Lots of ways. Simplest is to use separate hard drives for each OS. You can then attach each to primary and secondary channels on your hard drive controller. At boot time, disable relevant channel in BIOS to boot desired OS.

Or, you can use hard drive caddies connected to just one channel, and load relevant drive for your OS.

Or... you can just use 98. There isn't much that wouldn't work in DOS 7.1

Note the description of this forum, "Getting old DOS games working on modern hardware." Ask old hardware and configuration questions in Marvin. Marvin, the Paranoid Android

In the past, I used MS-DOS 6.20 and Win98 on the same HDD just fine.
Of course, this was before insanley hughe HDDs were common.
My "big" SCSI drive for example, was 1,5GB, so I was able stay on FAT16.
Whenever I needed real MS-DOS, I selected F4 or F8 during boot and chose "Previous DOS version".
That way, I could separate real-mode DOS from DOS 7 (+lots of drivers) without being required to create a boot menu.
https://www.computerhope.com/msdossys.htm

Azarien wrote:

Or... you can just use 98. There isn't much that wouldn't work in DOS 7.1

This.

1] Simplest method would be to have 6.22 and W9x on two different HDDs. Boot the desired HDD, voila.
2] Second simplest method would be to have them on same HDD, but on their own respective primary partitions. Use a bootmanager (for older systems, for example "Smart Boot Manager") to boot the desired (and autohide the other), voila.

jaZz_KCS wrote:

2] Second simplest method would be to have them on same HDD, but on their own respective primary partitions.
Use a bootmanager (for older systems, for example "Smart Boot Manager") to boot the desired (and autohide the other), voila.

Yup. Back in the late 90s/early 2000s I experimented with a nice, colourful boot manager from Paragon (or was it PTS ?)..
I didn't really need it, but it allowed me to easily mult-boot DOS, Win9x and OS/2 Warp (and Linux ?).

We've been through this before, and folks on Vogons LOVE suggesting convoluted solutions for simple problems.

1. There is no need to dual-boot DOS 6 and Win98, almost ever (the only reasonable scenario I can think of is that justifies it is running Win3.11)
2. For dual-booting just DOS 6 and Win98, there is no need to have anything other than Win98 itself managing it - no third-party boot managers and definitely no separate drives

I've also discussed this before. Just after Windows 95 was released, I decided to dual boot between DOS 6.22 and Windows 95 (on the same HDD) by using OS/2 Warp 3's Boot Manager.

However, after a while, I realised there was no need to dual boot, since Windows 9x has DOS built in.

You can still dual boot between DOS 7.x & Windows 9x by setting up a boot menu: How to create a boot (start up) menu under Windows 9x/ME

I would argue this is less about the necessity of having 6.22 present when also rocking 98, but more of a preference. One could argue that most ppl here never stumbled upon software that would run in genuine 6.22- but not in a 7.0/7.1 environment.

Also other borderline scenarios come to mind, for example having to rely on PCMCIA CDRom devices, and having the Cardsoft drivers + the CDRom drivers in addition to 7.0/7.1 eating more conventional memory out of the box due to the infused system files is a tad inconvenient. Remember, DOS 7.0/7/1 do use more conventional memory out of he box.

jaZz_KCS wrote:

Remember, DOS 7.0/7/1 do use more conventional memory out of he box.

I think DOS=NOAUTO takes care of that.

dr_st wrote:

jaZz_KCS wrote:

Remember, DOS 7.0/7/1 do use more conventional memory out of he box.

I think DOS=NOAUTO takes care of that.

Aye, almost completely. On a related note, the only software that was giving me headaches was some third party PCMCIA driver once that I couldnt get working under 7.0/7.1.
Other than that I have encountered none personally.

collector wrote:

Note the description of this forum, "Getting old DOS games working on modern hardware." Ask old hardware and configuration questions in Marvin. Marvin, the Paranoid Android

Moved to Marvin -> Software.

dr_st wrote:

• For dual-booting just DOS 6 and Win98, there is no need to have anything other than Win98 itself managing it - no third-party boot managers and definitely no separate drives

That's correct, Win98 (and Win95, too) will automatically add the previous installed DOS version to its boot manager. However, that only works if you install the retail version of Win9x. Most people seem to own the OEM version, which only installs on an empty hard disk and thus does not offer that feature.

That said, the way "Previous DOS version" works in Win9x is quite weird.

derSammler wrote:

That's correct, Win98 (and Win95, too) will automatically add the previous installed DOS version to its boot manager. However, that only works if you install the retail version of Win9x. Most people seem to own the OEM version, which only installs on an empty hard disk and thus does not offer that feature.

I did not know that (or maybe I forgot). Is that really the case and is there no workaround available? That's pretty bad.

derSammler wrote:

That said, the way "Previous DOS version" works in Win9x is quite weird.

I second that. It only works if the partition is not using FAT32 filesystem also.
From what I vaguely remember (please double-check!), DOS 7 has an altered boot loader code.
It can find its system files anywhere on the partition, including in sub directories.

By comparison, DOS 6.x requires them to be located on a fixed location on the partition.
So if one of them gets moved around accidently, except command.com, maybe, DOS 6.x can't boot anymore.
(This could happen because of third-party disk fragmenters etc.)

That's why it can chain load MS-DOS 6.x also, I believe.
The old system is stored in/loaded from a binary file.
Again, I'm speaking under correction here.

In the end it's all preference, I guess. Some people just like to continue DR-DOS,
PC-DOS, MS-DOS because they are used to it, rather than using it because of technical reasons.
To their defense, MS-DOS 6.x comes with a full set of utilies, from which some of them check the DOS version number.

XOSL is a nice boot loader. It needs it's own tiny partition to operate. OS/2 v3 had a funcky function that you could boot between each OS/2 and Dos as you wished if on a Fat16 partition or you could use it's boot loader to go from Dos fat16 to OS/2 in hpfs and of course OS/2 can read/write to fat16 partitions.

As others have mentioned you can use Win9x to get to the Dos prompt and operate from there no problem. For that matter you can do the same for NT 3.5x/4 if you want but make a selection from its boot loader. Some older programs will have version issues but most things should work ok. Obviously if you install on fat32 you do not use old dos hdd utilities and such. That could work out bad.

Windows 3.1x can run fine on a fat32 partition.

As jo said it's just a matter of preference.