RAM (RANDOM ACCESS MEMORY) and ROM (READ ONLY MEMORY )

There are several major differences between a ROM (READ ONLY MEMORY) chip and a RAM (RANDOM ACCESS MEMORY) chip.

RAM (RANDOM ACCESS MEMORY)

A RAM is also called as read/write memory. The RAM is a volatile types memory. It allows programmer to read or write data. If the user wants to cheak excuation of any program, user the feeds the program in RAM memory and executes it. The result of execution is then checked by either reading memory location contents or by register contents.

There are two kind of RAM…….

1. SRAM ( Static Random Access Memory)
2. DRAM (Dynamic Random Access Memory)

SRAM (Static Random Access Memory)

SRAM consists of flip-flop; using either transistor or MOS. For each bit we require one flip-flop, Bit status will remain as it is; unless and until you perform next write operation or power supply is switched off.

Advantages of SRAM..

1. Fast Memory.
2. Refreshing circuit is not required.

Disadvantages of SRAM…

1. Low package density.
2. More costly.

DRAM ( Dynamic Random Access Memory )…

In this types of memory a data is stored in form of charge in capacitors. When data is 1, the capacitor will be charged and if data is o, capacitor will not be charged. Because of capacitor leakage currents the data will not be hold by these cells. So the DRAMs require refreshing of memory cells. Dynamic RAM has to be refreshed periodically generally every to millisecond. So need refreshing circuit. It is a process in which same data is read written after a fixed interval.

Advantage of DRAM..

1. High package density
2. Low cost

Disadvantage of DRAM..

Required refreshing circuit to maintain or refresh charge on capacitor, every after few milliseconds.

ROM ( READ ONLY MEMORY)

A ROM is non- volatile memory and it is the parmanent type of memory ( READ ONLY MEMORY ) contains are not lost even when is power supply is switched ‘off’. However, the user can not write into a ROM it contains written into at manufacturing time.

The data stored in the ROM can’t be changed, or at least not easily but these day you can erase data quickly. Examples are given below..

More recent generations, such as EPROM or Flash EEPROM (flash memory), the content can be deleted and rewritten multiple times, but it is still considered “read-only”. The main reason for keeping it named “read-only” is that the process of reprogramming (erasing and writing) is usually slow and can only be written in places determined by formatting.

There are four kinds of ROm..

1. Mask ROM
2. PROM (Programmable Read only Memory)
3. EPROM (Erasable Programmable Read only Memory)
4. EEPROM (Electrically Erasable Programmable Read only Memory)

Mask ROM…

The program or data are parmanently installed at the time of manufacturing as per requirement. The data cannot be altered. The process of permanent recording is expensive but economic for large quantities.

PROM (Programmable Read Only Memory )

The basic function is same as that of masked ROM, but in PROM, we have fuse links. Depending upon the bit pattern, fuse can be burnt or kept intact. This job is performed by PROM programmer.

It is use high current pulse between two lines. Because of high current, the fuse will get burnt;effectively making two lines open. Once a PROM is Programmed we cannot change connections, only a factility provided over masked ROM is, user can load his program in it. The disadvantage is a chance of regrowing of fuse and changes the programmed data because of aging.

EPROM ( Erasable Programmable Read only Memory)

The EPROM is Programmable by the user. It uses MOS circuitry to store data. They store 1’s and 0’s in form of charge. The information stored can be erased by exposing the ultraviolet light which erases the data stored in all memory location. For ultravoilet light a quartz window is provided which is covered during normal operation. Upon erasing it can be reprogrammed by using EPROM programmer. This types of memory is used in project developed and for experiment use. The advantages is it can be programmed erased and reprogrammed. The disadvantage is all the data get erased even if you want to change single data bits.

EEPROM (Electrically Erasable Programmable Read only Memory)

This is similar to EPROM except that the erasing is done by electrical signals instead of ultraviolet light. The main advantage is the memory location can be selectively erased and reprogrammed. But the manufacturing process is complex and expensive so do not commonly used.

What is the main differences between RAM and ROM

Data storing in these types of Memory..

RAM is volatile memory which could store the data as long the power is supplied.

ROM is a non-volatile memory which could retain the data even when power is turned off.

