ROM memory or read-only memory is an internal hardware element that is usually built into the motherboard .
It cannot be modified (or at least not easily) so it usually contains the firmware that allows the operation of the equipment. Its storage capacity is limited. Modern computers have 4, 8 or 16 Mb, enough to host the SMBIOS code, responsible for initializing basic processes on the computer such as activating POST, detecting hardware , establishing the basic execution environment or loading priority RAM memory paths.
ROM has changed over time, from being an unalterable memory (MROM) to working like a flash memory . The different types of ROMs available today are:
Programmable Read Only (PROM) or Programmable One Time (OTP) memory . Reconfigurable with specialized equipment. It offers the highest security as it is resistant to rootkit attacks .
Erasable Programmable Read Only Memory (EPROM) . Allows up to 1000 erase and rewrite cycles. They are usually equipped with a label that protects them from ultraviolet light (UV erases information).
Electrically Erasable Programmable Read Only Memory (EEPROM) . The most common in current commercial applications. They are slower than traditional ROMs. Flash memory is a specific type of EEPROM that is faster and more robust (supports up to a million erase and rewrite cycles). It is also worth mentioning the EAROM subtype, slow but more secure.
The main specifications of the RAM memory units are: reading speed, writing speed, resistance and robustness of the storage against high temperatures and radiation emissions .
Storage units in hardware components
Although ROM is rarely discussed outside of the chipset environment , it could be argued for its inclusion within this segment. We have preferred not to do so to protect the prominence of RAM memory cards and physical storage units, blocks that we investigate in the following sections.
RAM memory or random access memory is a storage device that accelerates the speed of access and reading of information in use . They minimize the time taken to obtain the required data.
The RAM differs from the physical storage units which is volatile: the stored memory is lost when power is removed.
This hardware has undergone multiple evolutions since its conception in 1959 (MOS transistor, also known as MOSFET). Currently, RAM is presented in two main branches: SRAM or static RAM and DRAM or dynamic RAM .
The first group concluded its evolution in 1995 with a 256 Mb device developed by SK Hynix, then Hyundai Electronic Industrial. The DRAM reached 4 Gb in 2011 from Samsung, and then it derived in new technologies such as synchronous dynamic RAM or SDRAM that in its types DDR2, DDR3, LPDDR2, LPDDR3, LPDDR4 and LPDDR5 are widely used today; or synchronous graphics RAM and high-bandwidth memory (HBM and HBM2) which are also current.
The different typologies have very different specifications that make them incompatible with each other.
The latest developments in RAM are the types GDDR5X and GDDR6, the technology used in Nvidia’s Ray tracing applications .
Another possible classification talks about SIMM (Single In-line Memory Module) memories and their evolution: DIMMs (Dual In-line Memory Module). Modern RAM memory cards are included in the latter family. Laptops are often equipped with smaller memory sizes called SO-DIMMs (only the form factor changes, not the technology).
The most important specifications of RAM are: capacity, capacity limit tolerated by the installed operating system, frequency and latency .
RAM limits the number of running processes on your computer. The operating system contains an address known as swap space that can come in the form of a file or partition. This item helps to manage data coming from RAM when the random access memory in use is close to being full. This excess of available RAM is known as virtual RAM; the name should not be misleading as this memory is located on the SSD or HDD and does not have the defining characteristics of RAM.
When the available RAM is exceeded, this file increases in weight. When the defined weight limit is exceeded, errors appear. In general, operating with the RAM memory to the limit slows down the processes of the computer and is not recommended , both from a performance point of view and from a hardware preservation point of view .
It should also be noted that memory that has gone through a period of inactivity in RAM may be compressed. This state is sometimes known as ZRAM (Linux) or ZSWAP (Android) . This prevents paging to disk (with much lower read and write speeds) and increases RAM performance. Optimized use of this technology allows you to get the most out of installed RAM without the need to upgrade hardware .