The document presents information on synchronization, asynchronous communication, synchronous communication, and external storage devices. It discusses how synchronization joins multiple processes and requires an established rhythm between devices. Asynchronous communication has no global clock and encodes timing in symbols, while synchronous communication requires synchronized clocks running at the same rate. The document also describes different types of external storage devices, including magnetic storage using disks, optical storage using laser light technology, and solid state storage like flash memory.

1. PRESENTATION ON SYNCHRONIZATION AND
EXTERNAL STORAGE DEVICES
Presented By:-
1. Anit
2. Diwakar
3. Jitendra
4. Mausam
5. Ujjwal

2. SYNCHRONIZATION
• Idea that joins multiple processes to perform a certain action
• Used for transferring signals from one electronic device to
another
• Must be a certain rhythm established between both devices
• Two types of synchronization
i. Asynchronous
ii. Synchronous

3. ASYNCHRONOUS
• A system having no global clock, instead operating under distributed
control
• Any timing required to recover data from the communication symbols is
encoded within the symbols
• Data is not transmitted at regular intervals, thus making possible
variable bit rate
• And the transmitter and receiver clock generators don’t have to be
exactly synchronized all the time
• Activities take place outside of real time system
• E.g. file transfer, email and the World Wide Web.

4. SYNCHRONOUS
• Synchronous communication requires the clocks for transmitting and
receiving devices that are synchronized running at the same rate
• Data is sent in continuous stream at a constant rate
• No start or stop bits are required
• Due to these reasons this permits more information to be passed
over a circuit per unit time.
• Activities takes place in real time system
• E.g. telephone conversations and instant messaging.

5. EXTERNAL STORAGE DEVICES
• Kind of devices that temporarily stores data & information for
transporting from one to another computer
• This devices are not permanently fixed inside the computer
• It also works as data back up
• This data may be useful at such times as fire or theft because important
data is not lost.
• Types of external storage
• Magnetic storage
• Optical storage
• Solid state storage

6. MAGNETIC STORAGE

7. MAGNETIC STORAGE
• It is the storage of data on a magnetized medium
• There are two magnetic polarities, each of which is used to represent
0 or 1
• It is a form of non-volatile memory.
• Recorded on the surface of the rotating disks
• Information is recorded in bands and each band of information is
called a track
• The tracks on the surface are divide into invisible segments called as
sectors
• E.g. Hard Disk , Floppy Disk, etc.

8. OPTICAL STORAGE

9. OPTICAL STORAGE
• Those media that use laser light technology for storage and retrieval
• Data is recorded by making marks in a pattern that can be read back
with the aid of light, usually a beam of laser
• Older example of optical storage that doesn’t require the use of
computers, is microform
• This is different from other data storage techniques
• Compact-disks can hold 700MB and DVDs can hold 4.7GB while dual
layered can hold 8.5GB
• Blu-ray disks can hold 25 GB for single-layer and 50 GB for dual layer.

10. SOLID STATE STORAGE

11. SOLID STATE STORAGE
• Flash memory is a form of solid state memory
• Was invented in 19990’s by Toshiba company
• Particular type of EEPROM
• Also non-volatile memory
• Called solid state because it has no moving parts
• Erasing is easier so called flash memory
• Faster transfer rates
• Small in size and light in weight
• E.g. memory cards, memory sticks, etc.

12. THANK YOU