computer architecture2 computers are comprised of three things the physical computer the...
TRANSCRIPT
Computer Architecture 2
We’ve come a long way
Computer Architecture 3
Computers: The Big Picture View
Computers are comprised of three things The physical
computer The operating
system The user and
programs running on the user’s behalf
Computer Architecture 4
What is a Computer?
Programmable machine designed to automatically carry out sequential operations
Basic functions Input data Process data Output data Store data (optional)
Is a calculator a computer???
Computer Architecture 5
Computer Components
1. Monitor (Visual display)2. Motherboard3. CPU4. RAM5. Expansion cards
(maybe)6. Power supply7. Optical disc drive
(maybe)8. Hard disk drive9. Keyboard10. Mouse (or touch)
Computer Architecture 6
Computer Architecture 7
Computer Components
Central Processing Unit (CPU) Memory Storage Peripherals
Computer Architecture 8
Central Processing Unit
Computer Architecture 9
CPU Cooler
Computer Architecture 10
Central Processing Unit
The CPU is the “core” of the computer Performs two basic operations
Arithmetic Add, Subtract, Multiply, Divide, …
Logical AND, OR, XOR, NOT, …
Does the same thing over and over Fetch – get the next instruction from memory
Instruction is a sequence of bytes Decode – determine what action the byte(s) specifies Read – read required data from the memory address
(optional) Execute – carry out the encoded instruction
Fetch – Decode – Execute cycle can be used to implement any program
Computer Architecture 11
Program Loading
CPU executes the fetch–decode–execute cycle
When a program executes Loads its instructions into memory from file Tells the CPU the address of the first
instruction CPU keeps track of which memory
location contains the next instruction CPU fetches an instruction
CPU counter updates to the location of the next instruction
Computer Architecture 12
CPU Speed
The CPU performs the fetch-decode-execute cycle hundreds of millions of times per second
CPU’s “clock speed” tells you how many steps it can perform each second 1GHz clock speed translates into (roughly) one
billion steps per second Controlled by an oscillating crystal inside
the CPU Provides the “ticks” for the CPU clock
Computer Architecture 13
Memory
Physical device used to store data or programs
Two types Volatile
Short-term memory Requires power to maintain information
Random-access memory (RAM) Non-volatile
Retains information when not powered Generally used for long-term storage
Computer Architecture 14
Random Access Memory (RAM)
Computer Architecture 15
Storage
Non-volatile devices used to store data when the computer is not powered on Magnetic
Floppy disk, magnetic tape, hard drives Electromechanical
Paper tape, punched cards Solid-state
EEPROM, Flash memory Optical
CD, DVD, Blu-ray
Computer Architecture 16
Mechanical vs. Solid State
Computer Architecture 17
Memory vs. Storage
Storage devices retain information when powered off Why bother with volatile memory?
Storage devices are MUCH slower than memory Accessing the same data on a hard drive
multiple time would slow down overall performance
Computer Architecture 18
Peripherals
Devices attached to a host computer Not part of host’s core computer architecture Expands host’s capabilities
Common peripherals Input devices
Mouse, trackpad, scanners, audio input Output devices
Displays, printers, speakers Network cards Storage
Computer Architecture 19
In-Class Demo
Fetch-Decode-Execute example Find the following
Type and speed of CPU Amount of RAM Hard drive storage space