MultiMediaCard
Videos
MultiMediaCard is a memory card standard used for solid-state storage, originally introduced in 1997 by SanDisk, Siemens, and Nokia. Designed as a compact, low-pin-count, postage‑stamp‑sized card alte
Undersides of an MMC (left) and SD card (right) showing the differences between the two formats
Top of four types of MMC cards (clockwise from left): MMC, RS-MMC, MMCplus, MMCmobile, metal extender
Bottom of the same four cards
SD card
Videos
The SD card is a proprietary, non-volatile, flash memory card format developed by the SD Association. They come in three physical forms: the full-size SD, the smaller miniSD, and the smallest, microSD
MultiMediaCard
…cards such as CompactFlash, which was previously developed by SanDisk. It has since evolved into several variants, including the widely used SD card and the eMMC (embedded MMC) which is soldered directly onto a device's circuit board. While removable MMC cards have largely been supplanted by SD…
This microSDHC card holds 8 billion bytes. Beneath it is a section of a magnetic-core memory (used until the 1970s) that holds eight bytes using 64 cores. The card covers approximately 20 bits (2+1⁄2 bytes).
Back side of a microSD card, showing its eight electrical contacts
Back side of a UHS-II microSD card, showing the additional row of contacts
Front and back of an SD Express card