Hacker News Reader

minimaxon Learning to Read X86 Assembly Language

It also didn't have memory segmentation, otherwise known as The Worst Thing.

The examples in the post are clearly x86-64 running in 64 bit mode. I.e. it's running in flat model... there is no segmentation to worry about.

minimaxon 'Flash crash' trader loses US extradition battle

They claim he was spoofing trades... That's more the domain of HFTs, where you can automate the process, not a lone trader, however sophisticated.

They have him in emails literally saying things like "If I keep entering the same clip sizes, people will become aware of what I am doing rendering my spoofing pointless" and "I need to know whether you can do what I need, because at the moment I’m getting hit on my spoofs all the time and it’s costing me a lot of money."

It's not a huge reach for the government to claim he was spoofing when he himself claims he was spoofing.

How could a small trader like that possibly move enough volume to even budge the market as a whole, never mind crash it?

I think people who aren't familiar with trading (especially futures trading) don't understand that Sarao was spoofing massive size. He was placing orders for 500+ contracts at multiple levels in the book... that's on the order of $100M notional value. He was more of a pro than people like to believe.

minimaxon Ripgrep – A new command line search tool

In contrast, GNU grep uses libc’s memchr, which is standard C code with no explicit use of SIMD instructions. However, that C code will be autovectorized to use xmm registers and SIMD instructions, which are half the size of ymm registers.

I don't think this is correct. glibc has architecture specific hand rolled (or unrolled if you will lol) assembly for x64 memchr. See here: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/x86...

minimaxon Banks Sprint to Meet $493 Trillion Swaps Market Margin Rules

The collateral isn't limited to cash.

Eligible collateral for initial margin includes cash, debt securities that are issued or guaranteed by the U.S. Department of Treasury or by another U.S. government agency, the Bank for International Settlements, the International Monetary Fund, the European Central Bank, multilateral development banks, certain U.S. Government-sponsored enterprises’ (‘‘GSEs’’) debt securities, certain foreign government debt securities, certain corporate debt securities, certain listed equities, shares in certain pooled investment vehicles, and gold.

From here: https://www.gpo.gov/fdsys/pkg/FR-2015-11-30/pdf/2015-28671.p...

minimaxon 'Flash Boys' IEX stock exchange opens for business

On that case I think I agree with the Matt Levine take that "Back in September I was pretty sympathetic to DRW and after reading the CFTC's complaint. I'll double down on that.†" I guess we'll see what happens.

My only point was that some people think all HFT is bad, and here we have a complaint that actually the situation is reversed and it was actually all human market making that was bad. I don't think either statement is completely true, and I was trying to highlight the contradiction because the human market makers and the HFTs are, in a lot of cases, the same people.

† https://www.bloomberg.com/view/articles/2013-11-06/cftc-sues...

minimaxon 'Flash Boys' IEX stock exchange opens for business

Do you think when Don Wilson (founder of DRW) was making markets in the pits at the CME in the 80s that he was colluding with anyone is more what I was asking. Does he deserve to be labeled "crooked as a barrel of fishhooks?"

minimaxon 'Flash Boys' IEX stock exchange opens for business

What about all the human market makers that went on to found HFT firms. DRW, GETCO, Jump, Virtu, etc. Bad guys as well?

minimaxon 'Flash Boys' IEX stock exchange opens for business

I think labeling literally all human market makers as "crooked" is probably excessive...

minimaxon LendingClub CEO Resigns Following Loan Sales Review

There are no derivatives here. Jefferies was going to sell bonds backed by the loans. The payments on the loans would effectively flow directly to the bondholders.

A derivative (e.g. a CDS) would be more like a side bet between two (possibly unrelated) parties based on the performance of those bonds.

minimaxon The Impact of Index Investing: A Follow-Up

You are thinking about this wrong. The S&P 500 is a capitalization weighted index meaning the larger the market cap the larger the weight. If you constructed a total market index using the same capitalization based weighting scheme, you'd find the S&P 500 would account for about 80% of the index value. In that light it is actually pretty close to "the entire market."

minimaxon Why the NRA hates smart guns

I haven't tried obtaining a CCW in Chicago because the idea of wandering around Chicago carrying a gun seems totally ridiculous to me.

minimaxon Why the NRA hates smart guns

BTW, these people problems are the result of Democrat's policies in gun-free cities such as Chicago, St Louis, Oakland and Baltimore.

I don't know about the other three cities, but you can concealed carry in Chicago and that has been the case for almost three years now.

minimaxon Inside Equinix's NY4 data center where Wall Street trades

It's the same problem. Assume my GPS clock is synced to actual GPS. You turn on your spoofer and now my clock sees that the GPS source is running faster or slower than it should be so it falls back to the internal oscillator.

minimaxon Inside Equinix's NY4 data center where Wall Street trades

Any GPS clock you are going to find in NY4 is going to be sufficiently sophisticated to check the GPS signal against its internal oscillator in order to check for validity. It can fall back to the internal oscillator if the GPS time looks bad.

The other reason this is unlikely to be a problem is that network time protocols break all the time (oops someone did a maintenance and broke sync with the master clock). Lots of real world trading code has sanity checks on the time.

minimaxon Inside Equinix's NY4 data center where Wall Street trades

Or do! They closed the markets in the US for two days during Sandy even though NY4 (and the other US equity exchange data centers) were fine.

http://www.wsj.com/articles/SB100014240529702047893045780871...

minimaxon How gentrification really changes a neighborhood

The answer is a black person living in Atlanta in 1960. The American south of the 1960s was a place where cultural and institutionalized racism was alive and kicking. You should think about what a "rational" choice looks like under a system that is literally built to discriminate against and undermine an entire race of people.

minimaxon How gentrification really changes a neighborhood

Because you seem to be trying to establish some equivalence between Anna's circumstances and the author's. I think it's insulting. If I misunderstood the point you were trying to make I apologize.

minimaxon How gentrification really changes a neighborhood

I wonder if people like Anna moving in also felt the same guilt that the author of this piece does?

