Computers need to maintain certain settings (for example, date, time, some hardware settings, etc.) even when they are completely powered off. Such settings are used at start-up (among other uses). Where are these settings stored and maintained?

Computers need to maintain certain settings (for example, date, time, some hardware settings, etc.) even when they are completely powered off. Such settings are used at start-up (among other uses). Where are these settings stored and maintained?

• In the BIOS
• In Zone 0 of the hard drive
• In the CMOS
• In the Operating System 

 

EXPLANATION

CMOS, which stands for "Complementary Metal-Oxide Semiconductor", is a battery-powered semiconductor chip that stores information such as date, time and certain hardware settings. A tiny battery, similar to a watch battery, is what allows the CMOS to maintain information while the machine is powered off. As they are typically designed to last about ten years, and since most computers get scrapped before then, this is why you probably haven't had to replace many CMOS batteries.


While the BIOS uses data from the CMOS, these are two separate things. See the following for more information on the difference between the two and how they work together: http://www.computerhope.com/issues/ch001360.htm

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What do you call a series of SCSI devices working together through a host adapter?

What do you call a series of SCSI devices working together through a host adapter?

• An SCSI controller
• An SCSI chain
• Cabled SCSI
• RAID 

EXPLANATION

A series of SCSI devices working together through a host adapter is called an SCSI chain. The host adapter provides the interface between the SCSI chain and the PC.

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Why is the Power Factor (PFC) value listed on most modern PSU units?

Why is the Power Factor (PFC) value listed on most modern PSU units?

• It indicates the level of efficiency of the PSU
• It points to the materials used in the PSU (Gold, Silver etc)
• It relates with the thermal resistance properties
• Indicates coeficient for the longevity of the PSU 

 

EXPLANATION

The Power Factor value shows the efficiency of the power unit. The power unit capabilities are usually stated as W consumed by the unit (kVA). How much of this power will be available to the loads attached to the PSU however is dictated by the its conversion capabilities summarized by the PFC value. For example, a 1000W PSU with a PFC factor of 0.9 will be able to supply a total of 900W to it's loads.

The PFC itself measures the alignment of the the voltage sinusoidal against the current sinusoidal. If they match 100% you would get a PFC of 1 and hence the perfect lossless PSU. In realty >0.95 is hardly achieved and considered very good while 0.8 could be considered as average PSU. 0.7 is considered as a bad performing PSU

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Motherboards that support more than four sticks of RAM may require what to function properly?

Motherboards that support more than four sticks of RAM may require what to function properly?

• Buffered RAM
• Dual-channel RAM
• ECC RAM
• DDR3 RAM 

 

EXPLANATION

Motherboards that support more than four sticks of RAM may require buffered RAM to function properly.This helps you get around the electrical hassles, by adding a buffering chip to the DRAM stick that acts as an intermediary between the DRAM and the MCC.

SOURCE

https://www.coursehero.com/file/p7tjkcd/a-The-motherboard-requires-SDRAM-not-RDRAM-b-The-motherboard-requires-DDR-SDRAM/

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When it comes to associative memory, how does the memory locate the address of the data?

When it comes to associative memory, how does the memory locate the address of the data?

• The address of the data is supplied by the users
• The address of the data is generated by the CPU
• The data are accessed sequentially
• There is no need for an address, the data is used as an address 

 

EXPLANATION

Associative memory is memory capable of determining whether a given datum (the search word) is contained in one of its addresses or locations. Associative memory  is also referred to as content-addressable memory.
Unlike standard computer memory (random access memory or RAM) in which the user supplies a memory address and the RAM returns the data word stored at that address, associative memory is designed such that the user supplies a data word and the computer searches its entire memory to see if that data word is stored anywhere in it.

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What do registers provide for the CPU?

What do registers provide for the CPU?

• Enable the CPU to control the address bus
• Determine the clock speed
• Enable the CPU to address RAM
• Provide temporary storage of internal commands 

 

EXPLANATION

A processor register is a quickly accessible location available to a digital processor's central processing unit (CPU). Registers usually consist of a small amount of fast storage, which the CPU uses to temporarily store internal commands and data.
 

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What is the smallest data unit in quantum computing?

What is the smallest data unit in quantum computing?

• 1 Cubik
• 1 Cubit
• 1 Qubit
• 1 Quanbit 

 

EXPLANATION

A qubit is a quantum bit , the counterpart in quantum computing to the binary digit orbit of classical computing. Just as a bit is the basic unit of information in a classical computer, a qubit is the basic unit of information in a quantum computer
In a quantum computer, a number of elemental particles such as electrons or photons can be used, with either their charge or polarization acting as a representation of 0 and 1. In a classical system, a bit would have to be in one state or the other. However, quantum mechanics allows the qubit to be in a superposition of both states at the same time, a property which is fundamental to quantum computing.
See wikipedia entry for more information:
https://en.wikipedia.org/wiki/Qubit

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Which IRQ does COM1 commonly use?

Which IRQ does COM1 commonly use?

• 8
• 4
• 6
• 3 

EXPLANATION

Interrupt request (IRQ) 4 is normally used for the first serial port, COM1. This is also the default interrupt for the third serial port.
In a computer, an interrupt request is a hardware signal sent to the processor that temporarily stops a running program and allows a special program, an interrupt handler, to run instead. Hardware interrupts are used to handle events such as receiving data from a modem or network card, key presses, or mouse movements.

