25 December 2015

Trip Down Memory Lane

I got into building my own computers when Nvidia announced support for GPGPU on their G80 chipset (think GeForce 8800GTS/GTX/Ultra). Good times in 2008.

My one-upping started after this fellow rubbed his Core i7-920 in my Core 2 Quad Q9550's face. Game on! But really, I didn't have the funds or the knowledge to beat that.

Then a good friend Bayley showed up at MIT, and things got serious reasonably fast. In particular, my upgrade path looked something like this:
  • Core 2 Quad Q9550 4-core/8GiB DDR2
  • Some Intel Xeon W35xx 4-core/24GiB DDR3
  • 2x Intel Xeon X5650 6-core/24GiB DDR3
  • 4x AMD Opteron 6164 HE 12-core/128GiB DDR3 ECC
Then Bayley and I both realized that we had to switch to rackable computers for any sort of ease in managing hardware. I took a break from single-image systems and built half a blade server:
  • 2x Intel Xeon L5320 4-core/8GiB DDR2 FB-DIMM
While Bayley got a Sun Box®:
  • 8x AMD Opteron ??? 4-core/128GiB DDR2 ECC
In a valiant attempt to dethrone me, he patched the Sun's BIOS with the microcode for hex-core CPUs, but the computer only recognized one core of one processor of the eight that he put it. Much wow.

My AMD box cemented 1st place in sheer awesomeness for student-owned computers for a little over a year, until Bayley discovered mainframes on eBay:
  • Some IBM thing with 16x Intel Xeon E75xx 6-core/256GiB DDR2 ECC
Mind you, I have cemented awesomeness density, since my AMD box fits perfectly in 1U, while Bayley's monstrosity needs 16U, and a whole lot more power. :-) Not to mention that it blew a circuit breaker while trying to install Ubuntu…

Leave it to me, my worst enemy, to dethrone myself. I wanted to repackage the AMD box into a legitimate 1U chassis that I found on eBay for not too much money, since it had sat on a piece of cardboard (for insulation!) atop the dorm dresser. After the computer happily booted in the chassis, I jiggled one of the unscrewed heatsinks and shorted the motherboard. A nice spark flew from a voltage regulator to the copper heatsink and poof!

gg no re Bayley


There's also a GPU story, which I shall not neglect. I went to MIT with my trusty aforementioned 8800GTS 320MB. A few swapfests later, Bayley wound up with a quartet of GTX 460s. It was mainly used for benchmarking Holy Balls, a demanding multi GPU raytracer, and got really toasty after a while. Good old Fermi.

The cryptocurrency scene started getting traction with the advent of profitable scrypt-coin mining. AMD cards were far superior in hashes/watt and competent in hashes/sec. Bayley got his hands on a few AMD 7850s, the preferred mining card, among other cards. I went extra long and got 11 cards from various sources (newegg, eBay, etc) since retailers caught on to the mining demand. Luckily I was able to dump my cards at cost (after eBay commission) after Mt. Gox blew and before everyone else wanted to dump their cards. Bayley kept mining, and even upgraded to 7950s as well as a 6990 when prices decreased and good deals appeared.

But wait, I'm back! I had the privilege of acquiring a new Mac Pro (affectionately known as the "trash can") with dual AMD D700 graphics cards. For all intents and purposes, they are two workstation grade cards (think neutered W9000s), each with 6GiB VRAM. So I can confidently say that I retake the GPU crown.


Meanwhile, with the abundance of swapfests at MIT, Bayley acquired multiple storage nodes for not too much money (and the networking infrastructure to back the system). To top that, he accidentally won half an SGI Altix and soon to be the glorious 1TiB of RAM on eBay.


GiB and TiB stand for Gibibytes and Tebibytes, because I'm anal and care about these distinctions.

