if verification fails, it'll recopy or correct it. However it's
implemented, the end result is the copy you get is guaranteed to be
identical as the source.

Am I right in saying that without the /v option, you can end up with a
corrupted file?

When you copy a file in Windows Explorer (drag and drop or Ctrl-c/x),
which behaviour do you get?

Thanks!
iDon

On 5 Dec 2005 16:52:34 -0800, idon.wong@gmail.com wrote in
comp.os.ms-windows.programmer.win32:

Actually, MS-DOS never defined "copy /v" that way, and I don't know
that any version of cmd.exe does, either.

In MS-DOS, "copy /v" used a special mode of the NEC floppy disk
controller (FDC) that read the data from the disk and computed the CRC
for each sector, comparing it to the CRC stored at the end of the
sector. The FDC just threw away the data, did not send it to the
processor, just a result code for each sector indicating that the CRC
matched the data on the disk.

The behavior for hard disk drives, when they came along, was similar.
MS-DOS "copy /v" never actually compared the data written to what was
supposed to be written, merely verified that the data written was
readable without error.

I don't know what Explorer does, however.

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://www.eskimo.com/~scs/C-faq/top.html
comp.lang.c++ http://www.parashift.com/c++-faq-lite/
alt.comp.lang.learn.c-c++
http://www.contrib.andrew.cmu.edu/~a...FAQ-acllc.html

You can type help in CMD window.
It isn't enough explanation, but it says what MS want to say.

So, what?

So, what?

So, what?