SDHC card
Short for Secure Digital High Capacity card, the SDHC card is an improved version of the standard SD card with a storage capacity up to 32 GB. Because SDHC works differently then a standard SD card, it is not backward compatible with legacy SD devices.
The 3 versions of the SDHC card, along with their physical dimensions, are shown below.
· SDHC - 32mm x 24mm x 2.1mm.
· Mini SDHC - 21.5mm x 20mm x 1.4mm.
· Micro SDHC - 15mm x 11mm x 1.0mm.
The SD Association created three speed classes that help identify the write speed for SDHC cards. This Class Speed Rating is shown on the card as a 2, 4, or 6 surrounded by a large "C." In the above picture, you can see the 2 surrounded by a C on the first SDHC card. Below, is a break down of these speeds.
· Class 2 = 2 MB a second.
· Class 4 = 4 MB a second.
· Class 6 = 6 MB a second.
Backward Compatible
Sometimes called downward compatible, backward compatible is a term used to describe software or hardware that is compatible with previous versions of software or operating systems. Without backward compatibility, a program that works with one computer processor or operating system would stop working with the new version. For example, almost all software running on a Windows 7 computer would work after you upgrade to Windows 10.
Most developers and manufacturers try to keep their products backward compatible and have been doing so since the Intel 80286 (first backward compatible processor) was released in 1982. However, a technology manufacturer may choose to sacrifice backward compatibility when releasing a new version of an older technology. For example, when Microsoft released the Xbox One gaming console which succeeded the Xbox 360, the Xbox One was initially not backward-compatible with any of the Xbox 360's games.
You should be using "backward compatible" or "backward compatibility" in all your writing. In other words, it should always be "backward" and not "backwards" when used in this context.