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19 Cards in this Set
- Front
- Back
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Von Neumann Architecture
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Has memory: stores and retrieves instructions and data
a central Processing Unit with control unit( fetch instruction from memory, decode, execute) and Arithetic Logic Unit (mathmatic calculations) input/output |
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Von Neumann Bottleneck
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memory speed is much slower than CPU ( 400/800 MHz at 3.8 GHz)
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Fetching cycle for Von Neumann architecture
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1) obtain instruction
2) Decode what fixed instuction it is 3) Operand (fetch necessary data) 4) execute 5) store result 6) repeat |
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Universal Computing Architecture
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* Von Neumann (by practice)
-universal (tested in practice) -structured (resource inefficiencies) -build *Turing (by theory; standard one) -universal (in theory) -unstructured (resource efficient) -was not, could be(?) used in practice |
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Turing Machine
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minimalist model of mathematical reasoning and computing
-formal model of computational device to model any computable function. |
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TM components
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* infinite tape (memory. moves left or right)
*read/write head *finite control unit |
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operations of TM
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-head reads symbol
-head then can move left/right -computational steps overwrite last symbol read -moving head and output depends on 1) current symbol on tape 2) 'state of mind' of device |
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Formal notation
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∑- denotes the alphabet
must contain △ and cannot contain →or ← △ is the initial cell three types of transitions |
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Overwrite current cell (I)
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((s,a),(q,b)) if machine is in state s and current cell has a then jump to state q and write b in current cell
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move right (II)
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((s,a),(q,→))
if in state s and current cell has an a then jump to state q and move the header one cell to the right |
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Haulting Problem
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because assume that can construct a TM that could determine if any TM halted on ANY input was possible
-> theoretically this cannot be possible. halting problem can be solved on many imput data but not all -implication is that cannot decide whether an arbitrary input program ends in an infinite loop. |
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Goedel's incompleteness theorem
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Not all true statements about arithmetic are provable by any finite set of axioms
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Human-computer interface
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-human's function in a continuous (analog) mode
-computers run in simulated discrete mode (digital) -compatibility depends on the speed of digital mode (sampling of continuous signal) can represent anything if can make it into a function |
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Digital Signal Processing (DSP)
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is manipulation of signals using digital techniques
goes through ADC→DSP→DAC→output signal |
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Analog into digital signal
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sampling frequency Fs= 1/ts (s being a subunit)
if characteristic time of signal variance changes with time, data compression can be obtained with non-uniform sampling (more points at faster oscillations) |
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Nyquist theorem
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if the highest frequency component in a continuous sample is fm, then the signal can be sufficiently reproduced only with sampling frequency higher than 2 Fm
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CPU( central processing unit)
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-ALU(arithmetic logic, non numerical operations)
-Control Unit( performs all low level hadware operations) -peripherals: external devices for sending in input or recieving output -slots: interface for attaching internal devices (PCI) -ports: interface for attatching external devices (USB) |
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CPU registers
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temporarily store data read from memory (specialized memory or general purpose)
- accessible at high speeds anything for processing is stored in registers Instruction register (IR)- commands to be performed Data Registers -Data input for command operations -program counter: register for instructions memory buffer/data register: data traffic |
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busses
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collection of wires connecting together internal components of the computer to transfer data
-data bus: carries actual data bits -addresss bus: transfers locations where to send data -control bus: carries status information advantages: versatile (allows to add new devices) and low cost disadvantages: limited speed- communication bottle nect different devices need various data rates. |
