Memory cards getting smaller day by day, different types of cards are now available in the market. Some company announced their product is fully waterproof and some claimed high capacity, highspeed. Here know more about SDHC (Secure Digital High Capacity) cards.
Concept of SD Memory Card
The SD Memory Card is a groundbreaking new bridge media that’s helping to pave the way for tomorrow’s fully networked society. This tiny, easy-to-use card offers a host of powerful advantages. It links various kinds of digital equipment through its easy connectivity, that supports a host of application formats and does not require the use of a PC. Further, the SD Memory card has the broad interoperability and compatibility needed to ensure that its applications will continue to expand far into the future. Already supported by more than 665* companies around the world, the SD Memory Card is well on its way to becoming the de facto standard memory card for digital connectivity. Soon, the SD Memory Card will provide universal access to an even wider array of multi-media data. The ubiquitous network era is coming, and its key is the SD Memory Card.
What is SDHC?
To support the higher capacity needs, SD cards are now requiring a different design. The new SD 2.0 specifications which supports 4GB and up, is called Secure Digital High Capacity (SDHC). The SD Association has created and defined 3 speed classes to help you identify speed and performance capabilities/minimum requirements of SDHC cards and their SDHC host products. Details on the SD 2.0 specification: http://www.sdcard.org or SanDisk.com/SDHC
Cards address data (read and write) at numerous speeds. Many factors impede this performance. SDHC guarantees a minimum read and write speed necessary to handle recording high quality video and audio. The maximum card speed may vary, but you can always depend on SDHC cards to meet your SDHC host product’s high quality performance requirements.
SDHC Compatibility Information
Because SDHC works differently (supports the new higher capacity cards) this new card format is not backwards compatible with legacy SD format host devices.
The SDA speed class rating was developed to identify minimum data transfer and latency requirements for a host application and provide a means for consumers to match those requirements with an appropriately rated SD card. For example, in the emerging application of real-time video capture (camcorders, camera phones etc), in order to ensure smooth capture and playback of video, the camera buffer RAM must never experience a data over-run or under-run. This requires that the card communicate certain parameters to the camera and then meet some minimum governing parameters. An SDA speed class rating of 6 means that the card will be able to transfer (with specifically defined latencies and data allocation units) data in a random fashion without interruption. Consumers should look at the intended host device to select the correct speed class rating in the card they buy. Since speed class 6 is currently the highest rating defined by SDA, it doesn’t necessarily mean that a speed class 6 is the fastest card that a consumer can buy for all applications.
By contrast, SanDisk’s minimum performance rating of, for example, 20MB/sec on Extreme III cards states the performance level that those cards will deliver for sequential write and read operations in non-real-time applications such as file transfers between a card and a computer or in digital cameras between the camera’s buffer and the card. In this case, the statement of performance allows customers to make a relative comparison between cards of differing performance and price points. SanDisk Extreme III cards are also speed class 6 rated.
Note: 1 megabyte (MB) = 1 million bytes; 1 gigabyte (GB) = 1 billion bytes. Some of the listed capacity is used for formatting and other functions, and thus is not available for data storage. Read more.
Various brand, capacity & types of Memory cards.