RAM and ROM are both types of computer memory used to store data, code, and other information that is used by the CPU to operate in real time. Embedded systems include both of these types of memory to perform certain tasks, each with their own individual purpose, advantages, and disadvantages. In this article, we’ll provide background into RAM and ROM and discuss their main differences.
What is RAM
RAM, or random access memory, is a type of storage for computer systems that is used to store data and programs that can be quickly accessed at any time by the device’s processor. It is considered the main memory in a computer and is often much faster to read and write to than other kinds of storage, like a hard drive.
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Flash memory is a type of EEPROM that can be erased and rewritten more quickly than a regular EEPROM device. This is because Flash devices support large-block erasures. Newer Flash memory designs also support greater write cycles exceeding 1,000,000 cycles.
Differences Between RAM and ROM
Data Retention
Like mentioned earlier, RAM and ROM differ significantly in their data retention capabilities. ROM is non-volatile, so it is able to retain data without power, while RAM is volatile, which means it retains data as long as the computer is powered. Essentially, ROM is used for permanent storage and RAM is used for temporary storage.
Storage Capacity
A ROM chip can store several megabytes (MB) of data, ranging from 4 to 8 MB per chip. A RAM chip, however, can store much more data, ranging from 1 to 256 gigabytes (GB) per chip. Computers these days often use around 16 GB to 32 GB of RAM.
Speed
Data accessing speeds and writing speeds are both superior in RAM. In terms of storage read speeds, ROM does this at a rate of a few MBs/second, whereas the read speed of RAM is a few GBs/second. With faster data access/read speeds, RAM boosts the processing speed of the computer. RAM is also faster and easier to write to than ROM. This is because ROM typically stores limited but long-lasting information and is more difficult to alter, with the exception of EEPROMs.
