Computer memory can be volatile (RAM) and nonvolatile (hard disk). The size of the first in modern computers is calculated in gigabytes, and the second - in terabytes.
Computer memory is a physical device for storing information. In modern computers, two types of data storage are widely used - on hard drives and in RAM. The size of RAM can be measured in gigabytes, and the capacity of hard drives can be up to several terabytes.
Computer memory usually refers to either RAM or the capacity of a hard drive.
RAM
Random access memory or random access memory (RAM) operates on the principle of volatile data storage. Its work is based on the use of transistors. After the computer is turned off, all data in RAM is erased.
The size of "RAM" is usually measured in gigabytes. Most modern personal computers use memory modules ranging from two to four gigabytes.
One gigabyte contains over a billion bytes. This amount of memory can hold one hour of regular video, seven minutes of high-definition video, or about two hours of CD-quality music.
If desired, users of personal computers can increase the amount of RAM by adding new modules. This allows the computer to run faster.
In gigabytes, "RAM" was not always measured. Even 15-20 years ago, the usual size for RAM was 128, 256 or 512 megabytes. This is 4-20 times less than in the case of modern computers.
HDD
If the main memory is responsible for the dynamic recording of data with which the processor works "on the fly", then the hard disk, as a rule, records information for long-term storage. This type of memory is not volatile - after turning off the computer, the data on it is not erased.
The hard disk stores information using the principle of magnetic recording. In modern computers, hard drives are measured in terabytes. One terabyte contains over a thousand gigabytes (or over a million megabytes).
The first hard drives, developed in the middle of the last century, were the size of a refrigerator and could only store a couple of megabytes. In 1982, IBM released a personal computer with a five megabyte disk.
The very first 1 terabyte hard drive appeared in 2007, released by Hitachi. It cost $ 370. The cost of modern HDDs with a memory capacity of 1 terabyte is about $ 60.
Memory, measured in terabytes, contains a huge amount of information. Thus, the entire archive of 500 million messages from Usenet users fits into 1.5 terabytes, and the entire Wikipedia database - 6 terabytes.
