Complete Computer Knowledge Portal

Monday, February 9, 2015

Difference Between Microprocessor and Micro Controller

Micro controller
It is Multipurpose, Programmable device that accepts digital data as input from external input unit, processes it as per instructions in its memory, and provides results as output at external output unit.
It is a Self Contained System with a processor core, memory, and peripherals and can be used as embedded system.
Software Protection
Software Protection is less achieved in Microprocessor based systems.
Micro controllers offer more software protection by locking the on chip memory and is made protected from external circuit.
Input/output Devices
Keyboard, Mouse, Screen, disks, printers etc.
Switches, Relays, LEDs, LCD Displays, radio Frequency devices ,Sensors
High, Because Devices like memory, disks, and interfaces are connected externally and has to be purchased separately.
Decreased net cost of the embedded system as a whole, Because no needs to connect external devices like Read/Write Memory, Timers etc., unless you desire to create something beyond the limit.

Difference between Burst Mode and Cycle Stealing Mode of DMA

Burst Mode of DMA
Cycle Stealing Mode of DMA
It is the DMA data transfer technique in which no. of data words are transferred continuously until whole data is not transferred.
It is the data transfer technique in which one data word is transferred and then control is returned to CPU.
Data Transfer
Data transfer Continues until whole data is not transferred.
Data is transferred Only when CPU is idle.
This is very fast data transfer technique and is used to transfer data for fast speed devices.
It is the slow data transfer technique as data is transferred only when CPU is idle
CPU Utilization
Low CPU Utilization because CPU remains idle until whole data is not transferred.
High CPU utilization because data is transferred when CPU has no task to perform.

Difference between LED and OLED Display

Acronym for
Light Emitting Diode
Organic Light Emitting Diode
It is a flat panel display that uses array of light emitting diodes as video display.
It is also a type of LED in which organic compound is used as emissive electroluminescent layer to emit light when electric current is supplied to it. These OLEDs are self illuminating.
LED displays can get extremely bright and have slight advantage.
OLED display can also produce brighter displays but shining OLED pixels to maximum results in reduced pixel life.
Hard Material is used as substrate and can not be used to make flexible displays.
OLED can be fabricated on plastic substrates and can be used for making roll up display and can be embedded in cloths in future.
Black Level
LED displays rely on LED backlights behind an LCD panel and can no produce dark blacks even with advanced dimming techniques that dim LEDs. Hence, LED Displays suffers to produce dark levels.
Dark blacks are the important factor to achieve excellent picture quality allowing higher contrast and richer colors and resulting more realistic images. OLED reigns as the undisputed champion, When it comes to black levels.

Difference Between Wi-Fi and Wi-Max

Acronym for
Wireless Fidelity
World Interoperability for Microwave Access
It is a wireless technology that allows any electronic device to exchange and transfer data wirelessly.
It a wireless technology which delivers carrier class, high speed wireless broadband at low cost and covering large distance than Wi-Fi.
IEEE Standard
IEEE 802.11
IEEE 802.16
It is basically an implementation of wireless Local Area Connection within a small building, a college, or an institutional building.
It is a wireless broadband metropolitan technology whose objective is to interconnect houses, buildings, or even hot spots to allow communication between them or with other networks.
Can be implemented by using low cost access pints.
Wi-Max technology requires costly infrastructure.
Frequency band
2.4 GHz to 5 GHz
Licensed/Unlicensed 2 GHz to 11 GHz
Channel Bandwidth
Wi-Fi 802.11b= 25 MHz
Wi-Fi 802.11 a/g=20 MHz
Adjustable 1.25 M to 20
Full/Half Duplex
Half Duplex
Full Duplex