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24 June 2009

Succeeding at finding an ice block

FailBot has its uses for troubleshooting a raid wipe. However, due of the wording of its /ra output ("{Player} fails at {boss action}."), I do suspect that this AddOn was devised under a sadistic mentality. However, don't fret, as this series of guides will give help avoid these embarrassments!

Sapphiron's Frost Breath AoEs the entire area for an enormous amount of damage. If you are not careful, you can easily end up a frozen corpse lying on the floor of his cold, cold lair. There are only two ways to avoid this demise:
  1. Be frozen in an ice block by Sapphiron's Icebolt.
  2. Hide behind someone frozen by Icebolt, breaking line-of-sight of the epicentre.

When doing this encounter, it is a good idea to zoom the camera out, so as to get a wide view of the area. To increase the maximum range of the camera, execute the following slash commands:
/console cameraDistanceMax X
/console cameraDistanceMaxFactor Y
where X and Y are arbitrary numbers. The valid range for X is 0-50 and its default value is 15. The valid range for Y is 0-3.4 and its default value is 1.

You can tell when Frost Breath will soon be cast when Sapphiron flies up into the air (an action conveniently accompanied with a raid warning). When this happens, all players should gather in a common area (though still keeping 10 yds of distance from each other, since Icebolt also AoEs). This will ensure that everyone does not need to run too far to reach an ice block. Also keep in mind the various Chills that may be up; it is a good idea to stay away from these.

With luck, Sapphiron will distribute three ice blocks evenly over the congregation; otherwise, they should still be in technical reach. He will fire them off in succession, so it is best to wait until the second one occurs before running for one. Avoid Chill areas, since they will slow movement speed by half if afflicted.

Once behind an ice block, it is a good idea to check your line-of-sight (or lack thereof). You can do this by attempting to cast a ranged ability at Sapphiron. If you are positioned correctly, you will get an error saying that you are out of line-of-sight; otherwise, adjust your position accordingly. Just wait until the flash of blue, and you will have successfully weathered a frost wyrm's icy breath!

20 June 2009

My Computer and I: Errors #134

Computers are only as good as people make them. Since human beings are prone to mistakes, the computer systems they build will likewise contain faults.



My desktop is a 3-year-old Dell Dimension 8400. It was high-end at the time it was bought, but regardless is starting to show its age. I have upgraded some of its parts since then to keep playing World of Warcraft bearable, but of course it will need to be replaced eventually.

I have had my share of computer problems with my current computer (not suggesting that Dell is necessarily a poor computer assembler, mind you). Other than high school computing studies, I have had no formal training in maintaining a computer, so I usually need to end up experimenting when something goes wrong. This regular will document my adventures in rectifying problems my Dimension 8400 experiences. Without further ado...

The Problem:
World of Warcraft would crash due to an Error #134.

Here is an extract from one of the many crash logs that WoW's diagnostic spat out:

World of WarCraft (build 9056)
Exe: C:\Program Files\World of Warcraft\WoW.exe
Time: Oct 23, 2008 8:46:14.671 PM
User: XXXXXXXX
Computer: XXXXXXXX
------------------------------------------------------------------------------

This application has encountered a critical error:

ERROR #134 (0x85100086) Fatal Condition
Program: C:\Program Files\World of Warcraft\WoW.exe

Failed to read file DUNGEONS\TEXTURES\WALLS\BM_HFIRE_SEWER01.blp.

Debug Details:

[2] err=0 text=SFileReadFile - DUNGEONS\TEXTURES\WALLS\BM_HFIRE_SEWER01.blp - Data\expansion.MPQ
[1] err=0 text=LoadSectorTable failed
[0] err=5 text=Win32 Read - Data\expansion.MPQ
Storm Error Msg:Reached the end of the file.


Background Information:
  • The variant of the Error #134 I experienced involved the system's reading a game file but failing. Unfortunately, this is still rather vague, so I had a difficult time troubleshooting it (it took a good year to resolve it).
  • WoW is memory-intensive compared to other computer games in the market. A memory upgrade would likely be more cost-effective than a video card upgrade.
  • Data would exist in the hard disk, hard disk controller, chipset (made up of the northbridge, southbridge and internal bus), RAM, memory controller, memory bus and graphics bus before reaching either the CPU or video card for processing. A fault in any of these components would corrupt the data in it and hence cause this error.
  • I essentially needed to find out which of the said components was acting up and deal with it accordingly.

