Wednesday, December 31, 2008

memory chips


Dynamic random access memory (DRAM) chips are single-transistor memory cells that use small capacitors to store each bit of memory in an addressable format that consists of rows and columns. Because capacitors are unable to hold a charge indefinitely, DRAM memory chips require a near-constant pulse of current to retain stored information.DRAM modules are collections of dynamic random access memory (DRAM) chips assembled on circuit boards. Electrically erasable programmable read-only memory (EEPROM) chips are similar to PROM devices, but require only electricity to be erased. Erasable programmable read-only memory (EPROM) chips are programmable, reusable computer chips that can be erased using ultraviolet light and reprogrammed with a PROM programmer or PROM burner. First-in, first-out (FIFO) memory chips are used in buffering applications between devices that operate at different speeds, or in applications where data must be stored temporarily for further processing. FLASH memory chips offer extremely fast access times, low power consumption, and relative immunity to severe shock or vibration. They do not need a constant power supply to retain their data. Memory chips are internal storage areas in computers. Although the term “memory chip” commonly refers to a computer's random access memory (RAM), this product area includes many different types of electronic data storage. Computer memory stores data electronically in cells. Without memory chips, a computer could not read programs or retain data.
The two most common types of memory chips are DRAM chips and SRAM chips. Dynamic random access memory (DRAM) is single-transistor memory cell that requires regular refreshes. DRAM chips consist of small capacitors for each bit of memory. Since capacitors do not hold a charge indefinitely, DRAM memory chips must be constantly refreshed to avoid losing its contents. In addition, the process of reading the contents of the memory are destructive, which means that extra time must be spent restoring the contents of memory addresses. Consequently, DRAM is slower than SRAM. Static random access memory (SRAM) is a volatile memory cell that does not require updates or periodic refresh cycles to keep the memory content intact.
Other types of memory chips use FIFO or Flash. First-in, first-out (FIFO) memory is used in buffering applications between devices that operate at different speeds. Flash memory is a form of electrically erasable, programmable, read-only memory (EEPROM) that can be erased and reprogrammed in blocks, rather than one byte at a time. Flash memory does not need a constant power supply to retain data and offers fast access, low power consumption, and relative immunity to shock or vibration. Flash memory chips have an approximant lifespan of 100,000 write cycles. Consequently, Flash is not suitable to be the main memory of a computer. Instead, Flash is used in digital cameras, cell phones, pagers, scanners, laptops, and video game memory cards.
PROM, EPROM, and EEPROM memory chips are also available. Programmable read-only memory (PROM) can only be written once. EPROM stands for erasable programmable read-only memory. These PROM memory chips can be erased through exposure to ultraviolet (UV) light and then reprogrammed. EEPROM memory chips are similar to EPROM chips; however, EEPROM can be erased electronically. Other, unlisted types of memory chips are also available.
Power specifications for memory chips include the supply voltage, the maximum and minimum operating currents, standby current, and power dissipation. Specialized specifications for memory chips refer to access time, cycle time, data retention, endurance, and operating temperature. Additional specifications for memory chips may also be available.
Other types of memory chips use FIFO or Flash. First-in, first-out (FIFO) memory is used in buffering applications between devices that operate at different speeds. Flash memory is a form of electrically erasable, programmable, read-only memory (EEPROM) that can be erased and reprogrammed in blocks, rather than one byte at a time. Flash memory does not need a constant power supply to retain data and offers fast access, low power consumption, and relative immunity to shock or vibration. Flash memory chips have an approximant lifespan of 100,000 write cycles. Consequently, Flash is not suitable to be the main memory of a computer. Instead, Flash is used in digital cameras, cell phones, pagers, scanners, laptops, and video game memory cards.
PROM, EPROM, and EEPROM memory chips are also available. Programmable read-only memory (PROM) can only be written once. EPROM stands for erasable programmable read-only memory. These PROM memory chips can be erased through exposure to ultraviolet (UV) light and then reprogrammed. EEPROM memory chips are similar to EPROM chips; however, EEPROM can be erased electronically. Other, unlisted types of memory chips are also available.
Power specifications for memory chips include the supply voltage, the maximum and minimum operating currents, standby current, and power dissipation. Specialized specifications for memory chips refer to access time, cycle time, data retention, endurance, and operating temperature. Additional specifications for memory chips may also be available.

Tuesday, December 30, 2008

ram


Everybody who are literally improved must have heard of ram.Yes it is included in computer system.so let me tell some thing more about ram.it stands for random acess memory,it is used as a memory sell for computer system .RAM is the most important factor in computer performance. If you don't have enough, adding RAM can make more of a difference than getting a new CPU.If your system responds slowly then you need more ram..It is of various types SRAM: Static random access memory ,DRAM: Dynamic random access memory , FPM DRAM: Fast page mode dynamic random access memory , EDO DRAM: Extended data-out dynamic random access memory , SDRAM: Synchronous dynamic random access memory ,DDR SDRAM: Double data rate synchronous dynamic RAM ,RDRAM: Rambus dynamic random access memory ,Credit Card Memory: Credit card memory is a proprietary self-contained DRAM memory module that plugs into a special slot for use in notebooks computer,PCMCIA Memory Card: Another self-contained DRAM module for notebooks,CMOS RAM: CMOS RAM is a term for the small amount of memory used by your computer and some other devices to remember things like hard disk and its comprisement,VRAM: VideoRAM, also known as multiport dynamic random access memory (MPDRAM), is a type of RAM used specifically for video adapters or 3d aceelerators.

The above are a few information about ram.