primarymemorymainmemory-180113103116.pptx

Ppt

1. Primary Memory (Main Memory)

2. Primary Memory (Main Memory) Primary memory holds only those data and instructions on which the computer is currently working. It has a limited capacity and data is lost when power is switched off. It is generally made up of semiconductor device. It is divided into two subcategories RAM and ROM.

3. Characteristics of Main Memory These are semiconductor memories. It is known as the main memory. Usually volatile memory. Data is lost in case power is switched off. It is the working memory of the computer. Faster than secondary memories. A computer cannot run without the primary memory.

4. RAM Random Access Memory (RAM)  is a type of computer memory that is used to temporarily store data that the computer is currently using or processing.  RAM is volatile memory, which means that the data stored in it is lost when the power is turned off.  It is also called read-write  memory  or the  main memory  or the  primary memory . The programs and data that the CPU requires during the execution of a program are stored in this memory.

5. RAM

6. Types of RAM Some of the more common examples are DRAM ( DynSRAM (Static random access memory) amic random access memory) SDRAM (Synchronous DRAM) DDR (Double Data Rate SDRAM) RDRAM (Rambus Dynamic random access memory ) Static RAM:  SRAM stands for Static Random Access Memory. It is a type of semiconductor which is widely used in computing devices and microprocessors. 2. Dynamic RAM:  DRAM stands for Dynamic Random Access Memory. It is made of Capacitors and has smaller data life span than Static RAM. 

7. Parameter DRAM SRAM Construction Constructed of tiny capacitors that leak electricity. Constructed of circuits similar to D flip-flops. Data Retention Requires a recharge every few milliseconds to maintain its data. Holds its contents as long as power is available. Cost Inexpensive. Expensive. Speed Slower than SRAM. Faster than DRAM. Storage Capacity Can store many bits per chip. Can not store many bits per chip. Power Consumption Uses less power. Uses more power. Heat Generation Generates less heat. Generates more heat. Typical Usage Used for main memory. Used for cache.

8. Advantages of Random Access Memory (RAM) Speed Flexibility Capacity Power Management

9. ROM ( Read-Only Memory) Read Only Memory (ROM)  is a type of computer memory that is used to permanently store data that does not need to be modified. ROM is non-volatile memory, which means that the data stored in it is retained even when the power is turned off. ROM is typically used to store the computer’s BIOS (basic input/output system), which contains the instructions for booting the computer, as well as firmware for other hardware devices. Stores crucial information essential to operate the system, like the program essential to boot the computer. Used in embedded systems or where the programming needs no change. Used in calculators and peripheral devices.

10. Kinds of ROM There are  five  basic ROM types Mask ROM PROM EPROM EEPROM FLASH ROM

11. Mask ROM Mask ROM (Mask Read-Only Memory) is a type of read-only memory (ROM) in which the data is programmed during the manufacturing process and cannot be reprogrammed by the end user. It gets its name from the fact that the data is physically "masked" onto the chip during its fabrication.

12. PROM ( Programmable Read Only  ) PROM, is a type of memory chip that can be programmed by user according to needs ,after manufacturing. Unlike standard ROM (Read-Only Memory), which comes pre-programmed from the manufacturer, PROM allows customization according to some specific needs. once data is written onto a PROM chip it cannot be modified and erased.

13. EPROM  (Erasable Programmable ROM) EPROM chips can be rewritten many times. It is very cost effective. It retains memory even without power. It is re-programmable as mentioned above It is easy to erase EPROM completely by exposing it to ultraviolet light

14. EEPROM ( Electrically Erasable Read Only Memory. ) It can be erased and reprogrammed about ten thousand times. Both erasing and programming take about 4 to 10 ms (millisecond).  EEPROMs can be erased one byte at a time, rather than erasing the entire chip. Hence, the process of reprogramming is flexible but slow. The method of erasure is electrical and immediate.

15. FLASH ROM FLASH ROM are used for android devices. There is also something called as custom rom. It will provide you better functionality, user interface, features and more. Many android users are going for custom roms , as they help them change the look and feel however they want.

16. Questions