Microsoft MS-DOS CD-ROM Extensions
Installation Instructions
29 March 1989

This document explains how to install MSCDEX.EXE and associated CD-ROM device drivers without using the SETUP program.

If you have a floppy based system, create a bootable MS-DOS floppy disk you would like to copy MSCDEX to. This can be done by connecting to drive A, inserting your normal bootable floppy (the disk you normally use to start your computer) into drive A and a blank unformatted disk in drive B and running diskcopy.

Next, copy the contents of the MSCDEX floppy onto your bootable floppy. Insert the MSCDEX floppy into drive A and leave the bootable floppy that was just created in drive B. Type the following to copy the files:

	COPY A:\*.* B:\

If there is not enough space to copy the files, you will have to make room on your disk by deleting unnecessary files and then repeating the above procedure.

If you have a hard-disk based system (usually drive C), insert the MSCDEX floppy disk into drive A and type:

	COPY A:\*.* C:\

Once this has been accomplished, the files CONFIG.SYS and AUTOEXEC.BAT need to be modified to complete the installation of MSCDEX.

To do this, connect to your bootable drive and edit the file CONFIG.SYS. If the CONFIG.SYS file is not there, you will have to create it. First, scan the contents of CONFIG.SYS to see if there is a LASTDRIVE command line in it. This line will either have to be modified or added to read:

	LASTDRIVE=Z

This lets MS-DOS know that it will have to allocate enough drive records to account for the additional CD-ROM drive letters. It's a good idea to have this line as the first entry in the CONFIG.SYS file. The last drive in fact only needs to be the largest drive letter that will be used on the system. For example, a PC with 2 floppy drives (drives A and B), a hard disk (drive C), and two CD-ROM drives (drives D and E) would only need LASTDRIVE=E. A PC that is on a network though will typically allocate more drive records than are used so that new network drives can be added after booting.

Next, add entries for each device driver that is going to be installed. The entry will read:

	DEVICE=<driver.sys> /D:<device_name> <driver specific switches> 

The name of the device driver, driver.sys, will be replaced by the full path name of the device driver that is being installed. This will include the drive letter of the bootable drive followed by the pathname of the device driver if the device driver was installed in a subdirectory. If the above directions were followed, then the device driver will be located in the root directory. For example, on a hard disk system that boots off drive C, a sample entry might read:

	DEVICE=C:\DRIVER.SYS /D:MSCD001

For the Hitachi driver, this should read:

	DEVICE=C:\HITACHI.SYS /N:1 /D:MSCD001

The next parameter /D:device_name is the name MSCDEX will use to find the device driver. When the device driver is installed, this name is what will be used by the device driver to name itself. Every installed device driver must have a unique name. In addition, due to the way that MS-DOS handles file opening, if there is a device driver with the same name as a file in a directory, then a file open call on that name will open a handle to the device driver and not to the file. For this reason, you will want to chose a device_name that will not likely be chosen as a file name later. We recommend using names of "MSCDXXX" where XXX is three digits. This will allow CD-ROM device driver entries to be located in config.sys by the setup program at a later date.

The remaining fields for driver specific switches are device driver dependent and will be specified in the documentation that describes that particular device driver.

Next, AUTOEXEC.BAT needs to be edited to include an entry to invoke MSCDEX each time the system is booted. If your PC is also on a network, the network software must be installed before MSCDEX. Otherwise the network will not install, since MSCDEX will not allow the network to be installed second.

If your AUTOEXEC.BAT file starts up a 'shell' program such as DOSSHELL or Windows, or runs another BAT file, you will need to make sure the line that starts MSCDEX is ahead of the line that starts your 'shell' or BAT file. Otherwise MSCDEX will not have a chance to start the CD-ROM drives once your 'shell' or BAT file begins.

A sample entry in AUTOEXEC.BAT to install MSCDEX would be:

C:\MSCDEX.EXE /D:MSCD000 /D:MSCD001 /M:20 /V /E

Include the drive letter of the bootable disk and the full pathname for MSCDEX. If the above directions were followed, MSCDEX will be in the root directory. Each device driver will have a device_name listed on the command line to MSCDEX following '/D:'. MSCDEX will use this parameter to locate each of the device drivers and this name must be the identical to each of the device_name fields used for each device entry in CONFIG.SYS.

The /M:<value> switch determines how many sector buffers MSCDEX will allocate when it installs itself. The larger this value is, the more sector cache entries are available and the less MSCDEX will have to read directly from the CD-ROM drive. It is especially important that there be enough entries to cache the path table, and the more entries available for directory sectors, the less MSCDEX will have to reread the directory files. Typically, each drive should have at a minimum about 4-5 buffers per drive but the larger this value is, the better the performance will be.

Both the CD-ROM device driver and MSCDEX both require small amounts of additional memory to run which should not cause any problems. But if you do find after you have installed MSCDEX that some programs no longer run because there is not enough memory, you may want to review your CONFIG.SYS and AUTOEXEC.BAT files to locate other entries that consume memory such as GRAPHICS or FASTOPEN that you may not require and can remove.

There is an additional parameter /E which will tell MSCDEX to use expanded memory if it is installed and available. The verbose switch /V will ask MSCDEX to print additional information about memory usage during initialization.

For software that requires that the CD-ROM drive be on a particular drive letter, you can use the /L:<drive letter> switch. The SETUP program will not set this switch so you will have to edit your autoexec.bat file if this switch is needed. For example, the following will begin assigning CD-ROM drives at drive letter L:

MSCDEX /D:MSCD001 /L:L

There are also two other switches: /K and /S. /K causes MSCDEX to look for a Supplementary Volume Descriptor that identifies a shift-JIS Kanji volume for Japanese and /S specifies that MSCDEX patch DOS to allow CD-ROM drives to be shared on MS-NET based servers.
MSCDEX - Microsoft MS-DOS CD-ROM Extensions Version 2.20

Installation Instructions - Copyright (C) Microsoft Corp. 1989. All rights reserved - page {page|1}

Installation Instructions - Copyright (C) Microsoft Corp. 1989. All rights reserved - page {page|1}