execute data

I am not an electrical engineer doctor

2011-05-21T13:13:00.000-07:00

I've been looking at boosting the output of the IR leds for the laser tag host transceiver using an SN754410 H-Bridge but the math isn't quite coming out right.

So, something about this doesn't look right:


1,2 EN = Arduino's 5V
1A = PWM control signal
1Y = 3 TSAL6200 IR LEDs in parallel -> 100 Ohm resistor -> Arduino's ground
VCC1,VCC2 = Arduino's 5V
GROUND = Arduino's ground

For one, I am just now noticing that the TSAL6200 is rated to a max of 1.6V while I've been running at 5V (Nothing exploded). Given that the SN754410 is rated for a minimum 4.5V (maybe not the most appropriate part) I might have to step down the voltage on the output like this.
Second, it appears while the digital IO pin on the Arduino (what I am currently using) maxes at 40mA, the 3.3V line only does 50mA. There is no max listed for the 5V pin but one can assume comparable. This would imply I really can't drive the max amperage for the 3x LEDS (100mA each).
So, lets start again for an easy to acquire ~4.5 V supply, divide by 3 to be within the TSAL6200's max voltage, and add a draw of 300 mA:
Ohm's law:


0.3 A = 1.5V / x Ohm
5 Ohm = 1.5V / 0.3 A

Voltage Divider:


1.5V = ( Z2 / ( Z1 + Z2 ) ) * 4.5V
1/3V = ( Z2 / ( Z1 + Z2 ) )

I am guessing here but I think we want Z1 = 5 Ohm. With little confidence that is correct lets keep going:
Update: I've been corrected and we want Z2 to be 5 Ohm, see the comments for the new result.


1/3V = ( Z2 / ( 5 Ohms + Z2 ) )
5/3 Ohms + Z2/3 = Z2
5/3 Ohms = Z2 * 2 / 3
5 Ohms = Z2 * 2
2.5 Ohms = Z2

This gives:


1,2 EN = Arduino's 5V
1A = PWM control signal
1Y = 5 Ohm resistor -> 3 TSAL6200 IR LEDs in parallel -> Battery ground
                    -> 2.5 Ohms -> Battery ground
VCC1 = Arduino's 5V
VCC2 = 4.5V Battery
GROUND = Arduino's ground

So, where did I do it wrong?

Less Lazy Code

2011-03-12T15:08:00.001-08:00

I finally got around to getting rid of the UI glitches cause by TX in the laser tag host. New version here. Or you can grab the code here.

Yay lazer tag!

Lazer Tag Host Binaries part 2

2011-01-21T19:15:00.001-08:00

Ok, I took the previous post of binaries down because I thought those binaries might have been broken but it was just me. Here is a new link. They are tested and work in ubuntu 10.10 and windows 7. I know in windows 7 I had to install gtk# as well to get it to open. If your arduino isn't programed the app may hang, if it isn't plugged in you should be fine but won't get past the setup menu.

Download gtk 2.22
More Versions

Update: You also need a recent version of GTK installed in addition to gtk#.
Update 2: It appears that the release version doesn't work for everyone. Try the debug version if you are having issues.

Patents?

2011-01-16T14:51:00.000-08:00

Someone apparently located the LTTO patent (US7632187). That would have been totally useful.

Actually, reading it now it would have been super useful. It details all the bit fields. Most of mine just switch the whole byte on the game type because the LTTO only starts games with one set of settings. I guess there is quite a bit more I can do. Rapid tags? Neat!

This is how you build a laser tag hosting station

2011-01-14T19:17:00.000-08:00

Official Note: This works better if ground is connected to something, I suggest the middle pin of the IR receiver.

Clearanced-based Hierarchical Pathfinding (HPA*)

2010-11-13T05:44:00.000-08:00

Aigamedev.com seems to always have something interesting to read. This week it is using Annotated A* to find a path of at least minimum clearance through a graph. They also go into how you can reduce the graph to an annotated hierarchical pathfinding graph for near-optimal results at much greater speeds. The article is well explained and comes out with a very practical result.

If your not convinced maybe their talk on zombie brain AI from last month will convince you.