Working types of these Memory…

Data stored in RAM can be retrieved and altered.

Data stored in ROM can only be read.

Uses of these types of Memory..

Used to store the data that has to be currently processed by CPU temporarily.

It stores the instructions required during bootstrap of the computer

Speed of Memory…

It is a high speed memory.

It is much slower than the RAM.

CPU Interaction…

The CPU can access the data stored on it.

The CPU can not access the data stored on it unless the data is stored in RAM.

Size and capacity of these Memory..

Large size with higher capacity.

Small size with less capacity.

Cost or price

Costly than ROM

Cheaper than RAM

Used as/in

CPU caches, Primary memory.

Firmware, micro-controllers

Accessibility

The data stored is easily accessible

The data stored is not as easily accessible as in RAM

Importance of RAM in your smartphone..

RAM is read-write memory so data can be store again and again. If you get start your smartphone then operating system stored in RAM for work properly and faster when users gives command. Take a example of your application or apps you start and after some time get back and start another apps. After sometime if you start your first apps, then you can. Because RAM store your data. Condition is that if you don’t switched ‘off’. In back of screen RAM store and run as well as your smartphone ‘ON’.

Why it’s use in your smartphone.

In simple language, It stores all running and stored in smartphone. It it gives quick access to the smartphone. Whenever if you search your activity which done about 1 or more minutes ago. You can find easily same activity which you did done. Take example of Chrome if you open more than 4 or 5 pages, its your page data not history and current working on pages.

Why do you need more GB for your RAM..

The basic is that If the storege capacity of your RAM is high then you can run multi program in single smartphone. And you can also use multi apps for long periods with more data. Just like listening songs, pubg games, call, use internet browser, YouTube, WhatsApp, Facebook, etc more GB RAM make you multi person for handle more program by single smartphone.

Importance of ROM in your smartphone..

ROMs built into smartphones these days are much faster than traditional computer hard drives and they are also connected directly to the motherboard. In that ROM, that the bootloader is stored (a program that starts the device and loads the operating system likes kernel, Mac, Android, etc ), as well as the operating system itself and all user data and applications.

The modified versions of the operating system are also referred to as modified ROMs. If you search online, results will tell you that there are a number of customized ROMs that exist. different operating systems has their own Modified ROM.

Why it’s use in your smartphone

ROM is faster memory. it load your operating system in RAM for get started your phone. whenever you switch ‘ON’. It is directly connected to motherboard. It is fastest operating system loading in your smartphone.

Importance of RAM in your computer..

RAM is read-write memory so data can be store again and again. If you get start your computer then operating system get stored in RAM for work properly and faster when users gives command. Take a example of your application or apps you start and after some time get back and start another apps. After sometime if you start your first apps, then you can. Because RAM store your data. Condition is that if you don’t switched ‘off’. In back of screen RAM store and run as well as your computer ‘ON

Why it’s use in your computer…

In simple language, ROMs built into computer these days are much faster than traditional computer hard drives and they are also connected directly to the motherboard. In that ROM, that the bootloader is stored (a program that starts the device and loads the operating system likes Linux kernel, Mac, windows, etc ) as well as the operating system itself and all user data and applications.

Why do you need more GB for your RAM..

The basic is that If the storege capacity of your RAM is high then you can run multi program in single computer. And you can also use multi apps for long periods with more data. Just like word, excel, panting, editing, typing, listening songs, pubg games, call, use internet browser, YouTube, WhatsApp, Facebook, etc more GB RAM make you multi person for handle more program by single computer.

Importance of ROM in your computer..

ROMs built into computer these days are much faster than traditional computer hard drives and they are also connected directly to the motherboard. In that ROM, that the bootloader is stored (a program that starts the device and loads the operating system likes Linux kernel, Mac, windows, etc ), as well as the operating system itself and all user data and applications.

The modified versions of the operating system are also referred to as modified ROMs. If you search online, results will tell you that there are a number of customized ROMs that exist. different operating systems has their own Modified ROM.

Why it’s use in your computer..

ROM is faster memory. it load your operating system in RAM for get started your computer. whenever you switch ‘ON’. It is directly connected to motherboard. It is fastest operating system loading in your computer.