CompTIA A+ Cert Exam Guide Ch. 6 Flashcards
What is the External Data Bus (EDB)?
The EDB is a set of wires used to facilitate communication between the CPU and other computer components
What is binary code?
Binary is a code system used for computer computation/communication. Binary is represented by the numbers 1 and 0, where 1 is on and 0 is off. A CPU identifies a 1 if it detects an electrical charge on a wire and a 0 if not.
What is a register?
Microscopic semiconductor circuits that hold charges.
What are the General-purpose registers?
AX, BX, CX, DX;
What is Machine Language?
Lines of code;
What is the CPU’s instruction set?
All of the machine language commands that the CPU understands
What is the clock wire (CLK)?
A wire connected to the CPU; a charge on the wire indicates that a new piece of data is waiting to be processed
What is a clock cycle?
A single charge to the CLK wire;
How many clock cycles does a CPU require at minimum to process a command?
2 clock cycles
What is the clock speed of a CPU?
The maximum number of clock cycles a CPU can handle in a given period of time; it is the fastest speed at which a CPU can operate/process data
How fast is 1 hertz (1 Hz)?
1 cycle per second
How fast is 1 megahertz (1 MHz)?
1 million cycles per second
How fast is 1 gigahertz (1 GHz)?
1 billion cycles per second
What is the system crystal?
Quartz oscillator; sends out a pulse to the clock chip that regulates the speed of the processor and, thus, the rest of the computer
What is a program?
A series of commands sent to a CPU in a specific order for the CPU to perform work.
What function does memory serve for the CPU?
A HDD is too slow to serve up data at the rate the CPU can handle it. To facilitate the transfer of data from the HDD to the CPU, memory is used. Data is transferred from the HDD to memory where the CPU can grab it at a speed it can handle.
What is a branch?
A branch is an IF statement in a line of code for a CPU.
An individual 1 or 0
A bit
4 bits
A nibble
8 bits
A byte
16 bits
A word
32 bits
A double word
64 bits
A paragraph or quad word
What does DRAM stand for?
Dynamic Random Access Memory
Why is RAM called Random access memory?
The CPU can take bytes of information from any point on the RAM chip
What does a CPU use DRAM for?
Mail system memory; It stores programs for fast and easy access and data that the CPU actively uses
How does RAM connect to the CPU?
It connects to the CPU via the address bus. The CPU utilizes the Memory Controller Chip (MCC) to access the data stored on RAM
What does the Memory Controller Chip (MCC) do?
The MCC grabs data at specific locations in RAM and passes it to the External Data Bus where the CPU can access act on it.
How does the CPU communicate to the MCC which row of data it wants from RAM?
It uses a set of wires called the address bus to indicate the specific address in RAM it wants the Memory Controller Chip (MCC) to pull and place on the External Data Bus (EDB)
What is the address bus?
A set of wires attached to the CPU that allow it to communicate with the Memory Controller Chip (MCC) to indicate the address in memory it wants
What are the various types of Intel processors?
Common home use:
• Celeron, Pentium, Core
Low power/Smart phone:
• Atom
High-end Workstation/Server:
• Xeon, Itanium
What does Intel’s SpeedStep technology do?
It enables the CPU to run in a low-power mode until more demand is placed upon it. The CPU will automatically scale up its performance depending on the needs placed upon it by usage.
What is throttling?
Saving energy my making the CPU run more slowly when demand is light
How much memory can a 64-bit computer handle?
In theory, 16 exabytes of RAM.
What is virtualization?
The process of running more than one OS at a time. Both Intel and AMD have built in support for virtualization.
What is parallel execution?
The ability of a CPU to process multiple commands and parts of commands in parallel.
What four stages does a CPU take to get data from the EDB, calculate it, and send it back to the EDB?
- Fetch - Get the data from the EDB
- Decode - Figure out what type of command needs to be executed
- Execute - Perform the calculation
- Write - Send the data back to the EDB
How does pipelining work?
The 4 circuits/stages are organized within a CPU in a conveyer belt fashion. Data is pushed along to keep each stage working at the same time so no stages sit idle while one command is being processed.
In the past, the CPU would calculate a single command at a time. The CPU would need to complete the 4 stages for each piece of data before continuing onto the next piece of data
What is a pipeline stall?
When a complex command requires more than one clock cycle. This stalls the pipeline until the command is completed.
How does a modern CPU protect against pipeline stalls?
By using multiple decode stages
What is the Arithmetic Logic Unit (ALU)?
Circuitry within the CPU that handles simple, whole integer (numbers with no decimal points) calculations
What is the Floating Point Unit (FPU)?
Circuitry within the CPU that handles complex number calculations
What is cache in relation to the CPU?
