IRQ (Interrupt Request Line) 6 was commonly assigned to:

IRQ (Interrupt Request Line) 6 was commonly assigned to:

• Floppy drive controller
• LPT1
• Sound card
• Com1 

 

EXPLANATION

IRQs ((Interrupt Request Line) are hardware lines over which devices can send interrupt signals to the microprocessor. When you add a new device to a PC, you sometimes need to set itsIRQ number by setting a DIP switch. This specifies which interrupt line the device may use.
Prior to plug and play devices, users had to set IRQ values of devices manually when adding the device, such as a modem or printer, to a system.


The following list of IRQ numbers specifies what each of the 16 IRQ lines are used for.
IRQ 0System timerThis interrupt is reserved for the internal system timer. It is never available to peripherals or other devices.IRQ 1 KeyboardThis interrupt is reserved for the keyboard controller. Even on devices without a keyboard, this interrupt is exclusively for keyboard input.
IRQ 2 Cascade interrupt for IRQs 8-15This interrupt cascades the second interrupt controller to the first.
IRQ 3 Second serial port (COM2)The interrupt for the second serial port and often the default interrupt for the fourth serial port (COM4).
IRQ 4 First serial port (COM1)This interrupt is normally used for the first serial port. On devices that do not use a PS/2 mouse, this interrupt is almost always used by the serial mouse. This is also the default interrupt for the third serial port (COM3).
IRQ 5 Sound cardThis interrupt is the first choice that most sound cards make when looking for an IRQ setting.
IRQ 6 Floppy disk controllerThis interrupt is reserved for the floppy disk controller.
IRQ 7 First parallel portThis interrupt is normally reserved for the use of the printer. If a printer is not being used, this interrupt can be used for other devices that use parallel ports.
IRQ 8 Real-time clockThis interrupt is reserved for the system's real-time clock timer and can not be used for any other purpose.
IRQ 9 Open interruptThis interrupt is typically left open on devices for the use of peripherals.
IRQ 10 Open interruptThis interrupt is typically left open on devices for the use of peripherals.
IRQ 11 Open interruptThis interrupt is typically left open on devices for the use of peripherals.
IRQ 12 PS/2 mouseThis interrupt is reserved for the PS/2 mouse on machines that use one. If a PS/2 mouse is not used, the interrupt can be used for other peripherals, such as network card.
IRQ 13 Floating point unit/coprocessorThis interrupt is reserved for the integrated floating point unit. It is never available to peripherals or other devices as it is used exclusively for internal signaling.
IRQ 14 Primary IDE channelThis interrupt is reserved for use by the primary IDE controller. On systems that do not use IDE devices, the IRQ can be used for another purpose.
IRQ 15 Secondary IDE channelThis interrupt is reserved for use by the secondary IDE controller.

SOURCE

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Given a subnet address of 10.1.129.0/25, what is the broadcast address?

Given a subnet address of 10.1.129.0/25, what is the broadcast address?

• 10.1.129.25
• 10.1.129.127
• 10.255.255.255
• 10.1.129.255 

EXPLANATION

If we look at the address and subnet mask in binary, we can see the following:
0000 1010 . 0000 0001 . 1000 0001 . 0000 0000
1111  1111 . 1111 1111  . 1111 1111  . 1000 0000
Looking at the last octet, we can see that there are 7 binary zeros. These indicate that we have 7 host bits. When you change all of those bits to ones, you end up with:



 0000 1010 . 0000 0001 . 1000 0001 . 0111 1111
Converting back to decimal, we get:
10.1.129.127.

https://subnet.techlanda.com/

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In PowerShell, how do you list drives?

In PowerShell, how do you list drives?

• list-drives
• get-Psdrive
• dir PsDrives
• ls PsDrives

EXPLANATION

Get-PsDrive lists all physical and virtual drivers you can use with PowerShell to change just add : (colon) like:

cd HKLM:

SOURCE

http://go.microsoft.com/fwlink/?LinkID=113327

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What is the database design process used to increase integrity and reduce redundancy of data?

What is the database design process used to increase integrity and reduce redundancy of data?

• Relational Design
• Data Constraints
• Error Handling
• Normalization

EXPLANATION

This process is used to create the Entity Relationship Diagrams necessary to design a database. Each level of normalization is a new "normal form". Typically databases use 3NF or 4NF.
The higher the normal form the more relational your database will be.

SOURCE

https://en.wikipedia.org/wiki/Database_normalization

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In Chrome OS what command allows your to refresh a webpage on Chrome?

In Chrome OS what command allows your to refresh a webpage on Chrome?

• CTRL + R
• ALT + F4
• F5
• CTRL + F5 

EXPLANATION

in most browsers a simple F5 refreshes your webpage. However on Chrome OS F5 is the switch window key, therefore your need to use CTRL+R in order to refresh a page.

SOURCE

https://support.google.com/chromebook/answer/183101?hl=en-GB

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Which SQL Server edition does not require a license for production use?

Which SQL Server edition does not require a license for production use?

• Express
• Standard
• Developer
• Enterprise 

EXPLANATION

Both Standard and Enterprise require licensing.  Developer also does not require a license but cannot be used for production.

SOURCE

https://www.microsoft.com/en-us/sql-server/sql-server-2017-editions

 

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Open Shortest Path First (OSPF) uses which type of algorithm for its routing protocol?

Open Shortest Path First (OSPF) uses which type of algorithm for its routing protocol?

• Distance-vector
• Unidirectional link detection
• Frame-relay
• Link-state 

EXPLANATION

 Open Shortest Path First (OSPF) is a link-state routing protocol, rather than a distance vector protocol. The main difference here is that a linked-state protocol does not send its routing table in the form of updates, but only shared its connectivity configuration. By collecting connectivity information from all of the devices on the network, OSPF can store all this information in a database and use that information to build a topology map.

This information will allow OSPF to identify the best or shortest route to every other network segment on the network. The route selection is based on overall hops to the destination, as well as link speed or link cost.

The topology not only includes the best route to the destination as calculated by the Dijkstra algorithm (a search algorithm created by Edsger Dijkstra), but also, when possible, it includes a candidate or backup route to the destination.

After creating the topology map, OSPF populates the routing table with the chosen routes to each destination. As traffic passes from router to router, each router evaluates the best path to the destination network. In some cases, this process can lead to routing loops on the network, because each one is evaluating the path based on its own link state database.

The OSPF interior network protocol belongs to a single routing domain (or group of routers) known as an Autonomous System (AS). All routers belonging to the same AS share connection information and build their linked-state database from that information.

Specifically with OSPF, as opposed to link-state terminology in general, the primary, or best, route the destination goes through is the Designated Router (DR), although if it fails, the secondary or backup path will be sent to the Backup Designated Router (BDR).

OSPF typically uses multicast to share connection information with its neighbors, and this information is sent to the 224.0.0.5 multicast address.

OSPF is an open protocol and is defined in RFC2328 for version 2 of the protocol. Version 3 of OSPF has been updated to support IPv6 and is defined in RFC5340. Other than for the newly integrated support for IPv6, no major technical differences exist between version 2 and version 3.

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