Can Amiga support dual boot?

[guybrush]

I found this interesting application on Aminet, called "AmigaBootSelector". It is using different startup sequences to load different things, which is quite cool. Didn't get it to work yet but I saw some using it and it add a bit of diversity on the standard amiga boot.


Although I thought that it would be nice to have an actual dual boot; since I have 3.2 and 3.1; I would like to be able to boot on each OS without swap my SD card from my adapter (which involve opening the case).


Is the Amiga 1200 able to "select" different system partitions on the same disk? From what I remember, you can't have 2 DH0 and DH0 is what is used for boot, in conjunction with the bootable flag and the boot order integer value.

[Samurai_Crow]

Using a Kickstart 3.1 ROM and Workbench 3.1 and 3.2 is possible. Holding down both mouse buttons during startup takes you to the early startup screen which lets you switch, enable and disable drives and partitions. Using 3.2 Workbench requires Fast RAM and the ability to patch the 3.1 Kickstart but it is possible.

[fitzsteve]

I have a dual boot setup, 3.9 and 3.1, on the 3.9 I have the 3.1 partition hidden, if I want to run 3.1 I just go to the early boot menu and disable the 3.9 partition

[turrican3]

i remember to have something like that :
holdind f1 launch one startup.
holding f2 an other... f3 etc...
how it worked i don't remember exactly.

[AMIGASYSTEM]

Yes, but with OS 3.2, as Samurai_Crow said, it is necessary to have two kickstarts, OS 3.1 cannot start with KickStart 3.2 (Requires Icon.library and Workbench.library compatible), unless you mess with OS 3.1.

[guybrush]

Thanks; so it can be done. My 1200 has 3.1 roms and I load 3.2 rom via loadmodule.

So the only way to do this is to use the 2 mouse button menu? I was hoping to use something nice like AmigaBootSelector.

[thomas]

Technically a true boot selector is not possible. If something starts to boot, the boot drive has already been selected and cannot be changed any more. All you can do is to use a series of Assign commands to move the boot process to another partition and continue from there.

So from a user's perspective you could add something like AmigaBootSelector to the one partition with the hightest boot priority and get what looks and feels like a boot selector.

I didn't take a closer look to ABS, but if you say it runs different scripts and is configurable, I don't see why these scripts shouldn't be able to move the boot process to another partition rather than use what is on the local partition.

[Daedalus]

Originally Posted by AMIGASYSTEM

Yes, but with OS 3.2, as Samurai_Crow said, it is necessary to have two kickstarts, OS 3.1 cannot start with KickStart 3.2 (Requires Icon.library and Workbench.library compatible), unless you mess with OS 3.1.

If the 3.2 partition is still mounted while booting the 3.1 partition, it will work just fine.

[AMIGASYSTEM]

Yes, i didn't say otherwise, i just said that you need "two KickStart 3.1 and 3.2".

OS 3.1 Standard will not start with KickStart 3.2

[thomas]

You don't need two kickstarts and you don't need to mess with 3.1. As Daedalus pointed out, if the 3.2 partition is available, it will find the libs there, even if it boots from the 3.1 partition.

Only if you remove the disk with WB 3.2 and insert a disk with 3.1 instead, then it will fail to boot.

[AMIGASYSTEM]

I tested with two "different" disks, from Early Startup Control I disabled OS 3.2 (DH0) and started OS 3.1 from DH1, result ... request "Icon.library and Workbench.library".

I have not yet tested using partitions on the same disk

[thomas]

Originally Posted by AMIGASYSTEM

I disabled OS 3.2

You should read my and Daedalus' posts more carefully.

[Samurai_Crow]

Originally Posted by guybrush

Thanks; so it can be done. My 1200 has 3.1 roms and I load 3.2 rom via loadmodule.

So the only way to do this is to use the 2 mouse button menu? I was hoping to use something nice like AmigaBootSelector.

As long as you use loadmodule to access Kickstart 3.2 you're in the clear but you'll have to chain S:startup-sequence and redo a bunch of assigns if you don't want to split-partition boot devices.

[Thomas Richter]

Originally Posted by guybrush

Is the Amiga 1200 able to "select" different system partitions on the same disk? From what I remember, you can't have 2 DH0 and DH0 is what is used for boot, in conjunction with the bootable flag and the boot order integer value.

Yes, of course it can. The boot menu (press HELP or both mouse buttons) allows you to select the boot partition. You should refer to your system disk as SYS:, though. Not as DH0: (This is not windows, where the boot partition is always C: - remember that there is a difference between the partition name, the volume name, and the SYS: assign).

[AMIGASYSTEM]

Originally Posted by thomas

You should read my and Daedalus' posts more carefully.

Sorry Thomas but my English doesn't allow me to explain what I mean.

I know that if you don't disable only one KickStart is needed, but in my opinion to have an optimal dualboot you need one of the two partitions to be disabled. Booting a 3.1 OS with Kickstart 3.2 is not a genuine 3.1 OS.

[E-Penguin]

I've used this in the past to make dual boot systems
http://aminet.net/package/util/cli/MoveSYS

I use a boot selector to pick between 1.3 and 3.1, then depending on the version of exec move the sys: assign accordingly.

[AmigaHope]

You only need one kickstart (3.2), but you need at least one mounted disk with the icon and workbench libraries on them. This can be any mounted disk, even a floppy. If you want to boot from a 3.1/2.x/1.x drive using kickstart 3.2, and don't want your 3.2 partition mounted, just stick the 3.2 icon.library and workbench.library in the libs directory of your 3.1/2.x/1.x partition and it will work just fine. It will also work fine even if you softkick to the older kickstarts as they just won't try to load the newer libraries since the libraries will already be loaded in ROM.

The only potential problems will be if you try to mix 3.2 with 3.14/3.5/3.9 or are using an A4000T 3.1 ROM.