Those familiar with Northgate systems will tell you the platform is based on the Pick operating system. All data is held in a character format and dates are held as numbers.
Each date is a number relative to the 1st January 1970 so 365 would be 1st January 1971 and -365 would be 1st January 1969 and so forth.
This notion stuck with me and have since used the same approach a couple of times when migrating large volumes data between platforms using flat files.
The method of using views to migrate dates as a number relative to a chosen date using DATEDIFF function (SQL Server/Oracle) will save you space in any extract file. Times can also be tackled the same way output as seconds, thousandths of seconds, or even nano seconds relative to mid-night.
Moving these dates onto the target platform is then achieved using the DATEADD function (SQL Server/Oracle) by adding the number migrated to the relative date chosen against the previous extract.
This might seem like a little issue and little saving but with high data volumes prevalent these days it might just make a little bit of sense.
' hope this helps.....a little.