Project Athena as a Distributed Computer System

[Champine90] George A. Champine, Daniel E. Geer, Jr., and William N. Ruh, “Project Athena as a Distributed Computer System,” IEEE Computer, IEEE, vol. 23, September 1990, 40-50,

This paper describes an implemented distributed system, Athena, at MIT for students. It also compares this system to other distributed OS's. Supported by DEC and IBM

Assumed that computers were too expensive, to be bought by students but possibly cheaper in the future.

Key requirements:

* Scalability: must scale up to 10,000+ computers
* Reliability: must be available 24/7 even when some components fail.
* Public work stations: any user at any workstation.
* Security: System services must be secure even though individual workstations are not.
* Heterogeneity: The system must support a variety of hardware platforms.
* Coherency: All system applications must run on all workstations. Consistent look and feel.
* Affordability: low cost to own and operate.

Definitions:
user
client
server
service
name
binding
resolving
coherence
interoperability
authentication
authorization
fail-soft

mainframe model vs unified model
- security, resource allocation, privacy/network, mail, maintenance

other distributed os's:
* Amoeba
* Andrew
* Dash
* Eden
* Grapevine
* HCS
* Locus
* Mach
* Sprite
* V

Athena in terms of the requirements

System comparisons

Issues:
* naming: hosts, printers, services, files, users; replication vs. partitioning
* scalability: anything that scales linearly is probably not feasible in general.
* Security: authentication and authorization. centralized and encrypted password checking service. public-key cryptography. key distribution servers. access control lists and capabilities based authorization
* Compatibility: binary level, execution level, and protocol level.


Athena system design
* name service: Hesiod. Berkeley bind. fast front end to moira.
* file service: NFS, AFS
* printing service
* mail service
* real-time notification: Zephyr
* service management: Moira: configuration for mail, disk quotas, hardware config, post office allocation, and access control lists
* authentication: Kerberos. Login and out. Tickets.
* installation and update
* online consulting, discuss