The Ultimate Buyer’s Guide for Read Only Memory (ROM)

January 15, 2020

You’ve probably heard of Read-Only Memory (ROM) by now, even if you aren’t exactly familiar with computer terminologies. ROM basically functions as a kind of a storage medium on computers.


Long after you shut your PC’s down, ROM continues to retain that information for you so whenever the computer boots back up, that data is readily available. In other words, ROM stores data permanently on personal computers (PC) as well as several other electronic devices.In fact, ROM also contains the information (usually in the form of complex computer programs) that provides your PC with the information to allow for it to boot up properly.


Moreover, it also performs all kinds of major input/output tasks on the computer to allow for programs and software stored on your PC to run smoothly every time you access them. ROM is quite fascinating if you think about it. Electronic devices and computers won’t be able to function and exit without ROM.


For newbies to advanced computer techies out there, we’ve put together a comprehensive buying guide to help you make a more informed buying decision next time you get a ROM for your computer.


Hopefully, after reading through this ultimate buyer’s guide for Read-Only Memory (ROM), you will get a clearer picture of what read-only memory (ROM) is, how it works and all the things you need to know about read-only memory before making a final buying decision.


Read-Only Memory Ideas  You Should Know

What Is Read-Only Memory?




Read-Only Memory retains its content even after you shut down your computer, i.e. it is a form of non-volatile memory. Technically, it is an integrated circuit that works as a storage medium and is used with electronic devices and personal computers.


As the name suggests, it can be read-only, which means that it cannot be changed or altered. It is both permanent and non-volatile which means that the data can be stored even when the power connection is lost or removed. A great advantage of ROM is that it does not allow any kind of alterations or modifications to be made after it has been manufactured. So, if someone attempted to electronically modify ROM of a certain device, they simply wouldn’t be able to.


This ultimately suggests that all the relevant information has to be fed into ROM while it’s being manufactured. Once the production phase is over, however, the programs and the information would not be accessible. ROM in complex terms refers to a hardwired memory, which although it can be altered using its discrete circuits, does not affect its ‘memory’. In the contemporary world, newer technologies are now available for programming such types of ROM.



Things You Need To Know About Read-Only Memory

Things You Should Know


1. Capacity

A ROM chip holds the BIOS information for a computer among other important pieces of information. As it has to store only this, its capacity will not be and should not be huge. A few megabytes would do. A read-only memory chip stores its data in megabytes.


Usually, the read-only memory stores up to four to eight megabytes per chip. These days, the storage capacity of ROM is usually four megabytes per chip. Some ROM storage capacity ranged up to 8 megabytes as well.



2. Frequency

The frequency of ROM varies from device to device. Erasable Programmable ROM (EPROM) chips are the ones that allow its users to write and even rewrite them as many times as they want. These emit a specific frequency of ultraviolet (UV) light which in turn burns out all the minute alterations made in the EPROM to open its circuits.


3. Latency

The ROM’s latency plays an important role in CPU design. ROM latency refers to the amount of time it takes for all the programs on the computer to respond to a query made by the user. So, whenever you send a request or a command, for example, while using a software, the amount of time it takes your computer to respond to that request is what ROM latency is all about. ROM basically has blocks that can have both the output data and input address, which thereby gives a one or two clock cycle latency in between retrieving the data back and setting the address to input the data.


This might sound a little technical but stay with us. In order to reduce the latency rate, the common techniques including data replication have been used but they always don’t apply on things such as CD-ROMs as these operate on a universal constant linear velocity (CLV) scheme.


What Is ROM Used For?

ROM (Read-only memory)


Read-only memory (ROM) is used for updating the firmware. Firmware is the data that is stored on the read-only memory of a computer to give instructions regarding how the device is to be operated. As the content that is stored in the ROM can only be read and edited with either a huge amount of difficulty or not at all, it, therefore, remains suitable for updating the firmware.


The user is unable to change or delete this firmware without the use of some special programs, hence the data on the firmware remains on your device irrespective of whether you turn your device on or off.


Read-only memory can be used as a cartridge that allows one system to run one or more programs or games at the same time. Furthermore, read-only memory is primarily used for non-volatile storage. Additionally, it’s involved in the operating systems for BIOS.


So, all the hardware components on your PC that interact with each other, process requests and function by communicating with each other, do so because of ROM. Moreover, all software you run and use on your computers function because of ROM as well.


How Does ROM Work?

Almost all electronic devices and computers use ROM to function. Without ROM, the information stored on your devices, that you can readily access whenever you turn your device on, would be lost. But how does ROM work? Why is this data stored and not lost?


The answer to this is rather technical. But the general principle is that ROM is a form of an integrated circuit. So, the data stored on a ROM has to be manufactured that way. That information essentially provides your device with information on how to perform the functions that are supposed to perform. Unlike RAM (Random Access Memory), ROM uses diodes for its functions.


