Using ubuntu 12.04 LTS
Using tz 2012 j code/data
 
Tested each timezone mentioned in zone.tab, by zdump-ing each one.
Observed that each timezone had two lines that reported NULL, then a bunch of nice-looking pairs-of-lines, then two lines that reported “NULL”
 
I understand that this could be caused if you are using a 64 bit ubuntu on a 32-bit machine....
...I may have !!! migrated to a 32-bit ubuntu on a 32-bit machine...
 
The lines at the earliest/latest transition for each timezone are no longer “NULL”-containing (they mention 1901 and 2038, which I understand)
 
What is breaking my heart is “Why did the lines drop off the gmtoff value, now ending with the isdst value?”
 
Saw somewhere that tm_gmtoff is a GNU extension that may not be visible...
Please “illuminate”
 
Thanks,
Jim