Notes on Input & Output Devices
Dear Friends,As you know Computer is very important section to get a good score for Bank Exam.Today we are covering the study material on Input & Output,that will help you succeed in the upcoming exam.
Input Devices (How to tell it what to do): This unit makes link between user and computer. The input devices translate the information into the form understandable by computer.
- Keyboard- The most common and very popular input device which helps in inputting data to the computer
- Mouse- Mouse is the most popular pointing device and cursor-control device having a small palm size box with a round ball at its base which senses the movement of mouse and sends corresponding signals to CPU when the mouse buttons are pressed.
- Joy Stick- To move cursor position on a monitor screen. It is mainly used in Computer Aided Designing (CAD) and playing computer games.
- Light pen- It is used to select a displayed menu item or draw pictures on the monitor screen.
- Track Ball- Mostly used in notebook or laptop computer, instead of a mouse .This is a ball which is half inserted and by moving fingers on ball, pointer can be moved
- Scanner- A scanner allows you to scan printed material and convert it into a file format that may be used within the PC.
- Digitizer- It converts analog information into digital form.
- Microphone-Microphone is an input device to input sound that is then stored in digital form.
- Magnetic Ink Character Recognition (MICR)- MICR input device is generally used in banks because of a large number of check to be processed every day.
- Optical character recognition (OCR)- OCR scans text optically character by character, converts
Monitors: Monitors, commonly called as Visual Display Unit (VDU) are the main output device of a computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form. The sharpness of the image depends upon the number of pixels.
There are two kinds of viewing screen used for monitors.
- Cathode-Ray Tube (CRT): The CRT display is made up of small picture elements called pixels. The smaller the pixels, the better the image clarity, or resolution
- Flat- Panel Display: The flat-panel display refers to a class of video devices that have reduced volume, weight and power requirement in comparison to the CRT.
- Impact Printers: The impact printers print the characters by striking them on the ribbon which is then pressed on the paper.
- Non-Impact Printers: Non-impact printers print the characters without using ribbon. These printers print a complete page at a time so they are also called as Page Printers. Laser Printers, Inkjet Printers.
Notes on Memory Devices
As you know Computer is very important section to get a good score in Exam.Today we are covering the study material on Memory Unit ,that will help you succeed in the upcoming exam.Memory: Computer memory is the storage space in computer where data is to be processed and instructions required for processing are stored. The memory is divided into large number of small parts called cells. Each location or cell has a unique address which varies from zero to memory size minus one.
Memory is primarily of two types:
- Primary Memory/Main Memory: Primary memory holds only those data and instructions on which computer is currently working. It has limited capacity and data is lost when power is switched off.
- Secondary Memory: This type of memory is also known as external memory or non-volatile. It is slower than main memory. These are used for storing data/Information permanently.
- Random Access Memory (RAM): RAM is the internal memory of the CPU for storing data, program and program result. It is read/write memory which stores data until the machine is working. As soon as the machine is switched off, data is erased.
- RAM is volatile,e. data stored in it is lost when we switch off the computer or if there is a power failure. Hence a backup uninterruptible power system (UPS) is often used with computers. RAM is small, both in terms of its physical size and in the amount of data it can hold.
- Dynamic Random Access Memory (DRAM): A type of physical memory used in most personal computers. The term dynamic indicates that the memory must be constantly refreshed2 (reenergized) or it loses its contents. This type of memory is more economical.
- Static Random Access Memory (SRAM): A type of memory that is faster and less volatile than DRAM, but requires more power and is more expensive. The term static is derived from the fact that it does not need to be refreshed like DRAM.
- Synchronous Dynamic Random Access Memory (SDRAM): A type of DRAM that can run at much higher clock speeds.
There are mainly four types of ROM available:
- MROM (Masked ROM): The very first ROMs were hard-wired devices that contained a pre-programmed set of data or instructions. These kinds of ROMs are known as masked ROMs which are inexpensive.
- PROM (Programmable Read only Memory): PROM is read-only memory that can be modified only once by a user. The user buys a blank PROM and enters the desired contents using a PROM program
- EPROM (Erasable and Programmable Read Only Memory): The EPROM can be erased by exposing it to ultra-violet light for a duration of up to 40 minutes. Usually, an EPROM eraser achieves this function.
- EEPROM (Electrically Erasable and Programmable Read Only Memory): The EEPROM is programmed and erased electrically. It can be erased and reprogrammed about ten thousand times. Both erasing and programming take about 4 to 10 ms (milli second).
Cache Memory: It is a very high speed semiconductor memory which can speed up CPU. It acts as a buffer between the CPU and main memory.
Secondary Memory: This type of memory is also known as external memory.It is slower than main memory and non-volatile. These are used for storing data/Information permanently.Contents of secondary memories are first transferred to main memory, and then CPU can access it. For example: disk, CD-ROM, DVD etc.
No comments