Main Memory and its type in computer .pptx

Main memory

1. WELCOME ICT

2. Application of information and communication technology Application of information and communication technology Lecture 1# Instructor: Muhammad Naeem Khan

3. What is RAM? Random Access Memory, is a type of computer memory that allows data to be read and written randomly, meaning that the computer can access any location in the memory directly rather than having to read the data in a specific order. This makes RAM an essential component of a computer system, as it enables the CPU to access data quickly and efficiently. RAM is volatile in nature, which means if the power goes off, the stored information is lost. RAM is used to store the data that is currently processed by the CPU. Most of the programs and data that are modifiable are stored in RAM.  The block diagram of the RAM chip is given below: Different Types of RAM (Random Access Memory )

4. Mainly RAM have 2types SRAM (Static RAM) DRAM (Dynamic RAM ) What is SRAM? The SRAM memories consist of circuits capable of retaining the stored information as long as the power is applied. That means this type of memory requires constant power. SRAM memories are used to build  Cache Memory . SRAM Memory Cell Static memories(SRAM) are memories that consist of circuits capable of retaining their state as long as power is on. Thus this type of memory is called  volatile memory . The below figure shows a cell diagram of SRAM. A latch is formed by two inverters connected as shown in the figure. Two transistors T1 and T2 are used for connecting the latch with two-bit lines. The purpose of these  transistors  is to act as switches that can be opened or closed under the control of the word line, which is controlled by the address decoder. When the word line is at 0-level, the transistors are turned off and the latch remains its information. SRAM does not require refresh time. For example, the cell is at state 1 if the logic value at point A is 1 and at point, B is 0. This state is retained as long as the word line is not activated.  Types of RAM ?

5. DRAM stores the binary information in the form of electric charges applied to capacitors. The stored information on the capacitors tends to lose over a period of time and thus the capacitors must be periodically recharged to retain their usage. DRAM requires refresh time. The main memory is generally made up of DRAM chips. DRAM Memory Cell Though SRAM is very fast, it is expensive because of its every cell requires several transistors. Relatively less expensive RAM is DRAM, due to the use of one transistor and one capacitor in each cell, as shown in the below figure., where C is the  capacitor  and T is the transistor. Information is stored in a DRAM cell in the form of a charge on a capacitor and this charge needs to be periodically recharged.  For storing information in this cell, transistor T is turned on and an appropriate voltage is applied to the bit line. This causes a known amount of charge to be stored in the capacitor. After the transistor is turned off, due to the property of the capacitor, it starts to discharge. Hence, the information stored in the cell can be read correctly only if it is read before the charge on the capacitors drops below some threshold value.  What is DRAM ?

6. B.  Control Unit:   The Control unit coordinates and controls the data flow in and out of the CPU, and also controls all the operations of ALU, memory registers and also input/output units. It is also responsible for carrying out all the instructions stored in the program. It decodes the fetched instruction, interprets it and sends control signals to input/output devices until the required operation is done properly by ALU and memory. The Control Unit is a component of the central processing unit of a computer that directs the operation of the processor. It instructs the computer's memory, arithmetic and logic unit, and input and output devices on how to respond to the processor's instructions. In order to execute the instructions, the components of a computer receive signals from the control unit. It is also called the central nervous system or brain of the computer . C.  Memory Registers :  A register is a small, temporary memory inside the CPU. The processor uses it to store data that it is currently working on. Registers come in different sizes, such as 16-bit, 32-bit, and 64-bit, and each has a specific role. Some store data, some store instructions, and others hold memory addresses. 2. Central Processing Unit :

7. The output unit consists of output devices that are attached to the computer. It converts the binary data coming from the CPU to human understandable form. The common output devices are monitor, printer, plotter, etc. The output unit displays or prints the processed data in a user-friendly format. The output unit is formed by attaching the output devices of a computer. The output unit accepts the information from the CPU and displays it in a user-readable form. 3. Output Unit : 

8. The motherboard is like the backbone of a computer, connecting all the important parts such as the CPU, memory, and storage. It also helps distribute power, transfer information, and connect devices like a mouse, keyboard, or monitor. If there is a problem with the motherboard, a computer technician may open the PC to check for any loose or damaged connections, such as corrosion. They may also inspect the power supply to ensure the computer is receiving electricity properly. 4. Motherboard :

9. Thank You