Editing DOS/V (section)

=={{anchor|$FONT.SYS|$DISP.SYS|$IAS.SYS|$PRN.SYS|$PRNUSER.SYS|$PRNESCP.SYS|FONTX|FONTX2|DSPXVBE}}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&nbsp;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 method]]s 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.
* $FONT.SYS – Font driver<ref name="$FONT.SYS"/><ref name="Myers_1995_DOSV"/><ref name="ChaN_2012_FONTX"/>
* $DISP.SYS – Display driver<ref name="$DISP.SYS"/><ref name="Myers_1995_DOSV"/><ref name="ChaN_2012_FONTX"/>
* $IAS.SYS – Input assist subsystem (IAS) with front end processor (FEP) support driver<ref name="Myers_1995_DOSV"/>
* $PRN.SYS – Printer driver<ref name="Myers_1995_DOSV"/>
* $PRNUSER.SYS – Printer driver<ref name="Myers_1995_DOSV"/>
* $PRNESCP.SYS – Printer driver for [[Epson]] [[ESC/P J84]]<ref name="Myers_1995_DOSV"/>