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.NET windows services interview questions
1) What’s a
Windows process? It’s an application that’s running and had
been allocated memory.
What’s typical about a Windows process in regards to memory
allocation? Each process is allocated its own block of
available RAM space, no process can access another process’
code or data. If the process crashes, it dies alone without
taking the entire OS or a bunch of other applications down.
Why do you
call it a process? What’s different between process and
application in .NET, not common computer usage, terminology?
A process is an instance of a running application. An
application is an executable on the hard drive or network.
There can be numerous processes launched of the same
application (5 copies of Word running), but 1 process can
run just 1 application.
What distributed process frameworks outside .NET do you
know? Distributed Computing Environment/Remote Procedure
Calls (DEC/RPC), Microsoft Distributed Component Object
Model (DCOM), Common Object Request Broker Architecture
(CORBA), and Java Remote Method Invocation (RMI).
What are possible implementations of distributed
applications in .NET? .NET Remoting and ASP.NET Web
Services. If we talk about the Framework Class Library,
noteworthy classes are in System.Runtime.Remoting and
System.Web.Services.
When would you use .NET Remoting and when Web services? Use
remoting for more efficient exchange of information when you
control both ends of the application. Use Web services for
open-protocol-based information exchange when you are just a
client or a server with the other end belonging to someone
else.
What’s a proxy of the server object in .NET Remoting? It’s a
fake copy of the server object that resides on the client
side and behaves as if it was the server. It handles the
communication between real server object and the client
object. This process is also known as marshaling.
What are remotable objects in .NET Remoting? Remotable
objects are the objects that can be marshaled across the
application domains. You can marshal by value, where a deep
copy of the object is created and then passed to the
receiver. You can also marshal by reference, where just a
reference to an existing object is passed.
What are channels in .NET Remoting? Channels represent the
objects that transfer the other serialized objects from one
application domain to another and from one computer to
another, as well as one process to another on the same box.
A channel must exist before an object can be transferred.
What security measures exist for .NET Remoting in
System.Runtime.Remoting? None. Security should be taken care
of at the application level. Cryptography and other security
techniques can be applied at application or server level.
What is a formatter? A formatter is an object that is
responsible for encoding and serializing data into messages
on one end, and deserializing and decoding messages into
data on the other end.
Choosing between HTTP and TCP for protocols and Binary and
SOAP for formatters, what are the trade-offs? Binary over
TCP is the most effiecient, SOAP over HTTP is the most
interoperable.
What’s SingleCall activation mode used for? If the server
object is instantiated for responding to just one single
request, the request should be made in SingleCall mode.
What’s Singleton activation mode? A single object is
instantiated regardless of the number of clients accessing
it. Lifetime of this object is determined by lifetime lease.
How do you define the lease of the object? By implementing
ILease interface when writing the class code.
Can you configure a .NET Remoting object via XML file? Yes,
via machine.config and application level .config file (or
web.config in ASP.NET). Application-level XML settings take
precedence over machine.config.
How can you automatically generate interface for the
remotable object in .NET with Microsoft tools? Use the
Soapsuds tool. |
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