Non-volatile solid-state memory that offers fast write and read times, but not as fast as DRAM, and can withstand considerable shock (G-force). Generally known as CF (compact flash), it is popular storage on portable / hand-held devices including professional and consumer video and stills cameras. Also when packaged in a memory card or a ‘pen drive’ case, it is enormously durable, withstanding intense pressure, extremes of temperature and even water immersion.
There are many technologies applied to make CF cards and its development continues apace with increasing capacities: 2005 – 1GB, 2GB; 2006 – 4GB, 64GB, and later 128GB and 256GB (2010). Transfer rates are quoted in different ways. With the ‘x’ rating, multiples of the standard Compact Disk data transfer rate of 150kB/s (= x1) are shown. So a x600 memory card offers up to 90 MB/s – fast enough to record only slightly compressed HD. ‘Class’ is another rating, so Class 6 indicates a (minimum) transfer rate of 6 MB/s. UHS (Ultra High Speed – ) is a third speed rating system with UHS-1 supporting up to 104 MB/s.
In the professional market manufacturers tend to offer memory cards that bundle several CF chips to provide a particular high performance to match the needs of their products – typically high-end cameras and computers. Currently these offer in the order of up to a few TB storage. In 2010 Sandisk, Sony, and Nikon proposed developing a new 500 MB/s memory card with over 2TB capacity.
Flash memory is increasingly used to replace computer hard drives – with solid-state drives (SSD) – providing much higher speed of data transfers. Current offerings are up to 1 TB with faster read and write rates than disks, low power consumption and high robustness, these have many advantages. Cost prohibits a large-scale defection from the traditional rotating mass PC storage device – at the moment.