The Circumstances:
  • The problem only really manifested itself after I installed the Burning Crusade expansion.
  • Restarting the computer would lessen its frequency.
  • A different file would fail to be read each time.
  • Dalaran was a nightmare. I would crash every five minutes within its walls. I ended up binding my Hearthstone elsewhere and missed out on running Violet Hold in the meantime.

The Experience:
  • Deleting the WTF, WDB and Interface folders: I will be frank; this did not work.
  • Running Blizzard Repair: Unfortunately, this did not work either. However, I ran this utility multiple times and noted that the utility would find something to fix each and every time. Interestingly, this note was not needed to solve the problem.
  • Updating the video card driver: This caused WoW to crash sooner. It also made the UI overlay blink at random times. I ended up rolling it back to the original (3-year-old) driver.
  • Testing the RAM by running Windows Memory Diagnostic: WMD would test the memory modules to find any physical defects. The entire memory space passed, though borderline modules would act up only when working under a heavy load (like serving models and textures to WoW). WMD did not perform any stress testing, and WoW still kept on crashing.
  • Testing the hard drive: To do this, I essentially copied the client onto a USB hard drive and ran it from there. The idea was: a) if WoW did not crash, it was the hard drive's (or possibly the controller's or bus') fault; or b) if WoW kept on crashing, the hard drive was fine). WoW crashed yet again.
  • Replacing memory modules: By this stage, I was desperate and relying heavily on the results of the hard drive isolation test above. I was also determined to not miss out on the full Wrath of the Lich King expansion experience. I waltzed over to the nearby computer shop, bought a matched pair of 1GB 800MHz DDR2 memory modules (unfortunately they did not stock any 533MHz ones) and replaced the oldest matched pair on the motherboard (the factory-default 256MB 400MHz ones). To my amazement, WoW did not crash as often as it used to!

Implications:
  • The factory-default RAM modules were borderline faulty! Naughty Dell; I never suspected until I started playing WoW.
  • Random files would fail to be read because different files would be stored in the faulty cell(s) in different times.
  • Restarting the computer empties the RAM (which is good if there is lots of junk in there).
  • Dalaran is probably the poorest-designed capital city in WoW to date. Not only does it have multiple levels (note the Sewers), it is also quite cramped and would concentrate so many players in its small area.

07 June 2009

Sir, there's a ghoul in my spreadsheet.

Gristlegut tries so hard to feed all his ghouls, but some of them end up being neglected. This poor soul soulless being, in its quest for BRAINS, ends up stumbling upon the tasty cells of a living being spreadsheet. The uni student working on this for their matrices assignment will be very frustrated indeed.

04 June 2009

Random Ramblings to 19 June 2009

Body Mass Index (BMI)
A ratio which quickly indicates body mass. It is calculated by dividing the mass of the body (in kilograms) by the square of the height of it (in metres). A body's mass is considered normal under the BMI if it falls between 18.5 and 25; any less and it is considered underweight, while any more is considered either overweight or obese.

Foreign Currency Conversion Fee/International Service Assessment
The fee charged to credit card issuers by MasterCard and Visa respectively when a credit card transaction uses the global payments system to convert currency. For both companies, it is equal to 1% of the value of the transaction. Of course, the credit card issuer can pass this fee on (and add up to 2 extra percentage points onto it) to the cardholder.

Icosahedron
A solid figure with exactly 20 faces. In particular, a regular icosahedron is an icosahedron with faces of equilateral triangles. It belongs to a family of solids called the Platonic solids. A d20 die is in the shape of a regular icosahedron.


A model of a regular icosahedron made of toothpicks and Blu-Tack.

Pyrite
A mineral consisting of iron disulphide (FeS2). It has a lustrous brass-yellow colour and has been mistaken for gold (hence it it also known as fool's gold). Its molecules align to form an isometric crystal system. When struck against steel it creates sparks, hence its name's etymology of the Greek word for fire.

Res judicata
Translates to "something decided" from Latin. It is a principle in civil law stating that a single court case (in governments with a court system) may be heard and decided only once. It emphasises the finality in such litigation and avoids the problem of a defendant's being sued multiple times for the same matter. Criminal law has a similar principle of double jeopardy, where the defendant cannot be tried multiple times for the same crime.

