I wrote an blog post about this very topic not too long ago:

http://retropcbuilder.blogspot.ca/2016/11/dua … -95-follow.html

My method uses GRUB4DOS... others have other (equally valid) boot managers they prefer to use. It's really what you're comfortable with. Do you need to use a Dynamic Disk Overlay? If you do not, then your options are wide open. If you do, GRUB4DOS is the only one that I've personally tried that works well in that configuration.

I read over your blog post'. Would you happen to have a step by step guide for this without all the explanations and all, which you did a great job of by the way? I think that type of tutorial would be beneficial to a lot of people looking to do this!

fsmith2003 wrote:

How can this be done where DOS uses its 8gb of space

FAT16 DOS partitions are limited to 2 GB each. (I guess you could have a 2 GB primary partition and then an extended partition with a bunch of 2 GB partitions, but that would get weird pretty fast.)

This is really two separate questions.

1. How to dual-boot DOS 6.22 and Win98 SE
   
   This can be done without any external tools. Simply install DOS 6.22 and then install Windows 98 SE on top of it. Windows will recognize the existing DOS installation, and will add to its boot menu a "Previous version of MS-DOS" item, which you can select at any time to boot the old DOS. This works for all versions of Windows 95/98.
   
   Other methods exist, such as the Grub4DOS method detailed above.
2. How to allow DOS to use its maximum 8GB (well, really 7.8GB) and Windows see all the rest.
   
   This is more tricky and has to do more with how you partition your drive than with how you set up the boot. There is no problem making a 2GB primary FAT partition for boot, and divide the rest into as many FAT/FAT32 partitions you want. However, DOS 6.x has a total drive limit of 7.8GB, thus if you use 2GB for the primary, it will not see any extended partitions over 5.8GB in size.
   
   If you clump all the extra logical partitions into a single extended partitions, and their total exceeds 5.8GB, DOS 6.22 will see none of it - it will only have access to the 2GB FAT partition. In many use cases it's enough and that's what people do. However, if it's not enough for you, then you need to figure out a solution.
   
   Although I never tried, it may be reasonable that if you set up multiple extended partitions, the first of which is within the DOS 6.22 limit and only contains FAT partitions, then DOS will see just that, in addition to its primary partition, and you will have your maximum capacity for DOS. Windows should see the rest easily.

All this is mostly academic, though. There is no reasonable reason to dual-boot DOS 6.22 and Windows 98 SE. Just boot Windows 98 SE without its GUI. The one exception in which it may make sense is if you want to use Windows 3.x in addition to Windows 9x, and want them to be completely separate without potential hassle in arbitrating them.

dr_st wrote:

All this is mostly academic, though. There is no reasonable reason to dual-boot DOS 6.22 and Windows 98 SE. Just boot Windows 98 SE without its GUI. The one exception in which it may make sense is if you want to use Windows 3.x in addition to Windows 9x, and want them to be completely separate without potential hassle in arbitrating them.

This!
The files included in Windows\command are enough to run a dos games PC. (only one missing for me is dosshell which I copy across)
I just make a shortcut on the desktop to commonad.com and modify the autoexec.bat and config.sys in its properties.
Whole 2nd copy of dos 6.22 will just install disk tools which don't understand Win9x or fat32 so of limited use anyway and you can get more conventional memory with himem and emm386 that ships with 9x as a bonus as well.

The way I built my machine was to format 2GB partitions for DOS. My C: drive is for DOS and utilities, D: drive for 286/386 era games, E: drive for 486 and F: for Pentium. Then, I have a 3.5" CF dive, connected as IDE. I use a Microdrive and have a 98SE install. When I leave the Microdrive out, it boots DOS. When inserted, it boots Win98 and I can still see all of the DOS partitions/drive letters in Windows. This has worked very well for me.

Is there any particular reason that you need both DOS 6.22 and DOS 7.1 (which is what is "bundled" with Windows 98SE) on the same PC?

