ch 6: the cloud Flashcards
What is the definition of the cloud
the elastic leasing of pooled computer resources over the internet
Why is the term cloud used?
bc most early diagrams of three-tier and other internet based systems used a cloud symbol to represent the internet
what is three tier architecture
software application that organizes application into three computing tiers
-presentation tier/user interface
-application tier -where data is processed
-dara tier-where data associated with the application is stored and managed
Some benefits of moving to the cloud
-significant elasticity (limits financial risks and automatically adjusts for unpredicitable demand and allows leasing of capacity on a as needed basis for a fraction of the cost)
-improved scalability (allows an organization to respond to slow incremental growth in demand)
-lowerd costs (such as the costs of managing physical servers)
-pooled resources (which allow multiple users to share the same physical hardware through virtualization and enables the rapid development of new virtual machines)
why do organizations prefer the cloud
-lower costs
-ubiquitous access
-improved scalability
-elasticity
-virtualization technology
-internet based standards
the mainframe era
-1960s-1980s
-large scale high speed centralized computers
-thin clients (computer terminals), no internet and no cloud
the client server era
-1990s-2000s
-allowed clients (users) to send requests across the internet to servers
-internet but no modern cloud computing yet
the cloud computing era
-2008-current
-applications, data, and processing power can be used remotely
-accessed with a variety of devices including PCs (stand along clients), thin clients, mobile devices, and IOT devices
when does the cloud not make sense?
For organizations that are required by law to hav physical control or possession over their data
this results in them needing to be forced to create and maintain their own hosting infrastructure
-ex financial instutions
positives of the cloud
-small capital requirements
-speedy development
-superior scalability to growing/flunctuating demand
-known cost structure
-possibly best of breed security disaster prepardness
-no obsolescence
-industry wide economies of scale (cheaper)
-allowsfocus on core business not infrastructure
negatives of the cloud
-dependency on vendor
-loss of control over data location
-little visibility into true security and disaster preparedness capabilities
in house positives
-control of data location
-in depth visibility of security/disaster preparedness
in house negatives
-significant capital required
-significant development effort
-difficult nearly impossible to accommodate fluctuating demand
-ongoing support costs
-staff and train personnel
-increased management requirements
-annual maintenance costs
-cost uncertainties
-obsolescnence
what network technology supports the cloud
-personal area network (PAN)
-local area network (LAN)
-wide area network (WAN)
-the internet and internets
PAN
-personal area network
-devices connected around a single person
