1. Features

2. Current status

3. References

RSX180^[1] is a multi-tasking, multi-user, multi-terminal Operating System for the Zilog Z80 family of processors that is similar in both look and feel and design philosophy to DEC's RSX-11M OS for the PDP-11 series of machines.

The system was written as a hobby project back in the early 80s for the Intel 8080 CPU. It started life as a micro-kernel with a fixed number of tasks, but later grew to support dynamic tasks, a custom RAM-disk-based filesystem, device drivers, a CLI, and a very basic set of utilities. The system design was heavily influenced by RSX-11M, which was a popular multi-tasking OS at the time.

Most of the original 8080 code was lost after the project was abandoned, but part of the kernel was found in the early 2010s and ported to the P112 CPU board, which has a Z80182 CPU with built-in MMU. Many bugs were fixed in the process, the filesystem upgraded to make use of floppy and hard disk storage, memory management improved, and the utility programs were written again from scratch.

Features

• Multi-user
• Multi-terminal
• Priority-based, preemptive multitasking micro-kernel
• Round-robin scheduling of tasks of the same priority
• Custom two-level filesystem^[2]
• Modular device drivers
• QIO mechanism
• AST support
• Event flags
• Dynamic allocation of system resources
• Send-Receive task communication mechanism
• Kernel functionality extended by privileged tasks
• Task Directory for fast task activation.
• Tasks can be fixed in memory for even faster activation.
• Clock queue and time-scheduled task execution.
• Privileged and non-privileged users.
• CLI similar to MCR^[3]
• Fits on a single 1.44 MB floppy

Current status

References

• Energy policy of Scotland
• Energy policy of Sri Lanka
• Energy policy of Taiwan
• Energy policy of Tajikistan
• Energy policy of the Barack Obama administration
• Energy Policy of the Obama Administration
• Energy policy of the Republic of China
• Energy policy of the Soviet Union
• Energy policy of the USSR
• Energy policy of Uzbekistan
• Energy Poverty
• Energy price (disambiguation)
• Energy Probe
• Energy Processing Unit
• Energy production by country
• Energy production in Romania
• Energy production in the United States
• Energy profile chemistry
• Energy pyramids
• Energy quantization
• Energy rationing
• Energy rebate program
• Energy Recovery
• Energy Recovery Linac Prototype (ERLP)
• Energy recovery ventilator