CHAPTER 13

Table 13.30 Continued
Switch Function
CD/DVD Software and Drivers Chapter 13 771
/L: Designates which DOS drive letter you want to assign to the drive. For example, /L:G
assigns the drive letter G: to your CD-ROM drive. Two conditions apply: First, you must not
have another drive assigned to that letter; second, your lastdrive= statement in your
CONFIG.SYS file must be equal to or greater than the drive letter you’re assigning.
LASTDRIVE=G would be fine; LASTDRIVE=F would cause an error if you attempt to assign
the CD-ROM drive to the G: drive with the /L: switch.
/M: Enables you to buffer the data from the CD-ROM drive. This is useful if you want faster initial
access to the drive’s directory. Buffers of 10 to 15 are more than enough for most uses.
Any more is overkill. Each buffer, however, is equal to 2KB of memory. So a /M:10 buffer
argument, for example, would take 20KB of memory. Note that this does not significantly
increase the overall performance of the drive, just DOS’s initial access to the drive and the
access of large data blocks when the drive is reading live-motion video files, for example.
You can’t turn a 400ms drive into a speed demon by adding a 200KB buffer. With no /M:
argument added, MSCDEX adds six buffers as a default. That may be fine for most PCs and
CD-ROM drives.
/E Loads the aforementioned buffers into DOS high memory, freeing up space in the
conventional 640KB. Early versions of MSCDEX—anything below version 2.1—do not load
into extended memory. You must have DOS 5.0 for this option to load.
/K Provides Kanji (Japanese) language support.
/S Enables you to share your CD-ROM drive on a peer-to-peer network, such as Windows for
Workgroups.
Note that Windows 9x uses a built-in CDFS driver that takes the place of MSCDEX. It is configured
through the Windows 9x Registry and requires no AUTOEXEC.BAT command. USB-based CD-ROM/
CD-R/CD-RW drives are also configured through the Windows 9x Registry and use no CONFIG.SYS or
AUTOEXEC.BAT commands.
CD-ROM Support in Windows 9x and Windows NT 4.0
As stated earlier, Windows 9x/Me and Windows NT/2000 include virtually all the drivers you will
need to run your optical drive, making the software installation automatic. Windows automatically
recognizes most ATAPIIDE earlier, Windows 9x/Me and Windows NT/2000 include virtually all the
drivers you will need to run your optical drive, making the software installation automatic. Windows
automatically recognizes most ATAPI drives, and with the addition of the appropriate drive-specific
ASPI driver, most SCSI drives as well.
There are several new capabilities with CDs and DVDs in Windows 9x/NT. The most dramatic is the
Autoplay feature, which is available on Windows 95/98 and some versions of Windows NT 4.0.
Autoplay is a feature integrated into Windows 9x that enables you to simply insert a disc into the
drive, and Windows will automatically run it without any user intervention. It also detects whether
that particular disc has already been installed on your system, and if not, automatically starts the
install program. If the disc has already been installed, it starts the application program on the disc.
The Autoplay feature is simple. When you insert a disc, Windows 9x automatically spins it and looks
for a file called AUTORUN.INF. If this file exists, Windows 9x opens it and follows the instructions contained
within. As you can see, this Autoplay feature works only on discs that have this file. Most software
companies are now shipping CD-ROM and DVD-ROM titles that incorporate the Autoplay
feature.