[comp.sys.ibm.pc.misc] "Cannot disable A20 line" warning msg from HIMEM.SYS

alpert@chovax.enet.dec.com (Agent of Goldstein) (10/29/90)

When my system, a 386sx with NEAT motherboard, boots up I get the following
message from HIMEM.SYS:

	Installed A20 handler number 1.
	WARNING: Can't disable A20
	64K High Memory Area is available.

This occurs even if HIMEM is the only thing in the CONFIG.SYS file,
so it should not be a conflict with another memory manager.

I'm new to Intel/IBM architecture and don't really understand what
this message means or what its implications are; other than that
the A20 line has to do with an address line used in memory management.  

The system appears to otherwise function normally.  I know I have *not* 
seen this WARNING message on other systems as they boot up.  Any 
insights/explanations appreciated! 

-------------------------------------------------------------------------------
  Bob Alpert       { alpert@chovax.dec.com            }  Suspicion breeds
  DEC              { ...!decwrl!chovax.dec.com!alpert }  confidence.
  Cherry Hill, NJ  { alpert%chovax.dec@decwrl.dec.com }  
-------------------------------------------------------------------------------