What is the name of this small company producing operating systems and programming languages, whose employee Kathleen O'Brien programmed the Atari Assembler Editor?
Atari Assembler Editor: The Atari Assembler Editor is a cartridge-based development system used to edit, assemble, and debug 6502 programs for the Atari 8-bit family of home computers. Atari Assembler Editor:  It was programmed by Kathleen O'Brien of Shepardson Microsystems. Shepardson Microsystems: Shepardson Microsystems, Inc. (SMI) was a small company producing operating systems and programming languages for the Atari 8-bit and Apple II computer families.
Shepardson Microsystems