ROM Memory (Read-Only Memory)

Read-only memory, also known as ROM (read-only memory), is a storage medium used in computers and electronic devices, which allows only the reading of information and not its writing, regardless of the presence Or not from an energy source.

The data stored in the ROM cannot be modified, or at least not quickly or easily. It is mainly used in its strictest sense, refers only to English ROM mask, MROM (the oldest type of solid state ROM), which is manufactured with stored data permanently and therefore its content cannot be modified in any way. However, the most modern ROMs, such as EPROM and Flash EEPROM, can effectively be deleted and reprogrammed several times, even though they are described as “read-only Memory ” (ROM).

The reason for continuing to call them is that the rescheduling process is generally rare, relatively slow, and writing is often not allowed in random places in memory. Despite the simplicity of the ROM, the reprogrammed devices are more flexible and economical, so the old ROM masks are not usually found in hardware produced from 2007.


Developed by Toshiba, the designers explicitly broke with the practices of the past, stating that it focused on “being a replacement for hard disks”, rather than having the traditional use of the ROMPROM Memory as a non-volatile primary form of storage. In 2007, NAND has advanced considerably in its goal, offering comparable performance to hard disks, better tolerance to blows, extreme miniaturization (such as USB Ejemplomemorias and MicroSD memory cards), and much lower power consumption.

There are several types of memory:

· RAM (Random access memory): This is the same as main memory. When used by itself, the term RAM refers to read and write memory; That is, you can both write data in RAM and read them from RAM. This is in contrast to the ROM, which allows you to just read the read data. Most of the RAM is volatile, which means it requires a constant flow of electricity to keep its content. As soon as the power supply is interrupted, all data that was in RAM is lost.

· ROM (unalterable memory): Computers almost always contain a small amount of read-only memory that saves the instructions for starting the computer. In the ROM memory you cannot write.

· Prom (programmable unchangeable memory): An prom is a memory chip in which you can save a program. But once the PROM has been used, you cannot reuse it to save something else. Like the ROMs, the Proms are permanent.

· EPROM (erasable programmable memory): An EPROM is a special type of PROM which can be erased by exposing it to ultraviolet light.

· EEPROM (electrically erasable programmable memory): A EEPROM is a special type of PROM that can be erased by exposing it to an electrical charge.

PROM Memory

PROM is in English of programmable read-only memory, which means “programmable read-only memory”. It is a digital memory where the value of each bit depends on the state of a fuse (or antifuse), which can be burned only once. For this reason the memory can be programmed (the data can be written) only once through a special device, a programmer PROM. These memories are used to record permanent data in smaller amounts to the ROMs, or when the data should change in many or all cases.

Small proms have been used as function generators, usually in conjunction with a multiplexer. Sometimes they preferred the ROMs because they are bipolar, habitulamente Schottky, getting higher speeds.


A common PROM is found with all the bits in value 1 as the factory default value; The burn of each fuse changes the value of the corresponding bit to 0. The programming is done by applying high voltage pulses that are not during normal operations (12 to 21 volts). The term read-only refers to that, unlike other memories, the data cannot be changed (at least by the end-user).


The memory PROM was invented in 1956 by Wen Tsing Chow, working for the “Weapon Division”, of the American Bosch arma Corporation in Garden City, new York. The invention was conceived at the request of the United States Air Force, to obtain a more secure and flexible way to store the constants of the objectives in the digital computer of the MBI Atlas E/F.

The associated patent and technology were kept secret for several years while the E/F Atlas was the main missile in the United States. The term “burning”, referring to the process of recording an PROM, is also found in the original patent, because as part of the original implementation the internal diodes with an excess of current had to be literally burned to produce the discontinuity of the Circuit. The first Proms programming machines were also developed by engineers from the Arma division under the direction of Mr. Chow and were located the weapon laboratory of Garden City, and at the head of the Air Strategic Air Force command.

EPROM Memory

EPROM is the acronym of Eraseable programmable Read-Only Memory (erasable programmable ROM). It is a type of non-volatile ROM memory chip invented by engineer Dov Frohman. It consists of FAMOS cells (floating gate Avalanche-injection Metal-oxide semiconductor) or “Floating gate transistors “, each of which comes from factory without load, so they are read as 1 (so, an unrecorded EPROM is read as FF in all its Cells).

