This is a format created in the Acorn Draw program, intended for image visualization by using vector lines. It’s used for storing information in the publishing business (brochures, logotypes, etc.). The main advantage is it’s high quality source images when printing. It’s been in use since 1980.
is a format developed for the Shanda Bambook e-books, and is exclusive to those devices. Certain e-books produced by other companies can also view documents of this type. Shanda released its latest device in 2011 which is why this format is not widely used at present.