[comp.sys.amiga.hardware] Two megs of Chip RAM on an A2000 ??

xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) (11/25/90)

peterk@cbmger.UUCP (Peter Kittel GERMANY) writes:
> hollnbgh@coral.bucknell.edu writes:

>>  I was under the impression that the "2-Meg" Agnus chip was 
>>exactly the same as the 1-meg Agnus chip currently shipping in the
>>Amiga 500's, 2x00's, AND 3000's.  I thoght the CHIP was the same, 
>>but that the 3000's socket connected the 21'st address line (that
>>the 500's and 2x00's didn't connect to anything.)

>No, it has been told a little different on the net: The silicon chip
>inside Agnus is indeed identical in the 1-Meg and 2-Meg version,
>BUT the inner bondings from the silicon to the outside pins differs,
>so that in the 1-Meg version you have one address line not connected
>to the contacts at the edge of the Agnus case. So if you don't want
>to open that ceramic (or plastic) casing of Agnus and change the
>bonding (with your 80 W soldering iron :-), you better change the
>whole chip.


OK, next question. My 2000 currently sports 9.5 meg of memory. With this
daughterboard, which almost has to have a meg of memory _on_ it to
access the chip bus, if I've followed previous discussions correctly, do
I get to address 10.5 meg of autoconfiguring memory, 2 meg of it chip,
or does one of my existing meg become unusable to make room in the
address space for the other meg of chip ram?

                                                           /// It's Amiga
                                                          /// for me:  why
Kent, the man from xanth.                             \\\///   settle for
<xanthian@Zorch.SF-Bay.ORG> <xanthian@well.sf.ca.us>   \XX/  anything less?
--
Convener, ongoing comp.sys.amiga grand reorganization.

schweige@aldebaran.cs.nps.navy.mil (jeffrey schweiger) (11/25/90)

In article <1990Nov24.223511.5632@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes:


>OK, next question. My 2000 currently sports 9.5 meg of memory. With this
>daughterboard, which almost has to have a meg of memory _on_ it to
>access the chip bus, if I've followed previous discussions correctly, do
>I get to address 10.5 meg of autoconfiguring memory, 2 meg of it chip,
>or does one of my existing meg become unusable to make room in the
>address space for the other meg of chip ram?
>
>                                                           /// It's Amiga
>                                                          /// for me:  why
>Kent, the man from xanth.                             \\\///   settle for
><xanthian@Zorch.SF-Bay.ORG> <xanthian@well.sf.ca.us>   \XX/  anything less?
>--
>Convener, ongoing comp.sys.amiga grand reorganization.

According to Dean Brown of DKB Software (the makde of MegAChip 2000), it adds
an additional 1 Meg of autoconfig RAM.  The board does come with the 1 Meg on
it.  My question to you is how do you have 9.5 Meg of autoconfig memory at
present.  I thought the present limit was 9 Meg.  (I'll admit in advance that
I could quite possible be wrong in this).  In any event, the flyer I have for 
the MegAChip 2000 states that you can have a total of 10 Meg of RAM, 2 Meg of
Chip and 8 Meg of Fast RAM.

Jeff Schweiger

-- 
*******************************************************************************
Jeff Schweiger	      Standard Disclaimer   	CompuServe:  74236,1645
Internet (Milnet):				schweige@taurus.cs.nps.navy.mil
*******************************************************************************

xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) (11/25/90)

schweige@cs.nps.navy.mil (Jeff Schweiger) writes:
> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes:

>>OK, next question. My 2000 currently sports 9.5 meg of memory. With this
>>daughterboard, which almost has to have a meg of memory _on_ it to
>>access the chip bus, if I've followed previous discussions correctly, do
>>I get to address 10.5 meg of autoconfiguring memory, 2 meg of it chip,
>>or does one of my existing meg become unusable to make room in the
>>address space for the other meg of chip ram?

>According to Dean Brown of DKB Software (the makde of MegAChip 2000), it adds
>an additional 1 Meg of autoconfig RAM.  The board does come with the 1 Meg on
>it.  My question to you is how do you have 9.5 Meg of autoconfig memory at
>present.  I thought the present limit was 9 Meg.  (I'll admit in advance that
>I could quite possible be wrong in this).  In any event, the flyer I have for 
>the MegAChip 2000 states that you can have a total of 10 Meg of RAM, 2 Meg of
>Chip and 8 Meg of Fast RAM.

Yep, I've lost the ability to do simple arithmetic in my head.

Avail shows a total of 9,428,696 bytes of memory; a little is being eaten
somewhere, but that is still smaller than the 9,437,184 bytes in 9 megabytes.
My error; I thought a lot was being eaten (like perhaps all of workbench),
giving a higher total, and I hadn't bothered to do the math.