EPROM memories are programmed using an electronic device, such as ElCromemco Bytesaver, which provides voltages higher than those normally used in electronic circuits. Cells receiving load are then read as a 0.

How To Remove an EPROM

An EPROM memory can be erased with a UV-C type lamp, which emits radiation around the 2537 Å (Angstrom) or 254nm, at a distance of about 2.5 cm from the memory. The radiation reaches the memory cells through a transparent quartz window located on top of it.

To erase an EPROM it is necessary that the amount of radiation received by it is around 15 W/cm ^ 2 for one second. The actual erasing time is usually about 20 minutes because the lamps used usually have powers around 12 mw/cm ² (12 MW x 20 x 60 s = 14.4 W of power supplied). This time also depends on the manufacturer of the memory you want to delete. At this time all its bits are put to 1.

It is important to avoid overexposure of radiation time to eproms; That is to say, the luminous power supplied to the memory, because it produces a premature ageing of the same ones.
Because the solar radiation and even the artificial light from fluorescent tubes erases the memory slowly (from one week to several months), it is necessary to cover the window with an opaque label that avoids it, once they are recorded.

It should be clarified that an EPROM cannot be erased partially or selectively; Hence, as small as the eventual modification to be made in its content, it must inevitably be deleted and reprogrammed in its entirety.

Once programmed, an EPROM can be erased only by exposure to strong ultraviolet light. This is because light photons excite loselectrones cells causing them to unload. EPROMs are easily recognized by a transparent window in the top of the encapsulation, through which you can see the silicon chip and which supports ultraviolet light during erasing.

As the window quartz is expensive to fabricate, the OTP (one-time programmable) chips were introduced. The only difference with the EPROM is the absence of the quartz window, so it cannot be erased. The OTP versions are manufactured to replace both normal eproms and eproms included in some micro-controllers. The latter were progressively replaced by eproms (for the manufacture of small quantities where the cost is not important) and by flash memory (in the most used).

A programmed EPROM retains its data for ten or twenty years, and you can read an unlimited number of times. To avoid accidental sunlight erasure, the erase window must remain covered. The old bios of the personal computers were frequently EPROM and the delete window was usually covered by a label that contained the BIOS producer’s name, its revision and a copyright warning.

EPROM Eraser

An EPROM eraser is an optically opaque case, with a C type UV light source, which is also used to sterilize surgical instruments and/or as a germicide.

To erase the EPROMs, you cannot use the “black UV ” light (which is commonly used to check banknotes, tickets, etc.), which emit in the UV-A region (365 nm). The only light that works is the UV-C, (254 nm), which emits “dangerous light” or “germicidal” (Kills Germs). “Dangerous light ” because prolonged exposure can cause long-term cataracts and skin damage; However, a brief exposure, about 5 seconds continuous on the skin, should not cause more than a mild dryness, so it is necessary to take all precautions to avoid these problems. Since this type of UV-C light is in the sunlight, if an EPROM is left directly under it, in some days or weeks it will be erased; So it is necessary to protect the eproms once they have been programmed.

A white light fluorescent tube has a phosphor cover inside the glass. The UV light of mercury excites phosphorus, which re-radiates energy in the visible range. UV lamps for EPROM or germicidal drafts directly use mercury vapor light. The glass must be made of quartz, instead of ordinary glass, to prevent the glass from absorbing most of the UV rays. Quartz is more transparent in the UV lengths of Mercury.

They could also be erased if exposed to the electric welding light (electrode), with the risk that a spark will burn the chip, because the EPROM should be approached about 10 or 15 cm to receive sufficient radiation to erase them. In theory, they can also be erased with X-rays, “by using the EPROM graphs “, the erasing time will depend on the calibration/emission of the X-ray equipment used.

EEPROM Memory Meaning

EEPROM Memories (Electrically eraseable programmable read only memory, or electrically erasable read-only programmable memory) are also erasable PROM memories, but unlike these, they can be erased by a simple electric current, it is Say, even if they are in position on the computer.

