Memory banks










From: ah241

Date: 07/30/89-09:08:45 AM Z









From: ah241
Subject: Memory banks
Date: Sun Jul 30 09:08:45 1989


I have an Atari 800.  (Not one repair needed on it yet)  I would
like to expand the memory to 64K.  I have a 48K 800 and a extra
16K board.  I would like to know how atari stuck the extra 16K.

did they switch out the OS? or am I hopelessly lost.



** Answered by DOUG WOKOUN (aa384) on Fri Mar 10 17:22:10 1989 **

I don't know the answer to this
question and neither do any of the
other SysOps. 

If anyone has a solution, please
send a message to aa384
aa399 or aa400.  

                     Doug Wokoun
                       aa384
                   One of the Atari
                      Triumvirs

      Thanks for asking.........
Since this last message was left...
somebody left me a message with
some help....



---------------------------------------
Date: Mon Mar 27 19:39:44 1989
From: PETER C. HALLER (ae302)
Subj: 800 MEM UPGRADE

THIS CONCERNS ONE OF THE QUESTIONS IN TECH Q & A.  I HAVE
UPGRADED AN OLD 800 TO 256K AND IT IS NOT TRIVIAL. THE OLD 800
WERE ONLY DESIGNED TO HANDLE 64K. IT REQUIRES A COMPLETE 
REWORKING OF THE OS CARD AND PART OF THE MOTHER BOARD. GOING OVER
WHAT I DID FOR 256K, I THINK THAT TO ADD ONLY 16K MORE IS SILLY.

BASICALLY THREE THINGS WILL BE NEEDED TO EVEN ATTEMPT THE 
CONVERSION:

1) THE TECH REF NOTES;
2) A SPARE OS CARD
3) ROMS TO THE 800XL/130XE(I USED THE LATER)

ALSO I CONVERTED THE STANDARD MEM CARDS FROM 16K TO 128K AND 
THEN ADDED THE REQUIRED ADDRESS DECODING LOGIC NEEDED (AGAIN, 
NOT TRIVIAL.) THIS IS RISKY IF YOU DON'T KNOW WHAT YOUR DOING ( I DON'T RECOMMEN

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(THAT SAID- I DON'T RECOMMEND IT.) BUT STILL, THE MODIFIED
SYSTEM WORKS FINE. I DON'T HAVE IT ANY LONGER, BUT
MY BROTHER IS STILL USING IT AS FAR AS I KNOW.

WITH ONLY ADDING 16K (WHY?), THE COMPUTER I GUESS WOULD
BE ABLE TO USE SPARTA DOS 2.X AND HIGHER, THOUGH I'M NOT 
SURE (NEVER TRIED IT.) 

THINK IT WOULD BE CHEAPER AND LESS FRUSTRATING TO BUY 800XL
OR 130XE, BUT THEN EVERYBODY HAS THEIR OWN MOTIVES.

ANY QUESTIONS, LEAVE MAIL....

                        PCH

PS: WHEN I SAID HANDLE 64K - I'M SURE YOU KNOW THAT - I MEANT
TOTAL 64K - 48K RAM + OS AND MEMORY MAPPED CHIPS. THE PROBLEM 
BASICALLY IS THAT THE EXTRA RAM CAN BE PLUGED IN, BUT THE OS
IS FIXED - IE; CAN'T BE
DISABLED - THE XL/XE OS CAN BE ( I DIDN'T USE A FREDDIE CHIP 
(THAT WAS DUMB.)

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