Types Of Read-Only Memory

Types of ROM is one of the things you need to know about read-only memory. And the general difference between the major types of ROM stems from the way that they are manufactured. As mentioned earlier, the data or information is stored on ROM while they are being manufactured. In a way, that data or information is kind of set in stone upon their production.


Therefore, one of the ways a different type of ROM is differentiated is on the basis of how the information was written while they were being produced. Additionally, they may also differ in terms of their capability of the number of times they can be re-written.


1. Programmable ROM

The first type of read-only memory is the Programmable ROM. As the name suggests, it is created as a blank memory and is programmed after manufacturing.


The user purchases a blank memory and can later add the desired contents to it using a PROM program. Interestingly enough, this phase of burning is called PROM. There are many tiny fuses in a particular chip of PROM that is to be burnt during programming.


However, once the data is programmed, it cannot be altered afterward. Hence it can also be called a one-time programming device. 


The advantageous thing about the programmable ROM is that it can its programming can be done by using many different types of software and it also does not rely on the hard wiring of the particular program to the clip.


Plus, the data once entered in this type of ROM remains authentic and intact as it is impossible to change or remove the contents. However, this is the negative thing too as the data once entered on the programmable ROM can’t be changed or erased if any errors are detected.



2. Erasable Programmable ROM

Erasable programmable ROM is abbreviated as EPROM and is a non-volatile memory since it belongs to the family of ROM. hence, So, even after the power supply to your device is lost, the information is retained.


The limitation of PROM of not being able to change or alter data after programming was overcome by EPROM. It can be removed by exposing it to a beam of ultraviolet light for a specific time period and using an EPROM eraser.

Once exposed, the chip will return to its initial and original state and be ready for getting reprogrammed again.


Although this procedure can be repeated many times but repeatedly erasing it and rewriting it can make the chip useless. Once programmed the chip has the capability to retain it for up to ten years.



3. Electrically Erasable Programmable ROM

EEPROM or the electrically erasable programmable read-only memory is another type of ROM developed specifically to overcome the drawbacks of the previously existing types of ROM.


This ROM can be erased more easily by replacing the ultraviolet rays with the electrical signals. And this procedure can be done in only around four to ten milliseconds.


Also, it allows its users to remove or alter any one single byte of the data instead of the entire chip. Unlike the EPROM which could only be erased for a limited number of times, EEPROM can be erased, altered and reprogrammed as many as ten thousand times. The process will, however, be slow despite being flexible.



4. Flash memory

Flash memory is another type of ROM used in computers as a medium of storage. Flash memory is a universal flash programming non-volatile utility that can be easily erased electrically and reprogrammed.


It can store blocks of memory up to almost five hundred and twenty bytes and can be deleted, removed and rewritten at a specific time.


The advantage of using flash memory is that it has a high transferring speed and can save data even if the power connection is lost.


The flash memory is less prone to be damaged and is comparatively more economical than other small storage capacity drives. However, it is still more costly than a hard disk and the number of times you can read and write it is also limited.



How Much Does It Cost When You Buy ROM?



ROM such a CD-ROM can be of varying qualities and thus varying prices. These prices usually vary depending upon the interface, speed, latency rate, etc. that the CD-ROM drive uses.


A Standard IDE/SCSI CD-ROM Drive, which is considered as the slowest and the least durable costs relatively less than others its prices can vary between $50-$200.


In the case of Parallel CD-ROM Drive, the prices get relatively higher and they vary between $150-$300, due to obvious reasons for having an additional speed, faster interface, and even greater capacity in some cases as well. Finally, a PC Card and PCMCIA CD-ROM Drive usually cost between $100-$300 again due to having an advantage of better speed, faster interface accompanied by a huge capacity in most case. Thus, a good ROM generally costs around somewhere between $100-$300.


Where To Buy Affordable ROM?

Read-only memory is usually available domestically all over a region, particularly in the Information Technology (IT) or computer shops. For example, stores in the USA such as Computer Memory Store offer a great rate for ROM, enabling people to buy affordable ROM getting shipped to their own places.


Apart from that, affordable ROM which is probably of even better quality can also be shipped abroad, where shipping charges usually do apply. However, some online sites offering little to none shipping charges make ROM affordable and the people interested in buying affordable ROM need to visit such sites in order to make the best possible choice for themselves and for their PCs or Laptops.


What Is The ROM In The Computer?

ROM or read-only memory is a very important component of a computer. Almost every computer or electronic device depends on ROM for its functionality. It might look like a small device, but it’s an indispensable component of most modern electronic devices. Usually, ROM consists of a few kilobytes of code.


This code, more simply referred to as data or information, is what tells the computer what to do. ROM on a computer can only be read by the computer system and nothing can be overwritten. Most software and programs that you run on your computer upon bootup all function as a result of ROM.


