AWR1843BOOST: What is ChunkSize in example MATLAB code

Hi, in this post a MATLAB script is given for reading a binary file, see also below. However I have two questions:

1. What is the chunkSize? (specifically for the AWR1843Boost)

2. There should be an `end` instruction at some point but I am not sure where?

Thankyou in advance.

%*********************************************************************
%% read binary file
%*********************************************************************
fname = strcat(DirName,fileName);
fid = fopen(fname,'r');
    
adcOut = [];
inputLoadingPosition = 0;
for indexFrames=1:numFrames
    
    fseek(fid, inputLoadingPosition, 'bof');
    dataChunk  = fread(fid, chunkSize,'uint16','l');
    inputLoadingPosition = ftell(fid);   
    
    dataChunk = dataChunk - (dataChunk >= 2^15) * 2^16;
    
    % radar_data has data in the following format.
    % Rx0I0, Rx0I1, Rx0Q0, Rx0Q1, Rx0I2, Rx0I3, Rx0Q2, Rx0Q3, ...
    % The following script reshapes it into a 3-dimensional array.
    % size(adcOut) = [ADC samples per chirp x Chirps per Frame x Number of virtual Channels]
    
    len = length(dataChunk) / 2;
    adcOut(1:2:len) = dataChunk(1:4:end) + 1j*dataChunk(3:4:end);
    adcOut(2:2:len) = dataChunk(2:4:end) + 1j*dataChunk(4:4:end);
    adcOut = reshape(adcOut, Chirp_NUM_ADC_sample_size, numTXAnt*4, Chirp_NUM_Chirps);
    adcOut = permute(adcOut, [1, 3, 2]);
        
    %*********************************************************************
    %% Radar signal processing
    %*********************************************************************
    % Plot ADC Data for the 1st Chirp
%     figure(1);clf
%     plot(real(adcOut(:,1,1)),'r');
%     hold on
%     plot(imag(adcOut(:,1,1)));
%     legend('I-Channel', 'Q-Channel'); grid on
%     title('ADC data')
   
    
    
    % 1D range-FFT across the 2nd dimensions (samples), no zero padding
    fftSize1D = size(adcOut,1);
    radar_data_1dFFT = fft(adcOut,[], 1);%.*window_1D