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Part 2
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Entry 5: March 16th, 2012 3:40 EST. BDC Lair, 34% moon
Today was a fun-filled talk about instruction sets. We are in the process of creating an instruction set forour 6502 wannabe.
Each instruction is allocated 4 bytes of memory, and are laid out as follows.
| instruction | first byte | second byte | third byte | fourth byte |
| and | 000.00.00.x | 00.xxxxxx | xxxxxxxx | xxxxxxxx |
| or | 001.00.00.x | 00.xxxxxx | xxxxxxxx | xxxxxxxx |
| not | 010.00.xxx | 00.xxxxxx | xxxxxxxx | xxxxxxxx |
| if/branch | 011.00.xxx | xxxxxxxx | branch address | branch address |
| move | 100.xx.xx.x | xxxxxxxx | xxxxxxxx | xxxxxxxx |
These are not yet fully developed, as you can see by move and others, but they are great progress!.
I also started to develop my schedule for next semester. It looks like I will be taken hpc1, hardware 101, electricity 101, and another computer course that yet again has slipped my mind! that should be 13 credits, so financial aid? i think so!
March 28th, 2012; 10:25 EST
This weeks experiences haven't been fun filled, but I have certainly learned a lot. Maybe it is time for a little recap:
Storage: Volatile vs. Non-volatile.
Volatile memory refers to short term memory, such that is only kept when there is power to the memory. An example of this type of memory is RAM, which is used to store information temporarily while the computer is running. An example of this RAM is CPU RAM, which is used as quick access storage for the CPU.
Non-Volatile memory refers to long term memory, such that is kept whether there is power to the computer or not. An example of this type of memory is your hard drive, where most of your computers information is stored.
Understanding the difference between these two helps to shed light on what RAM is used for. Since the RAM is cleared every time the computer is powered off, it must hold information that is created when the computer is started, or when a program is started, but does not affect the programs start-up. In other words it does not contain any of the instructions for the computer of it's programs, just the information they create that is pertinent to it's current running state.
Entry 7: March Day, 2012
This is a sample format for a dated entry. Please substitute the actual date for “Month Day, Year”, and duplicate the level 4 heading to make additional entries.
As an aid, feel free to use the following questions to help you generate content for your entries:
- What action or concept of significance, as related to the course, did you experience on this date?
- Why was this significant?
- What concepts are you dealing with that may not make perfect sense?
- What challenges are you facing with respect to the course?
Remember that 4 is just the minimum number of entries. Feel free to have more.
Entry 8: March Day, 2012
This is a sample format for a dated entry. Please substitute the actual date for “Month Day, Year”, and duplicate the level 4 heading to make additional entries.
As an aid, feel free to use the following questions to help you generate content for your entries:
- What action or concept of significance, as related to the course, did you experience on this date?
- Why was this significant?
- What concepts are you dealing with that may not make perfect sense?
- What challenges are you facing with respect to the course?
Remember that 4 is just the minimum number of entries. Feel free to have more.
Keywords
asm Keywords
Data Bus
Definition
An internal element that transfers data between computer components, or between computers.
Demonstration
A bus is a way to connect a peripheral device for data transfer. They have evolved from a different card for every peripheral to universal busses to connect many different peripherals through the same bus. These busses can range from a system bus, to attach a cpu, to a universal serial bus to connect anything from a mouse or keyboard to another harddrive.
Few more examples:
- USB
- SYSTEM BUS
- SATA PORT
- ATA PORT
- VGA PORT
- CONSOLE PORT
- etc…
Address Bus
Definition
An address bus is a computer bus that is used to specify a physical address. When a processor needs to read or write to a memory location it specifies that memory location on the address bus.
Demonstration
Early processors used to you a single wire for each address bit that it sent, meaning a 32 bit address bus used a 32 wire connector. This was soon replaced by cutting the address in half and sending it in two waves, cutting a 32 bit address bus down to a 16 wire strip.
The width of the address bus determines the amount of memory a system can address.
interrupts
Definition
An asynchronous signal that indicates the need to look at a certain event or tell running software to change its execution.
Demonstration
Hardware Interupt:
- Causes the processor to save its state of execution and begin execution of an interrupt handler.
Software interupt:
- Implemented as instructions in the instruction set, which cause a context switch to an interrupt handler similar to a hardware interrupt.
- A signal to the system from an event that has originated in hardware, such as the pressing of a key on the keyboard, a movement of the mouse or a progression in the system clock.
