Perhaps you could expand on this as I was not involved in Y2K myself. Storing dates with 2 digit years doesn't seem to make much sense as a storage saving mechanism for me.
If you want to store only the year, why not store the years since 1900? That way in a single byte you can go all the way up until 2155. If you want to store it bit-aligned rather than byte-aligned why limit yourself to 00-99? 7 bits can store the year from 1900-2027.
If you want to store day + month + year with a two digit year you have 365.25*100=36525~ options. A two byte value can store up until 65535 options, which can hold all days until 2079.
If you are storing your dates as flat strings (DD-MM-YY or so) then you are already wasting such a large amount of bytes that "storage concerns" seem moot. You are already using 8 bytes to store a date that can be stored in 2 bytes, at that point why not use 10 bytes?
String formatting and display seems more obviously affected to me than storage.
If you want to store only the year, why not store the years since 1900? That way in a single byte you can go all the way up until 2155. If you want to store it bit-aligned rather than byte-aligned why limit yourself to 00-99? 7 bits can store the year from 1900-2027.
If you want to store day + month + year with a two digit year you have 365.25*100=36525~ options. A two byte value can store up until 65535 options, which can hold all days until 2079.
If you are storing your dates as flat strings (DD-MM-YY or so) then you are already wasting such a large amount of bytes that "storage concerns" seem moot. You are already using 8 bytes to store a date that can be stored in 2 bytes, at that point why not use 10 bytes?
String formatting and display seems more obviously affected to me than storage.