Hello Dr Bluescreen
Here's a document on the subject that I produced many moons ago.
To access CD-drive from :
A. “Command Prompt Only”
1. Reboot > hold ctrl ( in win98 ), or F8 ( in win 95 ),
Or [if “drive overlay software” is used to overcome outdated BIOS and gain use of large hard drive ] F8 ( in win 98 ).
2. Choose “Command Prompt Only” from the boot menu which appears.
3. At “C:\>” type “dosstart.bat” <enter> ( without the quotation marks )
[ This file is located at C:\windows\dosstart.bat , open it in wordpad if you’re curious.]
You now have DOS access to your CD-drive .
B. “Safe Mode”
1. Reboot ( as 1 above ).
2. As 2 above.
3. As 3 above.
4. At “C:\>” type “cd\windows” <enter>.
5. At “c:\windows>” type “win /d:m”<enter>.
The P.C. will now boot into “Safe mode with CD-drive access”.
c. “MS-DOS mode” ( This is designed to give access to CD-drives )
( You can only get to this from within windows. )
1. Boot into windows > “shut down” > “re-start in MS-DOS mode”.
The P.C. reboots and you have MS-DOS access to your CD-drive.
To create a win98 “startup disk” from “command prompt only”.
1. Go to “Command prompt only”. ( as A, 1, 2, above. )
2. Insert a blank, formatted floppy in “drive A”.
3. At “c:\>” type the following commands, pressing <enter> after each.
4. Follow the instructions on screen.
Notes on accessing CD-drives from DOS and Safe Mode
1. Why would you want to do it anyway?
A. These are the safest (though slightly slower) ways of running (windows?) “setup.exe”, to install or reinstall or confirm an installation and eliminate corrupted or missing (windows?) files (you may have other reasons).
1. If windows was booting you could fall back to “MS-DOS mode” (for a safer setup) or indeed
any of the other methods.
2. If windows is not booting fall back to “Safe mode with CD-drive access”.
3 If not booting to “safe mode” fall back to “command prompt only” with CD-drive access.
4. You could access the CD-drive from a DOS prompt using the win98 “startup disk”
[If the generic drivers on the disk don't work with your drive you will need to copy your drive's own drivers to the floppy as per Microsoft Article ID:Q190303]
But what if you had forgotten to make one, or lost it, and windows was failing to boot so you couldn’t make one ( see the method above ); or the drivers on the disk were incompatible with your CD drive? Using the “startup disk” is always an option at any time but the other methods are available even when it is not.
5. If you decide to run “setup.exe” the easy way (from within windows) microsoft recommends
That you use “ctrl + alt +del” repeatedly to close all but “Explorer.exe” and “systray.exe” in the “close program” window, since one or more programs may interfere with the activities of “setup.exe”.
Notes on C. “MS-DOS mode” (above)
1. When the P.C. reboots into MS-DOS mode, “config.sys” is read and a command line within it
Loads the “real mode” (16-bit) device driver supplied by the CD-drive OEM (Original Equipment Manufacturer). This is only true, of course, if the driver has been installed!
Next, “autoexec.bat” is read and a command line would load the windows driver “mscdex.exe”, this being the other partner, which links windows to the OEM CD-drive driver.
But wait! If windows 98 was installed, or indeed reinstalled, after this was in place it could, during installation, detect that your P.C. had a CD-drive for which it had a “safe mode” (32 bit) driver and would , in those circumstances, disable the use of “mscdex.exe” in windows by placing the “rem” command at the beginning of this command line. This tells windows to treat this line as a “remark” and ignore it.
However……so as to retain the use of these drivers in DOS mode (they are essential in DOS if CD-drive functionality is to be provided), a new file is created called “dosstart.bat” and an exact copy of the REM’d line is placed in it and this file is read during the “restart in MS-DOS mode” . By this neat little trick , “protected mode” drivers are operational in windows and “real mode” drivers are used in MS-DOS mode.
This fact is used at the “command prompt only” to activate the line in “dosstart.bat” to supplement “config.sys” and “autoexec.bat” and thus load the CD-drive driver pair. Windows safe mode can then be loaded ( if desired ) using the “win /d:m” command at the “c:\windows>” prompt. So you can pick whether to use CD-drive access from the one or the other. NEAT !
Another [backup] way of installing Windows is to copy the installation files from the CD to some partition other than c: [or another physical drive]in a folder name of your choosing [like Win98tmp]and using DOS commands to run the Setup.exe file. Windows will then install from the one Drive/Partition to the c: Drive
Apoint to watch when you try to access the CD-Drive is that you have a disk in the drive, and you are also using the correct drive letter. [The setting up of the RAMDrive sets the letters back by one
The lettering sequence is caried out automatically and in a very specific sequence [and I'm not an expert on this but here goes]
The HDD jumpered as Primary master must be formatted with a primary [Bootable] Partition and this is named "C". The Primary Slave [HDD ?] is named "D"[if you have your CD-Drive in this position it is called "D"]. The "logical Drives" in the "Extended Partition" on the Primary Master are given the next letters [E,F,G etc]. The Secondary Master [CD-Drive?]is then "Lettered", then the Secondary Slave.
As you can see, if you try to access the wrong drive letter you will fail.
Of course, using a Startup Disk eliminates this problem because it detects and identifies the CD-Drives, but it's generic drivers may not work your drive.