Global Object: FSCopy Anchor Link

The FS global object provides a unified virtual file system interface in KryonOS. It dynamically routes operations between external SD Card storage and internal high-speed flash memory.

Firmware driver details are available in the KryonOS GitHub Repository.

Storage Mount PointsCopy Anchor Link

File OperationsCopy Anchor Link

FS.exists(path)Copy Anchor Link

Checks if a file or directory exists at the given path.

• Parameters: path (String)
• Returns: Boolean

FS.readFile(path)Copy Anchor Link

Reads the entire contents of a text file into memory.

• Parameters: path (String)
• Returns: String (or null if the file could not be read).

FS.writeFile(path, data)Copy Anchor Link

Overwrites or creates a file with the provided text or byte data.

• Parameters:
  • path (String)
  • data (String or ArrayBuffer)
• Returns: Boolean (true if successful).

FS.appendFile(path, data)Copy Anchor Link

Appends text or byte data to the end of an existing file.

• Parameters:
  • path (String)
  • data (String or ArrayBuffer)
• Returns: Boolean

FS.deleteFile(path)Copy Anchor Link

Removes a file from the file system.

• Parameters: path (String)
• Returns: Boolean

FS.renameFile(oldPath, newPath)Copy Anchor Link

Renames or moves a file to a new target path on the same volume.

• Parameters:
  • oldPath (String)
  • newPath (String)
• Returns: Boolean

FS.getFileSize(path)Copy Anchor Link

Returns the size of the file in bytes.

• Parameters: path (String)
• Returns: Integer (or -1 if the file does not exist).

Directory ManagementCopy Anchor Link

FS.mkdir(path)Copy Anchor Link

Creates a new directory.

• Parameters: path (String)
• Returns: Boolean

FS.listDir(path)Copy Anchor Link

Lists all entries within a directory.

• Parameters: path (String)
• Returns: Array of directory item objects.

Each entry object contains:

• name (String): File or folder name.
• size (Integer): Size in bytes (0 for directories).
• isDir (Boolean): true if the entry is a subdirectory.

Code Example: JSON Configuration ManagerCopy Anchor Link

// Reading and saving structured JSON configurations
var CONFIG_FILE = "/local/settings.json";

function loadSettings() {
  if (!FS.exists(CONFIG_FILE)) {
    var defaultSettings = {
      brightness: 80,
      soundVolume: 50,
      theme: "dark"
    };
    FS.writeFile(CONFIG_FILE, JSON.stringify(defaultSettings));
    return defaultSettings;
  }
  
  var raw = FS.readFile(CONFIG_FILE);
  try {
    return JSON.parse(raw);
  } catch(e) {
    System.print("Failed to parse settings JSON: " + e);
    return null;
  }
}

function saveSettings(settingsObj) {
  var serialized = JSON.stringify(settingsObj);
  return FS.writeFile(CONFIG_FILE, serialized);
}

// Usage
var appConfig = loadSettings();
System.print("Brightness setting: " + appConfig.brightness);