View source for DG/UX

{{Infobox OS
| name                   = DG/UX
| logo                   = Data General logo.svg
| screenshot             = 
| caption                = 
| developer              = [[Data General]]
| source_model           = 
| kernel_type            = 
| supported_platforms    = [[Eclipse MV]] minicomputer line, [[Data General AViiON|AViiON]] workstation and server line
| ui                     = [[IXI Limited|IXI]] [[X.desktop]] environment
| family                 = [[UNIX System V]] with additions from [[BSD]]
| released               = {{Start date and age|1985|3}}
| latest_release_version = 5.4 Release 4.20 (MU07)
| latest_release_date    = {{Start date and age|2001|4}}<!-- see for example: http://www.linkedin.com/pub/john-schmidt/9/262/377, not suitable as a reference but no reason to doubt the accuracy -->
| latest_test_version    = 
| latest_test_date       = 
| marketing_target       = 
| programmed_in          = [[C (programming language)|C]]
| prog_language          = [[C (programming language)|C]]
| language               = [[English language|English]]
| updatemodel            = 
| package_manager        = 
| working_state          = Historic
| license                = 
| website                = 
}}
'''DG/UX''' is a discontinued [[Unix]] [[operating system]] developed by [[Data General]] for its [[Eclipse MV]] [[minicomputer]] line, and later the [[Data General AViiON|AViiON]] [[computer workstation|workstation]] and [[server (computing)|server]] line (both [[Motorola 88000]] and [[Intel]] [[IA-32]]-based variants).

==Overview==
By 1985 most computer companies offered [[Unix]] as an alternative to their proprietary operating systems.<ref name="desmond19850520">{{Cite magazine |last=Desmond |first=John |date=1985-05-20 |title=Prime adds Unix environment for 50 series users |url=https://books.google.com/books?id=ygHfUXZWXlcC&pg=PA7#v=onepage&q&f=true |access-date=2025-06-07 |magazine=Computerworld |page=7 |volume=XIX |issue=20}}</ref> DG/UX 1.00, released by [[Data General]] in March 1985, was based on [[UNIX System V]] Release 2 with additions from [[BSD|4.1BSD]]. By 1987, DG/UX 3.10 had been released, with [[4.2BSD]] [[TCP/IP]] networking, [[Network File System (protocol)|NFS]] and the [[X Window System]] included. DG/UX 4.00, in 1988, was a comprehensive re-design of the system, based on [[System V Release 3]], and supporting symmetric multiprocessing on the Eclipse MV. The 4.00 filesystem was based on the [[AOS/VS II]] filesystem and, using the logical disk facility, could span multiple disks. DG/UX 5.4, released around 1991, replaced the legacy Unix file buffer cache with unified, demand paged virtual memory management. Later versions were based on [[System V Release 4]].

On the AViiON, DG/UX supported [[multiprocessor]] machines at a time when most variants of Unix did not. The operating system was also more complete than some other Unix variants; for example, the operating system included a full [[C (programming language)|C]] compiler ([[GNU Compiler Collection|gcc]]) and also a logical volume manager. The OS was small and compact, but rich in features. It was simple and easy to install and did not require vast resources of memory or processing power. For example, a six-way [[Pentium Pro]]-based AViiON would support several hundred users using [[text terminal]]s.

The [[Logical volume management|volume manager]] built into the OS was simple, but very powerful. All disk administration could be performed online, without taking any file system offline. This included extending, relocating, mirroring or shrinking. The same functions could be performed on the swap area, allowing in-place migrations of disk storage without downtime. DG/UX 5.4 supported filesystem shrinking, "split mirror" online backup, filesystems up to 2 TB, and filesystem journaling in 1991.  Few vendors offered similar features at that time.

DG/UX had a high-performance and stable clustered filesystem. The [[Clariion]] storage [[Network-attached storage|NAS]] was connected by high-voltage [[SCSI]] controllers, and SCSI hubs. Each server had double SCSI controllers for failover reasons. Both controllers were master on the same bus, at the same time these filesystems were [[Network File System|NFS]]-mounted from the cluster-master's floating IP address. The data was written from each cluster node directly by the SCSI bus, but the orchestration, the inode tables, where written by the NFS-mount from each cluster member.

Later versions added support for [[processor affinity|processor and memory affinity]] to support their high-end multiprocessor [[Non-Uniform Memory Access|NUMA]] AViiON system.

==References==
{{reflist}}
*{{Cite web|url=http://www.accessmylibrary.com/coms2/summary_0286-9202012_ITM |title=DG-UX 4.00: DG's redesigned kernel lays the foundation for future UNIX systems|archive-url=https://web.archive.org/web/20070930212358/http://www.accessmylibrary.com/coms2/summary_0286-9202012_ITM |archive-date=2007-09-30 |url-status=dead}}

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[[Category:Data General]]
[[Category:UNIX System V]]
[[Category:1985 software]]
[[Category:Discontinued operating systems]]
[[Category:X86 operating systems]]