LazerTag Team Ops Packet - Part 4

2010-10-09T21:20:00.000-07:00

I figured out the final scoring details and completed the GUI. You can host a complete game from the GUI now and get all the score readouts.

The fields worked out as follows:

COMMAND_CODE_PLAYER_REPORT_SCORE_RECORDS
0x041-0x043, //command code (last two bits are the team number)
0x00, //game id
0x10, // team_number << 4 | player_number
0xXX, //player hit mask
0xXX, //hits from player indicated by first set bit in mask
0xXX, //hits from player indicated by second set bit in mask
... (the hit bytes sum to count_ones(mask_byte)
0x100, //checksum

The secret to determine the SCORE_RECORD was noticing that COUNTDOWN varied more then I noticed in my initial testing.

COMMAND_CODE_COUNTDOWN_TO_GAME_START
0x000, //command code
0x00, //game id
0x30, //seconds left in digit hex
0x08, //players on team 1
0x08, //players on team 2
0x08, //players on team 3
0x100, //checksum

If t2p0 shoots t1p0 and "players on team 2" == 0, then t1p0's gun will ignore the shot. Hence, those shots won't show up in the score report.

The following packets still have unknown values:
COMMAND_CODE_SCORE_ANNOUNCEMENT
COMMAND_CODE_PLAYER_REPORT_SCORE
COMMAND_CODE_GAME_OVER

Hey you, decode!

As always, get the code here.

LazerTag Team Ops Packet - Part 3

2010-09-29T22:41:00.000-07:00

More features working, more fields decoded. Still no score reporting. I found the 'damage' field and the 'still alive' field but not the who hit you with a candlestick in the library section. Get the Code.

COMMAND_CODE_SCORE_ANNOUNCEMENT
0x031, //command code
0x00, //game id
0x11, // team_number << 4 | player_number
0x0F, //unknown
0x100, //checksum

COMMAND_CODE_PLAYER_REPORT_SCORE
0x040, //command code
0x00, //game id
0x10, // team_number << 4 | player_number
0x00, //damage received
0x01, //still alive
0x00, //unknown
0x00, //unknown
0x00, //unknown
0x02, //unknown
0x100, //checksum

COMMAND_CODE_PLAYER_REPORT_SCORE_RECORDS
0x041, //command code
0x00, //game id
0x10, // team_number << 4 | player_number
0xXX, //unknown
0xXX, //unknown
0xXX, //unknown, looks like hits from a certain player but unable to determine which
0x100, //checksum

I also determined that 0x41 is actually sent by the gun. I am pretty sure it contains the hit report but I have been unable to decode it. With 3 guns it is sometimes 2 bytes of unknown data and sometimes 3. Lastly the 'rank' announce that cycles through all the players.

COMMAND_CODE_GAME_OVER
0x042, //command code
0x00, //game id
0x10, // team_number << 4 | player_number
0x00, //player rank
0x01, //team rank
0x00, //unknown
0x00, //unknown
0x00, //unknown
0x00, //unknown
0x100, //checksum

LazerTag Team Ops Packet - Part 2

2010-09-28T00:55:00.000-07:00

Good progress with the LTTO hosting gun!

The hosting packets are composed of:

9 bit command packet
[ 1 bit zero ] [ 8 bit command code]
8 bit data packet * n
9 bit crc packet
[ 1 bit one ] [ 8 bit sum of previous bytes ]

All of which use the 3000 ms mark, 6000 ms sleep, 3000 ms mark header.

The command codes discovered so far are:
COMMAND_CODE_CUSTOM_GAME_MODE_HOST = 0x02,
COMMAND_CODE_PLAYER_JOIN_GAME_REQUEST = 0x10,
COMMAND_CODE_ACK_PLAYER_JOIN_RESPONSE = 0x01,
COMMAND_CODE_CONFIRM_PLAY_JOIN_GAME = 0x11,
COMMAND_CODE_COUNTDOWN_TO_GAME_START = 0x00,
COMMAND_CODE_SCORE_ANNOUNCEMENT = 0x31,
COMMAND_CODE_PLAYER_REPORT_SCORE = 0x40,

The packet groups look like:
COMMAND_CODE_CUSTOM_GAME_MODE_HOST

0x002, //command code
0x00, //Game ID
0x10, //game time minutes
0x10, //tags
0xFF, //reloads
0x15, //sheild
0x10, //mega
0x20, //unknown
0x01, //unknown
0x100, //checksum

Where the first and last packets are 9 bits. The known values are base 10 hex where 9=0x09 but 10=0x10 and 0xff is 'unlimited'.

