According to Wikipedia: TempleOS is a x86-64 bit, non-preemptive multi-tasking, multi-cored, public domain, open source, ring-0-only, single address space, non-networked, PC operating system for recreational programming. The OS runs 8-bit ASCII with graphics in source code and has a 2D and 3D graphics library, which run at 640x480 VGA with 16 colors. Like most modern operating systems, it has keyboard and mouse support. It supports the FAT32 and RedSea file systems (the latter created by Davis) with support for file compression.

Terry suffered from schizophrenia and claimed his design decisions were dictated by God (there are many religious/biblical elements throughout TempleOS).