Module 3 Flashcards
IT hardware history:
1)Mainframe era (1959), IBM introduces a range of centralized data processing systems, replacing vacuum tubes with transistors.
2)1965 minicomputers were introduced, enabling decentralized computing.
3)Personal computing era (1981) IBM introduces PC (this is not the first though). Standalone system, no connection needed.
4)Client-server era (1983) started when the client-server model distinguishes between providers and requesters.
Moore’s law:
Chip performance per dollar roughly doubles every 18 months.
Technology drivers of infrastructure evolution:
1)Moore’s law and microprocessing power
2)Law of mass digital storage (Every year the amount of data stored doubles leading to decreased costs)
3)Metcalfe’s law and network economics (The value of network increases with the increase of users)
4)Declining communication costs over the Internet and telephone networks, due to the growth of internet.
5)Standards and network effects (Compatibility of products and network communications is established, leading to economies of scale and decline in price)
Components of IT infrastructure:
1)Computer hardware platforms (IBM),
2)Operating system platforms(Microsoft Windows),
3)Enterprise software applications(SAP),
4)Data management and storage (IBM DB2),
5)Networking and telecommunications (Microsoft Windows server)
6)Internet platforms (Apache),
7)Consulting system integration services (IBM, HP).
Future of computers:
1)Quantum computing (extends the binary universe)
2)Optical computers (using photons of electrons)
3)DNA computing (using DNA molecules for highly-parallelized computing)
What are Cloud computing and its advantages:
Refers to the provision of IT resources over the Internet.
Software and hardware are replaced over the Internet.
Advantages:
1)Reduces costs as Google and Apple provide a free development environment.
2)Increases flexibility for scaling as you can add more servers when there are more visitors.
Disadvantages:
1)May lead to higher long-term costs as it costs more the added space.
2)Dependence on providers (bankruptcy, disruptions).
3)Moving legacy systems to cloud could be costly.
Cloud computing services:
1) Infrastructure-as-a-service (IaaS): Builds the infrastructure of cloud-based technology. Allows users to instantly obtain or give up IT hardware resources. Offers the most customization, with firms choosing which products to install, and develop. (Amazon Web service)
2)PaaS (Platform): Helps developers build custom apps via an API that can be delivered over the cloud. (Google App engine)
3)SaaS(software): Global-based software which can be bought or sold. For example, email, calendar, office tools, etc.
Define the Internet:
A decentralized system of networks that links devices around the globe and enables data transmission among them.
Internet application transfer protocols:
1)HTTP (Hypertext transfer protocol) - for communication between web browsers and web servers
2)SMTP (Simple mail transfer protocol) - for email transmission
3)FTP(File transfer protocol) - for file transfers between clients and servers
Finding resources on the Internet (components of links):
URL (uniform resource locator) - used to find resources on the internet (uniform=standardised)
HTTP(application transfer protocol)://www(Host name).nytimes(Domain name).com(top level domain)/pages/tech(path)/index.html(file)
HTML( HyperText Markup Language) is used to format websites (how web looks like).
What is IP(Internet protocol) address:
P addresses are 32-bit numbers assigned to every device connected to the Internet, serves as a unique identifier.
IPv4 consists of 4 blocks ranging from 000 to 255. This allows 4.3 billion addresses, which was reached in 2015.
IPv6 uses 8 blocks. Adaption is slow as it is not backward compatible.
Define Domain Name service (DNS):
Serves as a phone book of the Internet. Takes domain and host as inputs and returns the IP address of the server providing the requested resource. Serious hacking issue.
What TCP (Transmission control protocol) and how it works:
Slices information that is to be sent to the source computer, IP routes these packages. TCP then at the target computer checks for completeness and reassembles packages.
Information is split and then reassembled because then only the part that has an error has to be resent not the whole file. Also, it can be sent through many routes and balanced.