The join game request is sent by the joining gun on recv of the above advertisement.

COMMAND_CODE_PLAYER_JOIN_GAME_REQUEST
0x010, //command code
0x00, //game id
0x00, //player id
0x00, //unknown
0x100 //checksum

The host then confirms the join by sending back the ids and team/player numbers

COMMAND_CODE_ACK_PLAYER_JOIN_RESPONSE
0x001, //command code
0x00, //game id
0x00, //player id
0x09, //some combination of team/player number
0x100 //checksum

The gun must then confirm this join to be part of the game by sending back both id's

COMMAND_CODE_CONFIRM_PLAY_JOIN_GAME
0x011, //command code
0x00, //game id
0x00, //player id
0x100 //checksum

If the host goes 60 seconds without getting another player it starts the game countdown at 30 seconds and starts sending countdown announcements once a second.

COMMAND_CODE_COUNTDOWN_TO_GAME_START
0x000, //command code
0x00, //game id
0x30, //seconds left in digit hex
0x02, //unknown
0x00, //unknown
0x00, //unknown
0x100, //checksum

Once the game starts the LTTO gun sends the 5 bit, all zero, 3k,6k,6k pulse once a second but it is not required. All guns will end the game after the timeout in the game announce. Then the host gun starts the score announce beacon.

COMMAND_CODE_SCORE_ANNOUNCEMENT
0x031, //command code
0x00, //game id
0x11, //unknown
0x0F, //unknown
0x100, //checksum

The player gun response is still a mystery but it looks like:

COMMAND_CODE_PLAYER_REPORT_SCORE
0x040, //command code
0x00, //game id
0x10, //unknown,
0x00, //unknown, hits?
0x01, //unknown
0x00, //unknown
0x00, //unknown
0x00, //unknown
0x00, //unknown
0x100, //checksum

More then one similar looking packet is exchanged. Determining the meanings will require multi-gun controlled tests. After the score is reported the host sends back command 0x41 which appears to report the hits per player. When all players have checked in the host spits out command 0x32 periodically, with still contents of unknown meaning.

LazerTag Team Ops Packet - Part 1

2010-09-26T16:29:00.000-07:00

Phoenix LTX

[ 3 bits - zero ] [ 2 bits - team ] [ 2 bits - damage ]

Team:
0x00 = Solo
0x01-0x03 = Team 1-3

Damage:
0x00-0x03 = Damage 1-4 (3-4 are only usable by LTTO as Mega-Tag)

LTTO

[ 5 bits - zero (for solo at least) ]

Location Pulse

#define LTTO_HDR_MARK_ONE 3000
#define LTTO_HDR_MARK_TWO 6000
#define LTTO_HDR_SPACE 6000
#define LTTO_ONE_MARK 2000
#define LTTO_ZERO_MARK 1000
#define LTTO_SPACE 2000

Goal-Oriented Action Planning

2010-09-02T20:09:00.000-07:00

I found a very good paper on AI planning by the guy that did the F.E.A.R. AI architecture.

Jeff Orkin's page on GOAP contains lots more links to even more details.

Learn something!

Phoenix LTX

2010-08-23T21:51:00.000-07:00

Hey look I made a lazer tag gun! It runs on Arduino using the IRremote library.

