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Part 1
Entries
Entry 1: September 7, 2012
This is the second week of school and our classes are finally starting to become in depth with the course. Of course i mean that like we are starting to dive into the meat of the courses and that makes me happy. In data comm we have started to work with a OS called Asterisk, which will allow us to make phone calls within a local area network. We are just kind of messing around with it to see what we can do and hopefully create our E alert system that we want to create. In data structures we have begun working with datatypes to make sure we are well known with our datatypes. We have to understand the difference and size of each type like int or char to fully understand what kind of data will be going in through our program. In hpc i will be creating a drum machine, so for starters i am just researching ways to create music through linux/C programming and hopefully soon start creating noise with this :D.
Entry 2: September 14, 2012
This week we are head way into making our programs and getting our projects together and such. In data comm we are starting to understand the basics of asterisk. We were able to connect some Voip phones to asterisk so we actually have something we can call to test. We have also discovered that we can throw on our own personal audio onto a certain number or phone number. But for now we just need to succesfully connect all our phones together so we can call each other, I will however try to start converting audio that we can use within the phones. In data structures we are starting on singly linked lists. Its a list of nodes that holds pointers that point to data in a list. but with this list we are only able to go forward so we must learn how to manipulate these lists so we can insert, append and delete nodes at any point in the list. In HPC i have actually started working on a program that will be able to record and playback what i have recorded which will be good cause i can make my own drum samples if i must. I will be accessing the dev/dsp sound driver to access the sound capabilities. So i will be working on this program and hopefully it will work.
Entry 3: September 21, 2012
In data structures we started to take a look at doubly linked lists. It is basically the same as a singly linked list but you have the ability to go forward and backwards. So it will be easier to navigate through a list since you can go back now, however new implementation needs to be learned. But until we really get into them, we are just working on singly linked list projects so we can totally understand for future projects. In Data comm i have been able to put a lot of audio onto the phone. I know exactly how to convert mp3 to gsm so it could be played over a phone line. Then we were able to get asterisk to speak to freeswitch now we just need freeswitch to speak to google voice so we can call anyone we want. So its still a work in progress. And in hpc i havent really touched anything in this class this, i have been focused on getting these projects done so i can work on my own independent project.
Entry 4: September 28, 2012
This week in data structures we still continues on with singly linked lists and just working on them. I have deletion completed but i still have to do insertion. I thought insertion was the same as append, which technically it is, but come to find out insertion is where you place a new node behind and not after like append. So i am little late on that program but i shall have it finished very soon. But other then that, we did more on learning doubly linked and we messed with a deugger little bit on friday. Its a really nifty tool but i think i prefer just debugging a program on my own. In data comm we are still trying to get freeswitch to talk to google but other then that, not much has been done. I added a little audio and i am going to figure out how to make my own automated audio for some audio fun. And in hpc i once again didnt really do much with it, i did some research but i really need to do a lot more if i plan on making this drum machine.
Keywords
Structure Pointer
Definition
A structure pointer is a pointer that points to a structure! Like any pointer,it points to an address in memory. And a structure has multiple elements in one block. Now you can pass and return these structures through functions to get the data you want but this is excessive data movement so to reduce this you would pass a pointer to the structure to the function. All we would have to do is reference the pointer to the struct then dereference it to receive the data we want.
#include <stdio.h> #include <string.h> struct tag{ /* the structure type */ char lname[20]; /* last name */ char fname[20]; /* first name */ int age; /* age */ float rate; /* e.g. 12.75 per hour */ }; struct tag my_struct; /* define the structure */ void show_name(struct tag *p); /* function prototype */ int main(void) { struct tag *st_ptr; /* a pointer to a structure */ st_ptr = &my_struct; /* point the pointer to my_struct */ strcpy(my_struct.lname,"Jensen"); strcpy(my_struct.fname,"Ted"); printf(" %s ",my_struct.fname); printf("%s ",my_struct.lname); my_struct.age = 63; show_name(st_ptr); /* pass the pointer */ return 0; } void show_name(struct tag *p) { printf(" %s ", p->fname); /* p points to a structure */ printf("%s ", p->lname); printf("%d ", p->age); }
References
data Keyword 1 Phase 2
Null Pointers
Definition
A Null pointer is a pointer that points definitively nowhere. It is a special pointer that is used to symbolize that the pointer is pointing at nothing or that there is nothing there. The null pointer is commonly used in malloc, when it fails it returns a null pointer because nothing happened so therefore you get nothing in return.
References
None on this one :)
Demonstration
There is no real way to demonstrate this, if this was compiled in a program it will just come up as undefined or 0 or NULL.
Link layer
Definition
The link layer is the lowest level in the TCP/IP model. It is a level that contains methods and protocols that only work on the hosts link. It is used in the connections of LAN and WAN, like a phone service that is local to a group or organization and maybe they will eventually branch out onto a WAN connection. This layer is to help connection 2 or more clients to be able to connect and communicate effectively.
