1. History

2. Limits

3. References

UNOS is the first, now discontinued, 32-bit Unix-like real-time operating system (RTOS) with real-time extensions.{{cn|date=August 2015}} It was developed by Jeffery Goldberg, PhD. who left Bell Labs after using Unix and became VP of engineering for Charles River Data Systems (CRDS), now defunct. UNOS was written to capitalize on the first 32-bit microprocessor, the Motorola 68k central processing unit (CPU).{{cn|date=August 2015}} CRDS sold a UNOS based 68K system, and sold porting services and licenses to other manufacturers who had embedded CPUs.

History

Jeff Goldberg created an experimental OS using only eventcounts for synchronization, that allowed a preemptive kernel, for a Charles River Data Systems (CRDS) PDP-11. CRDS hired Goldberg to create UNOS and began selling it in 1981.^[1]{{better source|date=August 2015}}

UNOS was written for the Motorola 68000 series processors. While compatible with Version 7 Unix, it is also an RTOS.{{cn|date=August 2015}} CRDS supported it on the company's Universe 68 computers, as did Motorola's Versabus systems.^[2] CRDS's primary market was OEMs embedding the CRDS unit within a larger pile of hardware, often requiring better real-time response than Unix could deliver.{{cn|date=August 2015}}

UNOS has a cleaner kernel interface than UNIX in 1981.{{cn|date=April 2015}} There was e.g., a system call to obtain ps information instead of reading /dev/kmem.{{cn|date=August 2015}}

UNOS required memory protection, with the 68000 using an MMU developed by CRDS;{{cn|date=August 2015}} and only used Motorola MMUs after UNOS 7 on the 68020 (CRDS System CP20){{cn|date=August 2015}} (using the PMMU (MC68851 PMMU)).

UNOS was written in the programming languages C and assembly language, and supported Fortran, COBOL, Pascal, and Business Basic.{{cn|date=July 2015}}

Limits

UNOS from CRDS never supported paged VM{{cn|date=August 2015}} and multiprocessor support had not been built in from the start,{{cn|date=August 2015}} so the kernel remained mostly single-threaded on the few multiprocessor systems built.{{cn|date=August 2015}}

A UNOS variant enhanced by H. Berthold AG under the name vBertOS added demanded page loading and paged processes in 1984,{{cn|date=August 2015}} but was given up in favor of SunOS because of the missing GUI and the missing networking code in Spring 1985,{{cn|date=August 2015}} when Berthold imported the first Sun to Europe.{{cn|date=August 2015}}

References

• Order of Council
• Order of CuChulainn
• Order of Cultural Merit, Korea
• Order of Cultural Merit (South Korea)
• Order of Dagon
• Order of Damballah Hwedo Ancestor Priests
• Order of Danica Hrvatska
• Order of Danilo
• Order of Danilo of Montenegro
• Order of Demolay
• Order of Duke Branimir
• Order of Duke Domagoj
• Order of Duke Gediminas
• Order of Ecclesia
• Order of Elks
• Order of Ennead
• Order of Ennead (album)
• Order of Enoch
• Order of Ernst August
• Order of Excellence (Jamaica)
• Order of Fiat Lux
• Order of Flemish militants
• Order of Fontevraud
• Order of Francisco de Miranda
• Order of Freedom of the Republic of Slovenia