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MultiMediaCard

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A MultiMediaCard, or MMC, is a standard for solid-state storage. This technology allows electronic devices to save and retrieve digital data. It was first introduced in 1997 by SanDisk, Siemens, and Nokia. The MMC was designed to be a compact alternative to earlier storage solutions. It features a postage-stamp-sized form factor that fits easily into small gadgets.

MMC card vs SDHC card undersides angle
MMC card vs SDHC card undersides angle

This standard is important because it helped create a unified way for mobile devices to store information.

The MMC works using a serial interface and a single memory stack assembly. This design makes it much simpler than older, high-pin-count cards. For example, the CompactFlash format used a 50-pin parallel interface. In contrast, the MMC uses only seven flat electrical contacts. This lower pin count reduces the complexity of the host device. By using a serial interface, the MMC can move data through a streamlined path. This makes the technology very mobile-friendly for digital cameras and handheld devices.

Over time, the MMC standard evolved into several distinct types. In 2002, a smaller version called the Reduced Size MultiMediaCard, or RS-MMC, was released. It was about half the height of a standard MMC and could reach capacities of 2 GB. Later, in 2004, the MMCplus and MMCmobile formats were introduced. These versions supported higher clock speeds of 26 MHz and 52 MHz. They also used wider 8-bit data buses to reach transfer rates of 52 Mbit/s.

Mmc-micro
Mmc-micro

Another variant, the MMCmicro, was created in 2005 to compete with microSD cards.

The history of MMC is a story of solving a fragmented market. In the mid-1990s, many different proprietary formats existed. Sony had the Memory Stick, and Olympus and Fujifilm developed the xD-Picture Card. These different types meant that storage was often incompatible between devices. To fix this, SanDisk, Siemens, and Nokia partnered in 1996 to create a universal standard. In 1998, 14 companies formed the MultiMediaCard Association (MMCA) to promote the format. This group worked to encourage many manufacturers to adopt the MMC standard.

While removable MMC cards became less common, the technology led to the Secure Digital (SD) card. Introduced in 1999 by SanDisk, Panasonic, and Toshiba, the SD card used the MMC electrical interface. However, it added features like digital rights management (DRM) and a mechanical write-protect switch. This helped the SD card surpass the original MMC in popularity. Today, many devices that work with SD cards also support older MMC cards. This shows how the original MMC design provided a foundation for much more common modern tools.

The most enduring part of this technology is the embedded MultiMediaCard, known as eMMC. The JEDEC Solid State Technology Association introduced the eMMC standard in 2006. Unlike removable cards, eMMC is soldered directly onto a device's printed circuit board (PCB).

Toshiba EMMC on iPad mini 2
Toshiba EMMC on iPad mini 2

It integrates NAND flash memory, a buffer, and a controller into a single ball grid array (BGA) package. This internal storage is common in low-cost smartphones, tablets, and budget laptops. It is favored because it is compact, affordable, and uses low power.

Different versions of eMMC offer different levels of performance. Version 4.0 was the first, but version 5.0 was released in 2013. This 5.0 version introduced the HS400 interface mode, which allows theoretical speeds of up to 400 MB/s. Version 5.1 arrived in 2015 to add command queuing and better reliability. The most recent update, version 5.1A, was released in 2019. While eMMC is faster than a traditional hard disk drive, it is slower than modern solid-state drives (SSDs). It remains a vital tool for everyday tasks like video streaming and web browsing.

Ultimately, the MMC standard connects to the broader world of computer architecture and storage evolution. It paved the way for more advanced technologies like Universal Flash Storage (UFS). It also influenced other interfaces, such as the CE-ATA used for small hard drives. Even the game cards used in the PlayStation Vita were based on the MMC standard. Although the original removable MMC cards have largely faded, the eMMC architecture continues to power much of our mobile computing world.

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File:MMC card vs SDHC card undersides angle.jpg
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File:Mmc-micro.PNG
Mmc-micro.PNG
File:Toshiba EMMC on iPad mini 2.png
Toshiba EMMC on iPad mini 2.png
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