References
List any sites, books, or sources utilized when researching information on this topic. (Remove any filler text).
- Reference 1
- Reference 2
- Reference 3
datacomm Keyword 1 Phase 2
VoIP. Voice overlay Internet Proticol
Definition
a system and internet proticol that allows to transmite and receive human voice form one place to another much like the preadvent the tele phone which is analog but in order to use it via computer and the interwebs u need to digitize the sound wave length, tone and pitch of a human voice then transmit via the VoIP system which im not intirely sure of all that happens.
References
- Astrisk pbx
- Astrisk pbx wikipedia
- netcat
- netcat wikipedia
- VoIp Wikipedia
Demonstration
Basically voip is like any other telephone except it is used threw the computer. You can connect to someone over the internet or someone inside your home. There is no code or executions to demonstrate how this works, download a voip softphone and boom! discover its magic by dialing in a number or 2.
ALSA/OSS/FIREWIRE
Definition
ALSA stands for Advanced Linux Sound Architecture. It provides sound and MIDI functionality to linux. It supports all types of different sound interfaces, has a safe design and it supports OSS (Open Sound System). Its free and open source so programmers all around have the ability to tinker with it and have fun (so to speak). FIREWIRE is kind of like an ethernet cable or a USB cable. However it has different goals it wants to achieve such as: fast data transfer, ability to handle multiple devices, easy use, plug and play, low cost and hot pluggable ability. It was first established by apple and later standardized by many. It is used mainly for the transfer of audio and media.
References
hpc1 Keyword 1 Phase 2
SPARC
Definition
SPARC is a scalable Processor Architecture RISC instruction set. This is a micro processor that is widely used in sun micro systems hardware.
References
Demonstration
Experiment 1
Question
Can i access the dev/dsp sound driver to enable use of my program?
Resources
Hypothesis
I feel this will not work because i do realize this is an outdated sound driver that has been replaced by ALSA. But i am curious if it is still able to be used at all, maybe its there i just have to find a way to access it and use it.
Experiment
I have a program written for HPC that will access this sound driver if it exists. After i have shown if the dev/dsp is there or not, i will try to locate it and see if i can still use it or not.
Data
1. Here is the program i have written that is suppose to record and replay the recording:
1 /* 2 *parrot.c 3 *Program to illustrate /dev/dsp device 4 *Records several seconds of sound, then echoes it back 5 *runs until Control-c pressed. 6 */ 7 8 #include <unistd.h> 9 #include <fcntl.h> 10 #include <sys/types.h> 11 #include <sys/ioctl.h> 12 #include <stdlib.h> 13 #include <stdio.h> 14 #include <linux/soundcard.h> 15 16 #define LENGTH 3 /*how many seconds of speech to store */ 17 #define RATE 8000 /*the sampling rate*/ 18 #define SIZE 8 /*sample size: 8 or 16 bits */ 19 #define CHANNELS 1 /* 1 = mono, 2 = stereo */ 20 21 /*this buffer holds the digitized audio*/ 22 unsigned char buf[LENGTH*RATE*SIZE*CHANNELS/8]; 23 24 int main() 25 { 26 int fd; 27 int arg; 28 int status; 29 30 /*open sound device*/ 31 fd = open("/dev/dsp", O_RDWR); 32 33 if(fd < 0) 34 { 35 perror("open of /dev/dsp failed"); 36 exit(1); 37 } 38 39 /*set sampling parameters */ 40 arg = SIZE; /*sample size*/ 41 42 status = ioctl(fd, SOUND_PCM_WRITE_BITS, &arg); 43 44 if (status == -1) 45 perror("SOUND_PCM_WRITE_CHANNELS ioctl failed"); 46 if (arg != SIZE) 47 perror("unable to set sample size"); 48 49 arg = CHANNELS; /*mono or stereo*/ 50 51 status = ioctl(fd, SOUND_PCM_WRITE_CHANNELS, &arg); 52 53 if (status == -1) 54 perror("SOUND_PCM_WRITE_CHANNELS ioctl failed"); 55 if (arg != CHANNELS) 56 perror("Unable to set number of channels"); 57 58 arg = RATE; /*sampling rate*/ 59 status = ioctl(fd, SOUND_PCM_WRITE_RATE, &arg); 60 if(status == -1) 61 perror("SOUND_PCM_WRITE_WRITE ioctl failed"); 62 while (1) /*loop until ctr-c*/ 63 { 64 printf("say something:\n"); 65 status = read(fd, buf, sizeof(buf)); /*record some sound*/ 66 if(status != sizeof(buf)) 67 perror("read wrong number of bytes"); 68 printf("you said:\n"); 69 status = write(fd, buf, sizeof(buf)); /*play it back*/ 70 if (status != sizeof(buf)) 71 perror("Wrote wrong number of bytes"); 72 /*wait for playback to complete before recording again*/ 73 status = ioctl(fd, SOUND_PCM_SYNC, 0); 74 if (status == -1) 75 perror("SOUND_PCMSYNC ioctl failed"); 76 } 77 } 78
