Getting an error on reading a file

I am using the current matlab script in which the file imu_data.bin is already existing

filename = 'imu_data.bin';
[inertial_data,time_stamps,raw_data]=parse_imu_data(filename);
%delete(filename);
i=0;
while i >=0
   filename1 = 'inertial_data.bin' ;
   file1 = fopen(filename1, 'w');
   fwrite(file1,fread(inertial_data,'uint8'),'uint8');
   i = i+1;
   fclose(file1);
end
% Plot data in SI units
figure(1),clf, hold on
plot(inertial_data(1:3,:)');
plot(sqrt(sum(inertial_data(1:3,:).^2)),'c');
grid on
title('Accelerometer readings');
xlabel('sample number')
ylabel('a [m/s^2]');
figure(2), clf, hold on
plot(inertial_data(4:6,:)'*180/pi);
plot(sqrt(sum((inertial_data(4:6,:)*180/pi).^2)),'c');
grid on
title('Gyroscope readings');
xlabel('sample number')
ylabel('\omega [deg/s]');
figure(3),clf, hold on
subplot(2,1,1);
plot(double(time_stamps)'/64e6,'b-');
grid on
title('Time stamps');
xlabel('sample number')
ylabel('[s]');
subplot(2,1,2);
dt = diff(double(time_stamps)');
for i=1:numel(dt)
    if dt(i)<0
        dt(i) = dt(i)+2^32;
    end
end
plot(dt/64e6,'b-');
grid on
title('Time differentials');
xlabel('sample number')
ylabel('[s]');

figure(4), clf, hold on
plot(sqrt(sum((inertial_data(4:6,:)*180/pi).^2)),'c');
grid on

Iam getting the following error message

"Error using fread
Invalid file identifier.  Use fopen to generate a valid file identifier.

Error in line
   fwrite(file1,fread(inertial_data,'uint8'),'uint8');"

Answer 1

[Walter Roberson]

Opening inertial_data.bin for writing failed. You should check to see which directory you are cd()'d to, as you might be in a directory that you do not have permission to write in.

[Nikhil Singh]

Mr. Walter I have tried the same thing earlier in the same directory in another script there it work fine.

filename = 'imu_data.bin';
file = fopen(filename, 'rb');
ctr = 0;
while ~feof(file)
 f = fread(file,8,'uint8');
 disp(f)
    ax = fread(file,1,'single');
    disp(ax)
    ay = fread(file,1,'single');
    disp(ay)
    az = fread(file,1,'single');
    disp(az)
    gx = fread(file,1,'single');
    disp(gx)
    gy = fread(file,1,'single');
    disp(gy)
    gz = fread(file,1,'single');
    disp(gz)
    fread(file,1,'uint16');
    filename1 = 'imu_dat.bin';
    file2 = fopen(filename1, 'w');
    ctr = ctr + fwrite(file2,fread(file,'uint8'),'uint8');
    fclose(file2);
end

this is the script Which I had used. its working good and The data is also correct. But for I don't know what happened second time.

[Walter Roberson]

Please show the result of

exist('inertial_data.bin')
dir('inertial_data.bin')
fileattrib('inertial_data.bin')
fileattrib('.')