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Which of the following is FALSE about DDR2 and DDR3 RAM?

Which of the following is FALSE about DDR2 and DDR3 RAM?

• DDR3 uses less power than DDR2
• DDR3 has fewer pins than DDR2
• DDR3 is not backwards compatible with DDR2
• DDR3 is faster than DDR2 

 

EXPLANATION

DDR3 is the successor to DDR2 memory technology. There are several differences between them. DDR3 is not backwards compatible with DDR2. While both types of modules have the same numbers of pins, the notches in the PCB are in different locations. In other words, a DDR3 module cannot be placed in a DDR2 memory socket, and vice-versa.

DDR3 modules run on 1.5V compared to the 1.8V that DDR2 modules require. The DDR3 decrease in voltage results in less power consumption and greater energy-efficiency at comparable speeds.
DDR3 is faster. DDR2 "JEDEC standard" memory typically stops at around 800MHz whereas the introductory speeds of DDR3 when it was released in 2007 started at 800MHz and is far faster than that now.

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What voltages should the two hot wires on a Molex connector read?

What voltages should the two hot wires on a Molex connector read?

• Red = 5 V; Yellow = 3.3 V
• Red = 5 V; Yellow = 12 V
• Red - 12 V; Yellow = 5 V
• Red = 3.3 V; Yellow = 5 V 

 

EXPLANATION

A Molex connector's red wire should be at 5 volts. The yellow wire should be at 12 volts.

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When running any kind of wires for networked equipment (ie. printers, PC's, video cameras, door locks and readers, etc,) who would be the ultimate authority to ensure code requirements are not violated?

When running any kind of wires for networked equipment (ie. printers, PC's, video cameras, door locks and readers, etc,) who would be the ultimate authority to ensure code requirements are not violated?

• The local fire marshal.
• The local building inspector.
• The state fire marshal and state building inspector.
• The authority having jurisdiction. 

 

EXPLANATION

The Authority Having Jurisdiction, or AHJ, is a general term for whatever agency has the ultimate authority concerning building and life safety codes for a given locality. That authority can vary by location and region, and also by what the actually work pertains to. It can be building inspector, fire marshal, a port authority if the property location falls under such province, a health inspector are some examples.
This may seem like an out of place question for IT matters, but considering many IT professionals are required, or prefer to do "do it yourself" (DIY) projects which sometimes involves running wires, it's important to know the laws and governance that regulate where and how wires are run, the type used, and if any special licensing is required to run such wires. Even a simple wire run in the ceiling from one room to another might run afoul of local building codes. It's also good to know if using contractors to insure they know what they are doing.

SOURCE

https://www.nfpa.org/Assets/files/AboutTheCodes/101/101_FAQs.pdf

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A 802.3af POE switch with a power budget of 80 watts can't power more than 5 or 6 IP cameras, rated to consume 6 watts max each, at a time. What is the most likely reason?

A 802.3af POE switch with a power budget of 80 watts can't power more than 5 or 6 IP cameras, rated to consume 6 watts max each, at a time. What is the most likely reason?

• Cameras are 802.3at POE.
• Cables are CAT5 instead of CAT6.
• IP cameras and switch are on different IP subnets.
• POE Class is not detected.

 

EXPLANATION

The most likely reason is the proper POE Class is not being detected. The Class determines how much power is reserved for the PD (powered device), in this case the IP cameras. If no Class is detected, then the switch defaults to Class 0 which reserves the max power per port of 15.4W (in 802.3af). 5 cameras reserving 15.4W per port is 77W, leaving nothing left over for the other cameras. If Class 2 was detected, then around 6.5W max is reserved for the port, so up to 12 cameras can be connected (assuming there is enough ports). 80W/6.5W = 12.3, or 12 devices rounded.

Even if the cameras were rated at 802.3at POE compliant, which is around 30W max, it is still a matter of Class detection since it should still work with a 802.3af switch since they are backwards compatible, and since it was stated the cameras used 6W max. POE is not dependent on CAT5 or CAT6 cable being used, and does not work at the Layer 3 level so does not use IP addressing.

With the citation, also see...
http://www.veracityglobal.com/resources/articles-and-white-papers/poe-explained-part-2.aspx

SOURCE

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

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What is the max transfer speed of USB 3.0?

What is the max transfer speed of USB 3.0?

•  5 Gbit/s
• 8 Gbit/s
• 10 Gbit/s
• 3 Gbit/s 

EXPLANATION

USB 3.0 is 10 times faster than USB 2.0. Using a new transfer rate referred to as superspeed it can transfer at speeds up to 5 Gbit/s. USB 3.1 Gen 2 transfers at 10 Gbit/s.

SOURCE

https://en.wikipedia.org/wiki/USB_3.0

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Which of the following operations does an ALU typically not perform?

Which of the following operations does an ALU typically not perform?

• Addition
• Multiplication
• Division
• Subtraction 

 

EXPLANATION

ALUs are designed to perform integercalculations. Therefore, besides adding and subtracting numbers, ALUs often handle the multiplication of two integers, since the result is also an integer. However, ALUs typically do not perform division operations, since the result may be a fraction, or a "floating point" number. Instead, division operations are usually handled by the floating-point unit (FPU), which also performs other non-integer calculations.

SOURCE

https://techterms.com/definition/alu

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