RAM stands for random access memory. So do you know what does random access mean? Here, random access means that CPU can directly access RAM’s address location, which is why it is named random access memory and quickly accessible.
RAM is stored on the motherboard in modules that are called DIMMs. DIMM stands for dual inline memory module. A DIMM is a dual inline module because it has two independent rows of these pins, one on each side. A dim memory module has either 168, 184, 240, or 288 pins, and then the dim is installed on the motherboard in the memory slots. A motherboard can have various number of memory slots. The average motherboard will have between 2 and 4 of them.
Ram is a volatile memory. RAM requires constant electrical power to store data, and if the power is turned off, then the data is erased. It only stores data which has to be currently processed. The storage capacity of RAM is high ranging from 64 MB to 16GB. Ram is the fastest and costliest memory of the computer because of its speed. It is a read-write memory of the computer. Which means the processor can read the instructions from the RAM and write the result to the RAM. That’s how data can be modified in RAM. There are two types of RAM.
We’ll be covering the following topics in this tutorial:
Types of RAM
Ram also comes in different types. First is Static RAM second is Dynamic RAM. Static RAM is one which requires the constant flow of the power to retain the data inside it. Here the interrupted power could result in loss of data. The static RAM is made up of transistors and latches. Static RAM is faster and more expensive than Dynamic RAM. It is mainly used as cache memory for the computer.
In contrast, dynamic RAM needs to be refreshed to retain the data. It holds because the capacitor is used in the construction of dynamic RAM, and the capacitor has a charge leakage property that’s why dynamic RAM requires a separate refresh circuit. A capacitor is like a small bucket that stores electricity, and it’s in these capacitors that hold the bit of information such as a 1 or a 0. It is slower and cheaper than static RAM, and it is highly dense.
The difference between SRAM and DRAM is speed. The older DRAM technology operates asynchronously with the system clock, which means that it runs slower than the system clock. Because its signals are not coordinated with it. But SRAM runs in sync with the system clock, which is why it is faster than DRAM. All the signals are tied to the system clock for better-controlled timing. As stated before, RAM is stored on the motherboard in modules called dims, and these dim come in different memory sizes. Today they range anywhere from 128 megabytes to 32 gigabytes per dim.
ROM, which is Read-Only Memory. As the name implies, it’s something you’re only going to read from and never write to. You should be immediately asking yourself well. If I’m reading something from it, something must have been written to it at one time.
Unlike RAM the raw memory can’t be directly accessed by CPU. the data first transferred to the real memory and then CPU can access that data from the RAM. ROM is a non-volatile memory. The data inside the ROM retains even if the CPU’s power is switched off the capacity of ROM is comparatively smaller than RAM. It is slower and cheaper than RAM. The data in ROM can only be read by a CPU. That’s why it is said read-only. The data in ROM cannot be modified. ROM’s towards the instruction that a computer requires during bootstrapping. I think you guys must be aware of bootstrapping process. It is a self-starting process where the basic software is loaded into the computer memory, after power on or on a reset.
So, ROM’s definition is written to once or a minimal number of times and often requires special equipment to do so. So, in the course of normal operations, you’re only typically reading from it.
Another fundamental difference between ROM and our previously discussed RAM is that ROM is semi-permanent or non-volatile in nature. And it will retain its information on it even if power is removed from it.
In contrast, our volatile RAM which when you lose its power, it’s loses its mind. Notice I’m using the word semi-permanent because just like a big eraser will work on your favorite textbook. You can erase ROM if you try hard enough.
Types of ROM
PROM: Short for programmable read-only memory, a memory chip on which data can be written only once. Once a program has been written onto a PROM, it remains there forever. Unlike RAM, PROMs retain their contents when the computer is turned off. A PROM and a ROM (read-only memory) difference are that a PROM is manufactured as blank memory, whereas a ROM is programmed during the manufacturing process. To write data onto a PROM chip, you need a special device called a PROM programmer or PROM burner. The process of programming a PROM is sometimes called burning the PROM.
EPROM: Acronym for erasable programmable read-only memory, and pronounced ee-prom, EPROM is a special type of memory that retains its contents until it is exposed to ultraviolet light. The ultraviolet light clears its contents, making it possible to reprogram the memory. To write to and erase an EPROM, you need a special device called a PROM programmer or PROM burner.
EEPROM: Short form of electrically erasable programmable read-only memory. EEPROM is a special type of PROM that can be erased by exposing it to an electrical charge. Like other types of PROM, EEPROM retains its contents even when the power is turned off. Also, like other types of ROM, EEPROM is not as fast as RAM.
We have a comparison chart which shows a substantial difference between RAM and ROM memory.
• RAM stands for random access memory whereas ROM stands for read-only memory.
• RAM is readable and writable. On the other hand, ROM is only readable.
• RAM is used to store the data that has to be currently processed by the CPU temporarily in contrast ROM stores the instruction required during bootstrap of the computer.
• RAM is a volatile memory as against ROM is a non-volatile memory.
• Data in RAM can be modified conversely data in ROM can not be modified.
• RAM sizes from 64 MB to 16 GB on the contrary ROM is comparatively smaller than RAM.
• There are two types of RAM static RAM, and dynamic RAM, whereas ROM has three types PROM EPROM and EEPROM.
• RAM is very expensive memory while ROM is comparatively cheaper than RAM.