The ABW file format is the default document format for the AbiWord word processing software and the format is based on XML. The ABW file format allows for advanced document layouts, rich text formatting, lists, tables, images and footnotes. ABW files are similar in nature to Microsoft Word DOC files, however, unlike Microsoft Word files, the AbiWord program can run on almost any computer operating system.
PBM is a Portable image in black and white. Can be opened with programs: Adobe Photoshop CS, ACD Systems Canvas 15, ACD Systems ACDSee 17, Newera Graphics Converter Pro, Corel PaintShop Pro X6. File contains 1 bit per pixel. PBM is a kind of file format PPM. And can be readable or binary.