Being prepared for disaster / Windows 95 System Files
Windows 95 has a pair of programs which ships on the Windows 95 cd rom that will do the backing up and restoring of systems files for you. They are called eru.exe and erd.exe and are located in the \other\misc\eru folder on the Windows 95 cd rom. From the filename I would assume that eru.exe is short for "Emergency Recovery Utility".
You may use them from the cd rom drive, but if you copy them to the windows directory and create a shortcut to eru.exe it will be easier to find them later. The files you need to copy are eru.exe, erd.e_e, and eru.inf. The eru.inf file is used to tell eru.exe which files to backup for you. By default it will backup the following list of files:
When you run the utility the first time, it will decompress erd.exe from the erd.e_e file and will put a copy of it in the destination of the backup files. You will have the choice of backing up to floppy disks or a folder on one of your hard drives.
Run it after each new install of a program, after you are sure that everything is still working correctly. If a new install causes a problem, you are prepared to restore the system to it's last known good configuration with erd.exe.
To restore the system files to their previous good state, you will need to reboot your computer into DOS mode. To do this, select START, SHUTDOWN, Restart in MS-DOS mode. If you aren't able to get windows 95 to run when you need to restore the system files, boot your computer, and when you see the "starting windows 95" message on the screen quickly hit the F8 key, and select the "Safe Mode Command Prompt Only" option from the boot up menu.
Now change to the folder where you saved the backup, and run erd.exe. [if you have access to that hard drive, if not, grab the floppy disks you made with eru.exe, you do have some don't you?]
If you're not familiar with DOS commands which you will need to run the recovery, here is the list of them for each situation I've mentioned in the last paragraph.
| From a folder on the hard drive | From a floppy disk |
| cd c:\erdfolder
erd |
A:
erd |
The first command assumes that you saved the backup in a folder on your C drive named "erdfolder". It is the change directory command [cd]. Just replace the drive and folder names with the proper ones for your backup. If your folder is a subfolder of another you will need to include the parent folder's name as well. Also if you've used long file names for the folders with spaces in the names, you'll have to add quotes around the path name in the command. Here's an example with a nested foldername with spaces on the D drive: cd "d:\A long folder name\erdfolder" The second command is of course the emergency recovery program itself. Make sure you hit enter after typing each of the above commands as dos won't do anything until you do. 8-) |
For this scenario you need to change drives to the A drive first. To do that just type A: and hit enter. Then issue the erd command as in the other example at the left. You can shortcut this a bit by just typing the following: A:\erd then hitting enter. |
Now lets have a look at that list of files again. I'll describe each of them a bit for you.
|
|
Default Location |
|
| config.sys | c:\ | This file loads device drivers needed for your hardware devices. It's not used as much under windows 95 as it used to be with dos or windows 3. There may be only a few lines of text in it. |
| autoexec.bat | c:\ | This file is used to load memory resident programs and run programs which are only ran once at boot up time. For more information of these first 5 files see DOS System Files |
| io.sys | c:\ | This is one of the dos files which is needed for system input/output operations. |
| msdos.sys | c:\ | This file has changed with windows 95. It used to be a binary program file, but is now a text file which has a few options which can be set similar to an ini file. |
| command.com | c:\ | The command interpreter for dos. This is the file that actually does the work for you when you're at the dos prompt typing those old dos commands like cd and dir. 8-) |
| user.dat | c:\windows | This file is part of the registry hive. It contains settings particular to the user or users on your system. |
| system.dat | c:\windows | This is the main hive of the registry file. It keeps settings for your software and hardware. If it gets corrupted it's likely your system won't work correctly, if at all. |
| win.ini | c:\windows | This file keeps settings on your fonts, file associations, and some device drivers and hardware devices which aren't kept in the registry. Some third party software also uses this file to save settings to instead of saving them in the registry. |
| system.ini | c:\windows | This file keeps system specific settings for things like your sound board, display, keyboard, and specifies the location of the password list files used by windows 95 to log on users. |
| protocol.ini | c:\windows | This file is used for network specific settings on your system if you're on a LAN or WAN. |
If there are other files you would like to add to your backup set you can edit the eru.inf file in a text editor to add them. These files must be files which live in the c:\ or c:\windows folders, and must be added to the proper section of the eru.inf file.
Make sure you save the file in plain text. Here are the contents of the default eru.inf file, which Microsoft provides on your operating system install disc. The comments in the file explain more about how to add files to the back up set.
; ERU.INF
Used by ERU.EXE -- Protected mode application, and must be in the Windows directory.
This ini file lists the files we wish to backup with ERU. The section headings point to the places that the ERU program will look to find these files.
Part of the job of this file is the creation of an order of precedence for backing up files when limited disk space is available.
The higher the filename appears in this file, the higher the precedence that the ERU program will give the file.
In this way it is possible to modify file "importance" without any changes having to be made to the application.
To facilitate this, section headings may appear more than once.
The [ROOT] section specifies that the file exists in the root directory of the boot drive. If the files don't exist (as in a diskless workstation) the program will continue.
The [WINDOWS] section specifies that the files can be found in the windows directory. If the files don't exist (just not there) the program will continue.
As noted above this second occurrence of [ROOT] is used to establish an hierarchy of files for a limited disk space situation. These files will be given the lowest importance.