How much memory will be free for apps ?

Too bad it's not open source.

("NC" creative commons)

Limitations:

  GUI64 does not use the VIC-II’s bitmap graphics mode, but operates in text mode. GUI64 is therefore character set–based... Strictly speaking, GUI64 should therefore be considered not a GUI, but a TUI (Text User Interface).

  Currently, there are no applications for GUI64. 

So, it is a file manager, inferior to an orthodox file manager. It supports the mouse, and it can launch BASIC. If you like your KERNAL ROM, you can keep your KERNAL ROM.

I never ran GEOS. I saw it advertised, and it seemed fascinating, but perhaps "too early". I had become fluent in BASIC and proficient at the command line. I could decipher the DOS commands and device IDs. For me, time spent on the Commodore 64 was programming, or in a game or application, rather than pushing files/objects around on the desktop.

One word: GEOS