In Addition of Alex information, you can check DougH docs is StoneField TechPapers.

www.stonefield.com -> Tech Papers -> Multi-user and Data Buffering Issues (20K)

"In FoxPro 2.x, developers edited records using SCATTER MEMVAR, editing the memory variables, and GATHER MEMVAR. The purpose of this indirect editing of fields was to protect the record by buffering it. With Visual FoxPro, data buffering is built in, so fields can be edited directly. This document discusses how data buffering works and explores strategies for selecting which buffering mechanism to use and how to handle multi-user conflicts."
http://downloads.stonefield.com/pub/buffer.zip