Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

J:\chds\mach3>chdman copy -i mach3.chd -o newmach3.chd
chdman - MAME Compressed Hunks of Data (CHD) manager 0.145u1 (Feb 19 2012)
Output CHD:   newmach3.chd
Input CHD:    mach3.chd
Compression:  avhu (A/V Huffman)
Hunk size:    380,496
Logical size: 40,410,197,184
Compression complete ... final ratio = 36.6%

J:\chds\mach3>chdman verify -i newmach3.chd -f
chdman - MAME Compressed Hunks of Data (CHD) manager 0.145u1 (Feb 19 2012)
Raw SHA1 verification successful!
Overall SHA1 verification successful!

J:\chds\mach3>