The SYM-1 Disk Operating System for eh Commodore 1541 Disk Drive Manual by Ronald Jordan was provide in printed form only.  The manual consists of the following sections:

1. Manual 2.8Mb PDF

2. Interface Drawing

3. Assembly listing 1.1 Mb PDF (lost in hard disk crash, can be supplied if needed)

4. Cross Reference Listing

5. Utility Disk Note (1 page)

I have included. Pages from Commodore 1541 Drive Manual (6 pages) that have additional information about the drive commands.