Multiple-task real-time PDP-15 operating system for data acquisition and analysis
William R. Myers · University of North Texas Digital Library (University of North Texas) · 1974
The RAMOS operating system is capable of handling up to 72 simultaneous tasks in an interrupt-driven environment. The minimum viable hardware configuration includes a Digital Equipment Corporation PDP-15 computer with 16384 words of memory, extended arithmetic element, automatic priority interrupt, a 256K-word RS09 DECdisk, two DECtape transports, and an alphanumeric keyboard/ typer. The monitor executes major tasks by loading disk-resident modules to memory for execution; modules are written in a format that allows page-relocation by the monitor, and can be loaded into any available page. All requests for monitor service by tasks, including input/output, floating point arithmetic, request for additional memory, task initiation, etc., are implemented by privileged monitor calls (CAL). All IO device handlers are capable of queuing requests for service, allowing several tasks ''simultaneous'' use of all resources. All alphanumeric IO (including the PC05) is completely buffered and handled by a single multiplexing routine. The floating point arithmetic software is re-entrant to all operating modules and includes matrix arithmetic functions. One of the system tasks can be a ''batch'' job, controlled by simulating an alphanumeric command terminal through cooperative functions of the disk handler and alphanumeric device software. An alphanumeric control sequence may be executed, automatically accessing disk-resident tasks in any prescribed order; a library of control sequences is maintained on bulk storage for access by the monitor. (auth)