Primary memory is sometimes known as main memory or “internal memory,” as well as primary storage. Primary memory refers to computer memory that is immediately accessible by the CPU via the data bus.
This enables a processor to access memory locations where active applications and recently processed data are saved. There are 2 parts of primary memory, RAM & ROM.
In this article we will compare and discuss RAM vs ROM memory as used in computer systems.
What is RAM?
RAM is an abbreviation for Random Access Memory. When the power supply to the PC or laptop is turned off, the information contained in this type of memory is gone. BIOS can also be used to analyze the information contained in RAM.
It is commonly referred to as the computer system’s temporary memory, cache memory, or volatile memory.
RAM is the computer’s quickest and most expensive memory. It can be both read and written to by the computer system.
The CPU (mainly) and other computer peripherals use the RAM to read instructions and other data, and also they use RAM to write and load data in it for quick retrieval later on.
RAM is divided into two major categories.
- Static RAM (SRAM)
Static RAM is a type of RAM that is manufactured from flip-flops and is used for main storage. It keeps data in the latches as long as the computer is turned on.
SRAM costs more and uses more power than DRAM. In a computer system, it serves as Cache Memory. SRAM, in terms of technology, employs more transistors than DRAM. Because of the latching design, it is quicker than DRAM.
- Dynamic RAM (DRAM)
Every few milliseconds, the DRAM chips on a circuit board must be refreshed.
This is accomplished by rewriting the data into the module. DRAM is based on capacitors which lose their charge (hence their data) over time.
DRAM directly accesses memory, maintains memory for a brief length of time, and eliminates data when the power is turned off.
DRAM is less expensive, but it can store a lot more data. Furthermore, it is sluggish and uses less energy than SRAM.
There is another type of DRAM called SDRAM which Stands for Synchronous Dynamic RAM.
When contrasted to asynchronous DRAM, synchronous random access memory remains synced with the computer’s clock, allowing for improved efficiency in data storage and retrieval.
There are also different types of SDRAM such as SDR, DDR1, DDR2, DDR3, DDR4, DDR5.
What is ROM?
ROM stands for Read-Only Memory. It is a term used to describe computer memory chips that carry persistent or semi-persistent data.
Unlike RAM, ROM is non-volatile; the contents in ROM will exist when you shut down your system.
ROM is categorized into three types: PROM, EPROM, and EEPROM.
PROM stands for programmable read-only memory, which is a memory chip that can only be written once.
Once a program is compiled to a PROM, it stays there indefinitely.
A PROM programmer, also known as a PROM burner, is required to write data to a PROM chip. Burning a PROM is a term used to describe the procedure of programming a PROM.
EPROM (erasable programmable read-only memory) is a form of memory that holds its contents until it is exposed to UV radiation. The ultraviolet radiation clears the memory’s contents, allowing it to be reprogrammed.
EEPROM stands for electrically erasable programmable read-only memory, and it’s a variety of PROM that can be wiped and reprogrammed using an electrical charge.
An EEPROM in a computer enables the user to upgrade the BIOS without having to enter it or replace any chips.
Difference between RAM vs ROM
If you consider the types and characteristics of these memory modules you can see that there are some fundamental and clear differences between them.
The defining difference between RAM and ROM would be that RAM is a read-write memory, whilst ROM is a read-only memory.
RAM temporarily stores the data that the CPU must process immediately. ROM, on the other hand, stores the system booting instructions.
RAM data is extremely volatile; it will persist as long as there is power to the system. When the power goes off, RAM memory is erased.
The information stored in Read-Only Memory (ROM) is not transient; it is permanent. Even if the power source is interrupted, the data will not be affected.
The Central Processing Unit (CPU) is the main component that accesses data stored in RAM.
If the Central Processing Unit (CPU) needs to access data stored in ROM, the data must be moved to RAM, after which the data may be accessed by the CPU.
A ROM chip in a computer normally contains very few megabytes of data (4-8 MB ROM is quite common these days).
A RAM chip, on the other hand, can carry far more data, measured in gigabytes. A gigabyte is equal to 1024 megabytes. These days, high-end PCs come with 16 GB or even 32 GB of RAM.
For high-end servers used in Data Centers, RAM can be in the range of 512GB up to 1TB per server.
Especially for servers used in virtualization (such as ESXi in Vmware), it is typical to see servers equipped with 512GB of RAM (or more).
RAM outperforms ROM in terms of speed; it accesses data considerably faster than ROM and speeds up the computer’s processing.
When it comes to storage read speeds, ROM operates at a few Megabits, whereas RAM operates at a few Gigabits. RAM is hundreds of times faster than ROM in a head-to-head comparison.
Talking about the physical aspects, RAM is a tiny rectangular chip that is put into a PCI slot, whereas ROM is an Integrated Circuit chip on the motherboard. In addition, RAM is frequently larger than ROM.
Why do our systems need RAM & ROM?
The random access memory (RAM) in your computer is one of the most significant components in influencing the performance of your system.
RAM provides temporary storage and access location for applications. It saves the information that your computer is actively consuming so that it may be immediately accessible.
The screen does not display immediately when you turn on your computer. It takes a while to appear since the computer’s initial instructions are stored in ROM and Hard Disks and must be executed during the booting process.
The booting procedure’s job is to turn on the machine. It loads the operating system into your computer’s main memory (RAM).
Moreover, software programs that users run (such as internet browser etc) are also loaded into RAM for faster access. The larger your RAM is, the more programs can be loaded into it, thus your system runs faster.
Regarding ROM, all computer firmware (which is a software program that remains attached to the hardware or is written on a physical device such as a keyboard, hard disks, graphics card, and so on) is stored in ROM chips.
This means that Firmware stored in ROM memory chips are used to tell the hardware gadget how to communicate with and interact with other peripherals.