COPY6FROM8.SAS This article explains how to move SAS datasets between version 6 and 8 and across computer platforms. SAS datasets are stored in files in binary format. Different computer system stores binary data differently. It can read Version 6 dataset without conversion, if the datasets are created on the same computer system.
Many factors are responsible for the incomparability.
A notable example is the length of variable names and labels. SAS Version 8 allows long variable names and labels. The Version 6 on the other hand limits the variable names to 8 bytes, and labels to 40 bytes. In order for datasets created by version 8 to be readable by Version 6, these variable names and labels have to be trimmed. SAS data sets into a transport file that can be moved from one system to another.