[comp.sys.atari.st] ST 4 meg limit

ugbernie@cs.Buffalo.EDU (Bernard Bediako) (04/15/89)

Will Tos 1.4 allow the ST to use more than 4 megs of memory (that IS all it can
address right?).  Also, is MINIX limited to 4 megs?  It doesn't use Tos.
Or is the 4 meg limit set in the hardware?
				thanks
			bernie

Bernard Bediako  --------=-=-=-=-=->	DOMAIN:	ugbernie@cs.buffalo.edu
"You CAN have your cake and eat it!"

rich@lakesys.UUCP (Richard Dankert) (04/15/89)

In article <5271@cs.Buffalo.EDU> ugbernie@cs.Buffalo.EDU (Bernard Bediako) writes:
>
>Will Tos 1.4 allow the ST to use more than 4 megs of memory (that IS all it can
>address right?).  Also, is MINIX limited to 4 megs?  It doesn't use Tos.
>Or is the 4 meg limit set in the hardware?
>				thanks
>			bernie
>
>Bernard Bediako  --------=-=-=-=-=->	DOMAIN:	ugbernie@cs.buffalo.edu
>"You CAN have your cake and eat it!"


	I don't belive that TOS or GEM have anythingto do with it. What it
boils down to is the MMU (Memory Management Unit) or better yet, the
MCU ( Memory Control Unit) that is the problem. It can only address two 
banks of ram. Now when the 16 MegaBit Dram that I had heard was developed in
Japan (?) comes around at a reasonable price, one bank would equal 16 Meg.

	TOS has (had?) a limit of 16 Meg, and GEM had a limit of 32 Meg.

Last I knew the 16 Meg Hard drice barrier had been broken in TOS 1.4, thus
allowing partitions to be 32 MEG, besides other nice fixes/enhancements.

rich.....
UUCP: rich@lakesys.lakesys.COM     {always .... }

hase@netmbx.UUCP (Hartmut Semken) (04/21/89)

In article <5271@cs.Buffalo.EDU> ugbernie@cs.Buffalo.EDU (Bernard Bediako) writes:
>
>Will Tos 1.4 allow the ST to use more than 4 megs of memory (that IS all it can
>address right?).  Also, is MINIX limited to 4 megs?  It doesn't use Tos.
>Or is the 4 meg limit set in the hardware?

Software isn't everything.

The custom chips in my ST (520 Rev C) have 22 bit adres registers.
So DMA, MCU, Shifter can adress 4 Meg. Nothing more...

hase
-- 
Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP
If there is something more important than my Ego, I want it caught and shot.
Now! (Zaphod Beeblebrox)