Why not just set up a start menu configuration under Windows that will allow you to boot into either DOS 7.1 or Windows?
Refer this topic: How to create a boot (start up) menu under Windows 9x/ME

I guess I want the "pure" DOS version instead of the one that works in conjunction with Windows. But at the same time would like the option to play some games on windows with the same machine.

fsmith2003 wrote:

I guess I want the "pure" DOS version instead of the one that works in conjunction with Windows.

Yes, but - why? Does it serve any functional purpose to you, or is it just for the sake of 'completeness'? Would you install DOS 5.00 as well and triple-boot them? 😀

fsmith2003 wrote:

I guess I want the "pure" DOS version instead of the one that works in conjunction with Windows. But at the same time would like the option to play some games on windows with the same machine.

Shortly after Windows 95 came out (many years ago), I also had a dual boot configuration by having DOS 6.22 on the one partition and Windows 95 on the other (I used OS/2 Warp 3's boot manager for this).
However, after a while, I realised that there was no real benefit of having both DOS 6.22 and (back then) DOS 7.0 on the same system.

Also bear in mind that DOS 7.1 can read and write to FAT32 partitions, while earlier versions cannot (at least, not "out of the box").

fsmith2003 wrote:

I guess I want the "pure" DOS version instead of the one that works in conjunction with Windows. But at the same time would like the option to play some games on windows with the same machine.

Nothing wrong with that, The only thing you will notice is the version number and unable to access the Fat32 partitions, but hell I've got 2 486's even though I have a P3 that plays all my dos games just as well or better.

I would say give using win98's dos a try, honestly it'll make your life so much easier. but if it still doesn't satisfy your nostalgic needs I would
Create a 2GB C:\ primary Fat16 partition for dos
Create a 2GB D:\ Fat16 partition for your dos games (hopefully you don't have more then 2GB of dos games)
Partition the rest of your drive as you wish using Fat32 for Win98 stuff

This will stop your drive letters moving round between the different OS's
Install DOS first to C:\
Install Windows 98 to E:\ it should ask if you want to keep your previous OS, it will create the boot menu for you

jesolo wrote:

Is there any particular reason that you need both DOS 6.22 and DOS 7.1 (which is what is "bundled" with Windows 98SE) on the same PC?

Why not just set up a start menu configuration under Windows that will allow you to boot into either DOS 7.1 or Windows?
Refer this topic: How to create a boot (start up) menu under Windows 9x/ME

That's how I usually do it. DOS 7.1 does offer some benefits over 6.22 wit FAT-32 support and so on, especially if longevity of the retro-rig is a concern.

I just create a multi-boot configuration using Autoexec.bat and Config.sys - then setup one to boot to 98 SE, another one clean so I don't need a bloody boot-disk to make in-system adjustments/diagnostics with nothing loaded, and then special entries for whatever software I choose to run if any have special needs, usually with one "regular" setup I use for everything. If I want to run Windows For Workgroups 3.11 (which I prefer not to on DOS after 6.22 because 32-bit Disk and File Access issues caused by 3xstart.exe patch), I'll use the w3xstart patch on it and run it that way with it's own entry using the C:\win98\command stuff to load it to full capacity on DOS 7.x. I also do this under 95 as well - though I don't do this much anymore since I like removable drive caddies better as I already have enough multi-boot configurstions going on, especially on MS-DOS 6.22 and older, and even more so true on older (<386) machines.

RJDog wrote on 2017-01-21, 04:50:

I wrote an blog post about this very topic not too long ago:

http://retropcbuilder.blogspot.ca/2016/11/dua … -95-follow.html

My method uses GRUB4DOS... others have other (equally valid) boot managers they prefer to use. It's really what you're comfortable with. Do you need to use a Dynamic Disk Overlay? If you do not, then your options are wide open. If you do, GRUB4DOS is the only one that I've personally tried that works well in that configuration.

