What is a BCL file?
A .BCL file serves different purposes depending on the software that creates it. Most notably, it is an Illumina Base Call File. Illumina sequencing instruments generate these files to store raw DNA sequencing data. Alternatively, a .BCL file can be a Batch Convert List used by Acme CAD Converter to manage text-based lists of CAD files for batch operations. Other systems, like the BlackBerry Enterprise Server or Siemens SICAM, use .BCL files for compressed server logs or power system data logs.
How to open BCL files?
Because a .BCL file can contain complex sequence data, a text-based CAD list, or a compressed log, you must use the correct software. You can use the bcl2fastq tool to convert Illumina data into standard .FASTQ files. For CAD file lists, use Acme CAD Converter. If it is a basic list or log, a standard text editor might work.
Best practices and troubleshooting
Before you open a .BCL file, verify its origin. Illumina Base Call Files are binary and exist inside complex directory structures. If you open these in a text editor, the data will look corrupted. For CAD lists, ensure the file paths inside the document are correct. Because .BCL has multiple possible meanings, we recommend using viewer.online/bcl to identify the actual format of your file.
Software and tools
viewer.online/bcl analyzes .BCL files to identify their exact format and creator software, shows which programs can open the file, and usually previews it.
Summary
Because .BCL files use the known UTF-8 format, viewer.online/bcl can safely open and display them online, eliminating compatibility problems.