In this PowerPoint representation we will come to know about the arithmetic and logic unit, input- output device and storage devices. In ALU we will se theSimplest Computer Building Blocks and its functions. Typical Schematic Symbol of an ALU. In input devices we will see examples like keyboard, mouse, scanner, joysticks and in output device we will come to know about printer, projector etc..

1. TAGORE GOVERNMENT COLLEGE
EDUCATION
POWERPOINT PRESENTATION
TOPIC: ALU AND STORAGE DEVICES
PRESENTED BY
RENU YADAV (B.Ed first yr)

2. WHAT’SALU?
• ALU stands for: Arithmetic Logic Unit
• ALU is a digital circuit that performs Arithmetic (Add,
Sub, . . .) and Logical (AND, OR, NOT) operations.
• John Von Neumann proposed the ALU in 1945 when he
was working on EDVAC.

3. The Simplest Computer Building Blocks
Instruction Register (IR) Program Counter (PC)
Control Unit (CU)
ALU
Accumulator (ACC)
0
1
2
3
4
5
.
CPU RAM
Status Register (FLAG)

4. Typical Schematic Symbol of an ALU
A and B: the inputs to the ALU
(aka operands)
R: Output or Result
F: Code or Instruction from the Control Unit
(aka as op-code)
D: Output status; it indicates cases such as:
•carry-in
•carry-out,
•overflow,
•division-by-zero
•And . . .

5. INPUTDEVICES
An Input Device is a peripheral (piece of computer hardware
equipment) used to provide data and control signals to an
information processing system such as a computer or
information appliance. Examples of input devices include
• Keyboards
• Mouse
• Scanners
• Webcam
• Joysticks.

6. KEYBOARD
In computing, a computer keyboard is a typewriter-style
device which uses an arrangement of buttons or keys to act as
a mechanical lever or electronic switch. A keyboard typically
has characters engraved or printed on the keys
(buttons) and each press of a key
typically corresponds to a single
written symbol. However, to produce
some symbols requires pressing and
holding several keys simultaneously or in sequence.

7. MOUSE
The computer mouse is considered an input device. With a
click of a button, the mouse sends information to the
computer. The computer mouse is an interesting device that
offers an alternative way to interact with the computer beside
a keyboard.
A typical mouse has two buttons. At the
top of the device you will find a left
and right button which allows for
“clicks”. There is a scrolling wheel
between the two buttons.

8. SCANNER
A scanner is a device that captures images from photographic
prints, posters, magazine pages, and similar sources for
computer editing and display. Scanners come in hand-held,
feed-in, and flatbed types and for scanning black-and-white
only, or color. Very high resolution scanners are used for
scanning for high-resolution printing, but lower resolution
scanners are adequate for capturing images for computer
display. Scanners usually come with software, such as Adobe's
Photoshop product, that lets you resize
and otherwise modify a captured image.

9. WEBCAM
A webcam is a video camera that feeds or streams its image in
real time to or through a computer to computer network.
When "captured" by the computer, the video stream may be
saved, viewed or sent on to other networks via systems such
as the internet, and email as an attachment. When sent to a
remote location, the video stream may be saved, viewed or
on sent there. Unlike an IP camera(which connects
using Ethernet or Wi-Fi), a webcam is generally
connected by a USB cable, or similar cable, or built
into computer hardware, such as laptops.

10. JOYSTICK
A joystick is an input device that allows the user to control a
character or machine in a computer program, such as a plane
in a flight simulator. They look similar to the control device
you would find on an arcade game, but nearly always include
extra buttons for additional functionality.
The first joystick was invented at the U.S. Naval Research
Laboratory by C. B. Mirick and patented in 1926.
It was a two-axis electronic joystick, similar to
the joysticks in use today, and was original
designed for remotely piloting aircraft.

11. OUTPUTDEVICES
• An output device is any peripheral that receives data from a
computer, usually for display, projection, or physical
reproduction. For example
• Monitor
• Printer
• Speaker
• Projector
• Headphones

12. MONITOR
The monitor is the piece of computer
hardware that displays the video and
graphics information generated by the
computer through the video card.
Monitors are very similar to televisions
but usually display information at a much
higher resolution. Also unlike televisions, monitors are not
usually mounted on a wall but instead sit at top of a desk.

