SD card (translated from Chinese into secure digital memory card) is a new generation of storage device based on semiconductor flash memory, which is widely used in portable devices, such as digital cameras, personal digital assistants (PDA) and multimedia players. The SD card was jointly developed by Panasonic, Toshiba and SanDisk Company of the United States in August 1999. The stamp-sized SD memory card weighs only 2 grams, but it has high storage capacity, fast data transmission speed, great mobility and good security. In the volume of 24mm×32mm×2. 1mm, the SD card combines SanDisk flash memory card control with MLC (multi-level unit) technology and Toshiba's NAND technologies 0. 16u and 0. 13u, and is connected with a special driver through a 9-pin interface, so there is no need for additional power supply to keep the information stored on it. Moreover, it is an integrated solid medium without any moving parts, so there is no need to worry about the damage of mechanical movement. The technical structure of SD card is based on the multimedia card (MMC) format, and its size is similar to that of MMC, with the size of 32 mm x 24 mm x 2. 1 mm ... The length and width are the same as MMC, but it is 0.7mm thicker than MMC to accommodate larger storage units. The SD card and MMC card remain upward compatible, that is, new SD devices can access MMC, and the compatibility depends on the application software, but the SD card cannot be accessed by MMC devices. (The shape of SD card adopts the track design with the same thickness as MMC, so that SD equipment can be suitable for MMC).
[Edit this paragraph] Mini SD card
The Mini SD card (pictured right) is smaller than the mainstream SD card (such as the one used on DC or DV), with a weight of only about 3g and a volume of only 2 1.5x20x 1.4mm, which fully saves 60% space compared with the ordinary SD card. Don't underestimate such a small shape, it can save 40% space for the volume of digital equipment. In order to produce smaller digital products such as mobile phones and DV. In terms of storage capacity, the Mini SD card is not bad at all, from 32MB to 1GB, or even several gigabytes. Mini SD was jointly developed by Panasonic and Sandisk. In order to facilitate more users to switch between different memory cards to use Mini SD, Sandisk has specially introduced an SD adapter card (as shown in the left), which can be used together with DC, PDA and MP3*** which now use SD cards. Mini SD is only 37% of the size of ordinary SD card, but its reading and writing efficiency remains unchanged, and its capacity is large, so it is completely compatible with standard SD card. The attached SD adapter card can also be used as an ordinary SD card. With more and more functions of consumer digital products, users' demand for large-capacity memory cards is increasing. At present, the capacity of 5 12M and 1GB has been gradually popularized, and will increase exponentially in the future. MINI SD card supports wear leveling algorithm, automatic error correction (ECC) and other functions, which makes MINI SD card have longer service life and lower power consumption. At present, mini SD cards on the market all support the standard interface of SD card (with adapter card, as shown in the left), so it is very convenient to use mini SD cards on the original SD card equipment, paving the way for the rapid popularization of mini SD cards.
[Edit this paragraph ]TF card
Also known as T-Flash card, the full name is TransFLash, which was jointly developed by Motorola and Sandisk and launched in 2004. It is an ultra-small card (11*15 *1mm), which is about 1/4 of the SD card, so it can be regarded as the smallest memory card at present. TF card can be used as SD card after SD card converter. Adapters can be used on devices that use SD as storage media. TransFlash is mainly developed for camera phones, which are used to shoot large images and download large video clips. TransFlash card can be used to store personal data, such as digital photos, MP3 players, games, mobile phone applications and personal data. , and also built-in copyright protection management system to protect downloaded music, videos and games. In the future, the new TransFlash will also be equipped with encryption function to protect personal data, financial records and medical care documents. The compact TransFlash allows the manufacturer to adopt this design without worrying about the size of the mobile phone. Another flexible application is that the supplier can replace it according to the different needs of customers at any time before delivery, which is an advantage that embedded flash memory does not have. -It is about half the size of a SIM card and equipped with a copyright protection management system, which is suitable for many multimedia applications. ◆ With the adapter, it can be used on digital products with SD card slots. ◆ Size:11mm *15 mm *1mm.
[Edit this paragraph ]MMC card
The translation of MMC card into Chinese is a "multimedia card". It's the standard for flash cards. Developed by Siemens and SanDisk*** in 1997, this technology is based on Toshiba's NAND flash memory technology, so it is smaller than earlier memory cards (such as CF cards) based on IntelNOR flash memory technology. MMC card is about the size of a stamp, about 24 24mm x 32mm x 1.5mm ... It has the characteristics of small size and light weight, weighs less than 2 grams, is impact-resistant, and can be read and written repeatedly for 300,000 times. The driving voltage is 2.7-3.6V At present, the capacity of MMC card is as high as 2 GB, which is applied to almost all devices using memory cards, such as mobile phones, digital audio players, digital cameras, PDA and so on. Due to the emergence of Secure Digital, few companies have built-in MMC slots in their devices, but a narrower MMC card with compatible pins can be used on all devices that support SD cards. However, some companies, especially Nokia, still fully support MMC. MMC card originally used 1 bit serial interface, but the newer standard allows 4-bit or 8-bit data transmission at the same time. In recent years, MMC card technology has been almost completely replaced by SD card, but it still has its role, because MMC card can still be read by SD card compatible devices.
