Many people would like to try the new Windows 95 Preview being offered by Microsoft, but, quite sensibly, they fear that installing a new, known-to-be-buggy operating system might destabilize their existing Windows installation. One little-discussed advantage of DOS' primitive architecture is that you have the power to drastically reconfigure your machine with a few commands; let's use this power to let you try out Windows 95 without losing your Windows 3.11 safety blanket. I suggest the following procedure, which must be carried out from the DOS prompt (not from within Windows):
You may also get a character-mode menu saying that Windows 95 didn't boot successfully the last time it was started. If this happens, choose option "1" for "Normal." If Win95 still won't come up, choose option "3" for "Bootlog.txt." The latter file contains a description of your last successful boot configuration (a very nice feature--I wish other OSes did this). I don't recommend the "Safe" boot option, as this disconnects many Win95 drivers that will subsequently have to be reconnected. Use that option only if you've added something to a running Win95 configuration that caused it to become unable to start up.
In essence, System Commander provides you with a way to store and retrieve operating system files on the fly. When you boot a system with Commander installed, instead of the familiar "Starting..." sentence, you see a small graphical menu that lists all the configurations available. Each operating system you have installed will appear in the menu. When you select an OS, Commander does any required setup and then steps completely out of the way. After you have made your OS selection, Commander is gone! It consumes no memory and interferes in no way with the boot process. The OS that is starting can't even tell that it isn't the primary operating system on your machine.
Technically, System Commander creates "snapshots" of OS configurations. When you create a new Commander entry, it saves all the vital files required by the current operating system into directories on your hard disk. For example, for DOS, it saves the boot sector, IO.SYS, MSDOS.SYS, DBLSPACE.BIN, COMMAND.COM, AUTOEXEC.BAT, and CONFIG.SYS. From then on, when you select that configuration, the snapshot is restored to its proper place. Hidden and configuration files magically reappear. To the operating system, it looks like nothing ever happened.
Commander is even smart enough to save changes before they're lost. For example, suppose that you selected DOS the last time you booted, and then you adjusted your AUTOEXEC.BAT file. If you reboot and switch to Windows 95, Commander will automatically save the changed AUTOEXEC file to its snapshot directory before reconfiguring for Win95.
System Commander is a remarkable piece of software. I use it to keep Windows for Workgroups 3.11, Windows NT 3.5 (in an NTFS partition), Windows 95 Preview, plain DOS, and OS/2 Warp on the same machine. Switching OSes is as simple as rebooting the machine and picking the new configuration from the menu. It's great for going back to naked DOS to play games, for example. No more juggling files and boot disks!
Commander also protects OSes from each other. Some OS install programs try to find and scrag competing operating systems. OS/2 Warp, for example, trashes NT's BOOT.INI file if it can find it. System Commander protects these sensitive files, so you can recover from childish install programs.
You can get out of some very deep trouble with System Commander. Sometimes, these new-fangled 32-bit operating systems will acquire exotic Ebola-like diseases that leave them unable to boot. System Commander can always get you back to good old primitive DOS, from whence you can usually launch the character-mode tools needed to rescusitate your fancy protected-mode multithreaded multitasking patient.
In using System Commander, I've only noticed one quirk, which is more the fault of the PC architecture than the software: it's better to do a hard reset when changing OSes, rather than a <Ctrl> + <Alt> + <Delete>. If your computer has no reset button, power down. Otherwise, you may find that the new OS is unable to enter protected mode, apparently some hardware aftertaste of the old OS being in the way. If you want to restart into the same OS, you can just give the three-finger salute.
As befits a program targeted at the more technical sort of user, System Commander has endless options and commands. You can create new configurations based on old ones, add files to be snapshoted (WIN.INI and SYSTEM.INI, for example), boot from floppies other than A:, and so on. Most of these options won't be needed by the typical user, but it's nice to know that they are there just in case. For general use, you can just install Commander, answer a few questions, and be all set.
To return to our example of provisionally adding Win95 to a DOS/Windows system, you will see that I mentioned installing System Commander just before you begin altering your configuration files. This will snapshot your current, running configuration, tucking the vital files away in a safe place. You then have a known, stable configuration to return to if you ever get into trouble or need to get some real work done.
Installing Win95 will temporarily disable System Commander. To reactivate it, after Win95 is running, you will need to "Restart in MS-DOS Mode." From the Win95 DOS prompt, change to the System Commander directory and type SCIN <Enter>. This loads the System Commander utility menu. Choose "Reinstall/Update." This reactivates System Commander. Then quit the SCIN utility and type EXIT <Enter> at the Win95 DOS prompt. This should load Windows 95. The next time you reboot, System Commander will allow you to snapshot your Windows 95 configuration, and you're in business.
The same procedure should work any time you want to install a new operating system: just get to DOS somehow and run the SCIN utility to "wake up" Commander. Then you can snapshot each new OS in turn.
Commander can also handle setups where the "active partition" must be changed before booting. This situation is most likely to arise if you are using an exotic operating system like Linux that can't at least start the boot process from a DOS partition. Certain OS/2 and NT installations may also need this feature; its use is described in detail in the documentation.
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