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What is EIDE?
Differentiate
between the user mode and monitor mode.
What is time
slice?
What are the
activities related to the Time shared user program management?
When an input file
is opened, what are the possible errors that may occur?
Explain PCB.
What is context
switching ?
What is cascading
termination?
Explain IPC.
What are sockets?
What is EIDE?
• EIDE is a bus called enhanced integrated drive electronics.
• The input output devices are attached to the computer by a set of wires
called the bus.
• The data transfer on a bus are carried out by electronic processes called
controllers.
• The host controller sends messages to device controller and device controller
performs the operations.
• These device controllers consist of built in cache so that data transfer
occurs at faster speed.
Differentiate between the user mode and monitor mode.
• User mode and monitor mode are distinguished by a bit called the mode bit.
• User mode uses bit 1 and monitor mode uses bit 0.
• At the boot time hardware starts with the monitor mode.
• Also, at the time of interrupt user mode is shifted to the transfer mode.
• System always switches to the user mode before passing control to the user
program.
• Whenever system gains control of the computer it works in monitor mode
otherwise in user mode.
What is time slice?
• The timer in CPU is set to interrupt every N milliseconds where this N is
called the time slice.
• It is the time each user gets to execute before control is given to next
user.
• At the end of each time slice the value of N is incremented and the record is
maintained.
• It also maintains the record of the total time user program has executed thus
far.
• This method helps in time sharing among the various users.
What are the activities related to the Time shared user program
management?
• Operating system is responsible for the creation and deletion of both user and
system processes.
• It also provides mechanism for the process synchronization.
• Suspending and resuming of windows is done by the operating system itself.
• Program needs resources like CPU time, memory, files, input output devices to
complete the task which is provided by the operating system.
• Mechanisms are also provided for deadlock handling.
When an input file is opened, what are the possible errors that may
occur?
• 1ST condition may be that the file is protected against access, here it
terminates abruptly.
• 2nd condition may be that file exists, then we need to create the output
file.
• If file with the same name exists then it may be deleted or program may be
aborted.
• In another case the system may ask the user to replace the existing file or
abort the program.
Explain PCB.
• PCB process control block is also called as the task control block.
• It contains information about the process state like new, ready, running,
waiting and halt.
• It also includes the information regarding the process priority and pointers
to scheduling queues .
• Its counter indicates the address of the next instruction to be executed for
the process.
• It basically serves as the storage for any information that may vary from
process to process.
What is context switching ?
• It is the process of switching the CPU from one process to another.
• This requires to save the state of the old process and loading the saved
state for the new process.
• The context of the process is represented in the process control block.
• During switching the system does no useful work.
• How the address space is preserved and what amount of work is needed depends
on the memory management.
What is cascading termination?
• If one process is terminated, its related processes are also terminated
abnormally then it is called cascade termination.
• It occurs in the case of parent child process.
• If the parent process is terminated normally or abnormally then all its child
processes must be terminated.
• The parent is existing and the operating system does not allow a child to
continue if its parent terminates.
• This child process is the new process created by the process called the
parent process.
Explain IPC.
• It is called as the inter process communication.
• The scheme requires that processes share a common buffer pool and code for
implementing the buffer.
• It allows processes to communicate and to synchronize their actions.
• Example : chat program used on the world wide web.
• It is useful in distributed computer systems where communicating processes
reside on different computers connected with a network.
What are sockets?
• A socket is defined as endpoint for communication, a pair of sockets is used
by the pair of processes.
• It is made of IP address chained with a port number.
• They use the client server architecture.
• Server waits for incoming client requests by listening to specified port.
• On reception of request, server accepts connection from client socket to
complete the connection.
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