[comp.sys.amiga] 1 Meg Chip memory function on B2000's

hedley@cbmvax.UUCP (Hedley Davis) (12/09/87)

I received an interesting phone call from a software vendor
who was attempting to help an individual over the phone.
Apparently his software was running extremely unreliably.
After a certain amount of discussion, it came out that the user
had a B2000 with 1 MEG of chip memory. Wow.

It seems that the dealer who sold the unit found that he could upgrade
his B2000's to 1 meg of chip memory simply by changing a couple of
jumpers on the PCB. He then sold this unit to the buyer as having 1 meg
of chip memory, and lo and behold, AVAIL indicates that there is indeed
1 meg.

Unfortunately, AGNUS cannot properly address all of this memory, and
even though the 68000 ( and therefore the memory manager type software )
can access it properly, alot of software will break as soon as the
blitter ( for example ) is directed to act on this memory. 

The insidious thing is that the system will function ok for a while
because the first memeory allocated out of chip memory will be the 
lower 512K which works just fine. Only when things get rolling will
the system fail.

Beware this 'enhancement'.

Hedley