Challenge for high-speed access technology to SSD

– We support the development of high-speed SSD access using a new logical interface to SSD called NVMe.

– HDD is connected by SATA and controlled by AHCI

HDD generally receives data read/write commands via SATA (Serial ATA). SATA can realize a data transfer rate of 6 Gbit/s as a theoretical value. When converted to Byte, the transfer speed is 750MB/s, and it has theoretical capacity to transfer a 3GB file in 4 seconds. However, in reality, the HDD does not fully use the transmission band of SATA, so the performance of the HDD itself depends on the speed of file copying operation.

On the other hand, the software modifies the HDD by sending read/write commands, but it is necessary to make an arrangement for the commands here. AHCI (Advanced Host Controller Interface) is the set of instructions and rules for this read/write method. AHCI is designed for optimum instruction transfer through SATA connection.

– With SSD, the performance peaks with the method of connecting with SATA and controlling with AHCL

Even if the HDD is changed to SSD, it is possible to read and write by AHCI control with SATA connection, but as the performance of SSD progresses, 6 Gbit/s transmission band becomes insufficient. Therefore, you can connect to the SSD using PCI Express, which can achieve a higher transfer rate than SATA. However, AHCI optimized for SATA connection could not fully utilize the capacity of SSD for PCI Express connection. To overcome this, a new logical interface called NVMe (Non Volatile Memory Express) was developed.