| 1 |
There are primary and secondary storage. Primary storage consists of RAM, ROM, and cache memory. ROM is classified into MROM (programmed during manufacturing), PROM (can be modified once by the user), EPROM (can be erased and reprogrammed), EEPROM (can be erased electrically and reprogrammed multiple times), and FLASH ROM (has high endurance, and can be erased and rewritten faster than EEPROM). RAM can be static and dynamic. Static RAM consists of interlocked transistors and requires a constant power supply and does not need refreshing. Dynamic RAM consists of transistors and capacitors and is cheaper but requires periodic refreshing and operates more slowly. Cache is a smaller, faster memory component that stores copies of recently accessed data. Cache is located on the CPU chip. The CPU checks the cache first for data (cache hit) before accessing the main memory. The whole process is controlled by a group of logic circuits called the cache controller. Cache ensures cache coherency, which means that the data in the cache and main memory remain consistent. There are two methods of writing to cache: in write-through mode, data is updated simultaneously in both the cache and main memory, while in write-back mode, changes are initially recorded in the cache and transferred to the main memory. The second method is faster but requires a more advanced cache controller. |
Комментарии