by A4000_Mad on 2007/12/20 0:43:20
I've just had a go at setting up a hard drive that can boot into either OS3.9 or OS4
(no idea why I choose to start these sort of things at 10 O'clock at night)
My findings........
1. I could *not* boot into OS4 then do a soft reset while keeping both mouse buttons held down to get the the 'Amiga Early Startup Control' and then choose to boot into OS3.9 partition. The result was a red screen (ROM error alert)
2. I could *not* boot into OS3.9 then do a soft reset while keeping both mouse buttons held down to get the the 'Amiga Early Startup Control' and then choose to boot into OS4 partition. The result was a red screen (ROM error alert)
3. With OS4 set as the partition with highest boot priority and doing a cold boot, I could *not* successfully go into the 'Amiga Early Startup Control' and choose to go into OS3.9 (it would just go into OS4 anyway)
4. I *was* able to boot into OS3.9, use 'HDToolBox' to give the OS4 partition a higher boot priority and do a soft reset into OS4.
5. I was *not* able to boot into OS4, use 'Media Toolbox' to give the OS3.9 partition a higher boot priority and do a soft reset into OS3.9. The result was a red screen (ROM error alert)
Conclusion:-
'Media Toolbox' and 'HDToolBox' seem to be an answer at this time
I would suggest that you leave 3.9 as the boot partition and play use the startup-sequence.
I havn't done this kind of thing myself but it shouldn't be too hard.
I'd go about it by renaming the startup-sequence to 3.9_startup-sequence and then create a new startup-sequence which gives you the option of booting into one OS or the other.
You will still need to do a cold reboot from OS4 though.
Here's a link to a beginners guide to AmigaDos
http://de5.aminet.net/docs/help/adosbegin.lha Start by looking at the ASK command.
To save headaches do some experimental scripts to execute from the shell before you move onto the startup-sequence.
