Transcript Dark Blue with Orange - dforeman.cs.bingh

Comparison of
Distributed
Operating Systems
Systems Discussed
◦ Plan 9
◦ AgentOS
◦ Clouds
◦ E1
◦ MOSIX
Plan9 - 1

History
◦ 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 - 2

Notable architecture:
◦ All system interfaces through file system. (preLinux)
Workstation - independent working
environment
 “Workstation” – aggregated resources,
remote and local.

Plan9 - 3

/proc
◦ All processes are visible as files

/net
◦ All network traffic read/written through file
system

Can import posix apps, emulate
Berkeley socket interface through APE
(ANSI/POSIX Environment)
AgentOS - 1
 Originally
designed by Harry
Chen at UC, Irvine (1998)
 Subsumed by The BioNetworking Architecture project
◦ Grants from NSF, DARPA, and AFOSR
Office of Scientific Research)
(Air Force
AgentOS - 2

Goal: Ubiquitous Access
◦ Nomadic and mobile users
Based on Java VM
 Agent based vs. RPC

◦ Adaptive vs. dummy communication

Byte code inefficiency
◦ Just In Time Compilers with caching
Clouds - 1

History
◦ Clouds is actually 2 separate operating systems
 Clouds V1, based on VAX kernel 1986
 Clouds V2, based on Ra kernel ~1989
 Purpose
◦ Support distributed research at
Georgia Institute of Technology
Clouds - 2
 Clouds
based on the object/thread
paradigm
 At OS level there is only one type of
object, clouds
 Ra kernel implements persistent
virtual memory
◦ Threads travel through objects
◦ Entry points
E1
E1 first distributed commercially in 2005.
 Very much like clouds

◦ Object/thread paradigm
◦ Difference: Threads outside of objects

Objects replicated and synchronized
◦ Redundancy vs. loss of efficiency in
replication
MOSIX - 1

Version 0 (1977) – research project on
process migration
◦ based on Unix 6
◦ tested on PDP 11/45 and diskless 11/10
connected by parallel I/O
◦ Named: UNIX with satellite processors.

Current Version, 10 (2006) [MOSIX2]
◦ Supporting Linux Kernel 2.6

Generic Solution – dynamic
management of resources.
MOSIX - 2
 Core
–
◦ adaptive sharing algorithms
◦ Preemptive process migration
◦ Load balancing
 Process placement
 System structure
 Compatibility:
◦ Connect with any Linux, only one MOSIX hub
required
MOSIX - 3
Cluster – collection of computers
 Grid – collection of clusters
 Partition

◦ Limited to 256 nodes (by IP addressing)
 Highly
secure
 Infinitely scalable
Impact on Current Systems

Impact on current systems
◦ Plan9 file system in Linux
◦ Clouds RPC model in later UNIX and
windows
◦ AgentOS theory behind Google Docs