Speed of comparison

[AlexL]

Hello.

I see on the main page of EDP the following user testimonial: "A great tool for Registry Compares. Bud Allen".

I tried the following command line with EDP v3.4.1.5:
ExamDiff.exe ExamDiff.exe ExamDiff.exe
On my computer at work with 2 CPU-s of 3 GHz and 512 MB RAM I was waiting till this command will finish for 37 seconds. Though comparing binary files is not the same as comparing text files, but this binary file is 20-30 times smaller than text registry files (my registry is 77 MB when exported in Unicode format); in addition, there were no differences. If we return to registry comparison: will it ever finish? First several seconds of such try ate 33 MB of memory and all disk performance for swapping, so I hardly could call Task Manager to kill EDP.

Can EDP really compare registry files?

Thank you.

[psguru]

Actually, running "ExamDiff.exe ExamDiff.exe ExamDiff.exe" produces almost instantaneous results in my testing -- binary comparison is much faster for identical files. When I tried comparing two different versions of EXP (3.4.1.5 vs. 3.4.0., the results were is follows:

Code: Select all

Block Size      Time
==========    ===============
1 byte         4 min, 50 sec
2 bytes        2 min, 30 sec
4 bytes        1 min

All this, however, has nothing to do with Registry comparisons, which are text comparisons. Binary comparison is inherently slower then text comparison, since binary files are first internally presented as Hex strings (hence increased memory consumption), which are later compared and which tend to have significantly more differences (especially when the comparison block size is set to 1 byte). E.g., comparing two Registry dumps of about 95 MBytes took me about 2.5 minutes on a 1 GB RAM machine.

[AlexL]

Actually, running "ExamDiff.exe ExamDiff.exe ExamDiff.exe" produces almost instantaneous results in my testing...

Did you try my settings? Probably you used "Auto text/binary", while I have "Treat binary files as text". I have to use this option because otherwise EDP thinks that texts, which use 2-nd half of character table, are binary files.

Thank you.

[psguru]

Same result with "Treat binary files as text": almost instantaneous result for ExamDiff.exe vs. ExamDiff.exe, and 28 seconds for ExamDiff.exe vs. its previous version.