for both DOS/V and PC-98. The DOS/V contributed the dawn of IBM PC clones in Japan, yet PC-98 had kept 50% of market share until 1996. It was turned round by the release of Windows 95. Drivers Three device drivers enable DBCS code page support in DOS on IBM PC compatibles with VGA; the font driver, the display driver and the input assisted subsystem driver. The font driver loads a complete set of the glyphs from a font file into the extended memory. The display driver sets the 640×480 graphics mode on the VGA, and allocates about 20 KB of the conventional memory for text, called the simulated video buffer. A DOS/V program writes the codes of the characters to the simulated video buffer through DOS output functions, or writes them directly and calls driver's function to refresh the screen. The display driver copies the font bitmap data from the extended memory to the actual video memory, corresponding to the simulated video buffer. The input assisted subsystem driver communicates with optional input methods and enables the text editing in the on-the-spot or below-the-spot styles. Without installing these drivers, the DOS/V is equivalent to the generic MS-DOS without DBCS code page support. $FONT.SYS – Font driver $DISP.SYS – Display driver $IAS.SYS – Input assist subsystem (IAS) with front end processor (FEP) support driver $PRN.SYS – Printer driver $PRNUSER.SYS – Printer driver $PRNESCP.SYS – Printer driver for Epson ESC/P J84 Versions In 1988, IBM Japan released a new model of the PS/55 which was based on the PS/2 with Japanese language support. It is equipped with a proprietary video card, the Display Adapter, which has a high resolution text mode and a Japanese character set stored in a ROM on the card. It supports Japanese DOS K3.3, PC DOS 3.3 (English) and OS/2. IBM DOS J4.0 was released in 1989. It combines Japanese DOS and PC DOS, which runs Japanese DOS as the Japanese mode (PS/55 mode) and PC DOS as the English mode (PS/2 mode). Although it had two separated modes that needed a reboot to switch between them, IBM Japan called it bilingual. This version requires the PS/55 display adapter. The first version of DOS/V, IBM DOS J4.0/V (J4.05/V), was released in the end of 1990. The word 'DOS/V' was quickly known to Japanese computer industry, but the DOS/V itself didn't spread quickly. As of 1991, some small companies sold