281 9282 9283 9284 9285 9286 Main memory is divided into many memory locations (or cells) Each memory cell has a numeric address, which uniquely identifies it 10
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Memory 9278 9279 9280 9281 9282 9283 9284 9285 9286 © 2004 Pearson Addison-Wesley. All rights reserved Main memory is divided into many memory locations (or cells) Each memory cell has a numeric address, which uniquely identifies it 1-18
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Storing Information 9278 9279 9280 9281 9282 9283 9284 9285 9286 10011010 Each memory cell stores a set number of bits (usually 8 bits, or one byte) Large values are stored in consecutive memory locations 11
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Storing Information 9278 9279 10011010 9280 9281 9282 9283 9284 9285 9286 © 2004 Pearson Addison-Wesley. All rights reserved Each memory cell stores a set number of bits (usually 8 bits, or one byte) Large values are stored in consecutive memory locations 1-19
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Figure 17.20 The dual nature of the adaptive immune system. Humoral (antibody-mediated) immune system Cellular (cell-mediated) immune system Control of freely circulating pathogens Control of intracellular pathogens Intracellular antigens are expressed on the surface of an APC, a cell infected by a virus, a bacterium, or a parasite. Extracellular antigens A B cell binds to the antigen for which it is specific. A T-dependent B cell requires cooperation with a T helper (TH) cell. T cell Cytokines activate T helper (TH) cell. Cytokines activate macrophage. Cytokines Cytokines B cell The B cell, often with stimulation by cytokines from a TH cell, differentiates into a plasma cell. Some B cells become memory cells. Cytokines from the TH cell transform B cells into antibody-producing plasma cells. Plasma cells proliferate and produce antibodies against the antigen. Activation of macrophage (enhanced phagocytic activity). TH cell Cytotoxic T lymphocyte Plasma cell A T cell binds to MHC–antigen complexes on the surface of the infected cell, activating the T cell (with its cytokine receptors). Memory cell Some T and B cells differentiate into memory cells that respond rapidly to any secondary encounter with an antigen. Lysed target cell The CD8+T cell becomes a cytotoxic T lymphocyte (CTL) able to induce apoptosis of the target cell.
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Producer Consumer Synchronized Circular Buffer Produced 1 into cell 0 write 1 read 0 buffer: Produced 2 into cell 1 write 2 read 0 buffer: Consumed 1 from cell 0 write 2 read 1 buffer: Produced 3 into cell 2 write 3 read 1 buffer: Produced 4 into cell 3 write 4 read 1 buffer: Produced 5 into cell 4 write 0 read 1 buffer: Produced 6 into cell 0 write 1 read 1 buffer: BUFFER FULL WAITING TO PRODUCE 7 Consumed 2 from cell 1 write 1 read 2 buffer: Produced 7 into cell 1 write 2 read 2 buffer: BUFFER FULL WAITING TO PRODUCE 8 Consumed 3 from cell 2 write 2 read 3 buffer: Produced 8 into cell 2 write 3 read 3 buffer: BUFFER FULL WAITING TO PRODUCE 9 Consumed 4 from cell 3 write 3 read 4 buffer: Produced 9 into cell 3 write 4 read 4 buffer: BUFFER FULL WAITING TO PRODUCE 10 Consumed 5 from cell 4 write 4 read 0 buffer: Produced 10 into cell 4 write 0 read 0 buffer: BUFFER FULL ProduceInteger finished producing values Terminating ProduceInteger 1 -1 -1 -1 -1 1 2 -1 -1 -1 1 2 -1 -1 -1 1 2 3 -1 -1 1 2 3 4 -1 1 2 3 4 5 6 2 3 4 5 Consumed 6 from cell 0 write 0 read 1 buffer: Consumed 7 from cell 1 write 0 read 2 buffer: Consumed 8 from cell 2 write 0 read 3 buffer: Consumed 9 from cell 3 write 0 read 4 buffer: Consumed 10 from cell 4 write 0 read 0 buffer: BUFFER EMPTY ConsumeInteger retrieved values totaling: 55 Terminating ConsumeInteger 6 6 6 6 6 6 2 3 4 5 6 7 3 4 5 6 7 3 4 5 6 7 8 4 5 6 7 8 4 5 6 7 8 9 5 6 7 8 9 5 6 7 8 9 10 7 7 7 7 7 8 8 8 8 8 9 9 9 9 9 10 10 10 10 10 Ref: http://userhome.brooklyn.cuny.edu/irudowdky/OperatingSystems.htm & Silberschatz, Gagne, & Galvin, Operating Systems Concepts, 7th ed, Wiley (ch 1-3)
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