private void updateViewToFilePos(long filePos) {
		model.clear();
		table.clear();
		try {
			List<String> lines = reader.readNextChunkFrom(filePos);

			// If the number of lines read is < 1, then we're at the end of the file. If we
			// try to read a chunk from here we'll get nothing in return and will have nothing
			// to display. So back up from the end until we get a full line that we can show.
			int i = 0;
			while (lines.size() < 1) {
				lines = reader.readNextChunkFrom(filePos - i);
				i += 1;
			}
			((FVTableModel) table.getModel()).addRowsToTop(lines);
			viewportUtility.moveViewportToTop();
		}
		catch (IOException e) {
			Msg.error(this, "Error reading next chunk of data", e);
		}
	}
Loads the first chunk and moves the viewport accordingly.
Ghidra/Framework/Project/src/main/java/ghidra/framework/main/logviewer/ui/FileViewer.java