ROS 1.1 ROS 1.2 – added floppy disk support. ROS 2.2 Software Operating systems The main operating systems were CP/M 2.2 if booted from disk or CP/NOS (a network-only version of CP/M) if booted from a file server. Systems running CP/M could access network services using CP/NET. There was also a version of MP/M which allowed multi-user access to a single disc unit shared among a small number of computers. Because of the serial interface to the disk drive, access could be slow if multiple users tried to save at the same time. But it was a cheap stepping-stone on the way to the 380Z server and an entry level network. Application software Many standard CP/M applications were available, such as WordStar. Research Machines also produced their own assembler (ZASM), text editor (TXED) and BASIC interpreter. Programs for the earlier Research Machines 380Z written in high-level languages, such as BASIC, or using only basic CP/M and standard firmware functions, could be run directly on the 480Z. Programs that wrote directly to hardware such as the high-resolution graphics cards were generally incompatible. References External links LINK 480Z on old-computers.com groups.io Research Machines RML380Z and 480Z Group VT100.net page with scanned-in manuals Personal computers Computers designed in the United Kingdom