View source for DSM Review, NFS, AFS

==Readings==

* [http://homeostasis.scs.carleton.ca/~soma/distos/2008-02-11/protic-overview.pdf Jelica Protic et al., "Distributed Shared Memory: Concepts and Systems" (1996)]<br />This paper reviews work in the area of distributed shared memory.

* [http://homeostasis.scs.carleton.ca/~soma/distos/2008-02-11/sandberg-nfs.pdf Russel Sandberg et al., "Design and Implementation of the Sun Network Filesystem" (1985)]<br />This is the original NFS paper.

* [http://homeostasis.scs.carleton.ca/~soma/distos/2008-02-11/howard-afs.pdf John H. Howard et al., "Scale and Performance in a Distributed File System" (1988)]<br />This paper describes AFS and compares it to NFS.

==Questions==

For the Protic paper, consider the following:
# What were the major problems addressed in DSM research following Kai Li's dissertation?
# Did these advances change the scope of environments and problems appropriate for DSM?
# Why aren't DSM systems commonly in use today?


For the NFS and AFS papers, consider these questions:
# What were the key design goals of NFS and AFS?
# How well did they achieve their goals?
# What are their limitations?
# How suitable are NFS and AFS in modern small networks?  Enterprise networks?  Internet-scale applications?  Why?

== In Class Notes ==
=== Goals of NFS and AFS ===
==== NFS ====
* Remote access like local access
* Scale to ~50 clients
* Portability
* Lightweight

==== AFS ====
* Remote access like local access
* Scale to 5000 - 10000 hosts
* Portability (POSIX)

=== Differences ===
==== NFS ====
# NFS does a system call for every read/write
# NFS can operate with diskless clients
# Lightweight clients
# Files are up-to-date, can be inconsistent
# Trusted clients
# Stateless

==== AFS ====
# AFS does a system call only on retrieving and storing a file
# AFS assumes clients have a hard disk
# Heavier-weight client
# Files may be stale, but data is consistent
# Untrusted clients
# Stateful

=== Contributions ===
==== NFS ====
* Kmalloc
* VFS
* (XDR, SunRPC)

=== Aside: Kerberos for Dummies ===
<pre>
1. Client Identification:    <client> ==> <kerberos> 
2. Client Request Ticket:    <client> <== <kerberos>
3. Authenticate with Ticket: <client> ==> <server>
</pre>