Is it possible to dual boot an Amiga with a single HD? If so what software is needed? Are there boot loaders available for the Amiga similar to GRUB?

The reason I want to do this is so I can installed Workbench 3.1 and AmigaOS 3.9 on the same HD. And maybe if this is possible to also have separate installations of ClassicWB and Linux on their too.
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I just select the correct partition in the Early startup menu.

I also recall setting the 3.1 partition which I don't use much to not bootable in HDToolBox then just make it bootable when I use it, but this may not be necessary.

I am not aware of any software which does this.
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2 bootable partitions, same priority. Main partition hads the **0: prefix and the second has **1: and then as SC said pick the drive in the AES screen. Thats how i run OS3.9 and OS4. Not the most gracefull of solutions but it does work. I suppose it could be done with an altered startup sequence and say a 3.1Libs and Libs folders etc and boot with no startup then type execute 3.1startup-sequence and edit it to set assigns to "assign Libs: sys:3.1libs" etc. but that would be very inefficiant and damn confusing.
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So you just set both partitions to the same priority? Does that mean that you will always have to select one due to it not knowing which to use first?
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It then boots due to the first device name e.g DH0: would be booted before DH1: if you don't use AES.
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Amigakit are looking into creating dual boot software for OS3xxx and OS4.

At the min, I just use the early startup menu.

There are plenty of programs to boot up different startup sequences, although that's not the same.
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http://classicwb.abime.net/classicweb/multiboot.htm
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That's more like dual startup-sequences than dual booting, loading different setups on the same partition and Workbench, but you could do something similar to boot two operating systems I would have thought.

You'd put 3.1 on the first partition and 3.5/3.9 on the second. Then setup a boot menu (or mouse button boot program like I did in the ClassicWB packs) in the original startup-sequence that goes on and executes other scripts.

It's not perfect however, as you'll have to have loads of assigns for things like C, S, ENV: etc. pointing to the second partition. Perhaps there are other complications; I don't know as I've never tried.

Must be a partition boot loader on Aminet, or you can just use the early startup menu to choose a partition as others have mentioned above.
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I'm quite surprised than no one seems to have directly developed a proper partition boot loader for the Amiga. Every other system I can think of has one.
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There's a little program called movesys that thakes care of all that dirty work (reassigning all those essential system drawers). I use it with my CF versions of ClassicWB.

It really shouldn't be too difficult. I have no idea how OS4 goes about initializing itself but with 3.5/3.9 it's simply a case of a slightly altered SetPatch command that loads the updated libraries (at least I think it is -- never really used it much).

Couple of IF/ENDIFs in the startup-sequence and you should have a working setup.

There's a working port of LILO that comes with the m68k, Amiga version of Linux. Never tried it myself though.
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