There is a variant of these memories, known as flash memory (TambiénFlash ROM or Flash EPROM). Unlike the classic EEPROM memories, which use 2 or 3 transistors for each bit to memorize, the EPROM Flash memory uses a single transistor. In addition, the EEPROM memory can be written and read Word by word, while the Flash can only be erased by pages (page size is constantly declining).

Finally, Flash memory is denser, implying that chips can be produced that contain hundreds of megabytes. Thus, EEPROM memories are preferable when you have to memorize configuration information, while Flash memory is used for programmable code (IT programs).

The action of reprogramming a EEPROM memory is called update.


It is a type of ROM memory that can be programmed, erased and reprogrammed electrically, unlike the EPROM to be erased by a device that emits ultraviolet rays. These are non-volatile memories.

The memory cells of a EEPROM consist of a MOS transistor, which has a floating gate (SAMOS structure), its normal state is cut and the output provides a logical 1.

Although a EEPROM can be read an unlimited number of times, it can only be deleted and reprogrammed between 100,000 and a million times.

These devices are often communicated through protocols such as I ² C, SPI and Microwire. At other times, it integrates into chips as micro-controllers and DSPs to achieve faster.

Flash memory is an advanced form of EEPROM created by Dr. Fujio Masuoka while working for Toshibaen 1984 and was presented at the IEEE 1984 electronic gadgets meeting. Intel saw the potential of the invention and in 1988 launched the first commercial chip of type NOR.

FLASH Memory

The flash memory derived from EEPROM memory allows the reading and writing of multiple memory positions in the same operation. Thanks to this, the flash technology, always by means of electrical impulses, allows much higher operating speeds compared to the original EEPROM technology, that only allowed to act on a single memory cell in each programming operation. It is about the technology used in devices called USB memory.

An USB Memory. The chip on the left is the flash memory. The controller is on the right.


The history of flash memory has always been closely linked to the advancement of the rest of the technologies to which it provides its services such as routers, modems, PC BIOS, wireless, etc. It was Fujio Masuoka in 1984, who invented this type of memory as an evolution of the existing EEPROM at the time. Intel tried to attribute the creation of this without success, although if it commercialized the first flash memory of common use.

Between the years 1994 and 1998, the main types of memory that we know today, such as the SmartMedia or the CompactFlash, were developed. Technology soon posed applications in other fields. In 1998, the Rio company commercialized the first digital audio player without mobile parts taking advantage of the mode of operation of the flash memory. This product would inaugurate a new class of players that would cause a revolution in the music industry leading to the Napster scandal, the launch of the IPod and the eventual replacement of tape and CD players.

In 1994 SanDisk began marketing memory cards (CompactFlash) based on these circuits, and since then evolution has reached small handheld devices of consumer electronics like portable MP3 players, memory cards for Video consoles and mobile phones, storage capacity for PC cards that allow to connect to wireless networks and a long etcetera, even arriving in space aeronautics.


Economically speaking, the price on the market meets Moore’s law by increasing its capacity and lowering the price.

Some of its advantages are great resistance to blows, high speed, low energy consumption and quiet operation, as it does not contain mechanical actuators or moving parts. Its small size is also a determining factor when choosing for a portable device, as well as its lightness and versatility for all the uses towards which it is oriented. In view of this, SSD discs that use flash memory instead of dishes begin to become popular.

However, all types of flash memory only allow a limited number of writes and deletions, usually between 10,000 and one million, depending on the cell, the precision of the manufacturing process and the voltage needed for deletion. In addition, its cost-capacity ratio is less favorable compared to other media such as optical disks and hard losdiscos.

Another feature has been the thermal resistance of some encapsulated memory cards oriented to high-end digital cameras. This allows operation in extreme temperature conditions such as deserts or glaciers as the temperature range supported ranges from-25 °c to 85 ° C.

The most common applications are:

· The USB keychain that, in addition to storage, can include other services like, fingerprint reader, FM Radio, voice recording and, especially as portable MP3 players and other audio formats.
· The PC Card (discontinued.)
· Flash memory cards that are used to store photos and videos on digital cameras. They are also common in mobile phones and tablets to expand storage capacity.

