1. Smart Media (SM Card)
SM card is a flash card 1995 1 1 released by Toshiba and Taec in June. It has been supported by Toshiba, Samsung, Sony, Sharp, JVC, Philips, NEC and many other manufacturers. SmartMedia is very small, with a size of 45mm×37mm×0.76mm, which is very light and thin, with a total weight of only1.8g. There is only a flash module and interface on the memory card, and there is no control chip, so the compatibility is poor. SM cards of different manufacturers, different devices and different models may be incompatible with each other. At present, the mainstream capacity of SmartMedia is 128MB, and the common capacities are 32M and 64M.
Second, compact flash memory (CF card)
CF card has good compatibility, so it is widely used. Compact flash memory was introduced by SanDisk Company of America in 1994. Because the flash memory module and the controller are made together, the external device of CF card can be made simpler, and there is no compatibility problem, especially when upgrading, it can also ensure the compatibility with old devices and protect the investment of users, which is supported by almost all operating systems. CF card has been widely used in digital products such as notebook computers. The size of CF card is 43mm× 36mm×3.3mm, which is only 1/4 of PCMCIA card. CF card itself is also compatible with PCMCIA-ATA function and TrueIDE. CF card supports both 3.3 volts and 5 volts, and can work under these two voltages. It has two interface standards, CF Type II and CF Type I. From the physical structure, the interval between each jack of CF Type II card and CF Type I card is the same, but the CF Type II card is thicker than the CF Type I card. The CF card looks only half as thick as the II card. In addition, the Type II card is wider than the Tpye I slot, so the compact flash TypeⅱII II card cannot be used in the Type I slot. At present, LEXAR has launched a CF card with a maximum capacity of 4GB.
Thirdly, multimedia card (MMC card)
MMC(MultiMediaCard), literally translated as multimedia card, is a multifunctional memory card jointly developed by SANDISK Company of the United States and Siemens Company of Germany on 1997 * * *. It can be used in mobile phones, digital cameras, digital video cameras, MP3 and other digital products. It has the characteristics of small size and light weight. The overall size is only 32mm×24mm× 1.4mm, and the weight is less than 2 grams. It is impact-resistant and can be read and written more than 300,000 times. The driving voltage is 2.7-3.6V At present, there are 64M and 128M, which are mostly used in digital cameras and MP3 players. Recently, there are also digital cameras using this card.
Fourth, secure digital card (SD card)
SD card is a secure digital card-a secure digital memory card, which was jointly developed by Panasonic Corporation, Toshiba Corporation and SanDISK Corporation of the United States in August 1999. Although SD card is developed according to MMC card, they are basically different products, and only compatibility is considered when designing. Therefore, in most cases, these two products are interchangeable, and they are a multi-functional memory card with many characteristics such as large capacity, high performance and more security. Compared with MMC, it has a password authentication function (SDMI specification) for data copyright protection. Now it is mostly used in MP3, digital video cameras, e-books, microcomputers, AV equipment and so on. The size is slightly thicker than that of MMC card, which is 32mm×24mm×2. 1mm, and the capacity is much larger. When the SD card was first introduced, the single card capacity ranged from 8 MB to 64 MB, and the transmission speed was 2MB per second. By the beginning of 2002, the capacity of a single card had reached 5 12 MB, and in 2004 it reached the level of 2G, and the data transmission rate also increased to 65,438. In addition, the reading and writing speed of this card is 4 times faster than that of MMC card, reaching 2MB/ s, and it is compatible with MMC card. Most sockets of SD card support MMC card. From the performance point of view, the biggest difference between the two is that the SD card emphasizes the security of materials, and the access rights of programs or materials in the card can be set through specific software to prevent users from copying at will and damaging the interests of owners. Of course, this function is useless for ordinary users. On the contrary, related systems and encrypted data will occupy 900K K memory card capacity. In addition, both SD card and MMC card use integrated solid media, and there are no moving parts, so there is no need to worry about data loss caused by mechanical movement damage.
Verb (abbreviation of verb) memory stick (MS card)
Memory stick is a mobile storage introduced by Sony in 1997. It is also called "chewing gum" memory card because it looks like a piece of chewing gum. Currently only Sony supports it. Different from other flash cards, the specifications of memory sticks are not public and can only be used after signing an agreement. The memory stick has a write-protection switch, including a controller, adopts 10 pin interface, and the data bus is serial. The maximum frequency is 20MHz, the voltage is 2.7V to 3.6V, and the average current is 45mA. At present, the mainstream capacity of memory sticks has reached 256MB. In order to meet the needs of copyright protection, Sony launched a new Magic-Gate memory stick, 1999, in February, adding MagicGate copyright protection technology. The new MagicGate memory stick is compatible with memory sticks, with a white shell and a prominent dot on the back to show the difference.
Six, limit digital card (XD card)
The so-called XD card is the abbreviation of English Extreme Digital, which means extreme number. XD card is only 20× 25mm× 1.7mm, * * 0.85cm3, weighing 2g, and its volume is only half that of SM card. Its flash memory reading and writing speed is one of the fastest memory cards at present, with a reading speed of 5MB, 16MB, and 32MB per second. The writing speed is 1.3MB per second, while the writing speed above 64MB is 3MB per second, and the power consumption during driving is only 25mW less than that of SM card.
Seven, Trans flash card (TF card)
SanDisk announced the launch of 256MB TransFlash on October 26th, 2004/kloc-0. TransFlash is the smallest flash memory card in the world at present, which is about 1/4 of that of SD card, and its size is15x11mm, which is the same as that of fingernail. 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.
Since TransFlash can also have built-in operating system and system data, mobile phone manufacturers and network providers can set customized storage combinations, add new software and upgrade applications. Since mobile phone customers need to change their memory cards frequently, the same memory card may require devices to share data with other electronic products. Therefore, SanDisk will also provide standard SD cards, miniSD cards, Memory Stick PRO Duo cards and multimedia card(MMC), and TransFlash can be compatible with the above memory cards in the same mobile phone.
Motorola's several mobile phones ——A780, E 1000 and a 1000—— are the first products to use TransFlash memory cards. With A780, E 1000 and A 1000, TransFlash has the functions of shooting, video recording, playing music and surfing the Internet.