In a conversion effort the records were similar size but had a record type that indicated which record was read. You would have a header or several header records for an order indicating:
Billing account#, address and shipping address,
Order Item detail
Item Bill of Material
Order total records
Usually the conversion effort separated theses individual records into separate database files. One quick way to bring the conversion along was to use a multiformat logical where the records would “appear” in the correct sequence. Listing , Invoice and shipping documents would use the multiformat logical so the rewrite effort could be minimized.
The rewrite effort could determine which program actually used the record infomation.
Inventory might not need shipping information but would need to use bill of matierial for proper inventory of the components.
Serial # records might be critical information to a product recall or warranty items.