SDF supports ¹⁾ multiple Retrocomputing experiences, including free user accounts on TOPS-20 and Symbolics Genera operating systems that are running live and accessible via the internet.

• twenex.org - SDF Public Access TWENEX
• TSS-8 User Tutorial
• ITS - Incompatible Timesharing System HTML tutorial system
• A guide to historical Unixes - Celebrating the 50th anniversary a tutorial and/or tips 'n tricks
• CDC 6500 Survival Guide
• Basic Programs