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andrewf

2,287 karma · joined August 1, 2007

{firstname}@sullust.net (checked every week or two) github.com/andrewffff
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andrewf··on Performance Hints
Level 1 data cache
andrewf··on Getting bitten by Intel's poor naming schemes
>"it affects Blizzard Creek and Windy Bluff models'

"Products formerly Blizzard Creek"

WTF does that even mean?

andrewf··on Sick of smart TVs? Here are your best options
Example: https://news.ycombinator.com/item?id=2509967 (the original source is gone and not in the Wayback Machine)
andrewf··on The stack circuitry of the Intel 8087 floating point chip, reverse-engineered
This is nuts, in the best way.

The operand fields of a WTL 3167 address have been specifically designed so that a WTL 3167 address can be given as either the source or the destination to a REP MOVSD instruction. [

Single-precision vector arithmetic is accomplished by applying the 80386 block move instruction REP MOVSD to a WTL 3167 address involving arithmetic instead of loading or storing.

andrewf··on Cloudflare outage on December 5, 2025
Quickly Googling about, a commonly repeated figure is that Akamai served 15% - 30% of Internet traffic in the late 2010's. They probably have less of the market today due to others growing, but they're not a minnow.

2024 revenue figures were $1.669 billion for Cloudflare, and $3.99 billion for Akamai, per Wikipedia.

andrewf··on DOOM could have had PC Speaker Music
Also all the sound stuff was outsourced! id hired Bobby Prince to make the music and licensed a playback library which seemed to have enough problems already with the supported sound cards. https://doomwiki.org/wiki/DMX

So they'd have had to extract this feature from a vendor where the relationship is already breaking down, or ditch it all and start from scratch with a new vendor, or inhouse code.

andrewf··on How Quake.exe got its TCP/IP stack
https://github.com/othieno/GPBB - the last chapter is a Quake retrospective.

There's also the columns he wrote for Dr Dobbs' Journal during development. They're like an expanded, illustrated version of GPBB chapter's first half. https://www.bluesnews.com/abrash/contents.shtml

andrewf··on What happened to Transmeta, the last big dotcom IPO
At the time I recall https://dl.acm.org/doi/pdf/10.1145/301631.301683 being an oft-discussed data point - speeding up DEC Alpha code by recompiling it into different DEC Alpha code using runtime statistics.

This was commonly cited in forum debates about whether Java and C# could come close to the performance of compiled languages. ("JITs and GCs are fast enough, and runtime stats mean they can even be faster!" was a common refrain, but not actually as true in 1999 as it is in 2025)

andrewf··on Direct File won't happen in 2026, IRS tells states
I'm just happy that, after years of not doing so, MS started correctly reporting the cost basis of vested RSUs on the 1099. (It should be the same as the amount reported as W-2 income).

I definitely feel the RSU grantors are the customer here, not recipients like you or I.

andrewf··on I'm making a small RPG and I need feeback regarding performance
Firefox runs the game well on the Mac, while the Neutralino build (presumably using the WebKit shipped with Safari) experiences some performance issues. Can you replicate the performance issues with Safari? If so you might be able to glean some insights from https://webkit.org/web-inspector/timelines-tab/

When profiling, it can often be useful to compare profiles of "working well" versus "not working well". So you could record a 10 second timeline when things are going smoothly, then a 5 second timeline when perf is bad - things that jump out on the second timeline are worth looking at.

andrewf··on Direct File won't happen in 2026, IRS tells states
Morgan Stanley at Work seems to track wash sales. Last year I had two vests in May, one week apart. I'd instructed the brokerage to sell some of those shares on vest. On the first date, I experienced a capital loss (less than $20), due to price movement between the RSU vesting and the broker selling the resulting stock. This was reported on the 1099B as a disallowed wash sale due to my acquisition of more stock with the second vest a week later.
andrewf··on AOL to be sold to Bending Spoons for $1.5B
My guess is that's indicative of the price Bending Spoons paid - they get a positive return on investment if they collect existing subscription revenue, and do a bit of work which keeps the existing userbase happy.

