"tell application Disk Copy" would result in sending the image file to the old "Disk Copy 6.3.3" (jan 1999) version in the utilities folder.. which is what famously has this 2gb limit and cannot checksum an image larger then 2gb
it is within disk copy app that it has the function (under utility dropdown) "calculate disk checksum" and "verify image checksum" the applescript doesnt process the udif image, it merely instructs disk copy to do so.. so even though it was ASR 2.2.4 version, it had this old script from v1.3.8 the old script, which was talking to the wrong version of disk copy... it wasnt using 6.5b13 (jan 2002) disk copy at all!!!
ASR 2.2.1 (2001)
ASR 2.2.3 (2001)
http://support.apple.com/kb/DL1262?viewlocale=en_US (posted Post Date: May 6, 1999)
so this 6.3.3 is from before may of 1999..!
disk copy 6.4 or above is neccessary to read UDIF images...
disk copy 6.4 (Mar 2001)
its amazing that apple never thought to upgrade disk copy version when it was putting out revisions 9.04, 9.1, 9.2??
but this was kept secret for "developers only"
ps. who is adam?