During the startup process, the computer checks all available SCSI
volumes, including the CD-ROM drive. If the CD-ROM disc contains the ".AppleCD" driver, it will be loaded and used by the computer to access the CD-ROM drive in lieu of the CD-ROM software that would have loaded if the extensions were not off. This works fine for most purposes.
However, some newer CD-ROM drives need slightly different information than those that shipped with earlier Power Macintosh computers to eject a CD-ROM disc. For example, your computer may have a quadruple-speed (4x) CD-ROM drive, but the system software CD-ROM disc you inserted may load a CD-ROM driver for a double-speed (2x) CD-ROM drive.
This causes the -50 error, which indicates that the internal parameters being used to eject the CD are incorrect. You should be able to eject the CD-ROM disc if you restart the computer again, and press the eject button on the CD-ROM drive before the computer displays "Welcome to Macintosh".
Article Change History:
28 May 1996 - Updated technical information.