Computer Architecture & Organization

1
Computer Architecture Organization

• Instruction set, number of bits used for data
  representation, I/O mechanisms, addressing
  techniques, etc.
• e.g. Is there a multiply instruction?
• Control signals, interfaces, memory technology,
  etc.
• e.g. Is there a hardware multiply unit or is it
  done by repeated addition?

Architecture ? attributes visible to the
programmer
hmmm chicken/egg problem ?
Organization ? how features are implemented
2
What Should I already know re Computer Arch
Org ?
connected devices Peripherals
Black Box !

communication links
keyboard
computer
mouse
network
display
. . .
. . .
telephone
disk / optical
cable
wireless
speakers
printer
other ?
other ?
3
Function Structure
ITBB

• SYSC 2001 will look inside the black box (ITBB)!
• peripherals and commn links are outside black box
• Will construct various models of ITBB components
• Function ? the operation of individual
  components as parts of the structure
• Structure ? how components relate to each other

4
Function
IMPORTANT SLIDE !

• ALL computer functions are
• Data PROCESSING
• Data STORAGE
• Data MOVEMENT
• CONTROL
• NOTHING ELSE!

Data Information
Coordinates How Information is Used
5
Functional view of Black Box
Operating Environment source/sink for information
connections to peripherals and commn links
MOVEMENT
ITBB
CONTROL
PROCESSING
STORAGE
6
Operations (1) Data movement
e.g. copy a file between disks
7
Operations (2) Storage
e.g. load a text file for editing
8
Operation (3) Processing from/to storage
e.g. compute an intermediate result from some
operands save for later use
9
Operation (4)Processing from storage to I/O
e.g. compute and display a result from some
operands
10
Structure - Top Level ITBB
More Black Boxes ITBB!
Peripherals
Computer
Input Output
Computer
Central Processing Unit
Systems Interconnection
Main Memory
Communication lines
What about Function?
11
Structure - The CPU
CPU
Arithmetic and Logic Unit
Computer
Registers
I/O
CPU
System Bus
Internal CPU Interconnection
Memory
Drilling Down I(ITBB)!
Control Unit
What about Function?
12
Structure - The Control Unit
Too deep for SYSC 2001
Control Unit

CPU
Sequencing Logic
ALU
Control Unit
Internal Bus
Control Unit Registers and Decoders
Registers
Control Memory
What about Function?
13
Brief History of Computer Evolution

• Two phases
• before VLSI 1945 1978
• ENIAC
• IAS
• IBM
• PDP-8
• VLSI 1978 ? present day
• microprocessors !

VLSI Very Large Scale Integration
see text discussion
14
Growth in CPU Transistor Count
Cell 234 M
Pentium Evolution
PowerPC Evolution
Moores Law
15
Speeding Up the Processor

• Pipelining
• On board cache
• On board L1 L2 cache
• Branch prediction
• Data flow analysis
• Speculative execution

chicken / egg again ! well see some of these as
the course progresses
16
But Performance Mismatch!

• Processor speed increased
• Memory capacity increased
• Memory speed lags behind (and increasing slower
  than) processor speed

17
DRAM and Processor Characteristics
18
Some Solutions

• Increase number of bits retrieved at one time
• Make DRAM wider rather than deeper
• Change DRAM interface
• Cache
• Reduce frequency of memory access
• More complex cache, and cache on chip
• Increase interconnection bandwidth
• High speed buses
• Hierarchy of buses