20 December 2015

Car Mods III

After my first track weekend, I've learned a bunch about driving and a few things about mods. I'll start with mods since the list is shorter:

One of my instructors had a 991 C2S with Michelin Pilot Sport Cup 2s (R-compound tires, or semi-slicks). He claimed he could easily do 2:08s, which is about on pace with a 997.1 GT3 RS. I'm sure he was also running track brake pads, since R-compounds generate more heat than street tires. If I went this route, then my upgrade path would look like:
  1. Brake pads
  2. 19" rims
  3. Michelin Pilot Sport Cup 2s

The unfortunate thing about the Pilot Sport Cup 2s is that Michelin does not make them for my 18" rims (235/40 front, 265/40 rear), but they are available for the 19" rims (235/40 front, 295 or 305/35 rear). Then that's at least $1k for the rims, and $2k for a set of tires after tax. I also looked into Pirelli's P-Zero Trofeo Rs, which are available for my 18" rims and cost only $1.4k a set after tax. As for functional differences between the two tires, the Michelins offer less peak grip at 1.6g vs 1.8g, but the transition to sliding is more gradual at the limit than the Trofeo Rs. As for practical considerations, the Michelin has more treadwear, and has a reasonably long life expectancy. It is classified in a lower penalty group in autocross car classification.


I had one last track day this season with Hooked on Driving (HoD) at Thunderhill again. I improved my exit speeds on average, and greatly improved my entry speeds on T10 and T11. Overall, I was able to cut my best time by 6 seconds down to 2:21.xx. A huge difference between the Porsche Club (PCA) and HoD is that HoD puts turn-in and apex landmark cones on the track, while PCA doesn't. I agree with PCA that cones should not be present so that drivers develop their own references instead of relying on a temporary object that can get knocked out of position. However, they're really helpful and reinforced several of the turn-in points for me.

Carrying more speed through turns means that I'm falling out of my seat more and more and devote more energy to bracing myself. In particular, my left leg was super sore by the end of the day from standing on the dead pedal in turns. I've been researching various aftermarket race seats, specifically the halo-style seats (wraparound head support). Fitment is done mostly by hip width, so the driver is held securely in place, even with a standard seatbelt. A decent seat is also only $1k, and can be swapped into another car if I choose to run another vehicle.

I think I'll stick with the 3-mile Thunderhill course for next season, and explore other local tracks for the 2017 season, and at the earliest, the end of 2016 season. At my HoD day, I ran with their B group  (intermediate) for two sessions with my instructor, and felt pretty comfortable. I'm running at a mid-pack or slightly below median pace. With a bit more practice, I should be high B by the end of 2016, perhaps low C. For now, I'm hesitant about point-by passing nearly everywhere because it sounds scary, and am afraid that other people in the run group will dislike my conservative point-bys.

As for brake pads, I don't see any reason to upgrade. The car has 0.5g of deceleration during hard braking, and I haven't had any heat issues yet. Given that I won't upgrade the engine power anytime soon (car is plenty fast), I won't need more braking force to compensate. Same for rotors -- larger rotors in theory can better dissipate heat due to more surface area, and lots of heat may cause rotor warping, which also hasn't happened yet.

I will keep the suspension stock as well for the upcoming season. When I get better at discerning different adjustments, I'll consider adding a GT3 sway bar and adjusting camber/toe.


That's all for now. Here's to a safe and fun 2017 season!

27 September 2015

Health Insurance Gaps

I had been worried whether I should take COBRA health insurance coverage before my new policy becomes active, despite the fact that I most likely (P > 3sigma) won't need it. It turns out that if I have a gap in coverage less than three consecutive months, I won't have to pay any penalty.

For the curious, the penalty is prorated on a monthly basis, but billed yearly. For FY2015, one pays max(2% income above filing threshold, $325). The penalty increases in FY2016 to max(2.5% income above filing threshold, $695).

[1] http://healthinsurance.about.com/od/Penalty-Exemption-Uninsured/fl/9-Things-to-Know-About-the-Shared-Responsibility-Health-Insurance-Penalty.htm

31 August 2015

"I'm a car guy and it was a dream of mine."

So, how do young'uns (~new college grads) afford supercars?

As one involved in the local car scene, I've seen some number of folks around the same age as I who have pretty nice cars. Two weekends ago, I was at the Cars and Coffee at Santana Row and saw a guy who has a new BMW i8, which nominally lists for $135,xxx before taxes, fees, and dealer markup.