There are several standards of encapsulations promoted and manufactured by most of the multinationals dedicated to the production of hardware. The most common these days are Secure Digital, Compact Flash, and Memory Stick.

ROM Memory Types

The ROM memory, by the abbreviation of Read only memory, in Castilian means read-only memory.

This memory is the one used by electronic equipment, as in the case of computers. The information stored in this memory does not allow its modification by the user, hence its denomination.

There are currently the following classes of ROM memory:

PROM: By the acronym of Programmable Read Only memory, in Spanish programmable ROM, it is identified by being digital. In this kind of memory each of the bits is determined by a fuse, which is only possible to burn it only once. This generates that, by means of an PROM programmer, they will be programmed for only once. The PROM memory is used in situations where information needs to be transformed into all or most opportunities. It is also sought especially in that information that wants to be stored in a lasting way that does not exceed those of the ROM.

EPROM: Its acronym for Erase programmable read-only Memory, in Castilian, erasable programmable read-only ROM. This kind of ROM memory is a chip without volatility and consists of floating door transistors or FAMOS cells that are produced from the factory without any load. This memory can be programmed using an electronic device in which these voltages exceed the employees in electronic circuits. From this, the cells begin to be read as 1, before this is done as 0. This memory offers the possibility of being erased only if it is exposed to ultraviolet lights. At the time that the EPROM is programmed, it becomes non-volatile, that is, that the stored information remains there in a timeless way. However, it can be eliminated and reprogrammed with the use of high voltage levels. While they continue to be employed, they reveal some drawbacks, among them that the process of erasing the chip is always complete, ie it is not possible to choose a particular direction. On the other hand, to reprogram or delete them, they must move from their circuit and this process takes at least twenty minutes. This type of disadvantages have been surpassed by flash memories and EEPROM, so that the eproms are going into disuse in certain designs and applications.

EEPROM: Its acronym in English electrically erase programmable Read Only Memory, which means in Castilian programmable and electrically erasable ROM. This memory, as its denomination indicates it can be programmed, erased and reprogrammed electrically without the need for exposure to ultraviolet rays, for example as in EPROMs, which implies that they are non-volatile. At the same time of possessing the floating, like the aforementioned, it has a layer of oxide located in the drainage of the MOSFET cell, which facilitates that the memory manages to be erased electrically. To do this, no specific programmers or ultraviolet rays are required, it is possible to carry it out on the circuit itself. At the same time you can rewrite and delete bytes individually, and are more affordable and faster to reprogram than previous ones. The disadvantages it has in relation to the aforementioned are the density and its high costs.

Letter from Pilar Domínguez

Letter from Pilar Domínguez

Founder of the IPD and creator of the MPD

I am pleased to share with you the illusion of an exciting professional stage for the “Pilar Domínguez method” which, as you know, I created forty years ago.

I am proud to see how my method, which is now yours as well as you have integrated in your day to day, has become a benchmark in postural and Corporal intelligence.

With a team of professionals involved in the work of contributing quality of life to society, we contribute every day in a meaningful way to integrating the importance of postural awareness in the physical and emotional health of people.

I am happy for the recognition given to me by so many health professionals. They were key to deciding to create, almost 10 years ago, the Instituto Pilar Domínguez (IPD) as a professional space from which to share and transmit my long experience. With their thrust we are encouraged every day to continue investigating and evolving in this beautiful therapeutic adventure.

Today, I am excited to observe the growing demand and professional recognition of my method all over the world. For me, they represent the fruit of rigour and our implied way of understanding therapeutic work.

Therefore, IPD is my Project summit, the one that arrives in the maturity of my life, to spread the method to which I have dedicated all my professional work and for which I have guaranteed the continuity of the foundations of the method, namely, the values and the ethics with which the same Deb and continue to be taught.