What Devices Use ROM?

Many different devices are using Read-only memory for their storage. Almost every computer contains at least a small amount of read-only memory that stores the critical programs including the one that boots the computer. The ROM is found in a computer’s motherboard and it enables every computer to retain its memory even after it is shut down. Other electronic devices using ROM are also found. The usage of ROM can be seen extensively in calculators.


Laser printers also show the usage of ROM for storing their fonts in it. Even android phones these days benefit from ROM usage and just like computers, read-only memory also enables the phones to help them retain their contents.


A custom Android ROM is usually referred to as a mobile phone’s firmware that is based on an Android platform, powered by Google. Moreover, it is also referred to as a Linux system installed in usually all the devices. This Linux system consists of an operating system and some other device configuration files as well. These devices, to name a few, have ROM specially installed to help them retain their contents and make all those contents available for their users for their future use as well.



Frequently Asked Questions About Read-Only Memory

Many people have different questions regarding read-only memory as to what it is, where can it be used and how it operates. Others usually confuse the read-only memory with the random-access memory and hence mistakenly take the wrong buying decision.


Various online forums are bombarded with read-only memory FAQ and what needs to be known before buying them. Let’s take a look at a few of those.  


1. What is Read-Only Memory?

Read-only memory is a storage medium for personal computers and other similar electronic devices. It contains permanent and non-volatile data.


The data once stored on a ROM cannot be deleted, altered or removed. This makes ROM perfect for computer and several other electronic devices that use this information to function even after the device is turned on after being shut down for longer periods of time.  


2. How is ROM different from RAM?

ROM is read-only memory that is data storage medium in electronic devices like computers. The information stored once can be changed or reprogrammed later on. It is a non-volatile and permanent memory. On the other hand, RAM is read-only memory which is volatile and will be lost when the power supply is removed or lost. RAM is such a form of storage that can be randomly accessed at any moment, from any location and in any order.


RAM chips can be read faster than the ROM chips. There are two major types of RAM namely static RAM and the dynamic RAM whereas the ROM has three major types that are programmable ROM, erasable programmable ROM and electrically erasable programmable ROM.


3. Which devices can use ROM?

Almost every electric device can use a read-only memory. Modern-day personal computers use ROM to store their basic bootstrapping firmware, which is just a fancy way of saying they rely on ROM to function and start-up every time these devices are turned on.


Furthermore, several other components of the computer including hard disks, graphic cards, DVD drives, TFT screens, etc. all rely on the information stored in ROM for their proper functionality.


4. What are the examples of ROM?

It is a read-only memory frequently asked question that what the examples of ROM are. Well the example of ROM is the smartphone in your hand. The latest generation smartphones come with a ROM of different ranges including 16GB, 32GB, etc. The BIOS (basic input-output system) is another example of ROM that your computer uses in order to boot up.


Programmable Read-only memory (PROM) is also a type of ROM that is usually even more fragile than the normal ROMs. A huge drawback of these is that they can only be programmed once and are usually much inexpensive than the ROMs.


Erasable Programmable Read-Only Memory (EPROM) on the other hand can be rewritten many times and they are configured using an EPROM programmer. Apart from these, another type of ROM is the Electrically Erasable Programmable ROM (EEPROM). It is a read-only memory that can be erased, written, and even rewritten as many times one may want to.


This memory is non-volatile and this procedure of erasing and rewriting is usually done through a pulsed voltage. EEPROM is usually used in computers, microcontrollers for remote keyless systems and smart cards and other various devices as well to relatively store lesser data.


EEPROM also has another famous type of memory, known as the flash memory which uses in-circuit wiring to eradicate the memory. This is done by giving the entire chip (or blocks) an electrical field. Flash memory works a lot faster than the old-fashioned EEPROMs because it stores data in bits and pieces, which are usually the size of 512 bytes, enabling the flash memory to work faster and in a more efficient way.


Thus, to conclude, there are basically five examples of ROM, which include BIOS, PROM, EPROM, EEPROM and flash memory and all these are better and faster working as we move a level up.


5. What is stored in ROM?

Good question! ROM, being read-only-memory, stores data permanently and allows computers and other electronic devices to access this information and use this data for their functionality. Therefore, ROM stores all the programming information necessary to boot up a computer or any other electronic device for that matter.


All the queries and requests you send while working on your device are executed by your device thanks to ROM. ROM, therefore, stores diverse bits of information that are highly important for the effective functionality of your computer or electronic device.


Typically, ROM is not a key factor to consider an average user looking to buy a new PC or a laptop. However, knowing how ROM works can be an interesting insight that can lead to a more informed purchasing decision nonetheless. Hopefully, this guide shed some light on what ROM is, how it functions and all the various types of ROMs that exist across various computers, operating systems, and electronic devices.


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