So I have this DOS/9x machine.

And the DOS hdd broke a couple weeks ago, with no hope of a replacement.
So now it came to me that maybe I could use dual boot to have both DOS and the old Windows on the same drive.

Problem is, I don't know how to set that up, and running a search through the forum wasn't helpful either.

I was thinking of using Windows 95 OSR2.5 and either DOS 6.22 (last true DOS in existence) or DOS 7.1 (a bit better, including FAT-32 support).

So, how does one approach making a dual boot system?

If you install DOS first and Win95 later, you'll have the option 'Boot to previous Operating System' when you press F8 at boot. This will let you boot to DOS.
This is what used to work with Dos 6.22 at least... Dunno about 7.1

Same as what Reup said but isnt there a way to make the windows 95 sartup menu appear at every sart up if there is I would recommend that.

Well, you can configure the autoexec.bat and config.sys in such a way that a boot menu is displayed at boottime. Maybe that;s the route to go?

You need a bootloader (google it). The above suggestions are just tricks to get the Windows bootloader to always show up, but there's nothing stopping you from using one of the many free alternatives.

OK, I _think_ I found the solution - Google turned up a guide on the subject.

I'll see if I can make it work.

If it doesn't help, it's simple. Just install Ms-Dos, after it Windows 95. Windows 95 doesn't load automatically at startup (at least the usual Windows 95) if there's no line in autoexec.bat starting the .com file. So you can remove the win.com line from autoexec.bat and start Windows 95 from Dos through typing win at the prompt whenever you need it, and quit to Dos again through leaving Windows and starting in Dos-mode.
That's all about Ms-Dos 6.22 btw., not sure if Ms-Dos 7.1 would actually be even compatible with Windows 95 (might with OSR2.5 though, wasn't using that one). One advice about Ms-Dos 6.22 and Windows 95 (OSR) - when leaving from Windows to Dos and after again to Windows, don't type win the second or following times but instead exit to exit from current command.com running. That will save some conventional memory whenever you return to Dos again.

Had a setup like that a few years ago. Trying to start W95 from DOS6.22 resulted in a "this version of Windows is not compatibile with (blah,blah,blah)" message.

Of course, DOS 6.22 supports Windows 3.1 but not Windows 95 and later. I've been told (here's an explanation in Spanish--by SuperHuevis, scroll down) that it's like Reup says: define only one main partition for DOS and set it as active, then install DOS. Then install Windows, make the Windows installation program create a new partition --don't install it in the DOS partition-- and presto. By default you'll be able to boot DOS by pressing F8 as Reup said.

But there's another option to display a menu at the startup in order to choose which OS you want to load, instead of having Windows loaded by default unless you press F8. To enable it just go to Control Panel > System > Advanced Options.

<div class='quotetop'>QUOTE(the_fifth_horseman @ Jun 14 2006, 10:50 AM) [snapback]236689[/snapback]</div>Oh, but I forgot one important thing - when you install Windows 95 while you have Ms-Dos 6.22 or earlier installed, it replaces it with it's newer version of Ms-Dos, might be 7.1 then, don't remember. Otherwise it should work like I've written above.

<div class='quotetop'>QUOTE(the_fifth_horseman @ Jun 13 2006, 07:55 PM) [snapback]236508[/snapback]</div>Did you make it in the end?

Didn't have the time yet.