this page explains the Different Types Of Memory ROM modules for computers Like PROM EPROM EEPROM you can find in many of todays computer and gives you an explanation as what is the differences between these different types of memory modules. 
Thu Mar 15, 2012
Explain What ROM Memory is
This article will be focused on ROM memory and its different types of ROM memory available. The goal of this tutorial is to help you understand ROM memory. This is very helpful information when you are getting ready to take any type of tests, specially a computer certification exam. Once you have completed reading this short article, you will have a deeper understanding what ROM memory is. Be sure to read this complete article. Be sure not to skip any steps.
What is PROM Memory?
There are many types of computer memory. What is Computer Memory? Computer Memory is 1 and 0s stored as data into memory chips. Memory is data storage into logical paths of processed instructions required to store virtual data cells. Each cell contains a distinct address. Computers use memory to store temporary or permanent data for processing data much faster than reading and writing into disk drives. The exception is with SSD (Solid State Drives). SSD Drives are memory chips which store permanent data. Lets learn about different types of ROM memory:
The first type of memory we are going to look at is call ROM. ROM stands for: Read Only Memory
Read Only Memory is non-volatile memory and its physical memory.
non-volatile memory means, it does not get erase or overwritten. physical memory means its tangible (you can touch and feel)
in ROM, if there is no electricity flowing through the ROM chip, the memory stays and is not lost.
ROMs are use in programs to start computers. A good example of ROM memory is your computer Firmware.
While ROMs sound perfect, they are not. they have their limitations because once you write data into a ROM, it is burnt into the chip and it cannot be changed or deleted. For this reason, the following three types of ROMs were created. Lets take a look at all of them on the following slides:
Different Types Of ROMs
Lets take a look at some different types of ROM memories. On this slide show, we will explore each type of ROM memory to better understand how we use each type of memory. These different type of ROM memory where created to offer different features for each memory applications. For example, BIOS (or CMOS) is crucial type of memory embed into each mother board. Imagine if you had to load the BIOS into memory every time you booted your computer. Or how about if you were able to delete the BIOS only once. There are types of memory that you can only write once into it. there are also memory which you cannot write or delete, only read. These types of memory were created to avoid unwanted outage, but these types of memory are only found in critical components which if the data is modified or deleted, can have disastrous results. ROM is very important part of computer system components.
Programmable read-only memory - on this type of chip, you can write only once, and you cannot modify the burnt data in the ROM chip. Usually these types of chips came already installed on older mother boards where the BIOS was already soldered into the main board and you could not change the firm ware.
PROM was first invented by Wen Tsing Chow in 1956 for the Arma Corporation in Garden City, New York . The reason why PROM was created was because the United States Air Force needed a secure and flexible type of storage for the Atlas E/F ICBM's airborne digital computer - This is very heavy government stuff we are talking about. Did you know that the word 'burn' was patent by this company to describe the process of programming a PROM chip? Well, now you know
Erasable Programmable read-only memory - This type of memory you can rewrite data over the old data, but you cannot keep the old data. so once you burn the new data into the ROM chip, the old data is gone. A good example of EPROM is a new type of BIOS chip. If you want to update the Firmware on your BIOS, you can, but the old version of the firmware will be overwritten with the new one. EPROM ensures each process will be performed repeatedly and is more expensive then PROM, the advantages over PROM is that is capable of multiple updates.
Electronically Erasable Programmable read-only memory - This is the best of all the ROMs. With an EEPROM chip, you can change or edit the current data in the chip and still keep the data, you don't have to rewrite the whole data. NOTE: this is not like a flash drive. example of EEPROM chips include, the CMOS in your computer mother board or the BIOS in your computer. Have you ever had to update your BIOS? The only negative part about these types of ROMS is cost, they are much more expensive. Now that you've learned the different types of ROM memory, Take the quiz below. Is a simple quiz which covers these types of ROMs we just covered. EEPROM can write at any time and maintained previous data. EEPROM also has the advantage of non-volatile memory and the flexibility of being uneatable but its more expensive the PROM and EPROM.
Now that you have learned different types of ROM memory, we encourage you to take this short quiz to enhance your knowledge of ROM memory. Good luck.
Computer Memory Knowledge Quiz
This quiz will test your knowledge on Computer Memory. There are many types of memory systems in a computer. This is a helpful quiz if you are preparing for taking the CompTIA A+ exam. You will be asked some of these related question. Good luck!