Send:

void IRsend::sendPHOENIX_LTX(unsigned long data, int nbits) {

  enableIROut(36);
  //HEAD
  mark(PHOENIX_HDR_MARK);
  space(PHOENIX_HDR_SPACE);
  mark(PHOENIX_HDR_MARK);
  int i = 0;
  for (i = 0; i < 7; i++) {
    if (i % 2 == 0) {
      space(PHOENIX_LTX_SPACE);
    } else {
      mark(PHOENIX_LTX_ZERO_MARK);    
    }
  }
  //DATA
  if ((data >> 2) & 1 == 1) {
    mark(PHOENIX_LTX_ONE_MARK);    
  } else {
    mark(PHOENIX_LTX_ZERO_MARK);
  }
  space(PHOENIX_LTX_SPACE);
  if ((data >> 0) & 1 == 1) {
    mark(PHOENIX_LTX_ONE_MARK);    
  } else {
    mark(PHOENIX_LTX_ZERO_MARK);
  }
  //TAIL
  for (i = 0; i < 4; i++) {
    if (i % 2 == 0) {
      space(PHOENIX_LTX_SPACE);
    } else {
      mark(PHOENIX_LTX_ZERO_MARK);    
    }
  }
  space(PHOENIX_LTX_SPACE);

}

Receive:

long IRrecv::decodePHOENIX_LTX(decode_results *results) {

  long data = 0;

  int offset = 1;

  int i = 0;

  //HEAD

  if (results->rawlen != 18) {

    return ERR;

  }

  if (!MATCH_MARK(results->rawbuf[offset], PHOENIX_HDR_MARK)) {

    return ERR;

  }

  offset++;

  if (!MATCH_SPACE(results->rawbuf[offset], PHOENIX_HDR_SPACE)) {

    return ERR;

  }

  offset++;

  if (!MATCH_MARK(results->rawbuf[offset], PHOENIX_HDR_MARK)) {

    return ERR;

  }

  offset++;

  for (i = 0; i < 7; i++) {

    if (i % 2 == 0) {

      if (!MATCH_SPACE(results->rawbuf[offset], 2000)) {

        Serial.println(i, DEC);

        return ERR;

      }

      

    } else {

    

      if (!MATCH_MARK(results->rawbuf[offset], 1000)) {

        Serial.println(i, DEC);

        return ERR;

      }

    }

    offset++;

  }

  Serial.println("Data");

  //DATA

  for (i = 0; i < 3; i++) {

    if (MATCH_MARK(results->rawbuf[offset], PHOENIX_LTX_ONE_MARK)) {

    data << 1;

    data |= 1;

    } else if (MATCH_MARK(results->rawbuf[offset], PHOENIX_LTX_ZERO_MARK)) {

    data << 1;

    data |= 0;

    } else {

      Serial.println(i, DEC);

      return ERR;

    }

    offset++;

  }

  Serial.println("Tail");

  //TAIL

  for (i = 0; i < 2; i++) {

   if (!MATCH_SPACE(results->rawbuf[offset], 2000)) {

    return ERR;

  }

  offset++;

  if (!MATCH_MARK(results->rawbuf[offset], 1000)) {

    return ERR;

  }

  offset++;

  }

  

  // Success

  results->bits = 3;

  results->value = data;

  results->decode_type = PHOENIX_LTX;

  return DECODED;

}

Defines:

#define PHOENIX_HDR_MARK 3000
#define PHOENIX_HDR_SPACE 6000
#define PHOENIX_LTX_ONE_MARK 2000
#define PHOENIX_LTX_ZERO_MARK 1000
#define PHOENIX_LTX_SPACE 2000

TankTank 0.3.1 (Experimental)

2010-05-30T12:04:00.000-07:00

Less 'crashing into walls' Edition.

Download

Internet TankTank 0.3.0

2010-04-25T11:05:00.001-07:00

New version of tanktank with fewer unintended features and more candy! Internet servers via the server browser appear to work. You need to open port 18007 for TCP/UDP if you want it to work though.

CTF was rebalanced.

Spawns were color coded

Unused spawns were hidden

New teams arn't created after game start to keep it balanced

Vastly improve push zone drawing

Turn triangle around seems to help when people get stuck

Fix some laser issues

Drawing tweaks

Fix for cwd issue and empty maps

Draws properly on win7 now hopefully

Download

O yah, Lava!

SteamBirds

2010-04-05T21:03:00.000-07:00

Quite fun fighter plane game! If you are not playing it your are clearly the victim of lead poisoning.

