Information systems slide technical aspects of e commerce part 2

Technical Aspects of
E-Commerce Part 2 of 2
Mort Anvari


Introduction
- Review
- Hardware
- Firewalls
- Networking
- Cryptography

2


Review

PC

Web
Server

PC

Internet

R

SQL
Server

PC

FW

PC

Mail
Server

File
Server

PC

PC

3


Review
Application: Programs that
directly access the
presentation layer belong
at least in part to the
application layer.

CGI Script

User
Space

Web Server

Presentation

Operating
System
Space

Session
Transport

System

Network

I/O Layer

Software
Datalink

Motherboard
Physical
World

HD Controller
Hard Drive

Data

HTML
Pages

Video
Card

Network
Card

Hardware

Physical

4


Hardware
What is it?
- The physical components of a computing
system
- If it can be held in your hand it’s hardware
- If it can’t it’s software

5


Hardware
Application: Programs that
directly access the
presentation layer belong

at least in part to the
application layer.

CGI Script

User
Space

Web Server

Presentation

Operating
System
Space

Session
Transport

System

Network

I/O Layer

Software
Datalink

Motherboard
Physical

World

HD Controller
Hard Drive

Data

HTML
Pages

Video
Card

Network
Card

Hardware
Current
Topic

Physical

6


Hardware
- Architecture
- Hard Drives
- Backup Systems
- Network Interfaces

- RAM

7


Architecture
- CISC (Complex Instruction Set Comp.)
Can do complex operations
Can do many functions
i.e. 486, Pentium, PowerPC

- RISC (Reduced Instruction Set Comp.)
Can do a few simple operations
Faster than CISC
i.e. SPARC, HP9000
8


Hard Drives
- Single
A regular hard drive

- Mirrored
Fault-Tolerant
Expensive

- Drive Array
Fault-Tolerant
Slower but cheaper than Mirror
9

Hard Drives
- Highly Redundant Drive Enclosure
External to server
Can lose multiple drives
Very fast
Very expensive

10


Backup Systems
- DAT (Digital Audio Tape)
Fast, efficient and reliable
Tape sizes from 2-24GB
Backwards compatible

- DLT (Digital Linear Tape)
Very fast, reliability problems
Tapes can hold up to 70GB
New technology
11


Backup Systems
- Tape Library
Uses multiple DLTs or DATs
Uses many tapes
Robotic arm changes tapes

12


Network Interfaces
- LAN (Local Area Network)
Small in geographic size
Fast and cheap
Owned

- WAN (Wide Area Network)
Connects distant LANs
Slow and expensive
Rented
13


Random Access Memory
- Regular
Garden variety memory

- Parity
Checks for memory errors
Stops machine on error

- ECC (Error Checking and Correcting)
Checks for memory errors
Corrects errors
14

Firewall
What is it?
- A special computer system designed to isolate one
area of the network
- All network traffic going into or out of the isolated
area must pass through the firewall
- Only allows traffic to pass that meets a set of
criteria based on company policy
- Like the gate house in a jail
- It’s software
15


Firewall

PC

Web
Server

PC

Internet

R

SQL
Server

PC

FW

PC

Mail
Server

File
Server

PC

PC

16


Firewall
Application: Programs that
directly access the
presentation layer belong
at least in part to the
application layer.

Firewall
Software

User

Space

Presentation

Operating
System
Space

Session
Transport

System

Network

I/O Layer

Software
Datalink

Motherboard
Physical
World

HD Controller
Hard Drive

Data

Logs

Video
Card

Networ
k
Card

Hardware
Current
Topic

Physical

17


Networking
What is it?
- A series of devices called nodes
interconnected by communication pathways
- Nodes can be computers or devices that help
the network function
- Networks can be connected or contain sub
networks
- It’s made up of hardware and software
18


Networking

PC

Web
Server

PC

Internet

R

SQL
Server

PC

FW

PC

Mail
Server

File
Server

PC

PC

19


Networking
User
Space

Power
Point

Mail
Client

Web
Client

Application: Programs that
directly access the
presentation layer belong
at least in part to the
application layer.
Presentation

Operating
System
Space

Session
Transport

System

Network

I/O Layer

Software
Datalink

Motherboard
Physical
World

HD Controller
Hard Drive

Data

HTML
Pages

Video
Card

Networ
k
Card

Hardware

Current
Topic

Physical

20


Networking
- The OSI Model
- An Example Transmission

21


The OSI Model
- Framework describing network
protocols
- 7 Layers
- 1 Layer = 1 Aspect of Networking
- Layers only aware of neighbors
- Layers provide flexibility and
functionality
22


The OSI Model
The OS and the Network Card work together to make a
complete stack.
Application

Presentation
Session

The OS is responsible
for these functions

Transport
Network
Datalink
Physical

The Network Card is
responsible for these
functions

23


Application Layer
A
P
S
T
N

- Where actual services reside
- HTTP, FTP, Gopher, DNS etc.
- Not related to Applications you
use like Word or Excel

D
P

24


Presentation Layer
A
P
S
T
N

- Data “pre-processed”
- Compression
- SSL
- ASCII Translations

D
P

25