EEDC first presentation from group 1

1. EEDC
Execution
34330
Environments for Distributed Systems
Distributed
Computing
Master in Computer Architecture,
Networks and Systems - CANS
Homework number: 1
Group number: EEDC-1
Group members:
Hugo Pérez – vhpvmx@gmail.com
Sergio Mendoza – sergiomendo@gmail.com
Carlos Fenoy – carles.fenoy@gmail.com

2. Definition
You know you have a distributed systems when the crash
of a computer you have never heard of stops you from
getting any work done. - Lamport
A collection of independent computers that
appears to its users as a single coherent
system. - Tanenbaum

3. Definition
A distributed system consists of a collection of
autonomous computers, connected through a network
and distribution middleware, which enables computers to
coordinate their activities and to share the resources of
the system, so that users perceive the system as a single,
integrated computing facility.

4. General Architecture

5. Basic Architectures
● Client-Server
● 3-Tier
● N-Tier
● Distributed Objects
● Tigh Coupling
● Loose Coupling

6. Characteristics
Challenges:
● Heterogeneity
● Transparency
● Fault tolerance and failure management
● Scalability
● Concurrency
● Openness and Extensibility
● Migration and load balancing
● Security

7. Characteristics
Transparency:
● Entire distributed system should appear as a single unit
● Complexity interactions between the components should
be typically hidden from the end user.
(For the user)

8. Characteristics
Fault tolerance:
● Failure of one or more components should not bring
down the entire system

9. Characteristics
Scalability:
● System should work efficiently with increasing number
of users
● Addition of a resource should improve the
performance of the system.
++ --

10. Characteristics
Concurrency:
● Shared access to resources should be made possible

11. Characteristics
Openness & Extensibility:
● Interfaces should be cleanly separated and publicly
available to enable easy extensions to existing
components and add new components.

12. Characteristics
Security:
● Access to resources should be secured
● Only known users are allowed to access

13. Middleware
What is middleware?:
● Software layer between the operating system and
the applications on each site of the system.

14. Middleware
What Middleware offers?:
● Hiding distribution
● Hiding the heterogeneity
● Providing uniform, standard, high-level interfaces to
the application developers and integrators

15. Middleware
How it works?
● Client-side interface invoke functions that the
middleware provides

16. Examples
Search Engines

17. Examples
Search Engines
● Google has 36 data centers across the globe. With 150
racks 40 servers per data center, that would mean
Google has more than 200,000 servers. This enables a
sub-half-second response to an ordinary Google search
query that involves 700 to 1,000 servers.
CNet News, May 30 2008

18. Examples
Online Games

19. Examples
Online Games
● World of Warcraft
■ 20,000 computer systems
■ 13,250 server blades
■ 75,000 CPU cores
■ 1.3 petabytes of storage
■ 4,600 staffers
● Taikodom (a Brazilian gaming startup) use
a combination of a z9 mainframe to
handle transactions connected using a Gigabit
Ethernet to a cluster of blade servers with Cell
processors for graphics.

20. Examples
Social Networks

21. Examples
Twitter (March 14, 2011)
#tweets
● 3 years, 2 months and 1 day. The time it took from the first Tweet
to the billionth Tweet.
● 1 week. The time it now takes for users to send a billion Tweets.
● 50 million. The average number of Tweets people sent per day,
one year ago.
● 140 million. The average number of Tweets people sent per day, in
the last month.
● 177 million. Tweets sent on March 11, 2011.
● 456. Tweets per second (TPS) when Michael Jackson died on June
25, 2009 (a record at that time).
● 6,939. Current TPS record, set 4 seconds after midnight in Japan
on New Year’s Day.

22. Examples
Grid Computing

23. Examples
EGI (European Grid Infrastructure)
Resource Centres 348
Participating countries 58
Installed computing 364,500 cpus
capacity
Jobs/day 2010-2011 1,331,525

24. Questions?