+3 Bootstrap Loader
Posted: Sat Jun 22, 2019 1:01 pm
While developing my new +3 disk utility to create compilation disks of old games I initially just stuck to a basic loader which called the +3 DOS routines. After I got it all working decided to mess with the disk bootstrap and have finally got it working. Shame I'm like 30 years late to the party but has been a lot of fun figuring this stuff out
I've kept it pretty simple as my loader just copies the sectors in track 0 to memory and then executes it. It does run a bit fast than loading the autorun basic then the loader and frees up space from the disk as the bootstrap is in track 0. I am wondering how far you can go with it though especially as you can't really use page 7 which is needed for disk access and page 3 at the same time (where the bootstrap is stored in memory). Would be interested to see how the copy protected loaders from the 80s worked. Also very impressed in what is actually detailed in the +3 manual, I just skipped all of this as a kid!
Quick animated gif of my bootstrap loader in action
TomD
I've kept it pretty simple as my loader just copies the sectors in track 0 to memory and then executes it. It does run a bit fast than loading the autorun basic then the loader and frees up space from the disk as the bootstrap is in track 0. I am wondering how far you can go with it though especially as you can't really use page 7 which is needed for disk access and page 3 at the same time (where the bootstrap is stored in memory). Would be interested to see how the copy protected loaders from the 80s worked. Also very impressed in what is actually detailed in the +3 manual, I just skipped all of this as a kid!
Quick animated gif of my bootstrap loader in action
TomD