Stack operations
Definition
Stax yo! a stack is a last in, first out data gobbling beast! Also called a LIFO if you must. These work like a stack of papers. The last page you set on the stack is the top page, and you cannot access any of the pages below without first moving/removing the pages above it. They are commonly implemented using a linked list, but can also be implemented by use of an array.
There are three common stack operations, and they are as follows:
- push - add a node to the top of the list
- pop - remove the top node from the list
- peek - display the value of the top node
Demonstration
#include"stack.h" Stack *push(Stack *notes, int val) { Node *stick; stick=(Node *)malloc(sizeof(Node)); stick -> value = val; if(notes -> top == NULL) { notes -> top = notes -> bottom = stick; } else { notes -> top -> prev = stick; stick -> next = notes -> top; notes -> top = notes -> top -> prev; } return notes; }
Machine Word
Definition
It's a bunch o' bits wrapped up all nice and neat for a computer to read, like an instruction of sorts. The number of bits in a word(size, width, length) is defined by the proccessor design, or the computer architecture. The size of a word reflects the computers operation. Registers are often word sized, and the largest peice of memory that can be moved into working memory is the size of word. Common sizes today are 32 and 64 bit.
Depending on how the computer is structured, units of the word size can be:
- Integer numbers
- floating point numbers
- addresses → holders for memory addresses
- registers → processor registers
- memory-processor transfer
- unit of address resolution
- instructions → machine instructions
Storage
Definition
Puttin stuff in spots to keep it for a while. The retension of information.
short term
- Volatile memory
- Lost when power is yanked from the wall in a TMNA(teenage mutant ninja aliens) rage
- examples are ram and cpu ram
long-term
- non-volatile
- does not rely on power to save information
- examples are hard drive and cmos
subroutines
Definition
A portion of code running inside a program that has one specific purpose and is relatively independant of the rest of the code to be performed.
A subroutine is also called a subprogram, and as that insinuates, it will act much like a program itself, running inside a larger program. A subroutine is usually code that can be called multiple times from multiple places inside the program.
Subroutines are often collected into libraries, and contain programs such as mathmatical computations.
Fetch-Execute Cycle
Definition
The fetch-execute cycle is the basic operation cycle of a computer. This cycle is repeated by the CPU from startup to when the computer is shut down and is the process by which the computer retreives its instructions from memory.
The cicuits used in a fetch-execute cycle are:
- Program Counter - an incrementing counter that contains the memory address of the instruction to be used next.
- Memory Data Register - holds data fetched from memory
- Contol Unit - decodes the instruction in the instruction register and activates needed resources.
- Instruction Register - holds the instruction just fetched from memory.
- Memory Address Register - holds the address of the memory to be written to
- Arithmetic Logic Unit - Does logical and mathmatical operations
So, to break it down:
- Fetch the instruction
- Decode the instruction
- indirect vs. direct instruction
- indirect - effective address is read from main memory.
- direct - do nothing
- Execute the instruction
asm Objective
asm Objective
familiarity with how assembly impacts programming.
Definition
How assembly will impact the styles and flow of programming. How the code is put together in functions.
Method
General discussion on how assembly affects programming. Matt has expressed that assembly and processor commands can affect programming styles by helping to make code more efficient.
Measurement
The only good way to measure this is to review some code that I recently wrote to see if i can relate my new knowledge of assembly and processor instructions to coding styles.
Analysis
I can see how processor commands can affect programming styles. I can not yet really optimize any code or change the flow based on what the processor does/receives, but I believe that by the end of this course I will be able to optimize my code at least a little by being processor sensitive.
There is deffinitely room for improvement, I think I need to do some research on assembly commands so that I can better understand what the processor is being told because of the code I am writing.
Experiments
Experiment 4
Question
How can an ethernet cable provide power to an end device?
Resources
Hypothesis
Power over ethernet is done by sending a dc current over four of the wires.
Experiment
I will research PoE and find an example of how PoE sends a dc current over the same line that data is sent over. Also, there is a PoE phone in the lair, so i will mess around with that to see it in action.
Data
I hooked an IP phone up to a PoE supplier that adds a dc current to the ethernet cable. I also plugged an active ethernet cable into the PoE supplier so that it was supplying a dc current and an internet signal over the same line.
Wikipedia displays a great table that shows the pins used in a PoE setup for both 10/100 and gigabyte PoE connections.