2. I have run the program to get this message:
lab46:~/src/hpc$ ./parrot open of /dev/dsp failed: No such file or directory lab46:~/src/hpc$
3.Now i go for a search of the dev/dsp:
lab46:~$ cat /proc/asound/pcm lab46:~$ cd proc -bash: cd: proc: No such file or directory lab46:~$ cd .. lab46:/home$ cd .. lab46:/$ cd proc lab46:/proc$ cd asound lab46:/proc/asound$ cd pcm -bash: cd: pcm: Not a directory lab46:/proc/asound$ ls cards devices modules oss pcm seq timers version lab46:/proc/asound$ cat pcm lab46:/proc/asound$ cat devices 2: : timer lab46:/proc/asound$ cat cards --- no soundcards --- lab46:/proc/asound$ cd .. lab46:/proc$ ls 1 11118 11232 12735 16787 19 2274 24531 28441 28539 28600 3133 38 3978 4827 6485 asound interrupts modules timer_stats 10 11122 11233 12736 16788 19252 2275 24642 28449 28540 28601 3135 3803 3981 5 6918 buddyinfo iomem mounts tty 1001 11123 11235 128 16791 19253 2278 24849 28497 28549 28622 3136 388 3983 500 7 bus ioports net uptime 1014 11142 11272 12923 16889 19256 22800 2562 28502 28550 28629 3140 389 3984 5129 7504 cgroups irq pagetypeinfo version 1023 11143 11336 13 16890 2 22801 2565 28503 28558 28632 31855 3904 4 5130 8 cmdline kallsyms partitions vmallocinfo 1029 11147 11339 14 16900 20 22824 2566 28507 28559 29 31857 3907 4007 594 8015 cpuinfo kcore sched_debug vmstat 1038 11148 11348 14725 17 20034 22827 2570 28508 28582 29150 32 3959 4012 6 8141 crypto key-users self xen 1045 11152 11351 14727 178 20035 22891 25728 28517 28583 29151 32024 3961 461 629 8142 devices keys slabinfo zoneinfo 1079 11153 11356 14728 17863 20038 23 26269 28518 28592 29156 32130 3962 462 6310 861 diskstats kmsg softirqs 1088 11188 11364 14836 17864 20590 23492 26294 28522 28594 29572 32150 3968 475 6311 862 dma kpagecount stat 1098 11189 11896 15 18 21 23493 26299 28523 28595 29573 33 3970 476 6315 8643 driver kpageflags swaps 11 1121 12 15037 18303 2156 23497 26302 28527 28596 29576 34 3971 477 6365 9 execdomains loadavg sys 11112 11228 12337 15985 18976 217 24 27 28528 28597 3 35 3973 4821 6366 951 fb locks sysrq-trigger 11113 11229 12338 16 18977 218 24497 28 28534 28598 30 369 3974 4823 6444 960 filesystems meminfo sysvipc 11117 11231 12341 16406 18980 22 24498 28440 28535 28599 31 375 3977 4824 6445 974 fs misc timer_list lab46:/proc$ cd asound lab46:/proc/asound$ ls cards devices modules oss pcm seq timers version lab46:/proc/asound$ cd oss lab46:/proc/asound/oss$ ls devices sndstat lab46:/proc/asound/oss$ cat sndstat Sound Driver:3.8.1a-980706 (ALSA v1.0.21 emulation code) Kernel: Linux lab46 2.6.32-5-xen-amd64 #1 SMP Mon Jan 9 22:09:26 UTC 2012 x86_64 Config options: 0 Installed drivers: Type 10: ALSA emulation Card config: --- no soundcards --- Audio devices: NOT ENABLED IN CONFIG Synth devices: NOT ENABLED IN CONFIG Midi devices: NOT ENABLED IN CONFIG Timers: 31: system timer Mixers: NOT ENABLED IN CONFIG lab46:/proc/asound/oss$
Analysis
Based on the data collected:
- Was your hypothesis correct? Yes it was
- Was your hypothesis not applicable? It is applcable because its part of my project
- Is there more going on than you originally thought? Yes because i have read somewhere the dev/dsp can be found and enabled under ALSA. I feel its somewhere but maybe not under lab46. I will have to do further research on this to find out.
- What shortcomings might there be in your experiment? Maybe my program was wrong or maybe i did not look hard enough
- What shortcomings might there be in your data? I could be looking at the wrong data or just not looking in the right place
Conclusions
I now know that i must enable the use of ALSA in my program unless i am able to find a way to enable the use of dev/dsp under ALSA-oss. I believe i can find it and i will continue until i can. If i can not find it, then i will just have to modify and move on.