Consider the average new-grad (with well-off parents, so no student debt) who gets an offer at a big tech company, say, Hooli. The typical full time offer is $100,000 base salary, $15,000 sign-on cash bonus, an estimated $33,000 (63 shares) equity bonus paid at the end of the first year, and a projected $15,000 year-end cash bonus. Take home from the salary after tax and with the tax refund is around $75,000. Bonuses are taxed differently (roughly 50%), so that's approximately $16,000 from equity and $15,000 from cash bonuses. Since the tax refund, equity, and year-end bonuses are not received until the ~end of year 1, we only have $67,500 after tax with which to work, or approximately $5,625 each month.

As for costs, let's assume we live in Silicon Valley. We will garage our supercar, and apartments with garages don't come cheap. To cut costs, we'll split a 2-bedroom with a roommate, which should run around $4,000/month including bills, so $2,000/month each. Since Hooli provides free food (albeit not the best), we only need to cover meals on weekends. Assuming we eat $100/weekend, that's $400/month. Car insurance will probably run $350/month [1]. Amortized maintenance is about $250/month, though some makes such as BMW provide free maintenance. If we assume an average of 15,000 miles driven per year, 15mpg, and $3.75/gal, then that's $3750 in gas per year, or $312 per month. So far, we have $2313/month remaining.

For the BMW i8, which lists at $135,xxx, BMW quotes a lease of around $1,7xx/month for 3 years/30,000 miles with a $7,500 down payment (but before any incentives -- governmental, in this case). Add taxes and fees, that $1,7xx balloons to approximately $2,000/month, which leaves around $300/month for miscellaneous, or maybe even savings!

Other exotics in this price range (≤ $125,xxx), as of Aug 2015:
  • Various Porsche 911 Carreras
  • Jaguar F-type R
  • Maserati GranTurismo
  • Audi R8 V8
  • Various used Aston Martins
  • Various used Bentleys
  • Used Ferrari California or 430
  • Used Lamborghini Gallardo
  • Used Audi R8 V10
  • and more.

Now, let us expand our population to include those with student loans. The MIT Student Financial Services department reports that 40% of students have a loan, 32% are tuition-free, and 28% paid some tuition but didn't take out loans. The average cumulative debt for a student who graduated in 2012 is $20,800, so assuming that it grows at 6% yearly, would make approximately $26,500 for a student graduating in 2016. So we must resolve that before indulging.

The average new grad who gets a full-time offer at Hooli usually received an internship in the year preceding. These pay around $7,000/month now, which makes $21,000 for the summer. After 40% taxes and deductions, that's around $12,600. Add back a 15% tax refund, and your total is $15,750.

The sophomore year internship is usually less glamorous, if anything. These pay around $5,000/month now, which makes $15,000 for the summer. After the same tax calculation and adding the tax refund, your total is $11,250.


Now, the effective income from these two internships is barely enough to cover the average student loan. What about some less common ways to earn income?
  • Getting an on-campus job (i.e. research, tech support, teaching assistant) or externship during the semester or during winter break
  • Finishing your degree in fewer than 4 years, and maybe starting work early
  • Running an independent consulting firm given solid background knowledge
  • Tutoring other students at your college or at a nearby college
  • Contracting for a `sharing economy` company, e.g. ride-sharing, Handy, Fiverr, TaskRabbit
  • Collecting donations or subscriptions from running a popular twitch.tv stream or Youtube channel
  • Trading (on more than just the equity markets)


There you have it: this is how a new grad can afford an exotic.

[1] http://www.car-insurance.com/price-07/2015-bmw-i8-14316-base_4wd_2_dr_coupe_i3-insurance-quote.html

[2] https://due.mit.edu/news/2012/undergraduate-student-debt-mit

26 August 2015

Shit Traders Say

A compilation of colorful, memorable phrases and zingers I heard people in this industry say (mostly buy side quantitative and algorithmic traders) over the years. Inspired by Fred Baba (MIT '10)'s post and ye old @gselevator. Enjoy!

