Amiga os 3.1 vs amiga os 3.5

[Tempest]

I actually downgraded from OS 3.9 to OS 3.1

This was my setup on my a4000 and a3000T and this is my current setup on my a2000 and a1200. Although my a1200 and a2000 could easily run OS 3.9 I prefer OS 3.1, it's smaller and faster.

I've got a nice OS 3.1 setup with different options at boottime:

No action > Scalos 1.2d
Left mouse > Opus Magellan II
Left mouse and Shift > plain Workbench 3.1
Right mouse > CLI with Parm

[Tempest]

OS 3.5/9 support hard drives >8GB (new scsi.device) and have ATAPI support for CD ROMs, for which AFAIK there's no free alternative on Aminet.

Varthall

Look at NSDPatch, worked well on my a3000t to use >8GB harddrives. I think NSDPatch is also used in OS 3.9.

And there is also AmiCDFS which is free.