Page 63 - DCAP103_Principle of operating system

Principles of Operating Systems

Notes visible to all processes; they give applications a way to set up a communication channel. This
communication works as follows:
• The client opens a handle to the subsystem’s connection port object.
• The client sends a connection request.
• The server creates two private communication ports, and returns the handle to one of
them to the client.

Give the current Windows name.

If a client needs to send a larger message, it passes the message through a section object (or shared
memory). The client has to decide, when it sets up the channel, whether or not it will need to
send a large message. If the client determines that it does want to send large messages, it asks for
a section object to be created. Likewise, if the server decides that replies will be large, it creates
a section object. So that the section object can be used, a small message is sent that contains a
pointer and size information about that section object. This method is more complicated than
the first method, but it avoids the data copying. In both cases, a callback mechanism can be
used when either the client or the server cannot respond immediately to a request. The callback
mechanism allows them to perform asynchronous message handling.

Windows 2000 uses three types of message-passing techniques over a port
that the client specifies when it establishes the channel. The simplest, which
is used for small messages, uses the port’s message queue as intermediate
storage and copies the message from one process to the other. Under this
method, messages of up to 256 bytes can be sent.

How could a system be designed to allow a choice
of operating systems to boot from? What would

the bootstrap program need to do?

onsider a system that would like to run both Windows XP and three different
distributions of Linux (e.g., RedHat, Debian, and Mandrake). Each operating
Csystem will be stored on disk. During system boot-up, a special program
(which we will call the boot manager manager) will determine which operating
system to boot into. This means that rather initially booting to an operating system,
the boot manager will first run during system start-up. It is this boot manager that is
responsible for determining which system to boot into. Typically boot managers must
be stored at certain locations of the hard disk to be recognized during system start-up.
Boot managers often provide the user with a selection of systems to boot into; boot managers
are also typically designed to boot into a default operating system if no choice is selected by
the user.

Questions:
1. Explain process of Bootstrap loader.
2. Define working of Bootstrap loader in the term of process management.

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