Under the previous ownership, the gap between Evernote's valuation (ie what investors had put in) and revenue (what investors would getting back) was so great that just surviving wasn't a strategy; the business could only value the existing userbase and product as a starting point for building a much larger userbase. That's a path to enshittification.

andrewf··on Carmack on Operating Systems (1997)
He mentions https://en.wikipedia.org/wiki/Rhapsody_(operating_system) in the NeXTSTEP section, which was a stepping stone to OS X.

Windows stuck as the id tooling platform. I'm guessing by the time OS X was relevant, id Software had grown and all the tooling that would've benefited from Interface Builder was maintained by different folks. And Carmack was focused on getting the most out of various graphics cards, where Win32 drivers were both the cutting edge and what consumers had.

andrewf··on Public trust demands open-source voting systems
Australia hand-counts. In a federal election, a voter will typically cast a preferential vote for the lower house, and a more complicated proportional vote for 3 senate seats. Rarely, they'll vote on 1 or 2 propositions ("referenda"). This seems comparable to a federal US ballot (first-past-the-post votes for house/senate/president).

The US casts 10 times as many votes - so it seems reasonable for the US to hire 10 times as many poll workers? Hand-counting is O(n) i.e. constant per-capita, and it scales horizontally.

Local and state ballots in the US can feature tens of elected positions and propositions, I could imagine hand-counting them to be quite expensive.

andrewf··on Reverse engineering the 386 processor's prefetch queue circuitry
This is the same fellow who reverse engineered and cloned the Sound Blaster. https://blog.adafruit.com/2019/02/05/the-snark-barker-a-soun...
andrewf··on Apple’s Darwin OS and XNU Kernel Deep Dive
This presumes that Apple brought in Jobs as a decision maker, and NeXTSTEP was attached baggage. At the time, the reverse was true - Apple purchased NeXTSTEP as their future OS, and Jobs came along for the ride. Given the disaster that was Apple's OS initiatives in the 90s, I doubt the Apple board would have bought into a Linux adventure.
andrewf··on Go Optimization Guide
https://github.com/golang/go/blob/master/src/sync/pool.go#L2...

The GC calls out to sync.Pool's cleanup.

andrewf··on IronRDP: a Rust implementation of Microsoft's RDP protocol
That might practically be where VNC finds usage today, but when it was introduced in the 90s, remote desktops were the intended use case.

"In the virtual network computing (VNC) system, server machines supply not only applications and data but also an entire desktop environment that can be accessed from any Internet-connected machine using a simple software NC." -- https://www.cl.cam.ac.uk/research/dtg/attarchive/pub/docs/at... (1998)

andrewf··on 400 reasons to not use Microsoft Azure
Links in the original are dead but I think this is the Microsoft doc on “what could Windows do better” - https://web.itu.edu.tr/~dalyanda/mssecrets/hotmail.html
andrewf··on You don't link all of Libc
I think NT syscalls can change. https://j00ru.vexillium.org/syscalls/nt/64/

You're meant to go through ntdll.dll, but even that interface is documented as private/unstable.

andrewf··on Ask HN: Former Employees' RSUs at Risk After Startup's IPO
I'll add that, the original post says the vest date was in 2024 but the settlement date is in 2025. I'm a little surprised (but I'm not an expert!) that your taxable event is in 2025, rather than occurring on the vest date at that date's FMV. Generally the "vest" event is the point past which you have no (per some complicated definition) threat of forfeiture... but the company is threatening to forfeit the shares pending conditions...

In your shoes I'd be seeking an accountants' advice re: (1) do you already owe tax on these shares for tax year 2024? (2) if you don't take receipt of the shares for some process reason, might you still owe taxes on them?

Sorry you're going through this, I hope it's worth it in the end.

andrewf··on Ask HN: Former employees' RSUs at risk after startup's IPO
(Again, not an accountant, I repeat that because I might be wrong and I'd hate anyone to suffer because of that..)