13. PRINTER
In computing, a printer is a peripheral which makes a
persistent human-readable representation of graphics or text
on paper or similar physical media. The
world's first computer printer was a
19th-century mechanically driven
apparatus invented by Charles Babbage
for his difference engine. The first commercial
printers generally used mechanisms from electric
typewriters and Teletype machines The demand for higher
speed led to the development of new systems specifically for
computer use. In the 1980s were daisy wheel systems similar
to typewriters, line printers that produced similar output but
at much higher speed, and dot matrix systems that could mix
text and graphics but produced relatively low-quality output.

14. SPEAKER
Computer speakers, or multimedia speakers,
are speakers sold for use with computers, although
usually capable of other audio uses, e.g. for an MP3
player. Most such speakers have an internal amplifier, and
consequently require a power source, which may be by a
mains power supply often via an AC adapter, batteries, or
a USB port (able to supply no more than 2.5W DC, 500mA
at 5V). The signal input connector is often a 3.5 mm jack
plug (usually color-coded lime green per the
PC 99 standard); RCA connectors are
sometimes used, and a USB port may
Supply both signal and power (requiring
additional circuitry, and only suitable for
use with a computer).

15. PROJECTOR
An LCD projector is a type of video projector for displaying
video, images or computer data on a screen or other flat
surface. It is a modern equivalent of the slide
projector oroverhead projector. To display images, LCD (liquid-
crystal display) projectors typically send light from a metal-
halide lamp through a prism or series of dichroic filters that
separates light to three polysilicon panels – one each for the
red, green and blue components of the video signal. As
polarized light passes through the panels (combination of
polarizer, LCD panel and analyzer), individual pixels can be
opened to allow light to pass or closed to
block the light. The combination of open
and closed pixels can produce a wide
range of colors and shades in the
projected image.

16. HEADPHONES
Headphones are a hardware device that either plugs into your
computer (line out) or your speakers to privately listen to
audio without disturbing anyone else. The picture is an
example of a USB headset from Logitech with a microphone
and a popular solution for computer gaming.

17. STORAGEDEVICES
A data storage device is a device
for recording (storing) information (data). Recording can be
done using virtually any form of energy, spanning from
manual muscle power in handwriting, to acoustic vibrations
in phonographic recording, to electromagnetic energy
modulating magnetic tape and optical discs.
A storage device may hold information, process information,
or both. Types of storage devices
are:
• Hard disk
• Magnetic Tape
• Floppy Disk
• Optical Disc

18. HARD DISK
A hard disk is really a set of stacked "disks," each of which, like
phonograph records, has data recorded electromagnetically in
concentric circles or "tracks" on the disk. A "head" (something
like a phonograph arm but in a relatively fixed position)
records (writes) or reads the information on the
tracks. Two heads, one on each side of
a disk, read or write the data as the disk
spins. Each read or write operation
requires that data be located, which is an
operation called a "seek." (Data already in a
disk cache, however, will be located more quickly.)

19. MAGNETIC TAPE
Magnetic tape is a medium for magnetic recording, made of a
thin, magnetizable coating on a long, narrow strip of plastic
film. It was developed in Germany, based on magnetic wire
recording. Devices that record and play back audio and video
using magnetic tape aretape recorders and video tape
recorders. A device that stores computer data on magnetic
tape is a tape drive (tape unit, streamer).

20. FLOPPY DISK
A floppy disk, also called a floppy, diskette or just disk, is a
type of disk storage composed of a disk of thin and flexible
magnetic storage medium, sealed in a rectangular plastic
enclosure lined with fabric that removes dust particles. Floppy
disks are read and written by a floppy disk drive (FDD).

21. OPTICAL DISC
An optical disc is an electronic data storage medium that can
be written to and read using a low-powered laser beam.
Originally developed in the late 1960s, the first optical disc,
created by James T. Russell, stored data as micron-wide dots
of light and dark.