Perfect Computer Notes

Topic:  What is ROM Explain Different Types of ROM ROM ROM stands for Read Only Memory , because its contents can be read and used only and we cannot change or delete its contents. It is a non volatile memory. Its retains its contents even after switching off the computer. Therefore, ROM does not require electricity to retain its contents. ROM is a permanent memory. The instructions in ROM are written at the time of manufacturing by the manufacturer.   Importance of ROM in Computer System 1. One important reason a computer needs ROM is that instructions stored in ROM (called ROM BIOS - Basic Input/Output System)execute on start-up of computer and guide the computer what to do. They make the computer ready for work. 2. ROM contains a set of start-up instructions to check that memory is functioning well and check for other hardware devices. 3. These instructions also check for an operating system and load its necessary part into RAM, so that a user interface for example &quo

Today we are going to discuss Different Types of RAM, that is, Random Access Memory . RAM    /     What does RAM mean Ram stands for Random Access Memory . Data in RAM can be accessed directly. That is, we can access data directly from any location of RAM in the same time. This Random Access quality makes RAM a very fast memory. RAM is volatile. Data and programs in RAM are erased when computer is turned off. What does  RAM  do Therefore RAM is a temporary memory. It is used to store those data and programs, which are currently being executed by CPU. Ram is also called Primary Memory or Main Memory. Where RAM memory chip is installed? RAM chip is installed into one of the memory slots on motherboard, as shown in the figure: What does RAM mean Importance of RAM. 1.  A Program must be laoded in RAM for execution. The programs and data currently being executed are in computer's main memory, that is, in RAM. The programs and data needed by these pro

The devices that can be used to perform both functions -input and output- are called Dual Devices. These devices are also called Dual Purpose Devices or Both Input/Output Devices. With the help of a dual purpose device, we can enter data into computer as well as we can output data from the computer to outside world.  For example, Dual devices include:  Touch Screen Monitor, Modem, Network Interface Card, Sound card, Hard disk drive, Floppy disk Drive, Magnetic Tape Drive CD-Writer and DVD-Writer etc. These are also called Input/output devices, because they perform both functions. Touch Screen Monitor Dual Devices or Both Input / Output Devices - Touch screens Touch Screen Monitor is an input/output device. It uses a special touch sensitive screen. The User can enter data by touching icons or menus on the screen. As soon as the user selects a command from menu, output is displayed on screen. Commonly touch screen monitors use sensors to detect touch of finger.