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Re: ZipGS question
Well yall were right.. brought it down to 4224K mem (3megs on card) and it
boots..
Just a waste though.. I used to have a differnet rom3 and ran gsos w/ 7meg
total.. But I do remember having problems..
Charles
"Bill Garber" <willy46pa@comcast.net> wrote in message
SXSdnflZZvAMj_KjXTWcrg@comcast.com">news:SXSdnflZZvAMj_KjXTWcrg@comcast.com...
>
> Charles Claypoole <1@rebbsNotrash.hopto.org> wrote in message
> news:ZEvba.5$BG.2943174@newssvr11.news.prodigy.com...
> > Ok, I tested today and found that if I remove the gsram+ altogether it
> works
> > in gsos at full speed.. i reinstalled gsram and it doesnt..
>
> Try only having 5 mb in the ramGS+ and the one onboard leaves you with an
> even 6 mb. Might just work and still give you enough for your other work.
> ;-)
>
> > I read the manual and found that the gsram+ increases mem 6 megs.. I
have
> a
> > total of 7megs including system memory..
> >
> > I tried removing the roms and it had the same results.. I have the
> upgraded
> > roms for the rom 3 installed too..
> >
> > Tried removing those just to see if it works, but it would crash too..
> >
> > Hate to run w/o it since i use it to do alot of ramdisk stuff.
> >
> > Charles
> >
> >
> > "Rubywand" <rubywand@swbell.net> wrote in message
> > 3E670861.C17CD0F1@swbell.net">news:3E670861.C17CD0F1@swbell.net...
> > > Jeff Blakeney writes ...
> > > >
> > > > On Mon, 03 Mar 2003 11:50:07 GMT, Rubywand <rubywand@swbell.net>
> > > > wrote:
> > > >
> > > ....
> > > >
> > > > > The method for addressing memory beyond 4MB on the cards is a
> > > > >kludge; and, users are constantly experimenting to discover whether
> > > > >or not some system problem is related to non-support for the extra
> > > > >RAM.
> > > >
> > > > I wouldn't say it is a kludge. If I remember correctly, Apple said
> > > > that the max memory that the IIgs memory expansion slot can handle
is
> > > > 4 MB is because they only put address decoding circuitry on the
> > > > motherboard to handle decoding 4 banks of RAM. This is why, if your
> > > > memory card uses those bank select lines, you are limited to 256 KB,
> > > > 512 KB, 768 KB or 1MB if using 256 Kb memory chips or 1 MB, 2 MB, 3
MB
> > > > or 4 MB if using 1 Mb memory chips.
> > > >
> > > > If the memory card doesn't bother using those bank select lines and
> > > > instead decodes the memory address directly from the address lines
> > > > then there is no reason why the memory expansion connector cannot be
> > > > used to support up to 16 MB of memory.
> > > ....
> > >
> > > It seems like the problem is that the complete address is only
> > > available on the Address lines for up to 4MB-- you have 20 bits (1MB)
> > > plus two lines to select 1 of 4 banks.
> > >
> > > A workaround is to pick off bank information from the Data lines.
> > > There's a good discussion in IIgs Technote #21 Glenn A. Baxter and
> > > Jim Merritt ...
> > >
> > > >>
> > > ....
> > > Suppose a card were designed to latch the bank address directly from
the
> > data
> > > bus with the rising edge of the PH2 clock signal. It could use the
bank
> > > address to derive the proper RAM row address and never bother with
CROW0
> > and
> > > CROW1 at all. Directly latching the bank address would permit the
card
> to
> > > accommodate any desired RAM arrangement in 64K increments, including
an
> > odd
> > > number of rows. Although the technique is valid during CPU cycles, it
> > does
> > > not work during DMA cycles since the FPI never emits the DMA bank
> address
> > onto
> > > the data bus. During DMA cycles, any card that tries to latch the
bank
> > > address directly, instead latches the bank address that was put on the
> > data
> > > bus during the last CPU cycle, which is probably the wrong value.
> > > ....
> > > <<
> > >
> > > A possible fix could be some little module tacked onto the
> > motherboard
> > > which supplements the FPI and produces additional bank select lines.
> > >
> > >
> > >
> > > Rubywand
> > >
> >
> >
>
>
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