What is this weird file?

Yuds2003

What is 012345.678 in IBM DOS 4.0x?

Its contents are:
0000000000
1111111111
2222222222
3333333333
4444444444
5555555555
6666666666
7777777777
8888888888

What is the file's purpose?

raulthehelper

To me it seems to be a dummy file.

msdos6000

It's probable just a dummy file that was used for "testing the opreating system's files".