Wow, the infamous "merged product"... In '89 I joined MS to run the "LM/X" product, where we extended the Unix networking model to support the SMB protocols. A very interesting time where MS worked with HP to get the kernel and networking changes into the mainline code base while at the same time AT&T was doing their own version. Sun was pushing their implementation of PC NFS, and many interesting "standards" meetings were held. If I remember correctly, the PC networking protocols showed in in XPG4 (X/Open Portability Guide) in 1992.