So, with this daughterboard setup, I could go from the half meg chip, half
meg something (on chip bus but not chip?) on the mother board to two meg of
chip, one on the motherboard, on on the daughterboard, plus the 8 meg of
fast ram on the expansion card.  Nice.  I have _lots_ of use for more chip
ram; gobs of screens, for starts.

While I'm spinning dreams, there was once an indication that C= had given
back 4 mbytes of address space for user memory that had been reserved for
system use.  1) Is that true? 2) Has anyone ever built for sale a method
of making a 12 mbyte A2000? 3) Is this daughterboard/motherboard memory
already coming out of that 12 meg of address space, or is 14 meg an upper
limit for installed ram?  [Dream on.]

Put another way, just how much usable ram could I have in an A2000 without
going to a 68020 or 68030 processor, under today's rules, and does anyone
actually sell the goodies to make it possible?

                                                           /// It's Amiga
                                                          /// for me:  why
Kent, the man from xanth.                             \\\///   settle for
<xanthian@Zorch.SF-Bay.ORG> <xanthian@well.sf.ca.us>   \XX/  anything less?
--
Convener, ongoing comp.sys.amiga grand reorganization.

billsey@agora.uucp (Bill Seymour) (12/01/90)

In article <1990Nov24.223511.5632@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes:
:
:OK, next question. My 2000 currently sports 9.5 meg of memory. With this
:daughterboard, which almost has to have a meg of memory _on_ it to
:access the chip bus, if I've followed previous discussions correctly, do
:I get to address 10.5 meg of autoconfiguring memory, 2 meg of it chip,
:or does one of my existing meg become unusable to make room in the
:address space for the other meg of chip ram?

	Well, I haven't seen the daughterboard, but there are two possibilities
as I see it... They either have one meg of ram on their board, mapped to
$100000-$1FFFFF or they have two meg onboard, mapped to $000000-$1FFFFF. If
they have two meg onboard, it's possible they will remap the motherboard
memory to $C00000-$CFFFFF.
	First case allows to expand your 2000 to 11 megs, up one meg from the
10 megs supported now (Note, that's not 9.5...)
	Second case, part one, alos allows you to expand to 11megs.
	Second case, part two, allows you to expnad to a full 12megs. That is
very close to the maximum you could take a 2000 without a coprocessor card.
(You could actually hack up some memory into the 512K below the ROM, I believe.
And possibly to the 512K at $D00000...

:                                                           /// It's Amiga
:                                                          /// for me:  why
:Kent, the man from xanth.                             \\\///   settle for
:<xanthian@Zorch.SF-Bay.ORG> <xanthian@well.sf.ca.us>   \XX/  anything less?
:--
:Convener, ongoing comp.sys.amiga grand reorganization.

-- 
     -Bill Seymour                                            billsey@agora
***** American People/Link Amiga Zone Hardware Specialist  NES*BILL *****
Bejed, Inc.       NES, Inc.        Northwest Amiga Group    At Home Sometimes
(503) 281-8153    (503) 246-9311   (503) 656-7393 BBS       (503) 640-0842

billsey@agora.uucp (Bill Seymour) (12/01/90)

In article <1990Nov30.171201.21397@agora.uucp> billsey@agora.uucp (Bill Seymour) writes:
:In article <1990Nov24.223511.5632@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes:
::
::OK, next question. My 2000 currently sports 9.5 meg of memory. With this
::daughterboard, which almost has to have a meg of memory _on_ it to
::access the chip bus, if I've followed previous discussions correctly, do
::I get to address 10.5 meg of autoconfiguring memory, 2 meg of it chip,
::or does one of my existing meg become unusable to make room in the
::address space for the other meg of chip ram?
:
:	Well, I haven't seen the daughterboard, but there are two possibilities
:as I see it... They either have one meg of ram on their board, mapped to
:$100000-$1FFFFF or they have two meg onboard, mapped to $000000-$1FFFFF. If
:they have two meg onboard, it's possible they will remap the motherboard
:memory to $C00000-$CFFFFF.
:	First case allows to expand your 2000 to 11 megs, up one meg from the
:10 megs supported now (Note, that's not 9.5...)
	Woops! I fell into your trap there... :-) subtract a meg from all my
total memory numbers. You only have nine megs possible right now, this will
expand you to either 10 or 11 megs...
:	Second case, part one, alos allows you to expand to 11megs.
:	Second case, part two, allows you to expnad to a full 12megs. That is
:very close to the maximum you could take a 2000 without a coprocessor card.
:(You could actually hack up some memory into the 512K below the ROM, I believe.
:And possibly to the 512K at $D00000...


-- 
     -Bill Seymour                                            billsey@agora
***** American People/Link Amiga Zone Hardware Specialist  NES*BILL *****
Bejed, Inc.       NES, Inc.        Northwest Amiga Group    At Home Sometimes
(503) 281-8153    (503) 246-9311   (503) 656-7393 BBS       (503) 640-0842