(This is emulating the Model 16 using the trs80gp emulator and saving/load from virtual disk.)

Setting up a fresh disk

If you’re already in BASIC, just open another trs80gp emulator to create the new disk first.

• Insert a new disk by going to Diskette -> :1 <empty> -> <<unformatted dmk>>
• FORMAT 1 and “Y” when asked to Continue?

• Once formatting completes select Diskette -> :1 * <<unformatted>> -> Export… -> [fill out “File name:” field] -> [Save]
• Now load the saved disk with Diskette -> :1 * <<unformatted>> -> Replace… -> [select the disk file you just created] -> [Open]
• DIR 1 should show the empty disk in drive 1

Saving your work

• Compose your program in BASIC or BASICG (graphics BASIC)
• The filespec of TRSDOS-II files is filename/ext.password:drive_number (if you’re used to DOS 8.3 names or Windows, your habitual “extension” would be a “password” in TRSDOS-II)
• To save a program named “COS” with a “BAS” extension on Drive 1, type SAVE "COS/BAS:1"
• SYSTEM to exit basic.
• DIR 1 should should the directory of your disk with the COS/BAS showing. In my example below, I also tried to save “COS.BAS” which is actually “COS” with a password of “BAS”

Loading your work

• You can PRINT or DUMP your saved file with the COS/BAS filespec as before, but it will be a somewhat binary output and not plain text like you might expect from modern programming language files.
• Ultimately, you will have to go back to BASIC to reload with the same filespec (LOAD "COS/BAS:1“)

Resources:

• TRSDOS-II Reference manual for the Model 16 (and II & 12) – Toc, Chapter 1 & 2 from PDF documentation for the Tandy TRS-80 model II