Support for CD-ROM Changers in Windows 95

• Microsoft Windows 95
• Microsoft Windows NT Server version 4.0
• Microsoft Windows NT Workstation version 4.0

SUMMARY

Microsoft Windows 95 supports the use of CD-ROM changers (also known as jukeboxes). Although the protected-mode CD-ROM drivers should allow you access to your CD-ROM changer, the real-mode CD-ROM drivers are likely to be more reliable.

MORE INFORMATION

The reason real-mode drivers may be more reliable is because the CD-ROM File System (CDFS) virtual device drivers (VxDs), such as Volume Tracker (VOLTRACK.VXD), need to know whether each CD is accessible at boot. Each time a shell operation queries the system (for example, whenever you run My Computer or Explorer), you experience a time delay. The length of this delay depends on the number of CDs in the changer.

To work around this delay, you can set up a large CD-ROM cache. This is helpful only if you have large amounts of physical RAM. Please note that your cache may be used by something else, thus causing the CD shuffling to be slow anyway. Another workaround is to use the real-mode drivers.

If you are uncertain whether your CD-ROM is using real- or protected-mode drivers, check the Properties of the CD-ROM drive through My Computer. If the Capacity value of the CD is 127 MB, you are probably using real-mode drivers. If the Capacity value is an actual value (such as 370.9 MB), you are probably using protected-mode drivers. The Microsoft CD-ROM Extensions (MSCDEX) driver shows a capacity of 127 MB while in Windows regardless of the actual capacity. Also, if you are loading a CD-ROM driver in your CONFIG.SYS file and MSCDEX in your AUTOEXEC.BAT file, you are using real- mode drivers.

NOTE: Another issue experienced with CD-ROM changers is that a drive letter is used for each CD. This limits the number of network drives you can have.