mail-complaints-to="news_AT_tioat_DOT_net"   
   From: "Doug Bissett"    
      
   On Sun, 28 Nov 2010 12:31:26 UTC, Lars Erdmann    
   wrote:   
      
   > Doug Bissett wrote:   
   > > On Sat, 27 Nov 2010 11:57:17 UTC, Lars Erdmann   
   > >   
   > > I am pretty sure that the BIOS is supposed to write good data through   
   > > all of memory, even if you do the quick test.   
   >    
   > I don't think so. That's exactly what makes "Quick Power On self test"   
   > quick. It does not write to all memory but only to a fraction (the fraction   
   > used by DOS). You can tell the difference between writing and reading back   
   > to only 640k or to the whole 2GB.   
   >    
   >    
   > Lars   
      
   No, that isn't right. A quick test simply writes all zeros, and reads    
   it, then it writes all ones, and reads it, end of test, but at that    
   point everything should be in good parity (the zero and one tests may    
   be the other way around). An extended test does those two, then does    
   half a dozen pattern writes, and reads before it is finished. Of    
   course, different BIOS implementations might do it a little different.   
   One thing, for sure, is that by the time an operating system gets    
   booted, all of memory should be in good parity. If it is not, there is   
   something wrong.   
      
   --    
   From the eComStation of Doug Bissett   
   dougb007 at telus dot net   
   (Please make the obvious changes, to e-mail me)   
      
      
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