What is the different between Read Only Memory (ROM) and Random Access Memory (RAM)?

Whilst both Read-Only Memory (ROM) and Random-Access Memory (RAM) are primary storage devices used in electronics, most commonly in computers, there are differences in terms of their usage as follows;

 

Read Only Memory (ROM) is permanently written to the computer or a disk. It can only be reread, hence the name "read only." It can never be reused or rewritten on. Whilst ROM functions much slower  than RAM,  it stores data that can not be easily altered or reprogrammed . ROM is typically used for long-term data storage. Its contents are retained even when the device’s power is turned off.  . However, there are CD-ROM products that allow the user to write data into the CD depending on the “read & write” feature designed for that particular product.

 

Random Access Memory (RAM) is a computer's short-term memory capability. RAM is used by programs to hold temporary data. and can be accessed randomly at any time, in any order and from any physical location., allowing quick access and  allows the computer to read data quickly to run applications. It allows reading and writing. It can be written to over and over. Whilst  RAM functions much quicker than ROM,  it is only functional while the computer is turned on. Once the computer is shut off, the information is lost. Hence, if you only have RAM on the computer, you'd never be able to store any data.

 

Therefore, it is advisable that the user must have both RAM and ROM on the computer to enable him to have quick access that allows the computer to read data quickly to run applications utilizing the RAM,  and be able to save or store data that can not be easily altered or reprogrammed typically used for long-term data storage and such data are retained with the functional ROM  even when the device’s power is switched off  .  

They are both ways of storing data.

RAM is a volatile type of storage (is means when the ram chip has no power data will be lost) that has the characteristic of giving the same read and write time (while in physical storage, like hard drives or CD's, the read and write time is dependant of several factors like the place where it is stored in the disk, the rotation speed, arm movement speed, etc)

ROM by contrast is a permanent type of storage, by tradition encoded in microchips, that once programmed (in the chip) can never be altered. There are variations to this technology in order to overcome the limitation of the1-time write, like EPROMS that aloow you to change the content of the ROM chip using specific programs or features

In computer science,  ROM (Read-Only Memory) is in fact "write-once/read many times" memory.   There are other versions of this memory,  namely PROM (programmable read-only memory) and EPROM (Eraseable Programmable Read Only Memory) whose names explain the differences between all three types.

 

There are in contrast the "Write-Many/Read-Many" types of memory which can be written and read many times.   These fall within different categories depending on the type of  the memory and its access.    Those who are in computer science should be aware of such things as SAM (Sequential Access Method), ISAM (Indexed Sequential Access Method), VSAM (Virtual Sequential Access Method), ... and RAM (Random Access Method)   I hope this explains the underlying principle oof how to understand and differentiate the different types of memory !!

Memory is the electronic holding place for instructions and data that our computer's microprocessor can easily reach. This type of memory is known as Random Access Memory (RAM) and Read Only Memory (ROM) (a third type  is not related to our question).

RAM is the primary working memory that holds data and instructions while the computer is in use. RAM can be thought of as the memory that the computer uses to obey instructions you give it. RAM can be written to and read from. But the most important thing to remember about RAM is that if you do not save the information in RAM to a storage device (such as the hard drive or a USB Flash Drive) before you turn the computer off, the information in RAM will be lost.

 

ROM is more straight forward. ROM is built in memory that permanently stores instructions and data. The instructions and data in ROM are created when it is manufactured and it cannot be changed.

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Read-only memory or ROM is a form of data storage in computers and other electronic devices that can not be easily altered or reprogrammed. RAM is referred to as volatile memory and is lost when the power is turned off whereas ROM in non-volatile and the contents are retained even after the power is switched off.

Random Access Memory or RAM is a form of data storage that can be accessed randomly at any time, in any order and from any physical location in contrast to other storage devices, such as hard drives, where the physical location of the data determines the time taken to retrieve it. RAM is measured in megabytes and the speed is measured in nanoseconds and RAM chips can read data faster than ROM.

Comparison chart  

RAM

ROM

Definition Random Access Memory or RAM is a form of data storage that can be accessed randomly at any time, in any order and from any physical location., allowing quick access and manipulation. Read-only memory or ROM is also a form of data storage that can not be easily altered or reprogrammed.Stores instuctions that are not nescesary for re-booting up to make the computer operate when it is switched off.They are hardwired. Stands for Random Access Memory Read-only memory Use RAM allows the computer to read data quickly to run applications. It allows reading and writing. ROM stores the program required to initially boot the computer. It only allows reading. Volatility RAM is volatile i.e. its contents are lost when the device is powered off. It is non-volatile i.e. its contents are retained even when the device is powered off. Types The two main types of RAM are static RAM and dynamic RAM. The types of ROM include PROM, EPROM and EEPROM.  

agree with Mr. Jaime Estrada

RAM&ROM: RAM is a Temporary storage house of Information. Whenever we open any new document in computer and start typing then this Information is stored in RAM Until you Save it,The Information in the RAM Becomes permanent only after you have saved it into secondary storage devices Like Hard disk,Drive Partitions etc.After the Information is stored permanently it is called ROM.

RAM is Random Access Memory. ROM is Read Only Memory.RAM is the memory available for the operating system, programs and processes to use when the computer is running.  ROM is the memory that comes with your computer that is pre-written to hold the instructions for booting-up the computer.RAM is a type of volatile memory. Data in RAM is not permanently written. When you power off your computer the data stored in RAM is deleted.ROM is a type of non- volatile memory. Data in ROM is permanently written and is not erased when you power off your computer. There are different types of RAM, including DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory). There are different types of ROM, including PROM (programmable read-only memory) that is manufactured as blank memory (e.g. a CD-ROM) and EPROM (erasable programmable read-only memory).

A ROM chip does not require a constant source of power to retain the information stored on it, whereas a RAM chip does require a constant source of power to retain the information