Analysis
Based on the data collected:
- Was your hypothesis correct? yes
- Was your hypothesis not applicable? no
- Is there more going on than you originally thought? A little bit, PoE doesn't just send a dc signal over the lines, there is a standard as to which wires are used. The amount of power sent is always 36watts.
- What shortcomings might there be in your experiment? I don't know of any, but i could always lick the end and find out.
Conclusions
PoE is a very powerful tool that can be very useful when there are a lot of IP phones or wireless access points that need to periodically be reset. All one has to do is simply reboot the source of the ethernet cables and all end devices will be reset.
Experiment 5
Question
If I am connected to a gigabyte switch that has a dedicated line from roadrunner, will the download/upload of my computer by a gigabyte?
Resources
- tomshardware.com
- ethernetresources.com/sizeofspeed/speed$T10100
Hypothesis
I can only reach speeds of 100mbps or whatever the incomming line allows me to reach.
Experiment
I will hook my laptop up to a gigabyte router and do speed testing like speedtest.net, command prompt things to check speed rates, and network and sharing center.
Data
Speedtest.net claims 96mbps, 100mbps and 92mbps. network and sharing center claims anywhere from 56-400 mbps depending on what i'm downloading. command prompt, essentially doing the same thing speedtest.net, claims about 92-98mbps.
Analysis
Based on the data collected:
- Was your hypothesis correct? Yes! I received speeds of up to 100mbps
- Was your hypothesis not applicable? no
- Is there more going on than you originally thought? not that i can see
- What shortcomings might there be in your experiment? testing with gigabyte capabilities.
- What shortcomings might there be in your data? none that i know of.
Conclusions
Your connection speed is based on your hardware/connection. If everything allows 1000mbps, then you could essentially get 1000mbps. If you have a 1000mbps connection, and only a 100mbps port, then you will only get 100mbps.
Retest 2
Perform the following steps:
State Experiment
David Schoefflers experiment on autp typed variables. http://lab46.corning-cc.edu/opus/spring2012/dschoeff/start#experiment_2
Resources
Evaluate their resources and commentary. Answer the following questions:
- Do you feel the given resources are adequate in providing sufficient background information? Yes, he provided the source page for the auto variable
- Are there additional resources you've found that you can add to the resources list? yes, but they are unneeded because the actual source was provided.
- Does the original experimenter appear to have obtained a necessary fundamental understanding of the concepts leading up to their stated experiment? yes
- If you find a deviation in opinion, state why you think this might exist.
Hypothesis
State their experiment's hypothesis. Answer the following questions:
- I believe you will not be able to declare the auto typed variable without initializing it.
- Do you feel their hypothesis is adequate in capturing the essence of what they're trying to discover? yes
- What improvements could you make to their hypothesis, if any? not that i can see
Experiment
Follow the steps given to recreate the original experiment. Answer the following questions:
- Are the instructions correct in successfully achieving the results? yes
- Is there room for improvement in the experiment instructions/description? What suggestions would you make? a little example of what compiler/compiler attributes would be nice
- Would you make any alterations to the structure of the experiment to yield better results? What, and why? nope, the experiment is adequate to what needs to be tested.
Data
Publish the data you have gained from your performing of the experiment here.
1: #include<iostream> 2: 3: using namespace std; 4: 5: int main() 6: { 7: auto autovar; 8: cout << "enter value to put in auto typed variable: " ; 9: cin >> autovar; 10: cout << "value stored in auto typed variable - > " << autovar << endl; 11: 12: return (0); 13: }
I ran the same code and received the same errors in compiling
lab46:~$ g++ --std=c++0x autotest.cc -o autotest autotest.cc: In function 'int main()': autotest.cc:7: error: declaration of 'auto autovar' has no initializer lab46:~$
Analysis
Answer the following:
- Does the data seem in-line with the published data from the original author? yes
- Can you explain any deviations? none exist
- How about any sources of error? in using the same exact code, there are no deviations or errors.
- Is the stated hypothesis adequate? yes.
Conclusions
Answer the following:
- What conclusions can you make based on performing the experiment? the auto typed variable is very powerful, but follows most of the same rules as other variables.
- Do you feel the experiment was adequate in obtaining a further understanding of a concept? yes
- Does the original author appear to have gotten some value out of performing the experiment? yes
- Any suggestions or observations that could improve this particular process (in general, or specifically you, or specifically for the original author). The hypothesis was very direct, and the experiment was comprehensive, so i do not believe their are any suggestions to be made, other than maybe a little documentation along with the code, especially about the way it was compiled.
