Computer Babble Talk Dung X Nguyen Rice University
Computer Babble Talk Dung X. Nguyen Rice University
What is a Computer? • • Google for “How to build a PC” So many electronic components How do they work together? How to master this complicated “mess”? Abstraction!
Abstraction • Disregard non-essential details • Identify and focus on key components • Understand how they work together
Von Neumann Architecture • Google for it • http: //en. wikipedia. org/wiki/Von_Neuma nn_architecture • Memory • Arithmetic Logic Unit (ALU) • Control Unit (CU) • Input/Output devices (IO)
Memory • Stores Instructions and Data expressed in terms of 0’s and 1’s • 0 and 1 are called bits (binary digit) • Size measured in groups of 8 bits called byte; e. g. 2 MB (mega bytes) • Roughly speaking a byte is what it takes to store one keystroke • Speed measured in terms of number of bits per second called Hz; e. g. 100 MHz.
Memory Hierarchy • The faster the memory, the more expensive • From fast to slow – Register – Cache – RAM (Random Access Memory)
ALU • Performs Arithmetic and Logical Computation • Everything is expressed in terms of 0’s and 1’s
Control Unit • Performs 5 stages of Fetch-Execute Cycle – Fetch instruction from memory to instruction register (IR) – Decode instruction (read registers if needed) – Execute ALU operation – Access (read/write) memory (if needed) – Write to registers (if needed)
Example • http: //www. worc. ac. uk/departs/bm_it/co lin/New. Applets/Sam 2. htm
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