Within the IPD, as always, we will serve the people who come to practice the MPD; We will formally form the future MPD technicians, collaborate with health professionals through our IPD physiotherapy, a unique and pioneering integrative health work that integrates free active physiotherapy with MPD, we will continue to perform measurements , accompanying patients in their evolution, researching and attending international congresses to share our knowledge, in short, we will continue to grow and allowing the MPD to expand naturally and with quality assurances.

As you see, many are the reasons that feed the illusion that today moves me to share with you this stage of my professional life, in which at the head of IPD will watch for ethics, professional rigor and human quality remain the main values of our work Or, as it always has been.

A fond embrace,
Pilar Domínguez.

Method Pilar Dominguez (MPD)

The Pilar Domínguez (MPD) method favors correction and postural awareness. It is a method that uses the movement for therapeutic purposes.

It consists of a combination of controlled and supervised exercises of músculotendinosos stretching, muscle toning and relaxation aimed at preventing and correcting the harmful consequences of inadequate postural placement. The MPD provides the basic technique that is right and essential to integrate and organize the movement of the body in our daily activities, work or sports, as well as contribute to a global wellbeing.

During the classes the emphasis is placed on the conscious work of the antigravity musculature, the release of the peripheral joints, the facilitation of new neuromuscular patterns and the eccentric work of the musculature.

The exercises contained in the MPD are systematized and organized in two types according to the position of the feet during the class (parallel and opening). The objective is to condition the body and to obtain a suitable posture respecting the parameters, morphology and individual capacities. It not only works the amplitude of the movement, the strength and the elasticity, but it reeducates the posture, thus favouring the functioning of our organic, muscular-skeletal, digestive, respiratory, circulatory and nervous systems.

In addition to this preventive nature, it contributes to the improvement of numerous alterations, which is why its results have been widely supported by various professionals in the field of health.

Pioneer in classic bar use

This method is characterized by the use of a dance bar and the musical accompaniment of short piano pieces specially selected to accompany the cadence and rhythm of each exercise. These are characteristic elements of their own methodology and specialized in the field of postural health.

As practiced

It is practiced in small groups of up to a maximum of 25 people, making the teacher the precise indications to each person. The capacity is limited to guarantee that the student can be constantly supervised by a specialized technician to guarantee the proper work of bodybuilding, global stretching and postural placement.

This is a progressive work that requires constancy, minimum 2 times/week, to assess its effects. It offers a wide range of hours and total flexibility to recover a class and ensure full weekly practice.

Who can practice this method

It does not require prior preparation and can be practiced by anyone, at any age, who wants to do a controlled physical activity of quality. In addition, it contributes effectively to the aesthetic modeling of the body.

The structure of the classes and the applied pedagogy allow the profile of the people who practice the method and benefit from its results to be universal, practically without limitations of age, sex, socio-cultural characteristics and physical condition.

Ailments and adaptations

In the event of the existence of any ailment or physical limitation, the MPD has a series of adaptations of the exercises, reviewed by the technical consultant team and Pilar Domínguez, and collected in established protocols and included in the formation of the Teachers, who also receives ongoing training to ensure optimal praxis and updating of knowledge about the MPD.

The program of adaptations of the exercises allows to the people that by their characteristics, require a special rhythm, either by age or by some alteration like the pain, they can accede to the practice of the method.


The constant investigation of new applications of the method, has resulted in the emergence of several units of work that have activities and a specific methodology.


The Pilar Domínguez method is currently a benchmark in postural placement in both sports and medicine. Traditionally, the main user of the MPD had always been the one who arrived on the recommendation of a acquaintance. However, at the present time, more and more, are registered in the MPD centers users who are derived by different professionals of the medicine who seek in the MPD a complement that will help them to improve the different pathologies of their patients.

The Pilar Domínguez method is endorsed by numerous specialists and professionals in health and sports and is recognized as one of the most prestigious methods of postural correction.

Read Only Memory Types

Memory ROM (Read Only memory) is a type of memory where the data and instructions are stored by the manufacturer at the time of manufacture.

The ROM memory is a memory type that can store the data permanently or semi.

The data or instructions stored in ROM memory can only be read, and it is almost impossible or difficult to write new data. This is the reason why it is called read-only memory.

