What is the black technology to save 16/32GB iPhone APFS?

There is hope for iPhone users with 16GB of storage! You must have often encountered various reminders that your phone's memory is insufficient. If you install only a few apps, the space on your phone will be insufficient. However, all this will change when you upgrade to iOS 10.3, because you will find that your phone, which was originally insufficient, suddenly has more than 1GB of space. Why is this? It's all because Apple has upgraded and adopted the latest APFS file system.

Why can the APFS file system after upgrading to iOS10.3 help us save more memory? What is the APFD file system? Let's not talk about the file system for now, let's talk about the memory of electronic products. As we all know, the memory is a place where the messy things downloaded by your computer and mobile phone can be stored, and it is a memory device used to save information. The disk is a commonly used computer memory. The disk is divided into hard disk and floppy disk. The floppy disk is gradually eliminated by the times, and the hard disk is the main storage device today.

Hard disks are divided into mechanical hard disks (HDD traditional hard disks), solid state disks (SSD new hard disks) and hybrid hard disks (SSHD). HDDs are cheap, have a long lifespan and are cost-effective. SSDs have fast reading speeds and high prices, but due to limited reading times, their lifespan is shorter than that of HDDs, making them suitable for mid- to high-end gamers.

Why is the read and write speed of SSD so fast? As shown in the figure, an SSD hard disk consists of a main controller, DRAM cache, and NAND FLASH flash memory. The main controller is the brain of the SSD, and everything the SSD does is controlled by it; the DRAM cache is a high-speed buffer, and its specific function depends on the algorithm of the main controller. Some are used to store LBA tables, some are used for data cache, and some solutions have no external DRAM cache, and only a small amount of cache is built into the main controller. The purpose of doing this is for data security (such as SandForce), and some are to reduce costs (most entry-level main controllers); NAND flash memory is where data is stored, and all your data is stored in it. Flash memory is the main storage medium, and the quality of flash memory can directly affect all aspects of the hard disk performance including read speed, storage size and life. Although the performance of the main controller can also affect the read speed of the hard disk.

Because mobile phones cannot be installed in the same way as hard disks, the only memory installed on smartphones is NAND FLASH. Common types of flash memory include SLC, MLC, and TLC. Because SLC is too expensive, most smartphones are equipped with MLC and TLC modes.

So what is the "file system" in the APFD file system? What does it have to do with storage? The file system is an operating system used to define storage devices, that is, a method of organizing files on storage devices. The software organization in the operating system that is responsible for managing and storing file information is called a file system.

Simply put, it is like having a Ferrari 488. If there is no good driver, the full performance of this car cannot be brought into play. Therefore, whether it is SSD, HDD or MLC and TLC based on mobile phone flash memory, a powerful file system is needed to help the memory calculation to guide it to exert its strongest strength.

The file system is software based on storage hardware. For 30 years, Apple has been using HFS as the file system for its products. HFS was born in 1985, and the improved HFS+ file system was introduced in the 4GB hard drive version of the G3 PowerMac released in 1998. From the 4GB capacity of the traditional HDD mechanical hard drive in 1998 to the TB-scale SSD solid-state drive today, HFS+ can no longer withstand the massive changes and innovations in the storage field.

On June 14, 2016, Apple officially announced a new file system (also known as file format) - Apple File System (APFS) at WWDC. This new file system is optimized for flash memory/SSD (but can still be used for traditional mechanical hard drives), provides stronger encryption, copy-on-write metadata, space sharing, file and directory cloning, snapshots, fast directory size adjustment, atomic-level secure storage primitives, and improved file system underlying technology, and will be fully applied to all devices under the company.

In addition to supporting all the functions of HFS+, the newly developed APFS has also made outstanding improvements in the following aspects: Unlike HFS+ that uses 32-bit file IDs, APFS supports 64-bit index node (Inode) numbers, so that a volume can store up to more than 900 trillion files.

HFS+ can only initialize the file system of the entire storage device at the same time. APFS provides an extensible block allocator that can perform lazy initialization on data structures, thereby greatly improving the performance of large-capacity volumes.

APFS supports three modes of encryption: no encryption; single-key encryption for metadata and user data; and multi-key encryption for metadata, files, and even specific parts of files. In addition, APFS also includes other improvements and new features, such as sparse files, improved TRIM operations, and built-in support for extended attributes. The reborn APFS already has functions and features comparable to modern file systems such as BSD HAMMER, Linux btrfs, or OpenZFS.

Advantages of APFS:

compatibility

The new generation of APFD file system is highly compatible and is compatible with all iPhone devices from Apple Watch to Mac Pro.

Data encryption

Security and privacy are the design foundations of APFS. Many of Apple's devices and operating systems have long had encryption capabilities. OS X 10.7 Lion began to provide full disk encryption; iOS 4 began to use dedicated data protection technology to encrypt each file with a dedicated key. APFS integrates these two functions and provides a unified encryption mode for file system metadata.

Encryption is a feature natively supported by APFS, and users can choose any of the following encryption methods for each volume: no encryption, unified encryption with a single key, or multi-key encryption (encrypting each file with a dedicated key and a separate key for sensitive metadata). Multi-key encryption ensures the integrity of user data even if the physical security of the device is compromised. Depending on the specific hardware, APFS encryption can use AES-XTS or AES-CBC algorithms.

This encryption mechanism also enables an additional function: faster data erasure. Normally, when a user deletes a file from a device, the deleted content can be retrieved through many (free or paid) anti-deletion software available on the market. To avoid this, in the past, if you needed to delete files containing confidential information or retire a device that stored private data for use by others, you had to first use the erase function to erase the storage device, and you might have to perform this process multiple times. Depending on the capacity of the storage device, the whole process would take a lot of time.

For storage devices using the APFS file system, after enabling the encryption function, the secure erase process will become much simpler and faster. It is no longer necessary to spend a lot of time filling the storage device with random data multiple times. You only need to delete the encryption key.

As a winner of Toutiao's Qingyun Plan and Baijiahao's Bai+ Plan, the 2019 Baidu Digital Author of the Year, the Baijiahao's Most Popular Author in the Technology Field, the 2019 Sogou Technology and Culture Author, and the 2021 Baijiahao Quarterly Influential Creator, he has won many awards, including the 2013 Sohu Best Industry Media Person, the 2015 China New Media Entrepreneurship Competition Beijing Third Place, the 2015 Guangmang Experience Award, the 2015 China New Media Entrepreneurship Competition Finals Third Place, and the 2018 Baidu Dynamic Annual Powerful Celebrity.