"Let's make some money!" -Anon

"I think we're ready to make some money." -Anon right before the market opened

A: "CNBC says you should not open a family office with only $100 million. You should have at least $300 million."
B: "Do I look like I have $300 million?"
A: "I dunno"

"Oh that's right, I'm already fat." *drums belly* -Anon

"Sushi doesn't spoil. [few hours later] Sushi doesn't survive." -Anon

"How hard is it to order another five or six monitors?" -Anon

"Yeah, that's the monitor graveyard." *points to growing stack of monitors* -Anon

"How far along is your strategy from weaponization?" -Anon

"That bastard! I don't even think he knows what a symlink is! He's a N000B! With three zeros!" -Anon on outsourced IT

"What are the lucky and unlucky numbers in Asian cultures? I want to buy some Powerballs." -Anon on picking numbers on lottery tickets

"Everyone wants to jump in bed with [the head of research], but before you get to the sexy stuff you need to do some grunge work, like cleaning data." -Anon on data aggregation and cleaning

"Kinky bond math!" -Anon

"If there were a game in which I had a positive EV, I would be playing that [instead of sitting at my desk]!" -Anon

"Our long term goal is to take over the world, of course. Actually, only half, because someone else needs to be on the other side [of trades]." -Anon at a market making shop

"That's not appropriate lunch table talk; the interns are here." -Anon on trading strategies

"You work at a hedge fund now; you can pay." -Anon on splitting the check

"I just want to click buttons and make money!" -Anon

"I'm just too much of a type A for that kind of lifestyle." -Anon on "experiencing life" in the 20s

"One ought to enjoy life, really." -Anon on revving supercars in the dealer

"That's what you get for not making me PM..." -Anon on a job offer

"You don't want to be CTO; that's a tech role." -Anon

"I just wanna win, make some f*ck you money, and have my Porsche." -Anon (not yours truly!)

"Pok√©mon Driven Trading" -Anon on PDT Partners

On regressions:
A: "My regression looks promising!"
B: "What's the R^2 value?"
A: "NaN"
B: "LOL"

On historical data:
A: "What's the difference between 'C' and 'Call'?"
B: *shrugs* "I don't know; it's your data!"

On life goals:
A: "I will become God of this world."
B: "I will have more money than God."

"Screw bucket lists, let's be worth 8 figures and then we'll talk." -Anon

"When someone disappears, either they died or they joined Renaissance." -Anon on Renaissance Technology's 5-year noncompete

"Why do you want to ___? You could be making money instead." -Anon

On the uncertainty of Asian markets affecting US markets:
A: "Was today another ayyyyy lmao day on the markets?"
B: "Lol indeed"

A solicitor walks into the "trading floor"…
A: "Is anyone interested in free nights at a spa resort near Lake Tahoe?"
B: "How did you get in here?"
A: "The back door was open."
B: "[You] Son of a bitch…"

On Starcraft and home life:
A: "You don't have kids, you can practice Starcraft for 6 hours a day."
B: "But I have girlfriend!"
A: "Does she cook?"
B: "No I cook."
A: "Does she do the dishes?"
B: "Yes."
A: "Does she do the laundry?"
B: "Yes."
A: "Does she clean the house?"
B: "Yes."
C: "Sounds like you got the better trade."

"If you are long Bermuda shorts, is that a synthetic equivalent to being short pants?" -Anon

On the announcement of Ken Griffin's divorce settlement:
A: [quoting a comment from the internet] "Ken, from now on, just go the girlfriend route. Hard to weed out the gold diggers once you're past $50 million or so."
B: "Oh you mean the secretaries"

"I was out at dinner with a trader and his roommate. His roommate, who's in law, pays with a debit card. Trader pulls out his Capital One Platinum. I lay down my Amex Platinum." -Anon

"I think you should dump her. Not that interesting." -Anon on a candidate who kept rescheduling a phone interview

"Which animals' testicles have you eaten?" -PM on exotic foods

"Every time I walk by your desk, you have $1,000 in unspent money. Why aren't you spending your money?" -Anon on a game of StarCraft II

"My first instinct was to say 'if someone is thinking this, they probably have bigger issues to address in the first place.' But I once asked myself this in seventh grade, and then moved on with my life." -Anon on whether getting rich is worth the effort

On collecting cars:
A: "Have you considered collecting cars?"
B: "That's not how you stay married…"

"I don't live with 95% confidence intervals." -Anon

"I live and die by the 95% confidence interval." -Anon

"It is politically incorrect to suppress taking liquidity." -Anon

06 August 2015

Car mods II

Just kidding!

My Porsche-tracking friend says to keep my car mostly stock (with the exception of higher temperature brake fluid) and instead mod a track-focused vehicle, if necessary.

