Chapter 1 Overview

1.1 Virtual CD emulator overview

Virtual CD emulator is an MS-DOS program that runs on a PC compatible machine.
Receives the CD access command sent from the target box by communication with the VCD I / F board inserted in the expansion slot of the PC compatible machine, accesses the MS-DOS file according to the command, and accesses the CD drive Is realized in a pseudo manner.

The main functions of the virtual CD emulator are as follows.

 
 
 Pseudo CD playback emulation of MS-DOS file data
 GAME-CD disc image generation
 Pseudo CD playback emulation of GAME-CD disc image
 Partial update playback emulation of disk image
 Generate TOC file for Ito Once CD creation
 Error simulation
 Recording and displaying communication contents between VCD emulator and CD block
-Received commands and status
-Processing result (error) message
-Selection of communication content display (only errors, all)
 TOC information display
 Display correlation information
-Positional relationship between MS-DOS file and generated CD disk image 
 

The following three types of MS-DOS file formats can be accessed.

An MS-DOS file that contains data before creating a CD image. (Hereafter referred to simply as “data file”)
The data file is determined according to the access position of the CD access instruction received by the virtual CD emulator from the VCD I / F board, edited so that it becomes a CD image, and sent to the VCD I / F board.
As a result, the target box can receive data in the same form as entered from the CD drive. This emulation is called “direct DOS file access”.
In this case, if the data for creating the CD image is prepared, emulation can be started with simple preprocessing, but the data is sent while editing, so playback is performed at the same timing as the input from the original CD drive. You can not. Therefore, the channel interleave function (described later) that requires complex disk access cannot be supported in this operation mode. Similarly, the MPEG function cannot be supported.