ROM memory What is it, what is it for and what types are there in computing?

ROM memory is an essential part of our devices. Many, many people use it without even knowing that it exists, but its work is, without a doubt, invaluable in the world of technology.

We can anticipate that it is a type of memory that is used to boot our systems and, with it, the deviceswhether they are big or small. This comes from the factory and cannot be manipulated.

For the rest, we encourage you to get to know in depth what it is, the types that exist, how our devices use it and how it differs from the, already somewhat better known, RAM memory.

What is the ROM memory of a computer and what is it used for?

ROM is part of the hardware of the devices, be they computers, phones, tablets… and it is related to their boot process and their maintenance and their utilization capacities.

Definition

To define this concept, we will first go to its name, ROM, which is an acronym for Read Only Memoryor read-only memory.

The main characteristic of this piece of software that we have already seen that it is still a memory, it is that it is, initially, unalterable (Later we will see that there are ways to modify them, but it is not easy to do so, and less so at the user level).

So we have to ROM is non-writable memory, unsuitable for modification. This is largely due, in addition to the logical accidents that a user could cause due to ignorance, to the fact that include inside the firmware of certain hardwarethat is, a specific application for the control and performance of tasks.

Another essential feature is that it does not require electrical power, so storage is permanent. the ROM It is made up of a set of fairly basic programs that the system in question read on power up. These are provided by the manufacturer when mounting the chip. Physically, the ROM is located on a small chip which does not include anything else.

Functions on PC and mobile devices

ROM functions as both a data store and a software store. More specifically, what it saves is a compendium of codes and starting instructions, including language interpreters, OS programs, control programs, information tables…

It will also serve for hardware function check whom he accompanies and to help them recognize the operating system that moves the system and peripherals input and output.

Let’s see how he does it in each situation:

• BIOS: To work with the BIOS, which is a program that controls essential I/O interfaces, we have the BIO ROM, a read-only card on the motherboard. The BIOS is stored in ROM because it is necessary to read the rest of the memory elements of any computer, so we cannot store it in any of them.
• Bootstrap: It uses the disk and also the floppy drive to run the operating system by loading and executing random access memory. This occurs if there are malfunctions in the hard disk system.
• CMOS Configuration: Allows access to a screen that appears when the equipment is turned on and that allows the modification of certain system parameters.
• POST Power On Self Test: It is a bootable autorun software that seeks to test the system.
• Back: It is the copying of instructions from ROM to RAM in order to have them faster.
• Data storage: It only makes sense to store in them those that should not be modified while the device is useful, such as a lookup table.

Types and examples of ROM or read-only memory

Having some contact with the computer and having read the above, you can already imagine that, in effect, there are different types of ROM memoriesconsidering that it is programmable, read-only or erasable in one way or another, including, even, subtypes.

The basis of this classification is semiconducting:

Blunt read-only memory

Make a storage of information without electrical current. It is also known as non-volatile memory because it is not lost when the system is turned off.

PROM, OTP or Programmable Read Only Memory

Is that which requires the use of a programming device called a PROM to be written. It works at high voltage with the intention of create and destroy internal links on a chipwhich is why only a single schedule can be given.

EPROM or erasable programmable read only memory

This memory is programmable read only but can also be erasable. This is achieved when exposed to UV light for periods of time greater than 10 minutes. After that, can be rewritten with a high voltage process (Even more than you are used to needing). A cover is used to prevent erasure. We have the handicap of degradation, because the higher UV exposure, the more wear, being common to have about 1000 reprogramming cycles.

EEPROM or Electrically Erasable Programmable Read Only Memory

Its base is a semiconductor structure as the previous type, with the exception that the content or part of this is erased with electricity, in the same way that it is later rewritten. This implies that it is not necessary to remove the memory from the computer, although we do have to say that, compared to other memory jobs, it is a slower process.

In turn, we find these subtypes:

• EARM or electrically alterable read only memory: This is modified one bit at a time in a fairly slow writing process that requires the use of a high voltage of at least 12 volts. Its use occurs in infrequent partial writing apps and, sometimes, to store in a non-volatile way in order to obtain critical system configuration data from the computer where it is located
• Flash, Flash ROM or Flash EEPROM: Erasing and rewriting is faster and its resistance is very high, being able to offer more than a million cycles. It has replaced old ROMs in many cases.

It is essential to point out that, today, The term ROM is used to refer indistinctly to any type of Read-Only Memory.because, in fact, the original type is already in disuse due to the improvements that have been implemented until forming the different types that we have been seeing.

Is ROM memory and storage memory the same thing?

Absolutelyit is curious how the ROM concept has been mistakenly used to talk about storage memory of the devices, the one we use to download video games, movies, etc.

So much so that even in stores and on the devices themselves of certain brands (phones and tables mainly) it is called thatand we see it in the phone settings and in the descriptions that “experts” make in their stores to show you the new hot phone or a super computer.

ROM

• The ROM we have already seen that it is a tiny memory that has the basics to make it work the apparatus, a spark so to speak.
• is unalterable (in principle) by the user.
• It is located inside the equipment, in the form of chip.

storage memory

• The storage memory is another type of memory, much larger today, which is Where will everything that we are saving go? in the computer.
• We have full access to this content.; we can consult it whenever we want and it can also be deleted at will, using the space to save new information when we need it. The things that are saved in the storage memory are not essential or critical for the operation of the device, is all that content that we download and install voluntarily and that we want them to remain afterwards.
• The hardware that houses the storage memory is called HDD, being able to be both internal, as part of the equipment, or an addition, an external hard drive, which would be a hybrid storage peripheral. It is also considered a memory of storage the pen drivealthough the capacity is less, but it works the same.

Main differences between ROM and RAM memory

Easily confused by those who only make superficial use of computers and other devices, both concepts refer to memory systems of a device or equipment but they are not the same thing at all. You can see more in depth All the differences between RAM and ROM from here.

ROM

• We have already seen that it is memory of only readingthat is to say, a compendium of information that is only useful to read and, with it, start and maintain the correct operation of the equipment in question.
• It is basic startup, configuration and maintenance information, non-volatile, grouped on a small chip.
• Work with essential information, needed to boot the system.

RAM

• The RAM is the acronym for Random Access Memory or random access memory.
• This means that access is given to any byte of existing memory in our system without needing access to the preceding bytes.
• This is erasable, volatile, perishable, lostI eat very late, when it stops receiving power from a current source. It also turns out to be faster. Its physical format is a larger board with complex circuits.
• Work with secondary software that requires a temporary effort such as video games, browsers, etc.