Parallel and Distributed Databse

- In Parallel database the distribuition is governed solely by performance consideration.

- In Distributed databse distribution of data is governed by factors such as local ownership nad increased availability, in
addition to performance issues.

JDBC and ODBC are called GATEWAY PROTOCOL.

Architecture of Parallel DB :
1 - Shared Nothing
2 - Shared Memory
3 - Shared Disk

Architecture of Distributed DB :
1 - client Server
2 - Collaboration Server
3 - Middleware.

Types of Distributed DB :
1 - Homogenous
2 - Heterogenous

Fragmentation types :
1 - Vertical
2 - horizontal

a bit about Distributed System

Requirments of DS :
- Availability
- Reliability
- Maintainablity
- Security

Goal of DS:
- User Connectivity
- Openness
- Transparency
- Scalability
- Atomic Multicast

1 -Initally all things were consolidated.
1.1 - Disadvatage :
a - Single point failure
b - Performance bottleneck

1.2 - Solution : Remove centralization/consolidation
a - By Sharing Or Mirroring Or Replication Or Caching Or Distributing for
a.1 - PERFORMACE and RELIABILITY
a.2 - AVAILABILITY and SCALABILITY [achieved by Replication, Caching and Distribution]

3 - But with Sharing, Replication and Distribution comes
3.1 - Security Problems
3.2 - Consistency Problems. Solution : Synchronization
3.3 - Fault Tolerance Problems. Solution : Replication

4 - Also With Scalability comes LOSS OF PERFORMANCE.

random gyan

A software system can be categorize as open if it specifies and publishes interface between its system components.

Colors	Waveelength(nm)	Frequency(x10^14)
Violet	380-450	6.6-7.9
Blue	450-490	6.1-6.6
Green	490-560	5.4-6.1
Yellow	560-590	5.1-5.4
Orange	590-630	4.8-5.1
Red	630-760	3.9-4.8

Color is described by
1 -brightness
2 -hue
3 -depth of color

The resources where information objects are stored so that they remain sharable across the network are called SERVERS.

Types of Compression :
1. Lossless
1.1 - RLE
1.2 - CCITT Group 3 1D
1.3 - CCITT Group 3 2D
1.4 - lEMPEL ZIV & wELCH aLGORITHM [LZW]

2. Lossy
2.1 - JPEG
2.1 - MPEG
2.1 - Intel DVI (Digital Video Interface)
2.1 - CCITT H.261
2.1 - Fractals

A model is an abstraction of the information objects and the functions
Models are buuilt for a variety of Designs.
A good design helps in achieving optimum performance.

Topology option depends on:
1 - Application
2 - Size of Organisation
3 - Topology and Distributed System
4 - Location of various data servers

something about Security

The principal mechanism for ensuring secure communication is that of a secure channel.

A security policy descibes precisely which actions the entities in a system are allowed to take.

Security means Dependibility. i.e.
1 - Reliability
2 - Availibity
3 - Maintainablity
4 - Trust(Security)
  4.1 - Confidentiality
  4.2 - Integrity

Factors for Security
1 - Confidentiality
2 - Integrityy
3 - Availibility

Threats For Security
1 - Interception (unauthorized x confidential)
2 - Interruption (unavailable x available)
3 - Modification (unauthorized x integrity by authentication)
4 - Fabrication (modification of data)

Basic Security Mechanism :
1 - Encryption
2 - Authentication
3 - Authorization
4 - Auditing

Things/Assets to be protected
1 - Data
2 - Hardware
3 - Software


Controlling levels :
1 - User level : Software - Authentication and Encryption
  Hardware - Smart Card etc.
2 - Program level : Writing Secure Code, by OS, Policies,   Administration, Auditing
3 - OS level : Memory, File, user Authentication(PWD OR Challenge Response), AccessControl
4 - Network level : Hardware - Firewall, Caling, IDS
        Software - Encryption.
5 - Database level : Query, Recoed, Storage Media
6 - Admin Level : Organize, Authorize, Manage, AccessControl, Audit
7 - Legal, Policy, Ethical

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Ecological footprint

For every kind of energy or matter we consume to maintain our lifestyles, some natural resource, somewhere, gets used up, and waste is produced. The city is an ecosystem, with inputs in the form of land, water, energy, food and materials from the hinterland which, after being utilised, become waste, the output.

The Ecological Footprint is a measure of the load imposed by a particular population or economy on nature. It represents the land (and water) area necessary to sustain current levels of resource consumption and waste discharge by that population. It is an accounting tool that allows us to estimate the resource consumption and waste assimilation requirements of a particular human population or economy in terms of corresponding productive land area.

My Ecological Footprint was:

Food 0.3
Mobility 0.3
Shelter 0.6
Goods/Services 0.2
-------------- ---
Total footprint 1.5

Please make a visit at www.myfootprint.org.. to calculate ur ecological footprints and read the comments!!
"js chkout aap kitne dharti par boj ho" hehe...

renaming the blog

guys i was just thinking of renaming the blog.
this is because its no more an e news blog.
it has became a discussion blog.
so plz suggest some names.
start commenting.