There are a couple of different risks here. One is that you pre-pay the company for more than the FMV ends up being; it sucks, especially with interest rates being as high as they are, but you'll get the money back with your tax return filed next year.

A different risk is that the price is spiked high at the moment the FMV is determined, and then falls before you're able to sell the stock. This would leave you with a short-term capital loss which you'd only be able to claim back at $3,000/year - https://www.irs.gov/taxtopics/tc409#:~:text=If%20your%20capi... - unless you have other short term capital gains in the same year to offset it against.

Has the stock been volatile since the IPO? How does the daily trading volume compare to the number of shares that will exit lockup on 3/15? If I were in your shoes that would inform my evaluation of the risk.

andrewf··on Ask HN: Former employees' RSUs at risk after startup's IPO
On point 3 specifically: I work for a FAANG, and the employees need to nominate the percentage the company should sell-to-cover, they don't figure it out for you. If you're no longer employed by the company I don't know _how_ they'd figure it out. If RSUs are still W-2 income for a former employee (I don't know this?) it's the extra tax you'd pay on that much income - for me I estimate using the tax bracket it'll pull me into, plus any other applicable federal taxes (medicare, additional medicare, social security). They may need you to cover state taxes as well?

I'm not an accountant, you shouldn't rely on this post, and I don't know if/how you might get screwed on the other points.

andrewf··on Open source AI: Red Hat's point-of-view
GPL v2 and earlier let you charge distribution costs (v3's language is more complicated). In the late 80s you could order an Emacs tape from the FSF for $150, which is about $430 today!
andrewf··on How shut-down Bay Area tech companies ditch their fancy gear
The "private planes" were liquidated from https://en.wikipedia.org/wiki/Universal_Hydrogen - "The company's main product was intended to be a conversion kit to be retrofitted to existing aircraft to allow them to run on hydrogen fuel."

The "massive 3D printer" was liquidated from https://en.wikipedia.org/wiki/Local_Motors - "was an American manufacturing company focused on low-volume production of open-source vehicles and other products using multiple microfactories."

If an investor accepted the premise of the companies, these don't sound like outrageous assets to own.

andrewf··on People are bad at reporting what they eat. That's a problem for dietary research
I worked on calorie counting software in the 00's. We had desktop software that just used floats, meanwhile the Palm Pilot software was all integer math (counting things in 10ths and 100ths when that precision was needed.)

We'd get emails about people seeing 577 calories on the Palm Pilot and 578 calories on the desktop. "None of the numbers are that accurate anyway!" was a sensible answer but not very brand aligned.

andrewf··on I am (not) a failure: Lessons learned from six failed startup attempts
I think compared to 15 years ago there's (1) more capital (2) more founders [enabled by better tooling and well-known implementation patterns] (3) less low hanging fruit on the product side. Any given opportunity is more likely to have other, well-resourced, folks chasing it hard.
andrewf··on Red Hat Woos VMware Shops with OpenShift Virtualization Engine
AT&T sued them. https://www.ciodive.com/news/broadcom-att-vmware-settlement-...
andrewf··on Mistakes engineers make in large established codebases
Putting this in my web console:

  let susJsonString=JSON.stringify(JSON.stringify(JSON.stringify({foo:1})))
  console.log("initial:", susJsonString);
  try { 
    while(typeof susJsonString==='string') {
        susJsonString = JSON.parse(susJsonString);
        console.log("iteration:", typeof susJsonString, susJsonString);
    }
  } catch {
    susJsonString = {};
  }
I see:

  initial: "\"{\\\"foo\\\":1}\""
  iteration: string "{\"foo\":1}"
  iteration: string {"foo":1}
  iteration: object {foo: 1}
A comment explaining the sort of "sus" input it was designed to cope with may have been helpful.
andrewf··on CRT Simulation in a GPU Shader, Looks Better Than Black Frame Insertion
I think some OLED displays don't have backlights?

On manipulating the backlight to display a dark scene more power-efficiently: my TV that does this, if there's a small region of constant color (e.g. a TV station's logo) its brightness wavers noticeably as the rest of the scene changes.

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