[Coco] Patching NitrOS9 for 8 meg

RETRO Innovations go4retro at go4retro.com
Thu May 3 13:41:14 EDT 2018


On 5/3/2018 10:20 AM, James Jones wrote:
> Take a look in Chapter 2 of Kevin Darling's _Inside OS-9 Level II_. (
> http://wiki.yak.net/1087/InsideOS-9LevelII-KevinDarling_1987_.pdf)
Looked, but I don't see the concern over moving past 2MB.  Yes, one 
needs to move to words across the spectrum, but P$DATImg has 64 entries, 
only 16 of which are used currently.  What am I missing?

I don't think one needs to know about the state of all 8kB blocks in 
RAM, just the 8kB blocks currently mapped by a process.

(Yes, one needs a FREE/BUSY map of all blocks, but one only needs 1 bit 
per 8kB block, so only 32 bytes for 2MB, 64 for 4MB, 128 for 8MB, and 
16MB only needs a page of 256 bytes.)

Jim


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