Cross-platform running times markedly differ. For 2,000 HTML questionnaires of 120 kB each, containing 120 lines (with IDSS definition of a 'line'), 36 variables and a total of 192 characters to be parsed, on a laptop built in 2003, equipped with an Intel Mobile Celeron processor running at 2,4 GHz and 512 MB of DDR, the following results were obtained on generating a separated database (option -B) :
|GNU/Linux||Windows XP||Cygwin (with Windows XP)|
|< 20 seconds of processing time
(minimum 14 seconds out of 20 tests)
20-25 seconds of real time
|75-85 seconds of real time||> 4 minutes of real time|
Silent mode -W was used to cut down running times in all tests.
Under GNU/Linux, silent mode running times (options -ir -B -e -s -W) are slightly higher than gzip compression of the questionnaire directory (command 'tar -cf9z'), yet three times lower than copying the same directory from one file system to another ('cp -R') and four times lower than bzip2 compression (command 'tar -cf9j'). These are indicative results, which are likely to depend on hardware configuration.
Implementing an algorithm written in C limited to the core requirements of survey management made it possible to enhance input parsing performance. Many professional applications take a different approach, implementing general-purpose algorithms (notably regular expressions), whose complex routines allow for more layout flexibility at the expense of higher running times.
Commonly-used interpreted languages boast high-quality libraries for parsing HTML documents (VBA under Windows, Python and Perl in Unix systems) and perform varied tasks; however, IDSS runs faster by an order of magnitude at least.
Considering these comparative tests, it is advised to run IDSS under GNU/Linux (or more generally a POSIX standard) to process a large number of questionnaires.