Basically, the CPU can only store data and instructions in small registers so that it cannot store all the information needed for the entire program process, so to overcome this, the CPU must be equipped with a larger capacity storage device, namely main memory. Also called internal memory.
This unit can be thought of as a collection of boxes, each of which can store a piece of information, either data or instructions. Each location of the box is indicated by an address, which is a number that indicates a specific location of the memory box.
Difference between MEMORY and STORAGE
Illustration of the Difference Between Memory and Storage
In general, people are confused about distinguishing the terms memory and storage, especially when distributing each term. Meanwhile, the term memory refers to the amount of RAM installed in a computer, while the term storage refers to the amount of hard disk capacity. To describe it in general, it can be described as an office with a desk and a file cabinet. The file cabinet represents the computer's hard disk, with high storage capacity. The desk represents memory, with quick and easy access to search or reach, such as when working on a particular document at a particular time.
Another important difference is the nature of information storage, where storage will continue to store information as long as the computer is on or off. Whereas memory can only retain information while the computer is on. Therefore, many suggestions to frequently press CTRL+S to save changes to the document being worked on.
One of the tips for managing documents is not only to get used to saving every data change, the best anticipation is also needed, such as equipping your computer with a power backup (UPS), so that when there is a power outage you still have the opportunity to secure your archives.
RAM (Random Access Memory)
All data and programs entered via input devices will be stored first in the main memory, specifically RAM, which can be accessed randomly (can be filled/written, retrieved, or its contents erased) by the programmer.
The RAM structure is divided into four main parts, namely:
- Input storage, used to accommodate input entered via the input device.
- Program storage, used to store all program instructions that will be accessed.
- Working storage, used to store data to be processed and processing results.
- Output storage, used to store the final results of data processing to be displayed on the output device.
Input data will be stored first in input storage, if the data is in the form of a program, it will be moved to program storage, if it is in the form of regular data, it will be moved to working storage. The results of processing are also stored first in working storage and if it will be displayed to an output device such as a monitor or printer, for example, the results are moved to output storage.
Computer memory is divided into 16 blocks with special functions, most of which are as RAM (Random Access Memory) which functions as storage for processing results on the computer itself. For more details, the division of functions in this memory block is given roughly in the following table:
IBM PC memory block division
| Block | Fungsi |
|-------|-----------------------|
| 1 | RAM |
| 2 | RAM |
| 3 | RAM |
| 4 | RAM |
| 5 | RAM |
| 6 | RAM |
| 7 | RAM |
| 8 | RAM |
| 9 | RAM |
| A | EXTENDED VIDEO MEMORI |
| B | EXTENDED VIDEO MEMORI |
| C | PERLUASAN ROM |
| D | FUNGSI LAIN |
| E | FUNGSI LAIN |
| F | BIOS & BASIC |ROM (Read Only Memory)
Bios
ROM can only be read. ROM has been filled by the manufacturer in the form of an operating system consisting of basic programs needed by the computer system, such as programs to set the appearance of characters on the screen, filling in keyboard keys for certain control purposes, and bootstrap programs, this planting is often known as Embedded Systems.
The contents of the ROM (firmware) must not be lost or damaged because if this happens, the computer system will not be able to function. Therefore, ROM is designed for a specific purpose and cannot be modified (permanent). One example of ROM is Bios.
Currently, ROM development is increasingly rapid, the various types provide new experiences, such as:
- EPROM (Erasable Programmable Read Only Memory) which can be erased with ultraviolet light and can be reprogrammed repeatedly.
- EEPROM (Electrically Erasable Programmable Read Only Memory) which can be erased electronically and can be reprogrammed.
CACHE Memory
Previously we used the analogy of a room with a desk and a file cabinet to understand the relationship between basic memory and a computer's hard disk. If memory is like a desk that holds your work files for easy access, then the image of cache memory is like a bulletin board that holds papers that you return to from time to time. If you need information on the bulletin board, you can easily reach and find it.
Cache memory is a single package in current CPU technology, so if we look deeper into the DIE (CPU contents), the cache block will appear:
CPU Die Mapping