Memory is the electronic holding place for the instructions and data.
It's where information is stored for immediate use.
There are generally 2 types of computer memory: primary and secondary.
Primary memory is the memory, while secondary memory is storage.
The storage stores data on a long-term basis.
There are some types of primary memory:
1. Cache memory
- temporary storage area
- readily available to the processor
- also called CPU memory
2. RAM (Random Access Memory)
- any storage location can be accessed directly by the processor
3. Dynamic RAM (DRAM)
- a type of semiconductor memory
- typically used by the data or program code
4. Static RAM (SRAM)
- retains data bits for as long as power is supplied to it
- unlike DRAM, it does not have to be periodically refreshed
5. Double Data Rate SDRAM (DDR SDRAM)
- can theoretically improve memory clock speed to at least 200 MHz.
6. Double Data Rate 4 Synchronous Dynamic RAM (DDR4 RAM)
- a type of DRAM
- has a high-bandwidth interface
- allows for lower voltage requirements and higher module density.
- the successor to its previous DDR2 and DDR3 versions.
7. Rambus Dynamic RAM (DRDRAM)
- memory subsystem that promised to transfer up to 1.6 billion bytes per second
- consists of RAM, the RAM controller, the bus that connects RAM to the microprocessor and devices in the computer
8. Read-only memory (ROM)
- contains nonvolatile, permanent data that can only be read and not written to
- contains the programming that enables a computer to start up or regenerate each time it is turned on
9. Programmable ROM (PROM)
- ROM that can be modified once by a user
- enables a user to tailor a microcode program using a special machine called a PROM programmer.
10. Erasable PROM (EPROM)
- programmable read-only memory
- can be erased and re-used
11. Electrically erasable PROM (EEPROM)
- user-modifiable ROM
- can be erased and reprogrammed repeatedly through the application of higher than normal electrical voltage
- Unlike EPROM, it does not need to be removed from the computer to be modified
- must be erased and reprogrammed in its entirety, not selectively
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