please answer these questions d View w 20 Explain what happe
 please answer these questions
Solution
20) Opening a File Means we are accessing the file from memory and we are loading it from external Memory to Virtual Memory.
Logical I/O means the data is treated as sequence of blocks that are nmbered from 0 ti N-1
Physical I/O treats them by sector,platter.
21) Access methods refer to a mechanism of accessing data whereas device driver is a software that looks after particular devices connected to our machine internally or externally.
22) Processor bus is defined as the bus that provides the path for communication between the main buses send the central processing unit
The memory bus is the computer bus which connects the main memory to the memory controller in computer systems.
A system bus is a single computer bus that connects the major components of a computer system, combining the functions of a data bus to carry information, an address bus to determine where it should be sent, and a control bus to determine its operation.
The I/O Bus. A personal computer may transfer data from disk to CPU, from CPU to memory, or from memory to the display adapter.
23) If we are having more than one command set for execution then it is known as Batch Command File
24) Below are few functions
a) Opening a File b) Closing a File 3) Renaming a File etc..
25) Opening a File means we are physically accessing a resource that is predefined and launching a program means we are externally loading the data that is not predefined.
They are similar as both need the data to be transferred externally and difference are in terms of their functionalities
26)
27) Root directory lies on the top where all files are loaded
Home Directory is a location where the individual user has access
Working Directory is a place where we are currently executing programs
28) Assume we are at user
type cd home
cd youname
cd mac2.30
mkdir lab1
29) cat filename
nano filename
30) find -name \"filename\"
31) cp /usr/newos/file2 file
32) If any matching character at any location needs to be traced then wild card entry is the best
eg ls %.
It will list all file name having file name size of atleast 1.
33) If we want to copy data from external to file then we use it
<< filename then the data present externally will be loaded to filename
Filters are used to enhance the readability of execution
eg-cat,cut,grep.
Pipes are used to join two or more commands
34) A shell script is a computer program designed to be run by the Unix shell, a command-line interpreter.
35) Network Access layer, Internet Layer, Transport Layer, Application Layer
36) IP Address is address given to machines that are connected to internet.
MAC address is address given to machines by vendors who developed it
Port Number is through which external devices actually get connected.
Ip Address is needed as all systems that are connected globally needs to have unique addresses
For establing local Network we use MAC Addresses
Port are used for connecting devices forcommunication.


