MS-DOS critical errors
Error code
Meaning
0
Attempt made to write a write-protected disk
1
Unknown unit
2
Drive not ready
3
Unknown command
4
CRC data error
5
Invalid call structure
6
SEEK error on disks
7
Unknown data medium
8
Sector not found
9
End of paper, printer
A
Write error
B
Read error
C
General error
POST
Appendix
GB - 80