Exam 1

connecting existing networked computer systems into a
larger system

An existing network is extended with additional computers

a networked computer system in which processes and resources are necessarily spread across multiple computers

a networked computer system in which processes and resources are sufficiently spread across computers

centralized solutions do not scale, t or f

when a systems logic is central, as in it has the same knowledge base allthroughout. (data, business logic)

when a system has a genuinely centralized infrastructure. (servers and hardware)

what is an example of a system that is logically centralized but physically distributed?

Centralized solutions have a single point of failure, t or f

a single point of failure is often easier to manage and make

The phenomenon by which a distributed system attempts to hide the fact
that its processes and resources are *physically distributed across
multiple computers*, possibly *separated by large distances*.

transparency is handled through ___

the layer between operating systems and applications that facilitates transparency

Hide differences in data representation and how an
object is accessed

Hide that an object may be moved to another location
while in use

Hide that an object may move to another location

Hide that an object may be shared by several
independent users

you can completely hide all failures, t or f

you can be sure a computer actually performed an operation before a crash, t or f

Distribution transparency is a nice feature, but achieving it is a
different story, and it should often not even be a goal, t or f

A system that offers components that can easily be used by, or
integrated into other systems.

The average time until a component fails

the average time needed to repair a component

mean time to failure + mean time to repair

a component not living up to expectations (crashed)

a part of a component that can lead to failure (programming bug)

cause of an error (sloppy programmer)

Prevent the occurrence of a
fault

Build a component and make
it mask the occurrence of a
fault

Reduce the presence, number,
or seriousness of a fault

Estimate current presence,
future incidence, and
consequences of faults

A distributed system that is not secure, is not

information is disclosed only to authorized parties

Ensure that alterations to assets of a system can be made
only in an authorized way

verifying the correctness of a claimed identity

does an identified entity has proper access rights?

one entity can be assured that another will perform particular
actions according to a specific expectation

Encryption and Decryotion key are the same and kept secret

private key and secret key are used to send messages

a function that returns a fixed length string that is affected heavily by the input changes

when we use a hash function we are essentially creating a

Number of users or processes

Maximum distance between nodes

Number of administrative domains

a centralized service can be modled as a simple __

parallel computing type where the processors share memory

parallel computing type where each processor has private memory

Essentially a group of high-end systems connected through a LAN, with same OS and single tightly coupled managing nodes

Heterogeneous
Dispersed across several organizations
Can easily span a wide-area network,
plenty of nodes everywhere

An example of intregrating applications, this defines "transactions" of data between applications. EX: payroll account and Employee database communicating together

In EAI, data in a transaction is usually distributed, so a _ is responsible for coordinating the transaction

in our middleware, we can call functions that call functions on other applications, then return their returns to our middleware.

Messages are sent to logical
contact point (published), and forwarded to subscribed applications

distributed systems in which nodes are
small, mobile, and often embedded in a larger system, characterized
by the fact that the system naturally blends into the user’s
environment.

a pervasive system that is visible and autonomous and continuously interacting with the user (think a system of health monitoring sensors on a body)

a pervasive system of many mobile components (location is changing constantly) think all of your apple products and accessories

a pervasive system of many sensors

contains units for interfacing to users or external
applications

contains the functions of an application, i.e., without specific
data

contains the data that a client wants to manipulate through the
application components

Components are objects, connected to each other through procedure calls. Objects
may be placed on different machines; calls can thus execute across a network.

View a distributed system as a collection of resources, individually managed by components. Resources may be added,
removed, retrieved, and modified by (remote) applications

example of restful architechtures where Objects (i.e., files) are placed into buckets (i.e., directories). Buckets cannot be placed into buckets.
Operations on ObjectName in bucket BucketName require the following identifier

occurs when two components must operate at the same time or in a specific sequence to function correctly

occurs when one component needs a direct reference to another to function—like knowing its address, name, or interface.

is where data is described by attribute value pairs

in publish and subscribe model what is it called when you specify where an attribute = value

in publish and subscribe model what is it called when you specify a attribute withing a range

when we make middleware wrappers 1 to 1, it requires __ wrappers

when we make middleware wrappers through a broker, it requires __ wrappers

dumb terminal/mainframe configuration

client/single server configuration

each layer on separate machine

whats an example of client server architecture

A website consisted as a collection of HTML files
HTML files could be referred to each other by a hyperlink
A Web server essentially needed only a hyperlink to fetch a file
A browser took care of properly rendering the content of a file
this describes

A website was built around a database with content
A Webpage could still be referred to by a hyperlink
A Web server essentially needed only a hyperlink to fetch a file
A separate program (Common Gateway Interface) composed a page
A browser took care of properly rendering the content of a file
this describes

Comes from dividing distributed applications into three logical layers, and running
the components from each layer on a different server (machine).

A client or server may be physically split up into logically equivalent parts, but each
part is operating on its own share of the complete data set.

Processes are all equal: the functions that need to be carried out are represented
by every process
⇒
each process will act as a client and a server at the same time
(i.e., acting as a servant).

each data item is uniquely associated with a key, in turn used as
an index. Common practice: use a hash function

simple example of a p2p system that stores key value pairs

another example of p2p where nodes are in a ring with a hash, there are shortcut links between nodes too

Each node maintains a dynamic list of neighbors. The resulting overlay resembles a
random graph:

issuing node passes request for to all neighbors. Request is ignored
when receiving node had seen it before. Otherwise, searches locally for
(recursively). May be limited by a Time-To-Live: a maximum number of hops.

issuing node passes request for to randomly chosen neighbor,
. If does not have , it forwards request to one of its randomly chosen neighbors,
and so on

random walk is more communication efficient but takes more time to find result, t or f

we can upgrade p2p by having brokers or index servers to find data faster, this is called a

whats an example of superpeer networks that allows you to trade chunks in a swarm

what is the type of computing that puts all data in a cloud (large data centers) that is managed by platforms like amazon s3 storage system, and can be interacted with by many types of applications?

systems depployed on the internet where servers are placed at the edge of the network and serve as a boundary between enterprise networks and the internet.

these are common misconceptions: the cloud has bad bandwidth and latency, the cloud is unreliable, and that edge servers protect data, t or f

blocks are what in the blockchain

the block chain is __ only

A single entity decides on which validator can go ahead and append a block. Does
not fit the design goals of blockchains

A selected, relatively small group of servers jointly reach consensus on which validator can go
ahead.
None of these servers needs to be trusted, as long as roughly two-thirds behave according to
their specifications

Participants collectively engage in a leader election. Only the elected leader is allowed to append
a block of validated transactions.
Large-scale, decentralized leader election that is fair, robust, secure, and so on, is far from
trivial