Capture TankTank Fish 0.2.8

2010-01-11T14:12:00.000-08:00

Now with server browser and capture the flag support. ~~Also works better on vista/win7.~~

Also added an option to turn off UDP if your firewall explodes like mine does.

Mongo says get it now.

TankTank 0.2.5

2009-08-01T12:48:00.001-07:00

Network Multiplayer! Six game types! New Maps! Exclamation Points! New Shotgun! Pushy Zones! Chile Rellenos! Wait, that is lunch. But the other things! Some crashes! Avoid Grue!

Note: Join takes player to default server. To specify use ./tanktank client <ip>

Download

TankTank 0.2.0

2009-04-18T20:38:00.000-07:00

New version of tankttank. Release includes x64,x86,win32.

Supports six players on one keyboard. Get cozy! Although you can't change the number of players with recompiling. Also supports king of the hill, and proper score keeping in single or multi-player mode. Increased rotational damping and ground friction so people are actually capable of playing it. Makes it a little harder to kill yourself on a wall. Also added viewport sharing so you can see your screen with six players. Stay close or you'll get stuck offscreen and eaten by a grue.

O, there is sound now also!

Try the new King of the Hill
./tanktank ./levels/hill_eight.svg

Download

Mingw

2009-04-18T16:36:00.000-07:00

Maybe this is useful

Mingw + SDL

Catching data on the way out

2009-03-12T19:58:00.000-07:00

So, pulling variable contents off the stack in the middle of a function and dumping to a file via the debugger is easier then it appears. First, don't use ddd. This process over a few hundred thousand iterations would have taken hours, except it kept crashing ddd in the middle. Using gdb took mere minutes.

#For the dynamic case, stop where we can see what is going on
break some_dynamicly_loaded_function
run
#Now we know our loaded offset
break *some_dynamicly_loaded_function+length_of_said_dynamicly_loaded_function
delete 1

#Hook up commands to process data and continue
commands 2
#Get data from pointer argument
set $start = (((unsigned long*)$esp)[arg_index_of_paramater_you_want])
set $end = ($start + length_of_out_paramter)
append binary memory test.bin $start $end
cont
end

#Fix gdb because it will print every time breakpoint hits, which triggers pagination
set pagination off
#Go
cont

TankTank for Windows

2009-02-21T22:19:00.000-08:00

Alright. A few painful sessions with windows headers and piles of dlls and I've come up with a windows build of my game tank tank.

The controls are still listed here. The game itself didn't change much from 0.1.7 except that I no longer link against ImageMagick++ or SDL_mixer as I couldn't either of them to link properly. The latter was just crashing mingw's ld. That breaks text, and I never hooked up sound.

This release doesn't include source, I had to make a mess to cross compile and I don't want to clean it up.

tanktank-0.1.8.tar.gz

O yah, it works in wine just fine.

Delicious Coffee

2009-02-19T16:24:00.000-08:00

Ahh, getting no support is fun.

Delicious 32 libraries

2009-02-15T13:28:00.000-08:00

Missing 32bit devel packages on your 64 bit system?

Just install them apparently. You just have to compose the repo url then walk dependencies manually from otter bones. Or run that script. Otter bones included.

Runtime Stacks

2009-02-02T13:42:00.001-08:00

Mmm, Stacks

It does not appear to make a difference in glibc malloc catches at least.

Heisenbug

2009-02-01T15:43:00.000-08:00

You might even find a Heisenbug, which can be incredibly difficult to track down, since a) it surfaces very rarely, b) the conditions can be impossible to replicate, and c) introducing test code can "fix" the problem.

RFC2313

2008-12-03T00:26:00.000-08:00

RFC2313

The block type BT shall be a single octet indicating the structure of the encryption block. For this version of the document it shall have value 00, 01, or 02. For a private- key operation, the block type shall be 00 or 01. For a public-key operation, it shall be 02.

Sigh, sometimes I should look up error messages the first time I get them

Wireshark

2008-11-08T13:17:00.000-08:00

I can never remember any of this so I find cheating helps.

