RED BLACK tree Insertion function

rb_insert( Tree T, node x ) {
/* Insert in the tree in the usual way */
tree_insert( T, x );
/* Now restore the red-black property */
x->colour = red;
while ( (x != T->root) && (x->parent->colour == red) ) {
if ( x->parent == x->parent->parent->left ) {
/* If x's parent is a left, y is x's right 'uncle' */
y = x->parent->parent->right;
if ( y->colour == red ) {
/* case 1 - change the colours */
x->parent->colour = black;
y->colour = black;
x->parent->parent->colour = red;
/* Move x up the tree */
x = x->parent->parent;
}
else {
/* y is a black node */
if ( x == x->parent->right ) {
/* and x is to the right */
/* case 2 - move x up and rotate */
x = x->parent;
left_rotate( T, x );
}
/* case 3 */
x->parent->colour = black;
x->parent->parent->colour = red;
right_rotate( T, x->parent->parent );
}
}
else {
/* repeat the "if" part with right and left
exchanged */
}
}
/* Colour the root black */
T->root->colour = black;
}

C program for Matrix Multiplication:

‪#‎include‬ <stdio.h>

int main()
{
int m, n, p, q, c, d, k, sum = 0;
int first[10][10], second[10][10], multiply[10][10];

printf("Enter the number of rows and columns of first matrix\n");
scanf("%d%d", &m, &n);
printf("Enter the elements of first matrix\n");

for ( c = 0 ; c < m ; c++ )
for ( d = 0 ; d < n ; d++ )
scanf("%d", &first[c][d]);

printf("Enter the number of rows and columns of second matrix\n");
scanf("%d%d", &p, &q);

if ( n != p )
printf("Matrices with entered orders can't be multiplied with each other.\n");
else
{
printf("Enter the elements of second matrix\n");

for ( c = 0 ; c < p ; c++ )
for ( d = 0 ; d < q ; d++ )
scanf("%d", &second[c][d]);

for ( c = 0 ; c < m ; c++ )
{
for ( d = 0 ; d < q ; d++ )
{
for ( k = 0 ; k < p ; k++ )
{
sum = sum + first[c][k]*second[k][d];
}

multiply[c][d] = sum;
sum = 0;
}
}

printf("Product of entered matrices:-\n");

for ( c = 0 ; c < m ; c++ )
{
for ( d = 0 ; d < q ; d++ )
printf("%d\t", multiply[c][d]);

printf("\n");
}
}

return 0;
}

What could be the maximum size of virtual memory

Virtual memory is not limited by size of memory pointers in the machine, virtual memory limits are not the same as addressing memory space. More virtual memory than available in your pointer-based address space using paging can be addressed

Virtual memory upper limits are set by the OS: eg. 32-bit Windows the limit is 16TB, and on 64-bit Windows the limit is 256TB.

Max limitation is physical disk space.

To determine how much virtual memory you need, since the user's system contains the different amount of RAM, it is based on the system. By default, the OS will set the appropriate size for Virtual Memory. The default and appropriate size of Virtual Memory is:

<Amount_Of_System_Memory> * 1.5 = <Default_Appropriate_Size_Of_Virtual Memory>
Personally speaking, to maintain the good overall system performance, you should be using the default size of actual size for Virtual Memory and the triple the value of the size of the main memory for the maximum size of Virtual Memory.

Memory mapped I/O and I/O mapped I/O

The characteristics of isolated I/O or I/O mapped I/O are as follows:

- The devices of I/O are treated in a separate domain as compared to memory.

- A total of 1mb address space is allowed for memory applications.

- In order to maximize the I/O operations ( isolated ) separate instructions are always provided to perform these operations.

- One of the disadvantages is that the data transfer only occurs between the I/O port and the AL, AX registers.

The characteristics of the memory mapped I/O are as follows:

- In such scenarios the devices (I/O) are treated as a part of the memory only.

- Complete 1mb of memory cannot be used as they are a part of the memory.

- In case of memory mapped I/O operations no external separate instructions are required.

- There is data transfer restriction in case of memory mapped instructions.

Uniform Resource Locator (URL)

URL stands for Uniform Resource Locator. It is the address of a web page. Each page has its own unique web address (URL). This is how your computer locates the web page that you are trying to find.
Most web browsers display the URL of a web page above the page in an address bar. A typical URL could have the formhttp://www.example.com/index.html, which indicates a protocol (http), a hostname (www.example.com), and a file name (index.html).

Ping

Ping is a networking utility program or a tool to test if a particular host is reachable. It is a diagnostic that checks if your computer is connected to a server. Ping, a term taken from the echo location of a submarine, sends data packet to a server and if it receives a data packet back, then you have a connection.

example:
ping 172.16.103.1 –t

FTP

FTP is a client-server protocol that relies on two communications channels between client and server: a command channel for controlling the conversation and a data channel for transmitting file content. Clients initiate conversations with servers by requesting to download a file. Using FTP, a client can upload, download, delete, rename, move and copy files on a server. A user typically needs to log on to the FTP server, although some servers make some or all of their content available without login, also known as anonymous FTP.

Connect using FTP
To connect to another computer using FTP at the MS-DOS prompt, command line, or Linux shell type FTP and press Enter. Once in FTP, use the open command to connect to the FTP server, as shown in the example below.
open ftp.example.com
In the above example, you'd substitute example.com for the domain name or IP addressof where you are connecting. An example would be open 192.168.1.12.
Note: By default, the open command uses the TCP port 21 to make the FTP connection. If a different TCP port is needed for connecting to the domain name or IP address you are using, enter the port number after the domain name or IP address in the open command.
Once connected, a username and password prompt will appear. Once these credentials have been entered, the server allows you to browse, send, or receive files, depending on your rights. Some servers may also allow anonymous logins using guest or an e-mail address.
Send and receive a file in FTP
To get files from the server onto your own computer, use the get command as shown in the example below. In this example, you would get the file myfile.htm.
get myfile.htm