Internal storage of an Android phone: a complete guide

Internal storage is a fundamental part of any modern smartphone, without which the device simply cannot function. Unlike RAM, which is cleared when you reboot, internal storage retains all your data, settings and the operating system itself even after a complete power outage. This is the space where applications, photos, music, messenger cache and system files are recorded.

Many users confuse the concepts ROM (Read-Only Memory, although in smartphones this is rewritable flash memory) and RAM (operational memory), which leads to a misunderstanding of the reasons for “brakes” or lack of space. Internal memory in an Android phone it is a complex logical disk, divided into hidden and user-visible sections. Understanding this structure is critical for proper operation of the gadget.

When you buy a phone labeled “128 GB”, you receive a physical memory chip of a certain size. However, the space available to the user is always less than stated. This is due to the fact that part of the space is irrevocably occupied system partition with firmware,_recovery_ (recovery mode) and service data. Let's take a look at exactly how this storage is designed and how to effectively manage it.

Physical basis and memory types eMMC and UFS

The internal drive is based on NAND flash memory chips. The speed of your smartphone, the installation time of applications and the speed of copying files directly depend on the standard to which this chip is made. Two main types dominate the market: eMMC and UFS. Budget models are often equipped with standard memory eMMC 5.1, which operates on the half-duplex principle - data can either be read or written, but not at the same time.

More modern and productive devices use standard UFS (Universal Flash Storage), which operates in full duplex mode. This allows you to simultaneously read system data and write new files, which significantly speeds up the interface. The difference in speed between the old eMMC and the new UFS 3.1 or 4.0 can be up to ten times, which is especially noticeable when running heavy games or updating the system.

Physical wear and tear of memory cells is another aspect that is rarely talked about. Each type of drive has a limited resource of rewrite cycles. However, modern memory controllers use wear-leveling algorithms, distributing the load evenly across all cells. Therefore, during normal household use internal storage rarely fails before the smartphone itself becomes outdated.

⚠️ Attention: The writing speed to the internal storage may drop sharply if it is more than 90% full. It becomes more difficult for the controller to find free blocks for writing new data, which leads to noticeable “freezes” of the interface.

Logical structure of Android partitions

From the operating system point of view, the physical memory chip is divided into several logical sections (partitions). The user sees only some of them, while others are hidden to protect the integrity of the system. The basic structure includes a bootloader, a system partition, a data partition, and a cache partition. Understanding this hierarchy helps you understand why you can’t just “delete the system” to free up space for photos.

The section /system contains files of the Android operating system, pre-installed applications and libraries. It is usually mounted in read-only mode for the average user. An attempt to write data there without superuser rights (root) is impossible. The size of this section varies from 4 to 10 GB depending on the version of Android and the manufacturer's shell (for example, MIUI or One UI).

The most important section for the user is /data. This is where all your personal files, installed third-party applications, their settings and databases are stored. When you download a file from the browser or take a camera photo, it ends up in this section. There is also a virtual folder here /sdcard, which file managers display as “Internal memory”.

Section	Purpose	User access	Approximate volume
/boot	System kernel and ramdisk	Read only (Root)	32–64 MB
/system	OS files and system applications	Read only	4–10 GB
/data	User data and applications	Full access	Remaining of the total volume
/cache	Temporary system files	Cleared automatically	256–512 MB
/recovery	System recovery environment	Only through the Recovery menu	32–64 MB

What is the Vendor section?

The /vendor section contains specific drivers and libraries from the device manufacturer (Qualcomm, MediaTek, Samsung). It is separated from the main system to simplify Android updates without the need to rebuild drivers for each specific hardware.

Difference between internal memory and RAM (RAM)

A frequent question from newbies: “Why does the phone write that the memory is full if I still have a lot of space?” between internal drive (ROM) and random access memory (RAM). RAM is used to temporarily store data from running applications. It works hundreds of times faster than the drive, but is volatile - when the phone is turned off, all data in the RAM disappears.

The internal drive works like a hard drive. computer. It is slower, but is designed for long-term storage. When you launch a game, its files are read from the internal drive and loaded into RAM for fast processing by the processor. If the RAM is full, the system begins to use part of the internal drive as a swap file, which leads to a significant slowdown.

