Warrior of Ras: Volume I - Dunzhin is a fantasy role-playing video game developed by Med Systems Software. The game was released on the TRS-80 in 1982.
The player explores a new, randomly generated dungeon for each adventure. The character encounters monsters and human enemies, and experience points are awarded based on the disparity between the character's and the monster's statistics. The character's primary goal is the recovery of a treasure hidden on the deepest level which is guarded by a particularly effective team of monsters.
Dunzhin was ported to the Apple II, Atari 8-bit, Commodore 64, and IBM PC. The PC port is particularly interesting from a technical standpoint because it features digitized speech not found in the other versions in addition to the very unusual practice of performing all disk access via IN/OUT instructions to the floppy controller instead of using the BIOS (this was done both to improve performance and as a copy protection scheme). The PC version was not completely rewritten from the ground up, but instead contained the original Z80 code from the TRS-80 with an interpreter to convert it to x86 assembly language
Source: Wikipedia, "Dunzhin", available under the CC-BY-SA License.