The Arbortext Formatting Engine is invoked by the ACL format command. It uses a FOSI specification to translate an open XML or SGML document to an internal DVI (device independent) format stored on disk. The DVI file may be displayed directly in a Preview window or used as input to a content compiler which produces PostScript or PDF as explained in Producing PostScript and PDF from DVI. When Arbortext Editor is using the Serveur Arbortext PE for publishing, the formatter always runs on the Serveur Arbortext PE.

Internally the formatter has two parts, one built into Arbortext Editor and the Sous-processus Arbortext PE, and another in a separate program named PubTeX.

The Windows Task Manager allows you to check formatting progress. This action is useful if you suspect that PubTeX is hung, or that Arbortext Editor or the Sous-processus Arbortext PE is hung waiting for PubTeX to finish.