I didn't care for the article, but this comment is awful and you ought to feel bad about writing it. Did black people moving into an overtly racist white neighborhood in 1960s era Atlanta feel guilty about it? No, they were probably fucking terrified.

One day in June, a black family moved into a home on Woodbine Avenue, just over the southwestern Kirkwood border in Edgewood. That night someone set fire to it.

Did you read that part? Come on.

minimaxon Banning Some HFT Strategies Helped This Market Grow: Chart

Comments like these... they just show you have no idea what you're talking about. Investors are perfectly free to trade on the IEX ATS all day long in its current incarnation.

minimaxon Banning Some HFT Strategies Helped This Market Grow: Chart

Basically in their rulebook it says that all prop (as opposed to agency) flow must be passive, and if they find aggressive prop flow from a member they can terminate the membership.

The tie in to IEX is tenuous at best.

minimaxon The ETF Files: How the U.S. government inadvertently launched a $3T industry

One big factor in the success of these ETFs is automation (aka HFT). You don't get SPY quoted in size at a penny spread without the massive investments in research and technology on the part of the ETF market makers.

minimaxon Nanex Gets $700k Whistleblower Award from SEC

Yeah for a given price, fully hidden and the non-displayed portion of iceberg orders will be ranked (generally by time priority) behind any displayed shares. Most of the rules are meant to incentivize displayed size.

minimaxon Nanex Gets $700k Whistleblower Award from SEC

A U.S. equities exchange has to be registered with and approved by the SEC. There are currently 12 of them. As a registered exchange you have to play by certain rules, and in exchange your displayed top of of book is subject to the order protection rule, meaning that no other venues (exchanges, dark pools, ECNs, or broker dealers) are allowed to trade through your top of book quote without first routing an order to you for the full amount of the displayed size. Exchanges also get a share of SIP revenue (which is important to exchange economics).

In it's most technical definition, a dark pool is an ATS (specifically not an exchange) that has no displayed quote i.e. no market data whatsoever. Most ATSs in the US fit this definition, though there are also ATSs that display a quote. For example, IEX is an ATS that has feed for their top of book quote... so technically not a "dark" pool.

NYSE doesn't run a dark pool and it would be weird if they did. Most US equity exchanges support fully hidden (completely non-displayed) orders, so if you want to trade in the "dark" on NYSE you can just send a hidden order. I think this is one area where futures exchanges and equity exchanges differ. In futures you have icebergs but not fully hidden.

Wholesalers aren't allowed to give you a worse fill than the NBBO. That's the law. Often they will actually give you a tiny bit better than the NBBO on marketable orders. I think they do this so retail brokers can advertise price improvement. For most of the low cost retail platforms there is no ability to direct your order. You give it to the broker and I think basically if it's a marketable order they send it to the wholesaler and if not they post it to an exchange that offers a liquidity adding rebate (the brokerage keeps the rebate, natch). If you are willing to spend a little more on your brokerage account, you can use a platform like Interactive Brokers which does let you route orders directly.

minimaxon Nanex Gets $700k Whistleblower Award from SEC

This is almost right. NYSE and Arca are two separate exchanges (both owned by NYSE). Both exchanges offer FIX and binary gateway protocols. Annoyingly, the Arca binary protocol and the NYSE binary protocol are not the same protocol. NYSE does not suggest using the Arca gateway to access NYSE. They suggest you use a NYSE binary gateway to access NYSE.

minimaxon 'Flash Boys' Exchange Isn't About the Little Guy

One of the reasons that there are currently so many stock exchanges in the US is that while you aren't allowed to quote at subpenny levels, if you have several exchanges with different levels of make/take fees, you effectively have the ability quote (or remove liquidity) at subpenny price levels net of fees and rebates. In that scenario the proliferation of exchanges is less about competition and more about finding clever ways of negotiating the regulatory environment.

minimaxon A New Breed of Trader on Wall Street: Coders with a Ph.D

The pay in these sorts of articles is always overhyped. As with any business, the people making the most money at these kinds of firms are the owners of the firms. Consider this line

“As a trader, if you do well, you will retire before you turn 30,” said one employee on an industry message board.

That is basically 100% unattributed, unconfirmed bullshit.

minimaxon The Rise of Renting in the U.S

In the US, the 30 year fixed rate mortgage is the most popular type of mortgage by a wide margin.

minimaxon Glibc getaddrinfo stack-based buffer overflow

I think the other thing that changed is that branch predictors are roughly infinitely times better than they were in 1980. The is-this-subscript-ok check should be easily predictable and I wonder if these checks even cost anything in a hot loop on a modern CPU.

minimaxon How Low Can Central Banks Go? JPMorgan Reckons Way Lower

The rate difference only benefits hedge funds if USDJPY also plays along. That trade has fx risk and you're making it sound like a sure thing. If USDJPY goes the wrong way, the trade loses money and the average joe whose savings account is roughly flat looks pretty smart (in relative terms).

minimaxon How Low Can Central Banks Go? JPMorgan Reckons Way Lower

A leveraged fx position and an interest bearing savings account have very different risk profiles and it seems silly to compare the two.