XLS and TSV explained
The pre-2007 Excel format is a binary structure limited to 65,536 rows and 256 columns — limits modern datasets routinely exceed.
TSV is CSV with tab characters as separators. Because tabs almost never appear inside data fields, it sidesteps most of CSV's quoting problems.
- Where XLS files come from
- Spreadsheets from Excel 2003 or earlier, and some legacy export systems.
- Where TSV is used
- Bioinformatics, data pipelines and anywhere fields contain commas.