Captioning Diskette

2008-07-29T15:29:00.000-07:00

Captioning Diskette: A computer diskette with a caption file written on it. This file has captioning data used by an encoder to insert captions.

Leg bone?

2008-07-23T20:49:00.000-07:00

I have yet to massage the spleen.

TankTank - Version Good Enough

2008-07-19T22:30:00.001-07:00

Another game. The controls are a little jumpy, but real physics are not conducted in absolute impulses at 100 frames per second are they? It will eventually be a little more balanced, until then I might be the only one that is not continuously slamming into a wall.

Player 1
Arrow Keys - Movement
R-Ctrl - Grenade
R-Alt - Reload
R-Shift - Laser

Player 2
WSAD - Movement
L-... ...

tanktank-0.1.2.tar.gz

ghextris

2008-07-18T00:28:00.001-07:00

Seeing as I haven't gotten this merged into official debian upstream I thought I would show it off here. An expansion on the ghextris package that allows side-by-side two-player and a variety of color options.

ghextris_0.9.2-0_all.deb

Boolean Difference with object files

2008-04-29T16:30:00.000-07:00

if [ -f $OUTPUT_FILE ]; then
    rm -i $OUTPUT_FILE
fi

if [ -f $OUTPUT_FILE ]; then
    echo "Must remove ${OUTPUT_FILE}"
    exit
fi

rm -rf ./$INPUT_LIB_DIR
mkdir $INPUT_LIB_DIR
cd $INPUT_LIB_DIR

ar x $INPUT_LIB

cd ..

rm -rf ./$SUBTRACT_LIB_DIR
mkdir $SUBTRACT_LIB_DIR
cd $SUBTRACT_LIB_DIR

ar x $SUBTRACT_LIB

cd ..

rm -rf ./$OUTPUT_DIR
mkdir $OUTPUT_DIR

cd $INPUT_LIB_DIR

for a in ./*.o
do
    if [ -f ../$SUBTRACT_LIB_DIR/${a} ]; then
        echo "Skipping " ${a} > /dev/null
    else
        echo "Including " ${a}
        cp ${a} ../$OUTPUT_DIR
    fi
done

cd ..

for a in ./$OUTPUT_DIR/*.o
do
    ar r ./$OUTPUT_FILE $a 
done
ranlib ./$OUTPUT_FILE

rm -rf ./$INPUT_LIB_DIR
rm -rf ./$SUBTRACT_LIB_DIR
rm -rf ./$OUTPUT_DIR

Note: Code Formatting

Captcha

2008-04-26T13:49:00.000-07:00

Captchas have been in the news recently. Apparently computers can do a reasonable job at guessing them. I can't, thats for sure, but I can guess how I could write a program that could guess better then me.

Although, nobody is sure if it is computers or a room full of slave labour doing the guessing. But somehow they get a success rate greater then 26^6.

I am guessing the one here is xtuixj, but one can never be sure. It took me three failures before I got though blogger's captcha today.

Encrypt Your Encryptors

2008-04-20T01:02:00.000-07:00

EncFS + PAM = Delicious? Maybe. Don't change your password though, you will have to login until encfs stops letting you try login so your password will make it to GDM.

Brain Bug

2008-04-19T15:23:00.000-07:00

So, snails. The other fish have not yet figured out they are not food so they might not last very long. They haven't kicked it in a few hours, so, things are looking up. One of them is having more trouble, maybe he tastes like delicious bugs. If I tasted like delicious bugs, I would fear for my life.

Their mouth reminds me of Starship Troopers. The brain bug is coming for me and I don't know what to do.

Execute Sticky

2008-04-15T12:37:00.000-07:00

So,

ls -l
filename size date permissions
hosed.dat 900MB March 5, 2009 rwxrwxrwx
chmod -x
chmod +t
ls -l
filename size date permissions
hosed.dat ?? ?? ??

I thought I was crazy, but you must execute your sticky. 'man chmod'

RESTRICTED DELETION FLAG OR STICKY BIT
The restricted deletion flag or sticky bit is a single bit, whose interpretation depends on the file type. For directories, it prevents unprivileged users from removing or renaming a file in the directory unless they own the file or the directory; this is called the restricted deletion flag for the directory, and is commonly found on world-writable directories like /tmp. For regular files on some older systems, the bit saves the program’s text image on the swap device so it will load more quickly when run; this is called the sticky bit.

