Hardware

1
(No Transcript)
2
Hardware
1. Original concept Charles Babbage 1840s
2. 4 basic components of a computer
system input store mill output
(Now main memory Central Processing Unit)
3. No success is building a working computer
because of the limited technology until the
1940s)
3
4. 1st working computer Mark I (1940) but
still partly mechanical. 5. Research was funded
by the government because of World War II. 6.
1st all electronic computer ENIAC (1945-46)
Could perform 5000 computations per second! 7.
Internally stored program developed by
John vonNeumann (Princeton U. math prof.) 8. 1st
commercially available computer UNIVAC (1950
approx. cost 250,000)
4
9. 1960s - mainframes and minicomputers
(smaller versions) were developed with smaller
and more efficient electronic components
transisters and integrated circuits. 10. Size
decreased, cost decreased, but speed and
capability increased. 11. 1970s - personal
computers (microcomputers microprocessor on a
silicon chip) 12. 1990s - supercomputers (one
of a kind machines, bigger and more
expensive) 13. Todays computers perform
1,000,000 operation per second.)
5
14. Future? Molecular size computers BUT they
will require radical new technology rather than
just the smaller but same technology of the last
30 years.
15. Input devices keyboard, mouse, floppy
disk, hard disk, CD, OCR, scanners, 16. Output
devices monitor, printer, disk, 17. Secondary
storage (disks, tapes,) are considered permanent
(even though they can be erased, they are not
volotile).
6
18. Modem - best described as an interface
device. (modulator/demodulator - converts from
digital to analog to digital signal).
7
Memory How does a computer remember? 1.
Storage locations are called cells. 2. Smallest
addressable amount of memory can hold 1 character
and is called a byte. 3. A byte is made up of 8
binary digits (bits) which have only 2 state on
or off ( 1 or 0). 4. Two parts of main storage
are RAM - random access memory (volatile) ROM -
read only memory (permanent)
8
5. ROM is only a small amount of storage and is
usually measured in kilobytes. 6. RAM is the
major part of storage and is measured in
megabytes in todays computers. 7. Both data and
programs must be stored in memory before being
processed. 8. Data is information of any type
primitive such as integer, real, character or
objects such as Strings. 9. ASCII is a commonly
used coding system for character data. (28
characters possible.)
9
10. Example A 65 01000001
a 97 01100001 11. Unicode is a
recent extension of ASCII in which 216 characters
are possible. 12. All instructions as well as
data must be coded. Original programs (1950s)
were written in machine language (all 0s
1s) 13. Coding shortens instructions
significantly. See pp. 15-16 to compare high
level languages, and low level languages
(assembler machine).
10
Processing - the CPU 1. Two parts of the CPU
controller controls interaction of all parts
of the computer system. Ex. fetching
instructions handling input
output arithmetic/logic unit performs all
operations , -, , /, comparison(lt,gt,) 2.
We study these in more detail in courses such as
computer architecture and operating systems.
11
Networks - the newest aspect of computers to
significantly impact our lives. 1. LAN - local
area networks (consist of a server, and client
machines) 2. WAN - wide area networks (most
famous Internet ( a collection of connected
networks). 1st Arpnet (network of government
research computers) World Wide Web (created in
Europe 1989)
12
WWW required more uniformity. Results HyperTextM
arkupLanguage Web Browsers (special programs that
execute HTML files and connect with the
Internet) platform independent programming
language Java applets - special Java programs
which can be embedded in Web pages. Web page - a
document or file stored on a computer (somewhere)
that is turned on and connected to the
Internet. Gateway - a computer that controls
access to the Internet.