The Durango F-85 was an early personal computer introduced in September 1978 by Durango Systems Corporation, a company started in 1977 by George E. Comstock, John M. Scandalios and Charles L. Waggoner, all formerly of Diablo Systems.

[1][2][3] The F-85 could run its own multitasking operating system called DX-85M, which included an integral Indexed Sequential (ISAM) file system and per-task file locking, or alternatively CP/M-80.

[1][4][5] DX-85M utilized a text configuration file named CONFIG.SYS[5] five years before this filename was used for a similar purpose under MS-DOS/PC DOS 2.0 in 1983.

The F-85 used single-sided 5¼-inch 100 tpi diskette drives providing 480 KB utilizing a high-density 4/5 group coded encoding.

The machine was using a Western Digital FD1781 floppy-disk controller with 77-track Micropolis drives.