Transcript Chapter 1

Chapter 1
Computer Systems
Why study Computer Architecture?
Examples
Web Browsing -
how does the browser
access pages from a server? How can we
create graphics that can be loaded more
quickly?
Configuring Systems - How good is
the system? What kind of performance can
one expect for desired applications? What
additional information is needed to make a
more informed decision?
Example - Terminology
Java Example
Java is best described by a client-server
model. Program is compiled on the server
into a set of binary code words that
represent a generic, stack-based machine
language. On the server, the binary code
words are interpreted, then executed on a
virtual machine. Java uses a multithreaded paradigm, where new threads are
easily created by the programmer.
Computer Professional


Deeper understanding of the
computer itself - rather than
just a user
Understanding inherent
operations of a computer
promotes effectiveness in its
use
User



Awareness of the capabilities
and limitations of the computer
system
An understanding of OS
commands and internal
operations
Improved communication with
others
Programmer




Write more efficient programs
Know why some languages are
more efficient than others
Understand system errors more
clearly
Intermix machine language and
higher level language code
Systems Analyst




Be able to fix the appropriate
system to the application
Supports technical specification
of desired system
Learn tradeoffs of different file
system formats
Learn requirements for building
an internet
Important Fact
“In an era where technology
changes very rapidly, the
fundamental architecture of the
computer rests on a solid
foundation that has changed
only slightly and gradually over
the last 50 years” - Englander
Solid Foundation Has Not Changed




Von Neumann’s Architecture ‘45
Unix - late ‘60s
IBM/360 Machine Language - ‘64
identical to today’s IBM/390
Internet - 25 years old and same
protocols and paradigms
Computer Application
(compare w/WP)
Input-Output-Processing-Storage
What is Computer Architecture?




Data
• fundamental representation of facts and
observations
Hardware
• processes data by executing instructions, moves
data between storage, input and output
Software
• instructions executed by the hardware
Communications
• sharing data and processing among different
computers
Data Component







Text
Numbers
Pictures
Sound
Video
Animation
Charts
Much greater
variety in types
available today.
This component
actually has
changed in
format, but not
how it is used.
(We will discuss
more in Ch 3)
A Typical Computer System
Hardware
Software Component

Systems Software
• Operating Systems, Utilities

Applications Software
• fills a business need or solves a
business problem
An Overview
End User
Programmer
Application Programs
Utilities
Operating System
Computer Hardware
O/S Designer
Simplified OS Diagram
Communications Component





Computers do not operate alone
LAN or WAN
Hardware and Software
Components
EQ - communication channels
(wire, fiber optics, wireless,…)
EQ - protocols
In the Beginning - ENIAC
Electronic Numerical Integrator and Calculator
•
•
•
•
•
•
Publicly announced in 1946
First operational electronic, general purpose machine
Military use
80 ft long, 8.5 ft high, 2 ft wide
18,000 vacuum tubes
Programmable
Observation
Whereas… the ENIAC is equipped with 18,000
vacuum tubes and weighs 30 tons, computers in
the future may have 1,000 vacuum tubes and
perhaps weigh just 1 1/2 tons.
------ Popular Mechanics, March 1949
John von Neumann Principles - 1945





Stored Program Concept
Binary Processing of Data
Memory is addressed linearly
Memory is addressed without
regard to content
Memory holds programs and
data
Overview of Englander’s Text




Part 1 - Data
• Number systems, how other forms of
data are stored
Part 2 - Hardware
• CPU, memory, instruction sets, I/O
devices, storage devices
Part 3 - Systems Software
• Operating Systems, User Interface, File
Management
Part 4 - Networks and Data
Communications