Tragedy of the commons
A theory relating to resources that are freely available but can deplete (or "the commons", the British expression for open pastures). It states that such resources will continue to be exploited until it becomes fully depleted). It is a tragedy because the rational use of private cost-benefit analysis (where every individual has different of costs and benefits of using the resource) will produce such undesirable consequences. Hence support for the concepts of ownership and private property, in such a case cost-benefit analysis will be uniformly applied.

01 June 2009

Random Ramblings

Small tidbits of information are always interesting. This regular feature will record much of the trivia I have presented to my guild in World of Warcraft. So far:

32-bit signed integer
A sequence of 32 binary digits which represents a positive or negative whole number. 31 of those digits determine the number, while one digit determines the sign (positive or negative status). A 32-bit signed integer can represent 2^31 = 2 147 483 648 unique positive values. The amount of currency a World of Warcraft character holds is stored on Blizzard's databases as a 32-bit signed integer, leading to the fabled currency limit of 214 748g 36s 48c.

Adverse opinion
An auditor is a person who provides a professional opinion on the quality of a business' financial statements. When they provide an adverse opinion on the financial statements (which is normally unheard of), they are saying that the financial statements are any combination of inaccurate and poorly prepared.

Black hole
All bits of matter are attracted to each other through gravity. The larger a mass is, the more gravity it will generate. A black hole is a mass generating gravity such that the escape velocity (the speed which exactly absorbs the opposing acceleration of the mass' gravity) is greater than the speed of light (299 792 458 m/s). Their namesake comes from the fact that not even light can escape the gravitational pull of a black hole, leading to their black colour.

Carbohydrate
An organic substance which stores energy for metabolism. They are made up of carbon, hydrogen and oxygen, which, when a photosynthesising plant produces it, is come from carbon dioxide and water. Respiration breaks the carbohydrate down back to carbon dioxide and water, though some energy is released as well (which was formerly sunlight energy). Carbohydrates are composed of any number of saccharide units chained together. Monosaccharides (glucose, galactose, fructose, etc) are saccharide units in themselves, while disaccharides (sucrose, lactose, etc) are composed of two such units, and complex carbohydrates (starch, glycogen, etc) consist of many.

Diminishing marginal returns
A trend in the relationship between two values where the main value is (say X) increasing. At the same time, the other value (say Y) is also increasing, though its rate of increase is declining. It is possible for X to be large enough that Y can even be decreasing. In calculus terms, d2Y/dX2 is negative.

Fluorescent lamp
A light source that produces light through the fluorescence of phosphors on its discharge tube's surface. When it is operating, an electric current passes through the tube. Molecules of mercury (Hg) gas are excited by the current, which later release ultraviolet light. The phosphors then absorb this ultraviolet light, later releasing visible light. Fluorescent lighting is commonly used as backlighting for LCD monitors, explaining why many laptops are marked as containing mercury.

Induction motor
An electric motor which uses an alternating current to produce motion (namely in a rotating manner). A rotating magnetic field produced by the current pushes a set of magnets attached to a rotor. It is the foundation for all things that spin and use electrical energy to do so (fans are a notable example).

Natural law
Principles that arise from the workings of nature. As nature encompasses the entire universe, such principles are accepted to apply everywhere. Natural law is often used as a benchmark to judge the validity of positive law (law enforced by the authority of government) and is thought to inform a person's conscience.

Prisoner's dilemma
The problem that arises from the cooperation (or lack thereof) between two persons for a reward. If one person chooses to defect from the arrangement, that person will receive a higher reward than if they had cooperated, at the expense of the other person. However, if both defect from the arrangement, both will receive less reward each than if both had cooperated. Under these circumstances, both players are selfish, there is a limited amount of reward and defecting entails a certain cost (which the defecting person hopes that an increased reward from defecting will offset). The namesake arises from the classic scenario involving the silence/confession of two partners in crime.

Guildies, if there are any topic arisen you would like me to cover briefly here, just post a recommendation in the comments.

30 May 2009

Succeeding at left and right

The Thaddius encounter involves lots of movement, though its principle is very simple. Reviewing the guild's convention:
  • Facing the boss from the entrance, positively charged people go to the right.
  • Facing the boss from the entrance, negatively charged people go to the left.
  • When changing sides, stick to the left side while you are approaching the other side. This will only be necessary for as long as people react slowly to Polarity Shifts.
My mnemonic for the first 2 points is the mathematical convention for number line graphing. The positive direction is right from the origin, while the negative direction is left from the origin. My mnemonic for the 3rd point is Australian road rules. Keep at the left side of the road!