That's not going to happen for a while as:
  • The GT3 markets for all generations are extremely hot right now (waiting for bids to go away).
  • The GT4 just hit the market.

If I do choose to pursue driving education as a hobby, I would splurge for a 991 GT3 or RS for the robot transmission and chassis improvements. Here's to hoping the Rennsport division at Stuttgart will keep producing naturally aspirated GT3s!

Also, Ultraviolet is undeniably a cool color:

I also heard through the grapevine that (1) the new power height-adjustable bucket seats aren't swappable and that (2) dealers actively discourage customers from ordering cars with buckets, so finding one with buckets at a reasonable price sounds challenging. The problem with the current non-height adjustable buckets is that they sit too closely to the floor for me so as to obstruct my outward vision. I've also been actively researching how to raise the seat height with different side brackets.


Of course, these upgrades are predicated on demonstrable improvement measured at events. Currently I'm just running with PCA. I might consider Hooked on Driving when I have more experience.


As always, tips, tricks, and anecdotes are welcome!

04 August 2015

Car mods (future planning)

Jotting down notes about what to do about the car after I get sufficient track and autocross (AX) experience. I'm planning on sticking with the rear engine platform for the near future -- sorry mid-engine friends! Mostly basing my trajectory on that of my friend edmack:

0. Brake fluid

I'm going to Thunderhill raceway in a couple of weeks and Willows, CA is going to be extremely (perhaps unbearably warm), so high temperature brake fluid will probably be good.

N.B. What happens if your brake fluid is rated at too low of a temperature? After sufficient runs, your brake fluid will start to boil and then your brakes will not work, as in pressing or stomping on the pedal does nothing.

1. Brake pads

Probably Pagids. I hear this name frequently, if only from personal recommendations and the Panorama advertisements.

2. Big brake kit

Since I plan on sticking with 18" rims, mostly for the sake of cheaper tires, I can use at most 355mm front rotors (though I think I need to check the clearance of the caliper with the inside of the rim) and something smaller in the rear (maybe 332s?), if at all. Also I plan on using slotted rotors as opposed to drilled to decrease the chance of cracking.

My current brake pads are still barely worn (I'm pretty sure they're 8 years old!!!) so I might be able to get enough track experience to get the BBK with the upgraded pads; one must replace pads and rotors simultaneously.

3. R-compounds

Will probably go with Michelin Pilot Sport Cup 2s for street comfort, longevity, and performance. I plan on keeping the car street-legal for the near future.

4. Suspension

I'm new to various suspension geometries and parameters so will need to do a lot of research. I hear that the 911 (rear engine) platform tends to understeer because physics. Most of the weight is at the rear, so entering turns at sufficiently high speeds will cause the car to understeer.

5. GT3???

Now I'm just kidding myself (until I get a garage and more disposable income)!!!


As always, tips, tricks, and anecdotes are welcome!

15 May 2015

Fixing the power connector on Apple Cinema Displays (Aluminium)

Author's note: wiring done by dgorbik; writeup by yours truly

It turns out that after a while, if the power cable from the display is bent near the neck of the plug, the plastic clamshell over the plug will separate. Not only that, the cord will slowly stiffen and any bending motion will detach the wires, shielding, and epoxy from the metal connector. I have no use of a dead display (and am unofficially retired from the display-splicing scene), I gave my dead 30" Apple Cinema Display to my friend.

Not the 150W brick; they look similar. Source: Google Images.

It also turns out that the Cinema Display power connector looks very similar to that of the first generation Mac mini. Recall that the mini used an external 85W power supply, where one end was a reversible female 10-pin connector (2 sets of 5 pins) and the other end was an IEC Mickey Mouse connector. In fact, that 10-pin connector is, empirically, identical to the one used on the Cinema Display. I had one of those bricks so I gave it to my friend. He quickly cut both cables, revealing a red and black cables, and a thinner gray cable within the shielding.

Source: Google Images.

Simply color matching and soldering the cables didn't do the trick. My friend and I tried 3 different power bricks (150W), 3 different graphics cards, and 2 computers to no avail. Metering the donor cord appeared to give a bad reading, but turns out the wiring was backwards! (Tsk tsk Twiggy/Q88 team). So soldering black to red, red to black, and ignoring the gray wire worked.

Source: friend.