i had to get out my calculator:

6291455

9437184

---------------------
3145729
 
oh i get it now
 
so ram stops here
4194303

rom picks up here

4194304

man that is tight, but that is assumeing we have 4mb ram installed.

so it would be here if there was only 2 mb's of ram installed

2097151

Ah ha.. 

but in order to make it easy to use you want to stay with in the Start and stop of the allocation.

4325375, witch equals 131071 for rom

and the next start not he map is SCSI

5767168

witch leaves a difference of 1572864, so what is that 1.57 megs? between start of rom and start of scsi.