Transcript Parallel Interface

Homework
Question 1
• CD ROM disk is an example of an optical storage
device.
• CD ROM disks can only be used to read information
stored on them. The user cannot save data to a CD
ROM disk.
• Encyclopaedia is an example.
B) A floppy disk can store data and write data.
C) CONTROL UNIT - controls the flow of information.
It fetches instructions from memory and decodes
them into commands the computer can understand.
It controls the timing so everything happens in the
correct order at the correct time.
ALU - handles the calculations and logical
comparisons.
D) (i)Operating System - Another unit!
(ii) RAM can be edited and changed. Can be written to
and read from.
Laser Printer
Ink Jet Printer
• Operates using a laser
beam
• Operates by spraying ink
onto the paper
• Very expensive to buy and • High quality printouts
run
• Cheaper to buy than laser
• Fast output
• Cheaper to refill
• High quality printouts
• Quiet in sound
• Quiet in sound
Mouse
Touch Pad
Hand held device used for
selecting icons and menus
from the GUI
Touch sensitive pad used as a
pointing device for selection icons
and menus from a WIMP
environment.
When the mouse is moved This is done by moving your
it sends a signal back to the finger along the pad and double
computer.
clicking(tapping) to open icons.
3 types are wireless, optical Used on laptops
and multi-button.
Cheap to buy from £3-£16
Easy to use for experienced
users. Unsuitable for high
definition graphics.
Interface
In order to connect input, output and backing storage
devices to the computer an interface is required.
Interface is required because there are different
characteristics between peripherals and the processor.
Types of interface:
• USB
• ATA/IDE
• Serial
• SCSI
• Parallel
• Firewire
• PCI
UBS (Universal Serial Bus)
Allows a very fast communication between devices. A
desktop computer comes with about 2 USB port.
However, a hub can be connected allowing many devices
to connect.
Detected as soon as it is plugged into the computer.
Data transfer of about 12Mb per second.
ATA/IDE (Advanced Technology Attachment/Integrated
Drive Electronics)
Used for Hard Disk or CD/DVD ROM drives. Data
transfer rate of about 830 Mb per second.
ATA SOCKET
ATA CABLE
Serial ATA CABLE
Serial
A serial port is an interface on a computer system with
which information is transferred in or out one bit at a time.
Used to connect monitors, printers and Interactive
whiteboards.
SCSI (Small Computer System Interface)
Allows eight peripheral devices to be connected to the
computer in a daisy chain fashion.
This is located inside the computer.
Useful when combining scanner, CD-ROM drives,
printers etc.
Data transfer of about 4Mb per second – 80Mb per
second.
Parallel Interface
A parallel interface for connecting an external device
such as a printer.
Most personal computers have both a parallel port and at
least one serial port.
On PCs, the parallel port uses a 25-pin connector and is
used to connect printers or scanners.
Firewire
A very fast external bus standard that supports data
transfer rates of up to 400Mbps and 800Mbps.
FireWire can be considered a successor technology to
the obsolescent SCSI Parallel Interface.
Used for connecting digital cameras and iPods.
PCI (Peripheral Component Interconnect )
Expansion cards that are fitted inside a computer.
Used for graphics, sound, Ethernet and modem cards.
Modem
The word "modem" is a contraction of the words modulatordemodulator. A modem is typically used to send digital data
over a phone line.
The sending modem modulates the data into a signal that is
compatible with the phone line, and the receiving modem
demodulates the signal back into digital data.
MODEM
Wireless modems convert digital data into radio signals
and back.
Class Questions
1. Why is a keyboard sometimes called a QWERTY
keyboard?
2. What does OCR stand for?
3. State two advantages that an LCD panel has over a CRT
monitor.
4. Write a helpful of helpful advice to a friend who was
considering purchases of a:
1. Scanner
2. Digital Camera
Functions of an Interface
Data Format Conversion:
Changing data into a form that can be processed.
Serial / Parallel:
Parallel
Serial
-sending single bit in a
serial format requiring
only 2 lines
-sending groups of bits
on separate data lines
requiring multiples of 8
lines
-Faster speed
- good for long
distance
-Better for shorter
distance
-secure
-Risk of data collision
Functions of an Interface
Analogue to Digital Conversion
ANALOGUE
DIGITAL
Represented by a
wave
A step signal
representing
two state
reading 0 or 1
Infinite readings
Conversion required because computers don’t understand
analogue readings so measures of temperature or sound
etc.. Require to be converted into digital for storage and
use by computer programs.
Types of converters are ADC or DAC
Functions of an Interface
Voltage Conversion:
Where there is a difference in voltage settings this
difference must be compensated in order for the
mother board and devices to work together.
Usually around 5v
Protocols:
A protocol is a procedure of operation, in
some devices the procedure is different
and again these differences need to be
compensated for smooth running of
peripherals with the computer.
Protocol Example
Parity check: When sending bits these need to
be received and checked for accuracy and
security, two examples of how this is done is
using a parity check either set to odd or even.
Even parity – the no. of 1’s is an even number
Odd parity – the no. of 1’1 is an odd number
The parity bit makes the signal either odd or even
Functions of an Interface
Buffering: Temporary area of memory for holding data in
transit between a computer and peripheral. This will
compensate for differences in working speeds.
Spooler: A program using fast backing storage to
temporarily hold print jobs. As in the buffer this will
compensate for operational differences particularly speed.
Data is sent to backing store until printer is ready, freeing up
processor for user to continue. This is known as background
printing.
Advantage of spooling is the large capacity of backing
storage
Functions of an Interface
International Standards:
The use of standards means that computers can be used
with a variety of peripherals using the same standards
Solid State Storage
1. What is solid state memory?
2. Give two examples of flash memory.
3. Why do flash card readers often have more than
one slot?
4. Discuss the following features of flash storage:
Size, power consumption, reliability, capacity
Development Trends
Investigate and report on the following trends:
• Backing Storage
• Wireless technology
• Mobile phones
Practical Task
Investigate and write a report summarising hardware,
software and cost factors involved in producing one of
the following products::
Multimedia Catalague
Business Website
Include in your report resolution, capacity, speed
and cost of each piece of hardware you identify.
NB: You must not exceed £800