[Edit this paragraph ]RS-MMC card
MmcRS MMC card, MINI SD card and RS MMC card are also ultra-small flash memory cards that are listed soon? The standard size of SMMMC card is 24 × 18 × 1.4 mm, which is only half the size of standard MMC card and only slightly larger than the new dime. However, it inherits and follows all the advantages and performance characteristics of MMC card. RS-MMC card also supports many functions, such as automatic error correction (ECC), online real-time update program (ISP) and loss balancing algorithm, and it is superior to mainstream SD card and MMC card in power consumption and storage speed. As an extension of the current MMC card standard, RS MMC has solved the space problem that has long plagued mobile phone and consumer electronics developers, making it possible to design ultra-small electronic products. For this reason, the RS MMC card has been supported by mobile phone giants such as Nokia as soon as it is launched.
[Edit this paragraph ]MS card
Memory stick (MS card) [MS format: 1. Memory stick Pro (commonly known as long stick) 2. Memory stick Pro Duo (commonly known as short stick) manufacturing company: 1. Sony (Sony) 2. SANDISK (Many people don't know that SANDISK also produces MS cards, and the price is cheap. Good performance) Current (nominal) capacity: (as of April 0, 20081) 32mb, 64mb, 128mb, 256mb, 5 12mb 1g, 2g, 4g, 8g, and 2g. But mainly Sony digital products. Concept: Sony's unique personality created the birth of memory stick. This chewing gum storage device can be used in almost all Sony audio-visual products. The memory stick is light in appearance and comprehensive in function. Its high compatibility and unprecedented concept of "universal media" provide a new generation of high-speed and large-capacity digital information storage and exchange media for future high-tech personal computers, televisions, telephones, digital cameras, camcorders and portable personal audio-visual equipment. The advantages of memory stick include compact appearance, high stability, copyright protection function and convenient use in various memory stick series products, as well as a large number of products introduced by Sony that make use of this technology, such as DV cameras, digital cameras, VAIO personal computers, color printers, walkman, IC tape recorders, LCD TVs and so on. , as well as PC card converter, 3.5-inch floppy disk converter, parallel export converter, USB reader and other full range of accessories, so that the memory stick can easily connect PC and MAC. After the introduction of memory stick, a series of companies such as Samsung, Aihua, Sanyo, Casio, Fujitsu, Olympus and Sharp all expressed their support for this format. Sony is still seeking the recognition of memory chip format in the home appliance industry and IT industry. Sony will introduce more products representing the latest development of memory sticks to the domestic market in the future. The disadvantage of memory stick is that it can only be used on Sony digital camera, and its capacity is not large enough. On the basis of memory stick, Sony reduced the size to about 1/3, and designed and manufactured the memory stick Duo. The external size is only 3 1×20× 1.6mm, and the weight is doubled to 2g, which is very similar to xD card and very convenient to carry. This memory stick Duo is very convenient to be used in quite compact mobile phones and digital cameras, as well as mp3 players and other electronic products. In order to obtain greater capacity and higher speed, Sony has launched a brand-new memory stick PRO, which is jointly developed by Sony and Sandisk. Compared with the memory stick, the external volume has not changed, but it can achieve 8GB capacity. Old equipment will not be able to use this new memory stick PRO, but digital products with memory stick PRO slots can be backward compatible and use traditional memory sticks. In addition to serial transmission, Memory Stick PRO also supports parallel transmission, which enables simultaneous transmission and reception of various data. In parallel transmission mode, data is transmitted at a speed greater than 160Mbps (theoretical value), which makes it possible to record DVD-quality dynamic images in real time. With this high speed, Memory Stick PRO can also support advanced solutions brought by the coming broadband era. Memory stick PRO does not distinguish between blue and white stripes, and all memory stick PRO have copyright protection function. In March, 2003, memory stick Pro Duo was designed and manufactured on the basis of memory stick PRO, which is an improved product, adding parallel interface support to the old memory stick Duo. Memory stick PRO Duo packages and compresses all advanced functions of memory stick pro into Duo format. It uses higher density stacking technology. The memory stick Pro Duo not only supports serial transmission, but also supports parallel transmission, and can transmit data at the speed of 160Mpbs (theoretical maximum). In order to cope with the increasing number of advanced applications in the broadband era, this media provides a fast and simple way to copy high-resolution digital images and large-capacity demonstration data. Memory sticks allow recording of copyrighted content and high-speed data transmission, and maintain high compatibility in a wide range of product fields, including small mobile devices. By connecting the adapter, it can also be applied to products compatible with standard size memory sticks.