【Casio】 Σ-8700

The Casio &Simaga; Series steadily evolved into a true office-computer, with features like a real OS, a high-level language based application programming, multiple processes, communications capability and a CRT. The Σ-8700 "Kanji Office Computer", announced in 1979, integrated all of these features.

Kanji (Chinese character) processing placed a heavy load on CPUs and memory at the time, but high processing performance was achieved at a revolutionary low price.

Since memory was expensive at the time, conservation of memory used for displaying and printing kanji was a serious issue. Kanji font patterns were held in external memory, and moved into main memory each time kanji were displayed or printed, but this system was equipped with cache capability for controlling the replacement of patterns according to their frequency of use. Also, the CRT had to scan font patterns in the horizontal direction, and the dot printer in the vertical direction, so Casio developed a special memory unit which could be scanned in both directions (horizontal and vertical). Casio also applied for many patents relating to kanji processing.