The Durango F85 was an early office computer based around a 5MHz 8085 processor, sold in 1977. It had an impressive 64kB of RAM, upgradable to 128kB, and ran its own multitasking operating system call DX-85M, as well as CP/M. It had an interesting electric-typewriter form factor, with a little monitor sitting on the side of it — in operation you were facing the 14” printer.

It was touted as being portable. Which it was, if you were strong; the story is that they had to do an extensive search to find someone capable of lifting it for the following photo…

…and even then, they had to airbrush out the tendons in her neck from the effort!

It used 5.25 soft-sectored disks storing an impressive-for-those-days 480kBish on a side, using a proprietary 4-in-5 GCR encoding. They used 77 tracks, 12 sectors and 512 bytes per sector. Later models used double-sided disks; I don’t have access to an image of one so don’t know how they work (there’s a suspicious looking spare byte in the sector header which could store the side). As always, if you have one, please get in touch.

.obj/fe-readf85

You should end up with an f85.img which is 472064 bytes long.