UNOS is the first, now discontinued,

32-bit In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in 32-bit units. Compared to smaller bit widths, 32-bit computers can perform large calculation ...

Unix-like real-time operating system (RTOS) with real-time extensions. It was developed by Jeffery Goldberg, MS. 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 The Motorola 68000 series (also known as 680x0, m68000, m68k, or 68k) is a family of 32-bit complex instruction set computer (CISC) microprocessors. During the 1980s and early 1990s, they were popular in personal computers and workstations and w ...

central processing unit (CPU). 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 The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, ...

. CRDS hired Goldberg to create UNOS and began selling it in 1981. UNOS was written for the

Motorola 68000 series The Motorola 68000 series (also known as 680x0, m68000, m68k, or 68k) is a family of 32-bit complex instruction set computer (CISC) microprocessors. During the 1980s and early 1990s, they were popular in personal computers and workstations and w ...

processors. While compatible with Version 7 Unix, it is also an RTOS. CRDS supported it on the company's Universe 68 computers, as did Motorola's

Versabus VMEbus (Versa Module Europa or Versa Module Eurocard bus) is a computer bus standard, originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. ...

systems. 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. UNOS has a cleaner kernel interface than UNIX in 1981. There was e.g., a system call to obtain ps information instead of reading /dev/kmem. UNOS required memory protection, with the 68000 using an MMU developed by CRDS; and only used Motorola MMUs after UNOS 7 on the

68020 The Motorola 68020 ("''sixty-eight-oh-twenty''", "''sixty-eight-oh-two-oh''" or "''six-eight-oh-two-oh''") is a 32-bit microprocessor from Motorola, released in 1984. A lower-cost version was also made available, known as the 68EC020. In keeping ...

(CRDS System CP20) (using the MC68851 PMMU). UNOS was written in the programming languages C and

assembly language In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence be ...

, and supported Fortran,

COBOL COBOL (; an acronym for "common business-oriented language") is a compiled English-like computer programming language designed for business use. It is an imperative, procedural and, since 2002, object-oriented language. COBOL is primarily us ...

Pascal Pascal, Pascal's or PASCAL may refer to: People and fictional characters * Pascal (given name), including a list of people with the name * Pascal (surname), including a list of people and fictional characters with the name ** Blaise Pascal, Fren ...

, and Business Basic.

Limits

UNOS from CRDS never supported paged virtual memory and multiprocessor support had not been built in from the start, so the kernel remained mostly single-threaded on the few multiprocessor systems built. A UNOS variant enhanced by

H. Berthold AG H. Berthold AG was one of the largest and most successful type foundries in the world for most of the modern typographic era, making the transition from foundry type to cold type successfully and only coming to dissolution in the digital type era. ...

under the name vBertOS added demanded page loading and paged processes in 1984, but was given up in favor of

SunOS SunOS is a Unix-branded operating system developed by Sun Microsystems for their workstation and server computer systems. The ''SunOS'' name is usually only used to refer to versions 1.0 to 4.1.4, which were based on BSD, while versions 5.0 and l ...

because of the missing GUI and the missing networking code in Spring 1985, when Berthold imported the first Sun to Europe.

References

Discontinued operating systems Embedded operating systems Real-time operating systems Unix variants 68k architecture {{Operating-system-stub