Judge Thomas Penfield Jackson ordered Microsoft Corporation to turn over a document that the U.S. Department of Justice (DOJ) claims will prove that the software giant illegally tied Internet Explorer to Windows. The document--an Excel spreadsheet, as it turns out--details how much code in each DLL file in Windows is shared between IE and the operating system. Microsoft says the spreadsheet proves nothing.

The DOJ learned about the document when they reviewed an email written by Microsoft developer David D'Souza, who examined a file installed by IE 4.0 to determine which functions were shared by the Windows and IE. In D'Souza's test, a system's hard drive was accessed using the My Computer applet in Windows and then the Microsoft Web site was loaded over the Internet. D'Souza's determined that over 1,000 functions were used in both scenarios while 152 were specific to My Computer and 690 were specific to Web access.

"There is a HUGE amount of sharing and commonality here," D'Souza wrote in the October 1998 email to Microsoft VP Jim Allchin. Allchin is the next Microsoft executive to take to the stand in the antitrust case, coincidentally. Paul Maritz finished up on Thursday with some quick questions from Microsoft attorney John Warden.

But another comment in the email got the attention of the DOJ. D'Souza refers to an early DOJ witness, Edward Felton, who had successfully removed IE from Windows.

"Arguably, based on Felton's testimony, this list could be used to 'separate' \[this DLL file\] into two parts: Shared+shell and browser specific. So this may not be useful," he wrote.