SDHC memory cards: development history and technological features

Among the most successful standards of flash memory,present on the modern world market - SD. One of its popular varieties is SDHC. Based on the appropriate technology, the world's leading brands produce sufficiently large and reliable memory cards. What are the features of this standard? How did devices that support SDHC appear?

Specificity of SDHC cards

SDHC Memory Cards (or Secure Digital HighCapacity) are devices that operate in accordance with a standard that has become a further development of flash memory technologies such as SD, developed by the SD Card Association. The peculiarity of these devices is that their capacity can reach 32 GB. The file system that is most often used on such memory cards is FAT32.

One of the standards within whichan SDHC - micro memory card is produced. But in this case, together with the device, as a rule, you need to use the SD-adapter, through which you connect to a PC or other device that uses flash memory.

Usually it comes bundled with memory modules in the standard micro.

Compatibility

It should be noted that the standardSDHC memory card may be incompatible with devices that were originally designed to work with conventional SD-cards. The fact is that the principle of sector-based addressing (as in hard disks) is involved in it, in contrast to the byte one, which is implemented in the memory cards of the previous generation.

History of development of SD-cards

Before the world's IT engineers wereThe SDHC memory card was developed, which was preceded by the long and systematic work of the leading brands of the industry to standardize and improve the technology of flash devices used for file storage. So, in 1999, SanDisk, Toshiba, and Matsushita decided to create a new standard - SD, or Secure Digital. What was its specificity?

First of all, in support of DRM in accordance withSDMI criteria. In accordance with the concept proposed by the three brands mentioned above, the SD-format of memory cards had to compete with Sony's already-known Memory Stick technology. Three brands created a new organization, called SD Assiciation. Subsequently, its structure included the largest brands - such as, for example, Intel, AMD, Samsung, Apple.

As part of SD technology, 4 majorgeneration flash cards. The very first, functioning on technology SD 1.0, is able to place data in the volume up to 2 GB, the second - SD 1.1, works within the file size up to 4 GB. Limit value, which is characterized by SDHC - 32GB memory card. The next generation of flash memory - according to SDHX standard, can accommodate up to 2 TB of files.

Use SD cards and those that supportstandard SDHC in a variety of applications of digital technology. Appropriate devices can be used as carriers of virtually any type of file. They are exceptionally productive in terms of use in photo and video equipment. SD cards are available, reliable. Devices, working on SDHC technology - are also characterized by quite decent capacity.

How did SDHC cards appear?

How did the market for IT devicesan SDHC memory card? The first devices working in the SD standard, as we noted above, originally housed only up to 2 GB of data. For a long time this resource was enough to perform basic user tasks - for example, placing documents, photos, music files.

Gradually the needs of computer ownershave increased. In 2006, a new, more advanced standard flash memory - SDHC. In the same year, SD Associations also developed several speed classes for the respective devices. Within each of them, the minimum speed (in MB / sec) was recorded for reading or writing files.

SDHC memory cards, in general, coped withuser tasks. However, the needs of enthusiasts of digital electronics continued to grow. So the SDXC standard appeared, assuming the placement of files in a volume of up to 2 TB. Although, it should be noted, in an open sale such devices are rare and expensive (cheaper, as a rule, to buy an external hard drive).

The file system installed on the newestSD-cards - exFAT, which became the further development of FAT32. Among the significant advantages of the new standard proposed by Microsoft is the reduction in the intensity of data overwriting in a single sector.

How to choose the best SD card?

In some cases, the user canthe question is, what is better to buy - SDHC memory cards or, for example, SDXC devices? Everything depends, first of all, on the required capacity of the device. Another criterion is the compatibility of a computer or other device with the corresponding standard. The fact is that devices - cameras, PCs, card readers, old-style ones do not always support flash memory, released with the latest technology. At the same time, what is noteworthy, the support of those or other standards can depend not only on the hardware functions of the device, but also on the version of the firmware used on it. It can easily turn out that a simple software update will help the device - for example, the same camera, learn to recognize the newest SDHC memory cards or even SDXC.