How to open and write into a .byt file?

Hello all, I have a code which has .byt file. Was hoping any of the users here know how to write data into a .byt file. Thank you

[Walter Roberson]

Those are the binary files for the XACE emulator for the early Jupiter Ace computer, right?

[Srijith Rajeev]

@Walter- I am not sure about the XACE emulator but I know that its part of a MAT5 FORMAT: (5 files that end with *C.bmp, *I.bmp, *X.byt, *Y.byt, *Z.byt). It isn't a standard. The X-Y-Z.byt files contain the x, y and z co-orinates and I was interested in changing the co-ordinates but I don't know how to edit these files on MATLAB.

[Walter Roberson]

It appears to be http://www.engr.uky.edu/~lgh/soft/softmat5format.htm

[Srijith Rajeev]

@Walter: Yes it is. The project I am working on gives me MAT5 files beforehand and I wanted to stick to MATLAB if it was feasible.

Answer 1

[Walter Roberson]

datasetname = 'Tree84vq';   %ie if we are working with Tree84vqX.byt

newsuff = '_new';           %adjust to differentiate old file and new file
Xsuff = 'X.byt';
Ysuff = 'Y.byt';
Zsuff = 'Z.byt';
Xfilename = [datasetname Xsuff];
Yfilename = [datasetname Ysuff];
Zfilename = [datasetname Zsuff];
newXfilename = [datasetname newsuff Xsuff];
newYfilename = [datasetname newsuff Ysuff];
newZfilename = [datasetname newsuff Zsuff];

fid = fopen(Xfilename, 'r');
Xdata = fread(fid, inf, 'single');
fclose(fid);
fid = fopen(Yfilename, 'r');
Ydata = fread(fid, inf, 'single');
fclose(fid);
fid = fopen(Zfilename, 'r');
Zdata = fread(fid, inf, 'single');
fclose(fid);

now manipulate Xdata, Ydata, Zdata to make newXdata, newYdata newZdata

fid = fopen(newXfilename, 'w');
fwrite(fid, newXdata(:), 'single');
fclose(fid);
fid = fopen(newYfilename ,'w');
fwrite(fid, newYdata(:), 'single');
fclose(fid);
fid = fopen(newZfilename, 'w');
fwrite(fid, newZdata(:), 'single');
fclose(fid);

You might have noticed that I output to a different file name than was used for input. I always advise against overwriting existing files unless you are certain you have a backup. Especially until the code is fully tested.

[Srijith Rajeev]

Thank you @Walter. I have a doubt though, will the new file being saved be in .byt format?

[Walter Roberson]

Yes. .byt format is a list of single precision numbers in binary with no headers. That is what I read in and write out.