Computer memory
Download as PPT, PDF•11 likes•11,093 views
The document discusses the history and types of computer memory. It describes how early memory in the 1940s had a capacity of only a few bytes. The ENIAC was the first electronic, general-purpose computer capable of being reprogrammed. Delay line memory was an early form that stored data as acoustic waves in mercury delay lines. Magnetic core memory, developed in 1947, allowed memory to be retained after power loss and became the dominant memory technology of the 1960s. Modern computers use semiconductor memory such as RAM, ROM, cache memory, and flash memory. RAM allows random access and comes in dynamic and static varieties, while ROM is read-only and flash memory is non-volatile.
Computer memory
- 3. HISTORY OF MEMORY In the early 1940s, memory technology mostly permitted a capacity of a few bytes. ENIAC(Electronic Numerical Integrator And Computer): Firs electronic general- purpose computer . That is capable of being reprogrammed to solve a large class of numerical problems.
- 5. DELAY LINE MEMORY developed by J. Presper Eckert in the early 1940s. It is also used in digital computers. Delay line memory would be limited to a capacity of up to a few hundred thousand bits to remain efficient.
- 7. RANDOM ACCESS COMPUTER MEMORY The Williams tube and Selectron tube originated in 1946. In 1947 Jay Forrester, Jan A. Rajchman and An Wang developed magnetic core memory which allowed for recall of memory after power loss. The Selectron was limited to 256 bits, while the Williams tube could store thousands
- 10. MAGNETIC CORE MEMORY It was the computer memory of choice throughout the 1960s, until it was replaced by semiconductor memory.
- 11. MEMORY
- 12. MEMORY It holds the data and instructions that the Central Processing Unit (CPU) needs. Before a program can be run the program is loaded from the storage medium into memory. It allows the CPU to direct interact with the program. Memory is a need of every computer
- 13. TYPES OF MEMORY
- 14. TYPES OF MEMORY ROM (Read Only Memory) RAM (Random Access Memory) Cache memory Flash memory
- 15. READ ONLY MEMORY stores data without electrical current; it is the ROM (Read Only Memory) or is sometimes called non-volatile memory as it is not erased when the system is switched off
- 16. RAM Random Access Memory, can be accessed randomly. Any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers.
- 17. DDR2 RAM & DDR3 RAM
- 18. TYPES OF RAM
- 19. TYPES OF RAM There are two different types of RAM: DRAM (Dynamic Random Access Memory) SRAM (Static Random Access Memory).
- 20. DRAM Needs to be refreshed thousands of times per second while. Dynamic RAM needs to automatically refresh thousands of times per second; that's where it gets the name dynamic. Otherwise, it will forget the information it's holding.
- 21. SRAM Does not need to be refreshed, which is what makes it faster than DRAM. Both types of RAM are volatile, meaning that they lose their contents when the power is turned off.
- 22. CACHE MEMORY
- 23. CACHE MEMORY The cache is a smaller, faster memory which stores copies of the data from frequently used main memory locatio ns.
- 24. FLASH MEMORY
- 25. FLASH MEMORY Non volatile memory can be erased electronically and rewritten similar to EEPROM. Introduced by Toshiba in 1984. Most computers use it to hold up their startup instructions. Also used in many mobiles , smart phones , digital cameras and PDA.
- 26. FLASH MEMORY
- 27. THANK YOU