Shulou(Shulou.com)11/24 Report--

In November 1997, SanDisk and Infineon jointly launched the MMC (MultiMediaCard) memory card.

In August 1999, SanDisk launched the SD (Secure Digital) memory card in conjunction with Panasonic and Toshiba. The SD card has the same length and width size as the MMC card, slightly thicker (2.1mm VS. 1.4mm). Early SD card devices / readers are both compatible with MMC cards.

In January 2000, the SD Card Association was formally established, and the products with maximum capacity 64MB and transmission speed about 12.5MB/s were launched that year.

In March 2003, SanDisk unveiled miniSD cards for mobile devices such as mobile phones (now out of the market).

In February 2004, SanDisk and Motorola released smaller microSD cards (also known as TransFlash or TF cards).

The Motorola E398 (released in July 2004) is generally considered to be the first mobile phone with a TransFlash card.

In July 2005, the SD Card Association confirmed the microSD card specification, and the transmission speed was increased to about 25MB/s.

In January 2006, SD 2.0 introduced SDHC (including miniSDHC, microSDHC) cards with FAT32 file system and maximum capacity 32GB. The original version of the SD card uses the FAT12 / FAT16 file system, with a maximum capacity of 2GB.

In May 2010, SD 3.01 brought a SDXC (including microSDXC) card with an exFAT file system with maximum capacity up to 2TB, and a UHS-I high-speed bus with a maximum transfer speed of 104MB/s.

The Nikon D7000 (released in September 2010) is the first interchangeable lens camera that supports UHS-I SD cards.

In June 2011, SD 4.0 introduced the UHS-II bus. This kind of SD card (including microSD card) has two rows of contacts, which can achieve the transmission speed of half-duplex 156MB/s and full-duplex 312MB/s.

Fuji X-T1 (released in January 2014) is the first interchangeable lens camera that supports UHS-II SD cards.

In February 2016, SD 5.0 introduced video speed rating specifications, including V30, V60, and V90.

In November 2016, SD 5.1 added the A1 standard for App operational performance. On the basis of meeting the requirements of continuous reading and writing of 10MB/s, the requirements of random reading 1500IOPS and random writing 500IOPS are added.

In February 2017, SD 6.0brought the UHS-III bus of full-duplex 312MB/s and full-duplex 624MB/s, and the A2 standard of random reading 4000IOPS and random writing 2000IOPS. UHS-III is backward compatible with UHS-II, but so far no samples have been seen.

In June 2018, SD 7.0 brought SDUC with maximum capacity up to 128TB (including microSDUC), and SD Express cards based on PCIe 3.0 × 1 bus and NVMe protocol, providing the highest full-duplex 985MB/s transmission speed.

* the SD Express card is backward compatible with UHS-I, that is, the transmission speed of 104MB/s is at most on ordinary devices.

A-DATA is one of the few manufacturers that produce SD Express cards in large quantities, but there is no equipment to make full use of its speed.

In early 2019, SanDisk launched the "UHS-I overclocking card", which broke through the speed bottleneck of 104MB/s. After that, Kingston, Rexa and other manufacturers also added products with similar specifications.

* the UHS-I overclocking card can only achieve the nominal speed on the compatible card reader, and only the speed of the ordinary UHS-I card on the camera and other card readers can not replace the UHS-II card.

In May 2020, SD 8.0 introduced PCIe 3.0 × 2, PCIe 4.0 × 1, and PCIe 4.0 × 2, raising the maximum speed to close to 4GB/s (3938MB/s).

In May 2022, SD 9.0 added fast startup and secure startup features, creating a semi-embedded application scenario for SD cards.

This article comes from the official account of Wechat: camera Notes (ID:xjbiji), by Teng Fei et

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