NExS can load spreadsheets saved in the native format of Excel 5.0 or later. This format is called ``BIFF5'' for version 5 of the Microsoft Binary Interchange File Format, and is usually signified by a filename extension of .XLS. To the extent possible, formula information and the appearance of the original Excel spreadsheet is preserved. Charts contained in the .XLS file are not imported.
A .XLS file written by Excel 5.0 or later may contain more than one worksheet. Such a file is called a ``workbook.'' If the .XLS file being loaded contains a workbook, a pop-up dialog appears listing all of the worksheets contained in the workbook. The user must select a worksheet to be loaded from this list. Note that all worksheets in the workbook will be displayed in the pop-up dialog, even if they contain no data.
When an Excel spreadsheet is loaded, formulas and function names are translated to their native NExS equivalents. If a cell contains a formula which can not be translated, an error dialog is displayed and the cell's contents are discarded.
An important consideration when importing Excel files containing dates is that Excel files created on a Macintosh use a different date format than those created in Excel for Windows. Excel for Windows uses ``1900'' date format, which represents dates from January 1, 1900 to December 31, 2078. Excel for Macintosh uses ``1904'' date format, which represents dates from January 1, 1904 to December 31, 2078. NExS' native date format is fully compatible with the 1900 date format (except that it goes to December 31, 2099). NExS will automatically detect that an Excel worksheet is using the 1904 date format and compensate for it in all internal date/time functions. However, if the spreadsheet contains constant values which are interpreted as dates, calculations based on these values may be in error.
To load an existing Excel Worksheet: