GUI64

GUI64
Infobox
Developer	WebFritzi
Company	WebFritzi Inc.
Publisher	Friedrich Philipp
Release	2024
Licence	CC BY-NC 4.0
Platform	C64
Genre	Grafical User Interface
Operation
Media
Language(s)
Information	Current Version 1.9 (as of September 1, 2025)

Description

GUI64 is a graphical user interface (GUI) for the C64, first released in version 1.0 in November 2024. Although GUI64 may appear to be a standalone operating system, it is just a graphical layer running on top of the C64’s built-in ROM-based operating system, the Kernal. GUI64 presents files and directories in freely movable windows, allowing for easy file management on floppy disks as well as on disk images stored on SD2IEC devices. The current version of GUI64 is 1.9.

Operation

GUI64 can be operated using a mouse (such as the 1351 or compatible models) connected to Control Port #1, or with a joystick in Control Port #2 (right click with CBM key + fire). To enable support for the mouse wheel—e.g., for scrolling or in up/down controls (see below)—the Micromys adapter must be used. This functionality is also available when using the VICE emulator.

Look and Feel

The GUI64 desktop (Windows design)

Starting with version 1.9, GUI64 is available in two variants:

Windows-like interface

In this variant, GUI64 visually resembles Windows-style interfaces. The GUI is window-based, with a taskbar at the bottom of the screen, featuring a "Commodore (CBM) button" embedded on the left and a recessed clock button on the right. In between are the task buttons — similar to those in Windows 95.

Mac-like interface

This variant visually imitates the interface of the first Macintosh computers from Apple. The menus are not integrated into the windows but are displayed in a menu bar at the top edge of the screen. The system menu in the upper-left corner includes, in addition to the entries from the corresponding CBM menu in the Windows variant, an “About” entry, which in the Windows variant is part of the file browser’s menu.

In both versions, the desktop itself is empty except for two drive icons in the upper-left corner (in the Mac design: upper-right corner), and—unlike other interfaces such as C64OS or GEOS—does not support placing file icons directly on it. Instead, the desktop serves as a background for windows, which can be freely moved and positioned. Unlike GEOS, for example, GUI64 does not use the VIC-II’s bitmap graphics mode, but operates in text mode. GUI64 is therefore character set–based. For instance, windows cannot be moved pixel-perfectly, but are instead aligned to the 8×8-pixel grid of the character screen. The desktop consists of 22 rows (in the Mac design: 24 rows) and 40 columns of characters. Strictly speaking, GUI64 should therefore be considered not a GUI, but a TUI (Text User Interface).

Elements on the Desktop and in the Taskbar

The GUI64 desktop (Mac design)

Drive Icons

By default, the two drive icons are assigned to device numbers 8 and 9, but this can be changed via right-click on the icons. A double-click on a drive icon opens a file browser window, see below.

Commodore Button (Windows version) / System menu (Mac version)

Clicking the "Commodore button" (lower left) or the "System menu" (upper left) opens a menu with two entries: "Settings" and "BASIC." Selecting "BASIC" returns the user to the familiar BASIC editor of the C64, while clicking "Settings" opens a configuration window where the visual appearance of GUI64 can be customized. In the Mac version, there is another entry "About" which shows a small dialog with information on GUI64.

Time

Double-clicking the clock opens a dialog for setting the time. By default, the clock is set to "00:00" when GUI64 starts. In future versions of GUI64, it is planned to support reading the time from a 1541 Ultimate cartridge, from an Ultimate 64 board, or compatible SD2IEC devices.

Tooltips

Because the GUI64 screen has limited horizontal space, taskbar button titles are truncated to fit. Starting with GUI64 v1.8.1, users can see the full title in a tooltip by hovering over a button for at least one second. Tooltips are also displayed when hovering over desktop drive icons, showing the full path for drives such as SD2IEC.

Graphical Elements on the Desktop

Windows

The primary graphical elements that convey information in GUI64 are windows. Each window has a title bar at the top, with the window title on the left (Mac design: centered). In the Windows design, there are various control buttons on the right. One of these buttons is always an X-icon (X) to close the window; if the window supports minimizing or maximizing, corresponding buttons for those actions are also present. In the Mac version, there is only a button for closing the window on the left-hand side of the title bar. Windows-version: A minimized window disappears from the desktop but remains accessible as a button in the taskbar. Clicking this button restores the window to the desktop. This helps keep the desktop organized and clutter-free.

A special type of window is the dialog. Dialogs cannot be minimized and always retain full focus. This means that user input is restricted to within the dialog window only.

