IT infrastructure
An IT infrastructure consists of physical devices and software applications that are required to operate the entire enterprise.
What else does IT infrastructure include?
IT infrastrucutes aso include services budgeted by management composed of both human and technical capabilities.
What do IT infrastrucutre services include?
- Computing platforms used to connect employees, customers and suppliers in a coherent digital environemnt, including large mainframes, midrange computers, laptops and desktops.
- Telecommunication platform used for connectivity.
- Data management services that store, manage and analyze corporate data.
Moore’s Law
Originally Gordon Moore assumed that chip performance per dollar was doubling every18 months. Then it got adjusted by Moore to every 2 years, starting 1980. Now it is speculated to be every 2.5 years.
Chips&Transistors
Moor’s law refers to a chip based technology, devices using circuits with integrated transistors.
What is a transistor?
A transistor is a semiconductor-based switch, whose invention miniatuirized electronics. (1956 Nobel prize)
Chip-based components
- Microprocessor (executes programs)
- Random access data/RAM (volatile memory, data is lost when powered down)
- Flash or solid state drives (nonvolatile, data is retained)
Mechanical/moving components
- Hard disck drives (nonvolatile memory, uses magnetic rotating disk)
- Fans
- Disk drives
Data transmission
Exponential growth, isn’t limited to the microchip performance
Mainframe era (since 1959)
- late 1950’s IBM introduced a range of centralized “data processing systems” that replaced vacuums with transistor tubes
- mainframes larger, less powerful than today’s computers
- mainframes still relevant, powerful to enterprise networks
- IBM still the leading provider of mainframe
Minicomputers
1965 minicomputers, allowed decentralized computing
Personal computing era (since 1981)
- IBM PC introduced in 1981 (not the first)
- Standalone systems
- People started using them more at home=> Increasing use at work
- Software development (presentations, spreadsheet, games…)
- Multi-decade dominance of Microsoft operating systems
Client-server era (since 1983)
- Distinguishes between providers and requesters. Lap/dektops are clients that are networked to powerful server computers that provide client computers with variety of resources and capabilities.
- Clients initiate communication, but don’t share resources
- In Peer-to-Peer (P2P) networks, participants are both suppliers and consumers of resources.
Application transfer protocols:
- HTTP (hypertext transfer protocol): for communication between web browser and web server
- SMTP (simple mail transfer protocol): for email transmission
- FTP (file transfer protocol): for file transfers between clients and servers
Internet Resources
URL (unifrom resource locator) used to find resources on the internet.
Cloud computing
Cloud computing refers to the provision of IT sources through the internet.
- Instead of on-premise hardware, servers are provisioned through the internet on demand.
- Instead of purchasing and intalling software on your computer, you can access it as a web service through a browser.
What is Service Hosting?
Service hosting is usually shared between servers, which allows for higher fault tolerance and to balance and share requests.
HTML (Hypertext Markup Language): standard language used to format websites
TCP/IP
TCP (transmission control protocol) and IP (internet protocol) enable data transfer across the internet.
- TCP slices data into packages that are to be sent to the source computer.
- IP routes these packages to the target computer.
- TCP at the host computer checks for completeness and reassembles packages.
DNS
The domain name service (DNS) is like the phonebook of the internet.
- It takes host and domain as input and return the IP address of the server providing the requested resources
- DNS hacks one of the most dangerous, it can redirect users to malicious websites.
Advantages of cloud computing
- lower upfornt costs
- increases flexibility for scaling
IP adresses
IP adresses are assigned to every device connected to the internet. Provide unique identifier IPv4 consists of 4 blocks of digits ranging from 000 to 255.
- Allows for 4,3 billion addresses (reached in 2015)
- IPv6 extends to 2128 possible addresses by using 8 blocks of hexidecimal digits
- IPv6 additional improvements, but is not backwards compatible and adaption is slow.
DIsadvantages of cloud computing
- might increase long-term costs
- dependance on providers (bankruptcy)
- moving legacy systems to cloud may be costly
Types of computing services
- Infrastructure-as-a-Service
- Platform-as-a-Service
- Software-as-a-Service
IaaS
- Allows users to instantly obtain or give up IT hardware resources, such as storage, computing, networking capabilities.
- Cuztomization, firms can choose what to install, develop and maintain
