Chapter 3, from page 94 Flashcards
How can you calculate how many addresses exist for a given address bus?
By knowing the number of wires on the address bus, and raising that number as a power of 2; i.e. 20 wires would have 2 to the 20th power or 1,048,576 addresses. It is commonly called 1M.
To correct the actual number that the address lines provided, the International Electrotechnical Committe (IEC) invented special prefixes for binary values. What are they called?
Ibis, represented as 1 kibi = 1024, 1 mebi as 1,048,576, 1 gibi = 1,073,741,824, and 1 tebi = 1,099,511,627,776. They are abreviated as Ki, Mi, Gi, and Ti.
Bits and Bytes have different abbreviations. How would you represent 4 thousand bits? 4 thousand byes?
4Kb, 4KB
What is the ALU?
Arithmetic Logic Unit, the main number cruncher.
Who are the two most common pc CPU providers today?
Intel and Advanced Micro Devices (AMD)
The CPUs for mobile devices are provided by whom?
ARM Holdings
What is the difference between a pc CPU and a mobile device CPU?
ARM based processors use a simple, more energy-efficient design and the reduced instruction set computing (RISC) architecture.
What type of savings do ARM CPUs provide?
cost and battery life
Most of Intel’s desktop and laptop processors are sold under what brand names? Server chips are under what brand?
Core, Pentium, and Celeron brands. The high-end server chips are called Xeon.
AMD was able to clone Intel chips because?
AMD and Intel signed a cross-license agreement in 1976 giving AMD the right to copy certain types of CPUs
Is a tech able to swap Intel and AMD CPU chips today and have them work in the pc?
Not since 1995, when the licensing agreement was cancelled. They are no longer capable pin by pin, and will not work unless they are in motherboard specifically designed for either Intel or AMD.
If you purchase a Ryzen computer, you will be using an Intel or AMD CPU? A Celeron? An EPYC? A Xeon?
AMD, Intel, AMD, Intel
To reduce the model names of CPUs by utilizing what to show the different variations?
Code Names
How can you easily identify all the information about a CPU in a pc, etc?
Use the utility CPU-Z
Mobile pc device needs are different from desk top models in what ways?
consume as little electricity as possible, by extending battery charge and creating less heat.
How have the engineers designed the CPUs to use less energy?
They run in low power mode and scale up automatically if the user demands more power from the CPU
Define throttling.
saving energy by making the CPU run more slowly when demand is light.
Define thermal throttling.
when heat rises to the point that the CPU could be damaged, thermal throttling kicks in and cuts back on the available CPU time/space.
What is TDP?
Thermal design power, or the amount of heat a busy CPU generates, measured in Watts. This can help determine the kind of cooling needed.
Clock multipliers provide what service in the pc?
Multiply the clock speed of the computer to allow the system to run its full max speed. A Ryzen 7 pc runs at 100MHz. With a clock multiplier of x32, the machine can support a full load at a speed of 3.2 GHz.
Todays CPUs speed and multiplier are set automatically by using what function?
CPUID, or CPU identifier
How many bits does the current EDB use?
64 bits, which allows for 2 to power 60 addressing, or 16 EB (exabyte) of RAM.
The primary benefit of 64 bit computing is to support …?
more than 4 GB of memory, the limit with 32 bit processing. (Exam Tip)
The early CPUs were called x86 to fit the 80386 processor. What are the current 64 bit processors generally called?
x86-64
What is virtualization?
Intel and AMD have built in support for running more than one operating system at a time. Handled entirely by software, with hardware-based support to handle the memory allocation, or updating each OS.
The ComptTIA A+ objectives refer to virtualization support as?
The virtual technology CPU feature. (Exam Tip)
Parallel Execution does what?
Modern CPUs process multiple commands and parts of commands in parallel.
How is Parallel Execution accomplished?
Using multiple pipelines, dedicated cache, and the capability to work with multipple threads of programs at one time.
Name the four stages of pipelining.
- Fetch (data from the EDB)
- Decode (what type of command needs to be executed.)
- Execute (perform the calculation)
- Write (send the data back onto the EDB)
How does the pipeline work more efficiently?
each stage does its job with each clock-cycle pulse.
A CPU can operate with less than 4 stages. True or False
False. The minimum number of stages is 4 (see question 29).
Can a CPU have more than 4 stages, and if so, how?
Yes, with the use of cache. Some have up to 20 stages.
Define pipeline stalls.
If a complex command is called in, it may take more than one clock cycle to decode it, causing the pipeline to stop. Current processors use multiple decode stages to reduce the chance of pipeline stalls.
The CPU has two main blocks to handle math. What are they?
ALU, Arithmetic Logic Unit to handle integer math, and the FPU, Floating Point Unit, to handle complex numbers.
Define thread.
a series of instructions designed to do a particular job with the data
Modern CPUs (do, do not) execute instructions sequentially.
do not
Why do wait states occur? How are the wait states reduced in a pc?
Because the CPU runs faster than the RAM can supply it with code. To reduce wait states, CPUs come with built-in, very high-speed RAM called static RAM (SRAM)
How does SRAM work?
it preloads as many instructions as possible and keeps copies of already run instructions and data in case the CPU needs to work on them again. SRAM is called cache when used in this fashion.
L1 cache is located where? L2 cache? Where was the L2 cache eventually placed?
L1 cache is on the CPU. L2 was originally placed on the motherboard. Later L2 was moved to the CPU.
What computer parts ran on the frontside bus? On the backside bus?
CPU, MCC, and RAM connected to the address bus and EDB are on the frontside bus. The CPU connection to L2 (on the CPU) is called the backside bus.
To keep up with faster processors the frontside bus was doubled and even quadrupled. What do they call this?
double-pumped and quad-pumped frontside buses
On the exam, define how the L1, L2, and L3 caches will be described.
L1 is the smallest and fastest cache
L2 will be bigger and slower
and L3 will be the biggest and slowest cache
(exam tip)
