I use the XP boot menu to achieve this, you just need to install windows 98 first, have the 98 hard drive as first boot drive and I think the XP installer should do the trick!?

SPBHM wrote on 2019-12-30, 23:18:

I use the XP boot menu to achieve this, you just need to install windows 98 first, have the 98 hard drive as first boot drive and I think the XP installer should do the trick!?

I haven't tried this method, but I vaguely remember it from 20 years ago. Does this end up with XP installed on D: drive? So after booting to XP you see C: with Win98 and D: with XP?

What motherboard do you have and does the BIOS allow an F11 or F2 boot menu during POST ? I have an old P4 that has and does not require going into BIOS to change boot drive (also available on nearly all new motherboards). I installed Winx on one HD (with no other HDs) and then winx2 to second HD (also with no oher HDs). During POST hit the F key and choose which HD to boot from. Only quirk is with Win7 as it messes with 9x and xp restores but there is a reg fix for that...

Unfortunately my motherboard doesn't allow that. I can change it only through BIOS.

p6889k wrote on 2019-12-30, 23:23:

I haven't tried this method, but I vaguely remember it from 20 years ago. Does this end up with XP installed on D: drive? So after booting to XP you see C: with Win98 and D: with XP?

If they are on seperate physical drives, you will always get "C:" for OS you are currently using.
Also, if XP doesn't detect Windows 98 install from second drive, you can always add it manually to boot.ini file (manually or with boot editor tools).
The only real issue lies with making sure you can boot Windows 98 from XP (OS boot select), you *can't boot Windows XP from Windows 98 after all.

*exceptions : 3-rd party booting programs, Windows XP boot files on Windows 98 drive (you don't need a working XP OS for this to work).

agent_x007 wrote on 2019-12-31, 07:11:

If they are on seperate physical drives, you will always get "C:" for OS you are currently using.

You sure? by default c:\ should always be be the partition set to active with IDE 0 getting preference if 2 drives have an active partition.
unless your talking about 3rd party booters which can do this.

but to answer p6889k's question.
HDD1 partition 1 = c:\
HDD2 partition 1 = d:\
HDD1 any other partitions =E,F,etc
HDD2 any other partions = G,H, etc

Formatting any drives (say d:\) as NTFS will casue this drive to "hide" in Win98 causeing drive letters to reshuffle so e:\ would become d:\ and so on.
Because of this I always install XP on the last partition as it doesn't really care what drive letter it gets and keeps everything consistent

Well, that's how it worked last time I did Windows 98 + Windows XP install back to back on separate drives.
I did lock Windows XP drive from Win98 though (since I didn't wanted ScanDisk from it to screw around with NTFS hard drive).
Oh, and WIndows 98 drive had seperate FAT32 partition for stuff that I needed to share between 98 and XP.

I can confirm but not explain why, I have a Windows 98/XP system and a Win XP/Win 10 system, on the 98/XP system they are on different partitions on the same physical drive so I end up with 98 is always C and XP is always F. On the XP/Win 10 machine they are on 2 different physical drives and depending on which one I boot they swap places and both are C. This is just using the Windows multi-boot no 3rd party software.

Hmm interesting and cool! It's been good 10 years since I've used 2 different physical drives which is why I wasn't 100% confident.
Donno, this may change how I install my dul boots in the future....

I finally solved my problem, here's how:

1) Connect HDD1 only and install Windows 98
2) Physically disconnect HDD1
3) Connect HDD2 and install Windows XP
4) Connect HDD1, so that both HDD1 and HDD2 are connected.
5) Configure BIOS to set HDD boot priority as: 1 - HDD1 and 2-HDD2.
6) Install Plop Boot Manager to HDD1 MBR using floppy disk Plop installer.
7) Configure Plop.

Sweet, now I have completely independently installed Windows 98 and Windows XP on separate drives. I have no idea how Plop accomplishes booting them, but it does. Trying other boot managers such as Boot Magic 7, Boot Magic 8, System Commander 8.2 did not work regardless of which drive was set as the boot drive in BIOS and regardless of which drive's MBR record was used by the boot manager - I tried all the permutations. These boot managers only worked if both OSes were installed on the same physical HDD in separate partitions.

Now I need to add third drive with MS-DOS6 + Win 3.1.

I also tried hooking up both HDD1 and HDD2, installing Win98 on HDD1, then installing WinXP on HDD2 while HDD1 was connected. This worked as well, Windows provided its boot manager to pick Win98 or WinXP, but I didn't like that XP was installed into D: drive vs C: drive. It also makes WinXP dependent on HDD1/Win98/C: being connected to the system and working. The Plop solution allows me to have truly independent drives/installs. I can always uninstall Plop and control booting just through BIOS HDD boot priority setting as well if needed.

I also tried to install both win98 and winXP in similar fashion but could not get it to work. First I installed win98 on one hard drive and then I tried installing winxp on second hard drive but winxp installation froze in middle of installation and I couldn't get past that problem no matter how many times I tried.