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