gzz: Story of an unsuspected crash spiral (v.0706)

[Ted Nelson <ted@xxxxxxxxxx>]

Hi guys--

Yesterday I got a new kind of crash; it took Marlene and Ed to
 figure it out.  

I thought that I managed to work for an hour till it crashed hard
 (when I used the ESC key to go home). 

I started at maybe 4:30 pm, putting in the family data that I've been
 using in my demo of the prototype.  Since I was just adding and
 filling in cells (nothing risky, I figured), I was able to save that at 5 pm.

From that point I figured I'd better make frequent backups.

As I went on I did backups by copying the directory, not terminating
 the program.  But at 6 pm it crashed hard (use of ESC key and
 resulting strange condition).

I tried to restart with that same data, but it wouldn't.  

I tried to go back to the data from just before.  That wouldn't open
 either.  Nor would the previous.  None of the data between
 5 pm and 6 pm would open!

I assumed that somehow the jar files had been corrupted, or Java
 itself.  

Not so.  Marlene and Ed concluded that the corruption occurred
 between the first and second save, and that if I'd shut down at any
 time after the second save I would not have been able to reopen
 the file, due to some part of the shutdown and startup processes
 on corrupted data.

Lesson learned: shut down completely at backup time.

It just occurred to me-- could the successions of corrupted data
 have had to do with not shutting down?  Do you do some
 closure process on the data on shutdown that was not being
 performed properly by just dragging out a copy of the data
 directory?

Best, T

_________________________________________
Theodor Holm Nelson              
Project Professor, Keio University SFC Campus, Fujisawa, Japan
Visiting Professor, University of Southampton, England
 ?  e-mail: ted@xxxxxxxxxx   ?  world-wide fax 1/415/332-0136
 ?  http://www.sfc.keio.ac.jp/~ted/    ?  http://www.xanadu.net
 ? Coordinates in USA      Tel. 415/ 331-4422
  Project Xanadu, 3020 Bridgeway #295, Sausalito CA 94965
_________________________________________