Lack of internal space affects the ability to install new apps and save media files. Lack of RAM leads to background applications. are constantly unloaded and restarted when switching between them. For normal operation of modern Android in 2026-2026, it is desirable to have at least 6–8 GB of RAM and 128 GB of internal space.

Reasons for fast storage filling

Even with 256 GB of memory, users often encounter the “Not enough space” notification. The main reason for this phenomenon is uncontrolled growth. application cache. Messengers, such as Telegram or WhatsApp, automatically save all viewed photos and videos to internal memory. Over time, this “garbage” can occupy tens of gigabytes.

The second factor is system updates and log files (logs) After a major firmware update, temporary files may remain on the disk. installer, which the system does not always delete automatically. Also, some applications create backup copies directly to the internal memory, duplicating data that is already in the cloud.

The third common scenario is downloading content for offline viewing. Streaming services (YouTube Premium, Netflix, Spotify) allow you to download movies and music, although users often forget about these files. could be stored on a memory card or in the cloud.

⚠️ Attention: The folder Android/obb in the internal memory contains cache files of heavy games. Manually deleting this folder may cause games to stop launching or require re-downloading the data.

Cleaning methods and optimization. space

To free up space on the internal drive, there are several effective methods, from safe to advanced. The easiest way is to use the built-in cleaning tool. In the settings of most smartphones there is a section Settings → Storagewhere the system itself offers to delete unnecessary files, duplicates and cache.

Deeper cleaning requires manual intervention. It is recommended to check the folder Downloads (Downloads), where APK installation files are often accumulated after installing apps, as well as old documents. For messengers, it is better to use the built-in memory management tools: in the chat settings, you can select the storage period for media files or clear the cache using one. by clicking.

If the built-in tools are not enough, you can use third-party utilities, but be careful. Avoid “accelerators” and “cleaners” that promise miraculous memory freeing - they often consume resources themselves and display intrusive advertising. It is better to use proven file managers, such as Files by Google or Total Commander.

Memory expansion: microSD cards and clouds

Not all modern smartphones support the installation of memory cards microSD. Flagship models often lack this slot for the sake of moisture protection and saving space inside the case. If your phone supports cards, you can use them as portable storage for photos, videos and music, thereby relieving the fast internal storage.

There is a mode for the memory card to work as part of the internal memory (Adoptable Storage). In this case, the system encrypts the card and combines it with the main partition /data. This allows apps to be installed on the card, but there are risks: the card's speed is typically slower than the onboard UFS chip, which can slow down apps. In addition, if the card is lost or broken, the data will be lost forever.

An alternative to physical expansion is cloud storage. Services like Google Drive, Yandex.Disk or Dropbox allow you to store backup copies of photos and documents on the Internet. Setting up automatic uploading of photos and then deleting them from the internal memory is one of the most effective ways to maintain order in your storage.

⚠️ Attention: Settings interfaces and menu names may differ depending on the version of Android and the manufacturer's shell. If you do not find the described item, check the official instructions for your device model.

Frequently asked questions (FAQ)

Is it possible to transfer all applications to a memory card?

It is impossible to completely transfer all applications. System applications and some Google services are strictly tied to the internal storage to ensure stability. Regular user applications can be migrated if the developer has not prohibited this in the application manifest settings, but even in this case, some of the data will remain in the internal memory.

Why is there less memory available than indicated in the specifications?

Manufacturers indicate the volume in decimal notation (1 GB = 1,000,000,000 bytes), and Android displays it in binary (1 GiB = 1,073,741,824 bytes). In addition, a significant part of the space is occupied by the operating system itself and pre-installed software, which cannot be removed without obtaining root access.

Is it safe to format the internal memory?

Formatting the internal memory (resetting to factory settings) completely deletes all user data: photos, contacts, applications and settings. This is safe for the device itself and is sometimes necessary to solve software errors, but before the procedure, be sure to back up important data to the cloud or to a computer.

How to find the speed of your internal drive?

To check the read and write speed, you can use special utilities, for example, A1 SD Bench or AndroBench. These applications will test and show real speeds in megabytes per second, which will allow you to compare your drive with the eMMC or UFS standards.

What should you do if the phone says “Memory Full”, although there is space?

This could be a system caching error or a specific partition is full (for example, the data partition, while the system partition is empty). Try rebooting your device. If the problem persists, check to see if the cache folder of a specific application is not full, which could create a giant log file.