Breaking 1MB Chip Limit
16 messages in this thread
When you say 2-meg Agnus, is that to differentiate it from the 1-meg
Agnus, or are they the same chip? I was under the (very possibly mistaken)
impression that the Agnus chip I upgraded to was the one to be used in the
ECS, along with the new Denise which is not out yet. What's the scoop? 8^)
Harry,
The 2 Meg Chip is different than the 1 Meg Chip. One is a part
8372A and the other is an 8372B. The 1 meg Agnus (8372A) is the Enhanced
Agnus (officially the "Super Agnus") for the A2000 (and it will work in an
A500 also). The 2 Meg Agnus is for the A3000. Normally, the A2000
doesn't have the ability to address 2 meg of CHIP RAM even with the 2 Meg
Agnus chip…Dean's board corrects this situation.
Don
"Dean's board corrects this situation."
Don't you mean: "Dean's board addresses this situation."
grin>. Sorry, I couldn't resist.
Victor A. Wagner, Jr.
Vic,
Hehe…it "corrects" it, by "addressing" it. Hows that?
Don
Harry,
The 1Meg Agnus is the ECS version that normally fits into the A2000. The
2Meg Agnus is the ECS version that is designed into the A3000. There is a
minor(!) interface difference between the two chips, but they are
functionally compatable from the programmers point of view. The only real
difference is that the 2Meg Agnus shipped with the A3000 allows you to
upgrade to 2Meg of CHIP ram, the 1Meg Agnus is limited to 1Meg of CHIP ram.
The MegAChip board adapts the A3000's Agnus to the A2000 and adds the
additional meg of ram.
Dean
DKB Software
Dean,
Does the MegaChip board come with RAM? If so, what happens if the machine
is already maxed out? Do I dump a SIMM (or two, since the boards using 1
Meg simms upgrade in pairs!) or what?
-Chas
Charles,
Yes, the MegAChip comes with the required ram installed. If you
currently have a 9Meg machine, (8Meg FAST, 1Meg CHIP), installing the
MegAChip will simply increase the CHIP ram to 2Meg without affecting
anything else. In other words, your machine will now have 10MEg maximum.
Dean
DKB Software
Dean,
I have 4 megs 32-bit fast RAM, 2 megs 16-bit fast, and 1-meg 16-bit chip
RAM. I also have a Bridgecard which takes up 2 megs of address space-will
this make a difference?
-Chas
Chas,
I'll let Dean give you the definative answer…but based on what
he's said before…nope, no difference. MegAChip only adds to the amount
of CHIP RAM available, it doesn't take away anything.
Don
Chas:
You will have no problem with a setup like you described. I have exactly
the same setup, and the MegAChip board now brings my system upto 8 megs
total ( 4 megs 32 bit, 2 megs 16 bit, and 2 megs 16 bit Chip)
-Mike Schiller
In sunny Fort Lauderdale
Good, as I could really find a use for more CHIP ram. (Who couldn't?)
-Chas
Charles,
Nope! The additional Meg of CHIP RAM goes into a currently unused spot
of the memory map. This means that by installing the MegAChip 2000, you
simply gain an extra meg of capability. You for example currently have 6Meg
of Fast ram and a 2Meg bridgeboard, for a total of 8Meg of Fast ram memory
map. You also have 1Meg of CHIP ram. The MegAChip simply add 1Meg more of
CHIP ram without changing anything else.
Dean
DKB Software
Dean & Don –
OK, I understand now 8^). All these little chippies floating around can
get a might confusin' … Dean, please put me on your mailing list or
whatever list for one of these babies. Thanks …
Harry