-8<—- A quick search suggests both Bookmaster and DCF use a library called GDDM which sounds like it is a device independent graphics format / renderer. Perhaps the .BOO format is related to this? In a different avenue of exploration, looking at some .BOO files in a hex editor, they do appear to use EBCDIC text, and near the start of the file there seems to be a long sequence of word fragments: often the trailing part of words. That suggested to me that perhaps it might be some sort of lookup table-based compression scheme for the text. I haven’t investigated beyond that yet. Someone in IBM must know, I suppose. d

On Wed, 13 Dec 2023 at 21:18, brian--- via cctalk &lt;cctalk(a)classiccmp.org&gt; wrote: Well spotted. If I was unclear: I have downloads of both. I failed to make a note _where_ I downloaded them from. There are quite a few pages with download links that no longer work. This may have been where I found it! -- Liam Proven ~ Profile: https://about.me/liamproven Email: lproven(a)cix.co.uk ~ gMail/gTalk/FB: lproven(a)gmail.com Twitter/LinkedIn: lproven ~ Skype: liamproven IoM: (+44) 7624 277612: UK: (+44) 7939-087884 Czech [+ WhatsApp/Telegram/Signal]: (+420) 702-829-053