This collection of historical OS/2 diskettes is from the PCjs Software Archive.
The OS/2 CP-DOS Boot Disk (v7.68) contained a pre-1.0 version of OS/2 built on October 22, 1986.
The OS/2 SIZZLE Boot Disk (v7.68.18) contained a pre-1.0 version of OS/2 built on January 7, 1987, which was based on an interim source code fork known as “SIZZLE”, the code-name for a collection of changes intended to improve overall OS/2 performance.
The OS/2 FOOTBALL Boot Disk (v7.68.17) contained a prototype version of OS/2 from February 1987 that was designed to test two important new features of the Intel 80386 processor: paging and V86-mode. This prototype was forked from pre-1.0 OS/2 sources, and the only hardware it supported was the COMPAQ DeskPro 386-16.
The OS/2 FOOTBALL Boot Disk (v4.41.00) contained an updated FOOTBALL prototype. It was built in December 1987, using final OS/2 1.0 sources merged with assorted FOOTBALL changes, and although it was originally assigned version number 1.3, this version of OS/2 would ultimately become 2.0.
The OS/2 1.0 Debugger Disk contained a version of OS/2 1.0 built on October 12, 1988, which included the built-in kernel debugger used by Microsoft and IBM for internal development, along with a rudimentary program selector. For more details, see the OS/2 1.0 blog post.