NEC PC-9800 Quick Guide

DOS

Japanese NEC DOS

NEC DOS is a OEM license of Microsoft MS-DOS. Applications which rely on standard DOS function calls such as int21 and int2F will in general execute successfully on the PC-9800 platform.

Most US MS-DOS commands are available under NEC-DOS, but some have different names. NEC DOS provides FC (File Compare) rather than COMP. In addition, a useful CUSTOM command assists the user in managing the CONFIG.SYS file. The differences between NEC DOS and US MS-DOS are described in "PC-9800 Series MS-DOS 3.3"3.

Diskette Drive Letters

The first type of the booted device becomes A:. Therefore, if the user boots from a hard disk, the first hard disk partition is A:, the second hard disk partition is B:, the first floppy is C:, and so on. You can easily use the DOS IOCTL calls to determine a drive type. Under Windows, use the GetDriveType() function. Also of interest is the DOS int21 call which will give you the current boot drive.

FEP (Front End Processor)

In order to enter Japanese Kanji character text, the precise character must be selected from the thousands that are available. Roman letters (A, B, C) and single byte Kana characters may be selected directly from the keyboard. In general, additional software will be installed as a TSR which intercepts keyboard operations and provides a user interface so that the user may select the intended character. Many third parties have developed FEP utilities for the PC-9800 which provide features such as phrase conversion and dictionaries. Originally, FEP products were typically bundled with an application such as an editor or spreadsheet.

NECAI	NEC Kanji FEP (bundled with NEC MS-DOS)
ATOK	Just Systems (bundled with Ichitarou, most popular Japanese Word Processor)
VJE	Word for Windows, VJE-Pen, many others
WXII	Microsoft Windows
Matsutake	Matsu, Lotus 1-2-3 (DOS mode only)

FONT.SYS

Many types of applications need access to font bitmaps. In addition, flexible scaling is often a requirement for WYSIWYG applications and to optimize output images. CG Window hardware can be used for font bitmap access, however, only the sizes provided in ROM are available.

In order to provide access to variable sized font bitmaps, NEC included the FONT.SYS driver beginning with NEC DOS 5.0. This driver provides the application with function calls to generate a font bitmap for any size character, specifying both the border size and face size of the bitmap.

AVGDRV.SYS and AVSDRV.SYS

The PC-9821 platform supports the Advanced Graphics Driver and Advanced Sound Driver. In addition to the existing PC-9801-23 sound board, most PC-9821 systems include a PCM sound system.

GRAPH.SYS

Starting with NEC DOS 3.3, the GRAPH.SYS driver is included. This driver provides a hardware independent graphic function layer for applications. Applications using GRAPH.SYS do not write directly to hardware. Rather, they make calls to the GRAPH.SYS driver which will realize the display. This is similar to a BIOS layer for graphics mode applications.

For new PC-9821 based applications, use these advanced graphics and sound drivers.