<P> Converting a fraction of a day into hours, minutes and days by treating it as a moment on the day January 1, 1900, does not work for a negative fraction . </P> <P> Entering text that happens to be in a form that is interpreted as a date, the text can be unintentionally changed to a standard date format . A similar problem occurs when a text happens to be in the form of a floating point notation of a number . In these cases the original exact text cannot be recovered from the result . In the case of entering gene names this is a well known problem in the analysis of DNA, for example in bioinformatics . The problem was first described in 2004 . </P> <P> Microsoft Excel will not open two documents with the same name and instead will display the following error: </P> <Dl> <Dd> A document with the name'% s' is already open . You cannot open two documents with the same name, even if the documents are in different folders . To open the second document, either close the document that is currently open, or rename one of the documents . </Dd> </Dl>

Who developed ms excel and in which year