[BUG]: No such file or directory: '/tmp/heat_0.bin'

Is this a duplicate?

• I confirmed there appear to be no duplicate issues for this bug and that I agree to the Code of Conduct

Describe the bug

01.04.01 in C++ tutorial occasionally can't access temporary storage, which can be fixed by deleting and re-starting the runtime. We should move all temporary files generated by C++ labs from /tmp to local directory.

Steps to reproduce

The failure is rather random, not sure what triggers it.

Expected behavior

All cells in 01.04.01 should run without errors.

Actual behavior

01.04.01 in C++ tutorial randomly triggers the following error on Colab:

/content/Sources/ach.py in drawframe(i)
     28 
     29     def drawframe(i):
---> 30         with open(f"/tmp/heat_{i}.bin", 'rb') as f:
     31             height, width = np.fromfile(f, dtype=np.int32, count=2)
     32             data = np.fromfile(f, dtype=np.float32, count=height * width)

FileNotFoundError: [Errno 2] No such file or directory: '/tmp/heat_0.bin'
<Figure size 800x200 with 0 Axes>

Environment

No response

Additional context

No response

Start with the 01.04.01 C++ tutorial and the traceback location /content/Sources/ach.py. Trace where the C++ lab creates heat_*.bin and where ach.py reads it, then run all cells in the notebook on Colab. Done means the cells complete without the missing-file error and temporary files use the notebook's local directory rather than /tmp.