Comparison of Distributed Operating Systems

Systems DiscussedPlan 9AgentOSCloudsE1MOSIX

Plan9 - 1History Bell Labs 1984 2002 (and on)Plan 9 from Bell Labs based on Plan 9 from Outer Space.Replaced Unix as primary research platform. Based on 9P protocol. Accesses all resources, local and remote.

Plan9 - 2Notable architecture:All system interfaces through file system. (pre-Linux)Workstation - independent working environmentWorkstation aggregated resources, remote and local.

Plan9 - 3/procAll processes are visible as files/netAll network traffic read/written through file systemCan import posix apps, emulate Berkeley socket interface through APE (ANSI/POSIX Environment)

AgentOS - 1Originally designed by Harry Chen at UC, Irvine (1998)Subsumed by The Bio-Networking Architecture projectGrants from NSF, DARPA, and AFOSR (Air Force Office of Scientific Research)

AgentOS - 2Goal: Ubiquitous AccessNomadic and mobile usersBased on Java VM Agent based vs. RPCAdaptive vs. dummy communicationByte code inefficiencyJust In Time Compilers with caching

Clouds - 1HistoryClouds is actually 2 separate operating systemsClouds V1, based on VAX kernel 1986Clouds V2, based on Ra kernel ~1989PurposeSupport distributed research at Georgia Institute of Technology

Clouds - 2Clouds based on the object/thread paradigmAt OS level there is only one type of object, cloudsRa kernel implements persistent virtual memoryThreads travel through objectsEntry points

Clouds - 3

E1E1 first distributed commercially in 2005.Very much like cloudsObject/thread paradigm Difference: Threads outside of objectsObjects replicated and synchronizedRedundancy vs. loss of efficiency in replication

MOSIX - 1Version 0 (1977) research project on process migrationbased on Unix 6tested on PDP 11/45 and diskless 11/10 connected by parallel I/ONamed: UNIX with satellite processors.Current Version, 10 (2006) [MOSIX2]Supporting Linux Kernel 2.6Generic Solution dynamic management of resources.

MOSIX - 2Core adaptive sharing algorithmsPreemptive process migrationLoad balancingProcess placement System structureCompatibility:Connect with any Linux, only one MOSIX hub required

MOSIX - 3Cluster collection of computersGrid collection of clustersPartition Limited to 256 nodes (by IP addressing)Highly secureInfinitely scalable

Impact on Current SystemsImpact on current systemsPlan9 file system in LinuxClouds RPC model in later UNIX and windowsAgentOS theory behind Google Docs