Chapter 3 CD Emulator VCDEMU

3.1 Command specifications

command:

VCDEMU

Command name:

Virtual CD emulator

Form:

Body part of VCDEMU file name [-l log file name] [-f RTI file name]
[-j jumper setting position] [-u update information file]
[-ib input buffer size] [-vb transfer buffer size]

argument:

Body part of file name: Body part of the file to be emulated on CD

function:

• Performs CD emulation (CD pseudo playback operation).
  If no option is specified, the CD emulation target file is as follows.

  Disk image file: File name Body part .DSK
  Script file: File name Body part .SCR
  Disk configuration information file: File name Body part .RTI
  Log file: Do not create

• By specifying the "-u" option, CD emulation can be performed by partially updating the CD image.

• In real-time emulation mode, fast-forward scan playback / fast-rewind scan playback of CDDA tracks is possible. Control from the control screen of multiplayer etc.
  (Normal scan playback is not possible in direct DOS access mode)

• While transferring MODE1 and MODE2 data, you can intentionally generate a data transfer error by hitting the S key from the keyboard of a PC compatible machine for virtual CDs.

Example of use:

VCDEMU TST GAME

Option specification:

-l:

A log information file is created with the specified file name, and the log information is saved.

-f:

The disk configuration information file name becomes the specified file name.

-j:

Specify the jumper number of the VCD I / F board.
The value will be the same as the environment variable VCDIO.

-u:

Performs CD emulation by partially updating the CD image.
Specify the update information file output by VCDUTL.EXE.

-ib:

Specifies the size of the input buffer.
The value that can be specified is an integer in the range of 2 to 8, and a buffer of 4 Kbytes is secured for each unit.
By default, an input buffer of 32 Kbytes (8 by default) is reserved.

-vb:

Specifies the size of the transfer buffer.
The number that can be specified is an integer value in the range of 14 to 37, and specifies the number of transfer buffers to be secured. (One transfer buffer is sector size)
By default, 37 transfer buffers are reserved. (It may be less than this depending on the memory usage of the system)
The size of the allocated input buffer and the number of transfer buffers are displayed at the bottom right of the screen as shown below after the program is started.

Buffer: 02/07

Here, the numerator represents the size of the input buffer (in 4K units), and the denominator represents the number of transfer buffers. The number of transfer buffers displayed is an integer value divided by 2.

● About the number of tracks and indexes that can be emulated

If the number of tracks or the number of indexes in a track is very large, use the above two options to reduce the amount of buffer or adjust the balance between the input buffer and the transfer buffer to save memory and emulate correctly. You will be able to do it.

However, how to actually set it depends on the free space of the conventional memory of the PC compatible machine you are using and the length of the file name. As a reference example, the following is a guideline when the free space of conventional memory is 585KB.

Total index number	-ib setting value	-vb setting value
2000	No settings required	No settings required
3000	No settings required	No settings required
4000	No settings required	No settings required
4500	Four	No settings required
5000	2	14

If you start the emulator program without setting the above options, the total number of tracks that can be emulated x the number of indexes is about 4000, and with the minimum setting of -ib 2 -vb 14, it is about 5000. This is a calculation that can emulate a disk image of up to about 40 indexes for each of up to 99 tracks by default, and up to about 50 indexes for each with the minimum buffer set.
The CD builder can create a disk image with a maximum of 99 tracks x 99 indexes = about 10000 track indexes, but the track indexes that can be emulated using the emulator program VCDEMU.EXE are limited to about 5000. Will be.

● VCDEMU error message

The error messages displayed by the virtual CD emulator and their meanings are shown below. ** means any number and **** means any string. The error message is displayed in red on the screen.

Cannot allocate read buffer

The buffer for reading the data file could not be secured.

Cannot find RTI file ****

The specified RTI file was not found

Cannot find the beggining of TOC info.

The keyword indicating the start of TOC information was not found in the specified RTI file.

Cannot find the beggining of REL info.

The keyword indicating the start of the correlation table information was not found in the specified RTI file.

Cannot allocate memory for ISO9660 file info.

Unable to secure memory to store ISO9660 file information

Cannot allocate memory for DOS file info.

Unable to secure memory for storing DOS file information

Illegal relation table

There is an inconsistency in the correlation table information

Cannot open log file = ****

The specified log file cannot be opened

Cannot find DOS file in track **

The DOS file corresponding to the specified address was not found in track **

No File at this LSA **

The DOS file corresponding to the specified absolute time was not found

File <****> cannot be opened

DOS file **** could not be opened

Illegal offset

An address that exceeds the size of the disk image file was specified in real-time emulation

Not read

Data reading from DOS file failed

Cannot read data from disk image file

Data cannot be read correctly from the disk image file

TOC is not loaded

Attempted to display with TOC not loaded

REL table is not loaded

Attempted to display the correlation table information without being read