RC1DSANU@MIAMIU.BITNET (Ryan Collins) (08/28/89)
In reply to the msg about upgrading an Atari 800 to a full 64K, It can't be d
one without a major reworking of the computer. The Atari, being an 8-Bit
computer, can only access 64K of memory at one time. In the XL's and XE's
with 64K, only 48K is easily accessible at one time. To access the other 16K
that is "under the OS", mapped in the memory where the OS is, you must use
location $D301 of the PIA. Its 8 bits are used to turn internal Basic on/off,
turn OS on/off, turn Diagnostic Rom on/off,or select extra RAM (above 64K) if
there. The Atari 800 has this location of the PIA controlling joysticks 3&4.
To change it would require the newer OS out an XL be put in the 800, and
something would have to be done with internal Basic and the diagnostic ROM.
It would be so mush easier to buy an XL or XE. (Analog Mag has an ad for an
Atari 1200XL for $50.00!!!)
Ryan Collins
a.k.a Gozar
Ataris rule forever!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!KC95OPER@MIAMIU.BITNET (Kent Covert) (09/01/89)
I'm not exactly sure how to do it, but there is a book out (I't may be
hard to find) called Mapping the Atari by Ian Chadwick (I think) that tells
a great deal about the Atari OS as well as listing most of the memory addresses
in the computer. There is also a section telling some of the differences
between the old 800's and the XL's. You might try giving this book a try.
To tell you the truth though, it would probably be easier to just buy
an 800XL and not worry about it. You can buy one for around $60 or less if
you look. Or why not just upgrade to an ST?
Good Luck,
Kent Covert
Miami University of Ohio