Google will launch the final version of Android 13 later this fall. The company started testing Android 13 back in February 2022, and it officially showcased it, revealing the several features and improvements it'll come with, earlier this month at Google I/O.

Due to the time constraints and various other reasons, Google was, naturally, unable to deep dive into every feature that the Android 13 will come with. Android specialist Mishaal Rahman has now discovered another hidden feature of Android 13, the EROFS file system, that Google is reportedly planning to implement with the upcoming Android update. Here's everything that you need to know about it.

What is the EROFS file system?

OnePlus Android in hand

Source: Pocketnow video

Before we get to EROFS, you should know about what a file system is. A file system is basically the method and data structure an operating system uses to control how data is stored and retrieved. Think of it as a type of index for all the data stored in a device. Without a file system, it would be difficult for an OS to identify and retrieve files from the storage.

Every OS uses a different type of file system: Microsoft's Windows uses the NTFS file system, and Apple's macOS uses its own APFS file system. File systems such as FAT32 and EXT are some of the old file systems that are supported by most devices. Android devices also use different types of file systems — while most of the devices sold today use the UFS file system, most Android smartphones support the EXT4 file format since the operating system is based on Linux.

From HUAWEI to Linux to Android: Story of the EROFS File System

EROFS stands for Enhanced Read-Only File System. EROFS isn't really a ground-breaking new technology that Google has developed. Instead, it was created by the HUAWEI engineer Xiang Gao back in 2018 and has been in use in the HUAWEI phones for the past couple of years. EROFS, as the name suggests, is a read-only file system that Google is now planning to bring to all Android devices. Since it is a read-only file format, it will be used in only some parts of the OS. Nonetheless, it offers a number of benefits over the current implementation, about which we will talk at a later stage.

Fun Fact: Sometimes, EROFS is also referred to as the Extendable Read-Only File System.

When Xiang introduced the EROFS file system, he said that the new read-only format "focuses more on performance than purely on saving storage space as much as possible." As a proof of concept, he posted data comparing the sequential and random read/write speeds of a HUAWEI phone with an EROFS partition vs. the same phone that was using the EXT4-formatted partition. The results, as you can see down below, are promising.

HUAWEI EROFS versus EXT4

Source: HUAWEI

After a year of development, HUAWEI officially introduced the EROFS file system into its Android smartphone with EMUI 9.0.1, but it only became widely available with EMUI 9.1. Thanks to the improvements it offers, EROFS was integrated into the Linux operating system with version 5.4. It was adopted by HONOR as well. And now, thanks to Google making it mandatory for Android OEMs, other companies like OPPO, Samsung, OnePlus, and Xiaomi will support EROFS.

What are the advantages?

Talking about the advantages of the EROFS file system, it offers better performance and better data-saving techniques than the current solutions. While compressing data generally leads to bad performance, HUAWEI has developed a solution that offers the best of both worlds. Read speeds are about 25% faster than that of an EXT4 file system. When a system is flashed on an Android device with EROFS and an Android device without one, the EROFS Android device offers up to 2GB of more space, making it great for devices with limited storage capabilities. Moreover, since this is a read-only system, it offers better security in terms of protecting system files.

EROFS Advantages

Source: HUAWEI

In a research paper that Xiang filed, he says that the "EROFS outperforms existing compressed read-only file systems with various micro-benchmarks and reduces the boot time of real-world applications by up to 22.9% while nearly halving the storage usage." In simple terms, EROFS claims a major boost in performance all while decreasing the storage space used. How it will perform in the real world remains to be seen, but if the recent HUAWEI phones have suggested anything, it will be fast.

Not all Android 13 devices will benefit from the EROFS file system

The introduction of the new file system doesn't necessarily mean that all the Android 13 devices will use the new EROFS file system. The change will only be mandatory for the devices that launch with Android 13 pre-installed. Phone manufacturers can implement the new file system on their smartphones when they update their devices to Android 13, but it's not mandatory.

A back angle shot of Pixel 7 Pro

Source: Google

According to Mishaal Rahman, the upcoming Google Pixel 7 (and 7 Pro) will be one of the first smartphones to come with an EROFS file system partition. Similarly, you can expect smartphones from OnePlus, Samsung, Motorola, and others to switch to this file system when Android 13 becomes official.

And, oh, the EROFS file system will probably be only used for the read-only system partition. According to the figures reported, this will significantly improve the system's performance. On the other hand, the user data read-and-write partition will still use the good old EXT4 or F2FS file partition — unless Google has some plans for this as well. But, by default, devices running on AOSP (Android Open Source Project) or AOSP-based ROMs will not use EROFS.

EROFS seems like a promising Android 13 feature. Even though it may not be making headlines like the other best new Android 13 features, such as improved color theming and enhanced privacy and security, it is one of the features that could impact system performance and improve the longevity of the Android 13 devices. What are your thoughts on Google implementing EROFS in Android 13? Do you take a look at the file system of the devices before buying? Let us know in the comments section below!

References: Wikipedia - File System, EROFS, How2Shout, Android Police, Tech Target