Yah, swap device.

I'll download your streams.

2008-04-15T00:20:00.000-07:00

So, there are these magic pipes with trucks that get clogged if you ram your trucks then the 'premium content' stops flowing. Please, somebody think of the royalties.

"Streams mean not having to necessarily worry about copy protection - although the iPlayer team did have to make a few tweaks when some enterprising souls found a way to hack the streams.

Downloads mean you do have to worry about copy protection."
-Wii becomes home of online video

All of this means linux doesn't get content because the content might catch 'free'.

Make Work Fallacy

2008-04-05T23:03:00.000-07:00

Quite convenient. I've been wondering what to call my critique of the green movement for some time. As I expected, the economists know what they are doing and knew about it all along. You can't pay more for something and claim it is more efficient, it is inherently less.

While it is true the open market defers many costs of good onto the public, toxic waste, deforestation, claiming that less of those at any cost is for the better is a fallacy.

Leprechauns

2008-04-04T20:28:00.000-07:00

I am afraid I might have lied to some of you, I am sorry. I will put that behind me today. I might have confused Leprechaun: In The Hood (Leprechaun 5) with Leprechaun: Back 2 tha Hood. I am sorry, I would claim ignorance but it is no excuse. I can only hope you forgive me.

Maybe we can watch both of them together. We will all feel better about putting this behind us.

Thread Local Storage

2008-04-04T13:26:00.000-07:00

So, I've been wondering where exactly this magic thread storage comes from. Apparently it is just a symbol type that the thread subsystem will utilize to alloc on thread creation. That is super wacky, but is exactly what I wanted to know. Now I can write my lockless lock contention detector no problem.

__thread bool awesome = TRUE;

Using Thread Local Storage
http://docs.sun.com/app/docs/doc/817-1984/6mhm7pl2a?a=view

STT_TLS in ELF files
http://blogs.sun.com/ali/entry/inside_elf_symbol_tables

This could be complemented with symbol from pointer lookup via dladdr()
http://linux.die.net/man/3/dlopen

Delicious

2008-04-03T13:34:00.000-07:00

Delicious

It feels like scripting in windows

2008-04-02T18:50:00.000-07:00

#/bin/bash

function echo_cmd {

echo $*
$*

}

echo_cmd cp /dev/urandom /dev/null

Spam or Engineer?

2008-04-02T15:24:00.000-07:00

Ha, jeremi is a robot.

http://multidimensionalbit.blogspot.com/

Mint Sunshine

2008-03-28T22:05:00.001-07:00

1 shot creme de menthe
3 shots tequila
orange juice to suit

Network Timetable

2008-03-25T16:47:00.000-07:00

RFC 4. A little dusty, but has a nice picture of the internet. 4 computers.

http://www.faqs.org/rfcs/rfc4.html

.cgrc

2008-03-25T12:36:00.001-07:00

~/.cgrc

cg-help -c
cg-log -c -f
cg-diff -c --diffcore -b

Heap Graph?

2008-03-24T19:03:00.000-07:00

So, massif is the tool to use if you wonder about your heap.

"valgrind --tool=massif --stacks=yes [exec]"

You even get pretty graphs, although I won't attempt to replicate them here. As there is no respect for ASCII art.

Note: valgrind > 1.3.2

minty fresh filler

2008-03-21T23:45:00.000-07:00

Someone doesn't respect ASCII

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
. ` /
. ,../... .
. . / `\ / .
\ . o < ' ) =<
/\ . \ \ / \ . __
>=)'> `'\'"'"' /o \/
\/ . / o /, \__/\ .:/
/ . /--\ / / <')=< . ,,///;, ,;/

\__/ \ <')_=< >::::::::;;\\\
\ \_/ . ''\\\\\'' ';\
( \ . __
) <'_>< (
( ( ,/.. ` )
) ( ) <') `=< ) (
( ) ( ``\``` ( )
_____)_____(____)______________________________________)____(___________