KEYBOARD AND SCREEN INPUT DEVICESInput devices majorly contribute to the entire computer peripheral system. It makes the system user friendly. It allows the user to input the data on his own accord and the result after the computation on the screen. Keyboard is one such input device which can be connected to the system in multiple ways. For eg- All the laptops have built-in keyboard; keyboards are connected externally using wires or even wirelessly, to the CPU system of the desk computers/ personal computers. The new generation of the evolved computer/laptops, like Ipads, Notebooks etc. have an inbuilt keyboard which takes the input through the screen which is made touch sensitive.So, what are keyboards essentially? The basic layout of a keyboard is lifted off of the typewriter; instead of the words printing on the surface of the paper, here the pressed keys encode the data- pass it to the system- decode it- and then displays or performs whatever the required function. The conventional keyboards contain 84 or 101/102 keys. The keyboards have evolved along with us and there are keyboards with 104/108 keys available also different types like QWERTY, AZERTY, QWERTZ, etc. It ideally contains- Typing Keys A to ZNumeric Keys 0 to 9Function Keys f1 to f12Control Keys crtl, alt, start, etc.Special Purpose Keys Num Lock, Spacebar, Enter, Shift, etc.    THE ON SCREEN KEYBOARDThe OSK, also commonly known On Screen Keyboards are just built in tools which are substitute for the external keyboards. It requires the user to use the mouse pointer and select the key to be entered for the normal screen users whereas touch screen users can find it really amusing and useful by touching and entering the data easily. It is formally the same layout of that of the externally connected one.THE TOUCH SCREEN KEYBOARDThe touch screen keyboards are the gemical versions of the hardware keyboards. The appear on the screen a.k.a. the desktop or the monitor and the pressure sensitive screen allows the user to input the desires values through only a slight touch. It is widely used today in all the Ipads, Notebooks, touch laptops, even smartphones, etc. It is essential keyboard layout on the screen.They have to stacked keyboards- alphabetic keyboard and the alpha-neumeric keyboards sometimes to make it user friendly and viewable.