The CPU has a type of RAM called Static RAM (SRAM). To reduce wait states, the SRAM preloads as many instructions as possible and keeps copies of already run instructions and data in case it is needed again.
What is a wait state?
A pipeline stall that results from the CPU outperforming the RAM
Explain the levels of cache
L1 is cache stored on the CPU itself. It is the first cache the CPU checks for instructions.
L2 cache was originally stored on the motherboard but is now being stored in the CPU. This is the second cache that the CPU checks.
L3 cache is the third cache that the CPU checks.
The cache grows in size and slows in speed from L1 to L3
What is the frontside bus?
The address bus and external data bus that link the CPU to the MCC and RAM
What is the backside bus?
The connection between the CPU and the L2 cache
With which processor was hyperthreading introduced?
The Pentium 4
What is hyperthreading?
The ability of a processor to run multiple threads at one time. This allows the processor to function as though it were two processors.
What are the limitations of hyperthreading?
- The OS and applications have to be designed to take advantage of hyperthreading
- Though the CPU emulates a second processor, this does not double the processing power because the main execution resources are not duplicated
At what speed have processors reached their practical limit?
About 4 GHz
How have CPU manufacturers worked around the 4 GHz limitation of CPUs?
By producing multicore processors.
What does the Integrated Memory Controller (IMC) do?
Optimizes the flow of information into and out of the CPU;
What is the Integrated Graphics Processing Unit?
A discrete microprocessor that differs in both function and architecture from the CPU. It handles the processes required to put images on the screen. While the GPU has previously been separate hardware, chip manufacturers have been integrating a GPU into the CPU
What two questions must you ask before purchasing a CPU?
- Does the motherboard support an Intel or AMD chip?
2. What socket does the motherboard have?
LGA 775
Pentium 4, Celeron, Pentium 4 Extreme Edition, Core 2 Duo, Core 2 Quad, Xeon, and others
LGA 1155
Core i3/i5/i7, Pentium, Celeron, Xeon
LGA 1156
Core i3/i5/i7, Pentium, Celeron, Xeon
LGA 1366
Core i7, Xeon, Celeron
940
940 pins; Opteron, Athlon 64 FX
AM2
940 pins; Athlon 64, Athlon 64 X2, Athlon 64 FX, Opteron, Sempron, Phenom
AM2+
940 pins; Athlon 64, Athlon 64 X2, Athlon II, Opteron, Phenom, Phenom II
AM3
941 pins; Phenom II, Athlon II, Sempron, Opteron
AM3+
942 pins; FX
FMI
905 pins; A
F
1207 pins; Opteron, Athlon FX
What are some things to consider when installing a CPU?
- The pins - they are easily damaged
- Will the PSU provide enough power?
- Do you have adequate cooling?
- Should you overclock your CPU?
What is a Land Grid Array (LGA)?
A CPU layout; the CPU has hundreds of contact points on its underside that line up with socket pins; used with Intel CPUs
What is Pin Grid Array (PGA)?
A CPU layout; the bottom of the CPU has pins on the underside that line up with holes in the CPU socket on the motherboard; used with AMD processors
What is a Zero Insertion Force (ZIF) socket?
No force is required to insert a CPU into a socket on the motherboard. If any force is required, the CPU is not aligned correctly.
What options do you have for cooling your CPU?
Heat sink
Fan
Liquid cooling
What are the parts of a liquid cooling system and how does it work?
A hollow metal block that sits on top of the CPU, a pump to move the liquid, some device to cool the liquid, and hosing;
The liquid runs into the block on top of the CPU absorbing heat and then is pumped out of the PC to a device that cools the water down.
What is thermal compound?
An adhesive material that sticks the heat sink and fan to the CPU
What is overclocking?
Running your system at higher clock speeds than the CPU is rated for
What are three possible ways to change the speed, multiplier, and voltage settings for a system?
Manually by using a jumper, changing a CMOS setting, or software
What two adjustments to people make to overclock successfully?
- Change the bus speed
2. Increase the input voltage to the CPU
What is CMOS clear?
A jumper setting on most motherboards that allow a user to reset all CMOS settings. Using this can reset the clock speed of a CPU should something go wrong
What are the two main problems with CPUs?
Overheating and catastrophic failure
What are possible problems with CPU installation?
- Too much thermal paste - results in the impediment of heat flow from the CPU to the heat sink
- Not enough thermal paste - causes the CPU to heat up
- Failure to connect the fan power - does not dissipate heat and causes the CPU to heat up
What additional factors can play a role in the overheating of a CPU?
- The case fans can stop working, impeding airflow through the case
- Environmental factors can contribute to extra heat gain
What are possible signs of a catastrophic failure of a CPU?
- A sudden BSOD
- The sudden shutdown of your machine
- The smell of burnt electronics in connection with the sudden shutdown of your machine
