Apple Macintosh LC 630 DOS - Manual (Page 56)

CD-ROM discs and drives
You can use DOS and Windows CD-ROM discs in Apple CD-ROM drives.
To eject a CD-ROM disc in the PC environment, press x-Y. If the CD-ROM
disc cannot be ejected (because a file is in use or the CD-ROM disc is being
shared), the Macintosh beeps.
You can listen to audio CDs in either the PC environment or Mac OS, but you
cannot control them from both environments at the same time. For example, if
you began listening to an audio CD while working in the PC environment
and then switched to the Mac OS, you would have to return to the PC
environment in order to adjust the CD’s volume.
Playing an audio CD in Windows while running low-level media tools, such
as PC Tools or Microsoft Anti-Virus, may cause your system to crash. It is
best to reduce computer activity to a minimum while using such tools.
You cannot use more than one CD-ROM drive at a time in the PC
environment.
The PC sets up a drive letter (E) for a CD-ROM drive even if no drive is
connected. If no CD-ROM drive is connected to your system, you can use this
drive letter and free some memory by editing the AUTOEXEC.BAT and
CONFIG.SYS files.
In the AUTOEXEC.BAT file, add REM to the beginning of the line
LH C:\DOS\MSCDEX /D:CDDRVR /L:E
In the CONFIG.SYS file, add REM to the beginning of the line
DEVICE=C:\Apple\CDROM.SYS /D:CDDRVR
Prefacing these commands with REM makes DOS ignore them.
45 Operating in the PC Environment