Sorry to revive a 3 year old thread but I came here looking for help a week ago since I was going on this journey and I wanted to share my experience. I'm going to be playing some older games on this setup mixed with newer ones, and potentially even some of the rare Win 3.1 games, so I wanted to be absolutely sure I had all options open to me.

I took most of your advice, I created a 2 gig FAT16 Primary C:\ partition for DOS 6.22, then an extended 2 gig partition with a logical FAT16 partition that would be shared between them, and another ~28 gig (filling up 32 gig) Primary partition with LBA enabled and FAT32 for the Windows 98/DOS 7.1 side. I found XFDISK to be of particular help here, it's quite easy to use and you can use it to activate and deactivate partitions on the fly as well. Creating a boot disk that has GRUb4DOS and XFDISK is what I ended up doing while I was testing this out and trying out my options.

I had the OEM version of Windows 98 SE and that will not install in harmony with anything else, and furthermore it will only install onto the primary partition if it's at the start of the hard drive (as far as I could tell and I tried many options, the C:\ partition needs to start at cylinder 0 for it to accept installation, any other option and it complained that the drive wasn't formatted properly and all you could do was exit). I eventually got around it by having it install the files, then copying the files to another partition, moving the FAT32 partition and copying them back, then letting it finish installing. You could also easily use something like partition magic to just move the Win98 partition around after you've installed it, it isn't a limitation on bootup, it's just the original OEMSETUP phase that has this limitation.

I also set BOOTGUI=0 in \MSDOS.SYS on the WIn98 side to prevent it from autoloading into Windows 98, leaving another option in the menu to boot directly into DOS 7.1 without starting up Windows (the win98 option in config.sys then simply runs Win in the autoexec.bat to fire up Windows 98).

I mixed together a traditional DOS menu and your DOS4GRUB suggestion by doing something like this, it avoids the double menu conundrum.

DOS Side:

[menu]
...
MENUITEM=win98,Switch to Windows 98
...

[common]
...

[win98]
DEVICE=C:\GRUB4DOS\GRUB.EXE --config-file="unhide (hd0,1);hide (hd0,0);makeactive;chainloader (hd0,1)/io.sys;boot"

Win98 side:

[menu]
...
MENUITEM=dos622,Switch back to MS-DOS 6.22
...

[common}
..

[dos622]
DEVICE=C:\GRUB4DOS\GRUB.EXE --config-file="unhide (hd0,0);hide (hd0,1);makeactive,chainloader +1;boot"

This works fine, and if you set the switch option in the menu as the default, you could even enjoy an endless loop of booting either MS-DOS6.22 or Win98!

Following other advice here, this is definitely not needed except in some fringe cases, WIn98SE has ~15k more of conventional memory free (although I could free up more on the 6.22 side by using QEMM). I have around 615k free of conventional memory on MSDOS 6.22 but around 630 on the Win98 side. But both systems do work fine and I don't have to worry about the 3.11 Windows install being confused with the Win98 install.

and furthermore it will only install onto the primary partition if it's at the start of the hard drive (as far as I could tell and I tried many options, the C:\ partition needs to start at cylinder 0 for it to accept installation, any other option and it complained that the drive wasn't formatted properly and all you could do was exit).

I don't know if you tried it, but I think the key is simply setting the Active flag correctly. (It will definitely not boot from a primary partition that is not active.)

Jorpho wrote on 2021-03-07, 01:08:

and furthermore it will only install onto the primary partition if it's at the start of the hard drive (as far as I could tell and I tried many options, the C:\ partition needs to start at cylinder 0 for it to accept installation, any other option and it complained that the drive wasn't formatted properly and all you could do was exit).

I don't know if you tried it, but I think the key is simply setting the Active flag correctly. (It will definitely not boot from a primary partition that is not active.)

It does not matter if it's active or not. The partition was always active. This does not apply to non-OEM versions of Win98, it's just the OEM version that has this limitation. As soon as the partition was at the start of the disk, all was well.