Msg: 668 *Conference*

10-18-91 08:46:21

From: TRACY ALLEN

To : RICHARD HANSON

Subj: REPLY TO MSG #616 (OVERWRITTEN FILE)

Dear Rick,
   The OS _is_ busy.  In a disk operating system, files that get erased are
just tagged as ssuch in the directory, but the information remains in place for
some time until the space or sector is actually needed to write another file.
The M100 in contrast, keeps all files in the lowest part of memory in strict
order.  When one is erased, the OS closes up the space immediately.  Also, when
you enter TEXT, the computer scans all the free memory and fills unused bytes
with zeros.  That's why anyone who wants to try a cold start recovery; should
not try to edit anything using TEXT.  But when a file is erased and everything
in memory moves down to fill the empty space, the space at the top is left with
whatever was there before, until you enter TEXT or add something new.  And cold
start leaves everything in place.  
    
    I don't know what would cause the repeating pattern of a few bits of text
in memory.  In a cold start situation, the computer gets confused and starts
running at some point in memory that does not really contain computer
;instructions, but that the computer interprets as instructions nonetheless.
Kind of a "random program".  It can do really weird stuff and then loop around
to do it over and over again.
  
  Start of RAM in an 8K M100 is 57344, in a 16K M100 is 49152, and in a 24k
M100 or in a T200 is 40960.
   -- Tracy