The ROM memory stores data and instructions permanently, and when the electrical power is switched off, the data stored in the ROM is not lost. This is the reason why the ROM is called nonvolatile memory.

The ROM memory is used more frequently to store boot instructions from the PC, that is, the BIOS – Basic Input Output System (that program that goes into action as soon as we turn on the computer).

ROM Memory Types

The three main types of ROM memory that have been used on computers are as follows:

  1. PROM-Programmable ROM
  2. EPROM-Erasable Programmable ROM
  3. EEPROM-Flash ROM

No matter what type of ROM memory your system uses, the data stored in a ROM is not volatile and remains indefinitely unless you use special methods (in cases where it is possible).

PROM-Programmable ROM

As the name implies, these are memories that can be programmed through special devices. The PROM is a type of ROM memory that is produced without any stored information. The user then, possession of appropriate equipment is able to perform only one recording of values in their cells.

This type of memory only allows it to be a single program once, getting hopelessly lost if we want to change the inserted pogram.

EPROM-Erasable Programmable ROM

A very popular variation of the prom is the EPROM. An EPROM has as its main feature the ability to allow the contents of its cells to be altered when illuminated with light violet

EEPROM-Eletronic eprom/flash ROM

A more advanced type of ROM is the EEPROM, which means PROM erasable electrically. These chips are also called flash ROM and are characterized by their ability to be reprogrammed directly on the circuit board without any special equipment.

When using an EEPROM, or Flash ROM, you can erase and reprogram the ROM of the motherboard on a PC without removing the system chip or even open the computer case.

On the PC this type of ROM memory is where the BIOS, POST and SETUP programs are stored.

Tips to Find Out if Your HD is About to Die

Understand what are the signs of problems data by your computer and avoid losing your files.

It is possible to detect problems in the HD before the equipment is defective. Because HDs are one of the main forms of digital data storage, they are an essential part of the operation of a computer. What many people do not know is what the device is very sensitive. Fixed on a laptop or desktop, the hard drive has average life of five to 10 years, depending on the manufacturer and the environment.

With external models, it can be even smaller, as they stay on the move all the time. Thus, only three to five years of life are expected for apparatus of the type. After the failure, there is nothing to do: The only option is to buy another one. The information, in turn, will hardly be recovered – and at a high cost.

To ensure that important files remain safe, you need to take some care. It’s always good to be up to date with backups and use other storage spaces, including the cloud. Services with Google Drive, Dropbox, ICloud, and OneDrive are great allies at this time.

But these measures are especially important when the end of the hard drive life is imminent. The good news is that often the HDs “die” gradually, presenting in advance indications that serious problems are on the way. See below how to identify if your data is in danger.

Frequent slowdowns and latings

If your machine crashes and restarts on its own all the time, the “blue screen of Death” is frequent, or if the folders and files take several minutes to open, the hard drive may be responsible. Especially if failures occur after a new installation or even in Windows Safe mode. In fact, these symptoms may be caused by various problems, but in any way it is time to make a backup.

Corrupted data

Files that suddenly vanish, do not open at all or become corrupted, difficulties to save a file or even programs that stop working claiming they do not find an essential file. These are all typical signs of a HD with potential to hang at any time.

Strange sounds

Strange noises may indicate already advanced mechanical damage to the hard drive. When the needle is attempting to record or read data out of position, or if the motor is jammed, certain sounds are emitted. If you hear loud, squeaking, and repetitive clicks when using your computer and/or external HD, run to save your information. Still, maybe it’s too late.

Recognition failed

When the computer is no longer able to detect the HD, the defect may be both in one and the other. It is also worth verifying that the issue is not the cable or the connection on the motherboard and, if possible, test the disc on another machine. This is usually a logical failure, but if the problem is even on the hard drive, you will need to look for an expert to recover the data.

S.M.A.R.T. system

A tool capable of predicting problems with the hard drive is the S.M.A.R.T. T (“Analysis technology and self-monitoring reports”), a set of information stored in the operating system. There are programs for reading this data, which ascertain the conditions of the HDs connected to the computer, such as Crystal disk info. These tools, however, do not usually recognize deficiencies in early stages.