The hardest part of Phase 2 is figuring out which side you are supposed to go to for the first Polarity Shift. Get ready to change sides if you need to. Facing the wall helps, as this helps orient you according to the left and right directions.

Polarity Shift is then cast. You have 4 possible consequences:
1. If you are at the left, and you are positively charged, you switch sides.
2. If you are at the left, and you are negatively charged, you stay.
3. If you are at the right, and you are positively charged, you stay.
4. If you are at the right, and you are negatively charged, you switch sides.

Provided you take the right course of action, it is smooth sailing until the boss down. Simply change sides when your polarity changes. No more worrying about positives and negatives!

Originally posted here.

Don't slack off during the Thaddius encounter!

Aim: To calculate the drop in DPS of a single death in Phase 2 of the Heroic Thaddius encounter, subject to certain assumptions. To observe the change in total raid DPS as additional dps die.

Summary:
  • The minimum personal DPS needed to down Thaddius in time is 2186 DPS.
  • The total personal DPS is 100% average DPS + 115% bonus DPS from charge buff OR 215% of average DPS.
  • A 1-stack of the charge buff grants 218.6 DPS.
  • A single death of a healer drops total raid DPS by 1748.8 DPS, while a single death of a dps drops total raid DPS by 6230.2 DPS.
  • While DPS continues dropping as additional dps die, its rate of decline is decreasing.

The given:
  • Raid composition: 2 tanks, 7 healers, 16 dps.
  • Raid positioning: 12.5 players on each side of Thaddius, each side having 8 dps.
  • Thaddius' health: 27 600 000 HP.
  • Enrage timer: 360 seconds (6 minutes)
  • Average size of stacking group: 12.5 players.
  • Average stack of charge buff among dps: 11.5 stacks. This gives a damage boost of 115% of average personal DPS.
  • Healers do not dps, tanks do minimal damage (in this scenario, VERY minimal).
Detail:

The figure that will be used as the average personal DPS, fully buffed, is the minimum personal DPS needed to down Thaddius before the enrage. The total raid DPS is:
27 600 000/360 = 76 666.6666... DPS

The total personal DPS is:
7666.6666.../16 = 4791.6666... ~ 4700 DPS (attribute the extra 91.6666... DPS to the tanks :))

Total personal DPS is:
100% average DPS + 115% bonus DPS from charge buff (decimal 1.15) = 215% of average personal DPS (decimal 2.15)

The average personal DPS is:
4700/2.15 ~ 2186 DPS

That means the bonus DPS from the charge buff is:
4700 - 2186 = 2514 DPS

A 1-stack of the charge buff grants:
2514/11.5 ~ 218.6 DPS

Consider the death of a healer. That removes a 1-stack of the charge buff off the 8 dps on their side. So, the drop in DPS from that death is:
218.6 x 8 = 1748.8 DPS. That's about 524.6k damage over 5 minutes lost!

Consider the death of a dps. That removes the dps' total personal DPS plus a 1-stack of the charge buff from each of the 7 dps on their side. So, the drop in DPS from that death is:
7 x 218.6 + 4700 = 1530.2 + 4700 = 6230.2 DPS. That's about 1.87M damage over 5 minutes lost!

To observe the change in DPS using calculus, additional deaths will need to be considered in pairs (one dps from each group will drop total raid DPS by equal amounts) and we will assume that only the dps die. The change in total raid DPS from the first pair of deaths is:
-6230.2 x 2 = -12 460.4 DPS

Calculating the incremental changes in DPS from additional pairs of deaths, we get the following progression of values:
-12 460.4, -12 023.2, -11 586, -11 148.8, ...

This is in fact an arithmetic progression with common difference of 437.2 and first term of -12 460.4. Total DPS lost from n pairs of deaths will be the following sum of values:
S(n) = 218.6n^2 - 12 679n

Differentiating S(n) with respect to n:
dS(n)/dn = 437.2n - 12679. Since the first derivative is negative over the domain 0 < n < 8, S(n) will continue dropping.

Differentiating dS(n)/dn with respect to n:
d2S(n)/dn2 = 437.2. Since the second derivative is always positive, S(n) is decreasing at a decreasing rate.

We have the following trend:


Originally posted here.