The answer is firewall. It is a network security device that observes inbound and outbound network traffic and chooses whether to allow or block specific traffic based on a well-defined set of security rules. Firewalls have been a first line of protection in network security for over 25 years. The firewall present a barrier between measured and secured internal networks that can be trusted and untrusted outside networks, for example the Internet. A firewall can be software, hardware, or even both.
Answer:
- import java.util.Arrays;
- public class Main {
-
- public static void main(String[] args) {
- String [] first = {"David", "Mike", "Katie", "Lucy"};
- String [] middle = {"A", "B", "C", "D"};
- String [] names = makeNames(first, middle);
-
- System.out.println(Arrays.toString(names));
- }
-
- public static String [] makeNames(String [] array1, String [] array2){
-
- if(array1.length == 0){
- return array1;
- }
-
- if(array2.length == 0){
- return array2;
- }
-
- String [] newNames = new String[array1.length];
-
- for(int i=0; i < array1.length; i++){
- newNames[i] = array1[i] + " " + array2[i];
- }
-
- return newNames;
- }
- }
Explanation:
The solution code is written in Java.
Firstly, create the makeNames method by following the method signature as required by the question (Line 12). Check if any one the input string array is with size 0, return the another string array (Line 14 - 20). Else, create a string array, newNames (Line 22). Use a for loop to repeatedly concatenate the string from array1 with a single space " " and followed with the string from array2 and set it as item of the newNames array (Line 24-26). Lastly, return the newNames array (Line 28).
In the main program create two string array, first and middle, and pass the two arrays to the makeNames methods as arguments (Line 5-6). The returned array is assigned to names array (Line 7). Display the names array to terminal (Line 9) and we shall get the sample output: [David A, Mike B, Katie C, Lucy D]
Answer:
Tell her to hold the Shift key as she hits Enter.
Answer:
The flashdrive can hold 35389 400-pages-books
Explanation:
If 
of a page occupies 1 kB of memory, we can calculate how much memory a book will take
Now that we know that a book average file size is about 266,67 kB, we calculate how many of them can a 9 GB flash drive hold.
To do the calculation, we have to know how many kilobytes are in 9 gigabytes.
There is 1024 kilobytes in a megabyte, and 1024 megabytes in a gigabyte, so:
Finally, knowing the average file size of a book and how much memory in kilobytes the 9 GB flash drive holds, we calculate how many books can it hold.
The flashdrive can hold 35389 400-pages-books, or 14155776 pages of typical text.
Answer:
Blocking Mode
Explanation:
Spanning Tree Protocol is used to allow path redundancy in the network without creating cycles/circles also called loops.
When two parts of the switched network are connected via two or more Layer 2 switches this result in a loop.
This affects the performance of the network as the result of broadcast packets flooding.
STP puts one port of the switch to forwarding mode and the rest of the ports within the same part of the network to the blocking mode to avoid broadcast packet flooding. STP puts all the ports that are allowing redundant paths to blocking mode and the one port that is left after this is placed in forward mode.
Spanning Tree Algorithm is used by STP to determine the optimal path of switch to the network.
Bridge Protocol Data Units are used to share the information about the optimal path determined by the spanning tree algorithm with other switches.
This information helps STP to eliminate the redundant paths.
So this is how STP allows only one active path to the destination while blocking all other paths to avoid switching loop.