Controls

The graphical elements within windows are called controls. Each of these controls serves a specific function—even if that function is simply displaying text, as is the case with labels (see below). The controls available in the current version 1.9 of GUI64 are, in order:

Controls in GUI64 and Their Functions

Control	Purpose
Menu Bar	Allows display of menus and is always located directly below the window’s title bar in the Windows version and in the menu bar (top edge of screen) in the Mac version.
Button	A clickable button (with a visual 3D effect in the Windows version)
Listbox	A box containing selectable entries arranged in rows
FileListScrollBox	A box containing selectable entries in rows. Each row displays the file type (as an icon), the filename, and optionally the file size (in blocks).
Label	Single-line, non-editable text without a box
Multiline Label	Multi-line, non-editable text without a box (rows are separated with the "\" character)
Frame	A border frame used to group and separate controls
Colorpicker	A colored box. When clicked, it opens a menu with the 16 C64 colors. Once a color is selected, the button updates to reflect the chosen color.
Radiobutton Group	A list of options in rows without frame box for exclusive selection
UpDown	A control for displaying numerical values with integrated arrow buttons to increment or decrement the value (mouse wheel support)
Singleline Edit	A single-line input box for text entry
Progress Bar	A single-line box for displaying progress (e.g., during file copy operations)
ColorBox Label	A combination of a colored box (on the left) and a label (on the right)
TextViewBox	A box displaying non-editable text

Functionality

GUI64 allows users to work with drives and files. The following drives are detected and supported: Commodore 1541 floppy drive, Commodore 1571 floppy drive, Commodore 1581 floppy drive, and SD2IEC devices. GUI64 may also work with hard drives and other storage devices; however, due to a lack of testing, reliable functionality for these cannot be guaranteed at this time.

Double-clicking one of the drive icons on the desktop opens a file browser window, which—after loading—displays the contents of the medium (floppy disk, SD2IEC directory, or disk image within an SD2IEC directory). GUI64 can also handle dnp images. Files and directories are listed vertically within the window. Each entry shows the file type (as an icon), the file name, and, optionally, the file size (see the "View Menu" below). Entries can be selected by clicking on them. The list can be scrolled by either using the scrollbar on the right edge or the mouse wheel.

Running Programs

To run programs (equivalent to LOAD"...",x and RUN), a simple double-click on the corresponding entry in the drive window is required. This will display a progress bar in the taskbar, showing the loading progress. Once the file is loaded into the C64's memory, the file will be executed. To load a machine code file (without a BASIC stub, such as 10 SYS 2063), see "Boot" in the File menu. Note: GUI64 will not remain in the background after running a file and has to be loaded back into memory afterwards.

Opening Directories and Disk Images on SD2IEC Drives

When the file browser window displays the contents of a directory on an SD2IEC drive, directories and disk images (if available) will also be shown. Directories are represented by a folder-like icon. A double-click on a directory or disk image initiates a loading process, after which the contents of the selected directory or disk image will be displayed in the browser window.

Menus

Each file browser window in GUI64 has a menu consisting of the entries "Disk," "File," and "View." These menus provide the user with various options for manipulating drives, files, and directories.

The Disk Menu

The 'Disk' menu in GUI64 allows users to manipulate floppy disks (or disk images) and view information about the drive at the corresponding device number.

The 'Disk' menu of GUI64

The disk menu of GUI64

Entry	Function
Refresh	The contents of the disk are reloaded (e.g., after changing the floppy disk)
Device No	Opens a dialog for changing the device number
Info	Opens a dialog to display information about the disk and the drive
Format	Opens a dialog to format the disk
Rename	Opens a dialog to rename the disk (currently only for 1541 drives)
Close	Closes the window

The File Menu

The 'File' menu of GUI64 allows for copying or 'cutting' files, as well as deleting, renaming, viewing, booting files, and creating disk images.

The 'File' menu of GUI64

The 'File' menu of GUI64

Entry	Function
New	Opens a dialog to create new disk images (d64, d71, d81) or folders on an SD2IEC drive.*
Cut	GUI64 remembers the selected file for 'cutting'
Copy	GUI64 remembers the selected file for copying
Paste	Pastes the copied or 'cut' file onto the floppy disk, disk image, or into the directory
Delete	Opens a dialog to confirm the deletion of the selected file
Rename	Opens a dialog to rename the selected file
View	Opens a window to view the contents of the selected file in text or hex mode (currently only rudimentary implementation)
Boot	Loads the selected file to the memory address specified in the first two bytes of the file and instructs the processor to start the code from there (equivalent to LOAD"...",x,1: SYS xxxxx)

*Note: After creating a new image, the corresponding virtual disk needs to be formatted. For this, double click the image, click Format in the Disk menu and choose Full Format.

The View Menu

With the entries in the 'View' menu, the display in the file browser window can be changed.

The 'View' menu of GUI64

The 'View' menu of GUI64

Entry	Function
File Sizes	Displays file sizes in the file browser window (or not)
Lower Case	Switches to uppercase and lowercase display (or not)
Sort by Name	Sorts the directory and folder list by name
Sort by Type	Sorts the directory and folder list by file type
Sort by Size	Sorts the directory and folder list by file size
GUI64 Info	Opens an 'About' dialog with information about GUI64 (only Windows version)

Applications

Currently, there are no applications for GUI64. However, after the release of version 2.0, an interface for developers is planned, which will allow for the easy creation of applications for GUI64.

Development

GUI64 was developed by Friedrich (Fritz) Philipp, also known as WebFritzi. Especially during the implementation of the drive functions, he received valuable support from numerous members of Forum64, who assisted him with advice and guidance. Some code snippets originate from Codebase64.

Links

• Github webpage of GUI64
• Developer's webpage

Videos

• Playlist about the development progress of GUI64 (YouTube)