jcalvinowens

6 ms·

31.
by jcalvinowens 5mo ago
My employers have generally been fine giving me blanket permission to contribute to specific open source projects. The framing matters: don't say "can I please do some charity work because it makes me feel good". Say, "c
32.
by jcalvinowens 5mo ago
Yet again my plans for a productive morning have been derailed by an excellent new write up from Dmitry :) That hand rolled DAC for the touchscreen with the eight gpio lines is hilarious.
33.
by jcalvinowens 5mo ago
How fun! I'm glad it was interesting, please feel free to link to it :)
34.
by jcalvinowens 5mo ago
This is fun, thanks for sharing. I have a much more minimalist one for x86 Linux if you want to see what that looks like: https://github.com/jcalvinowens/asmhttpd
35.
by jcalvinowens 5mo ago
I have a self hosting Pi Zero W running Gentoo. It started as a joke, but I kept it because it's actually occasionally useful for testing new kernel releases. I found a fun bug with it a couple years ago: https://git.kernel.
36.
by jcalvinowens 6mo ago
Arms races suck. I've managed to find a few L7 tricks to catch the residential proxies and serve them an empty 200, but there are obvious trivial workarounds on the other end and if I start talking about them in public they won't
37.
by jcalvinowens 6mo ago
Every few weeks I run my nginx access logs through a script that uses the same textual ASN database to tally them up and spit out a summary report. There are many different sources for periodic textual ASN databases you can parse with UNIXy
38.
by jcalvinowens 6mo ago
Yeah, I dont know how anybody stays sane without it. I have a list of over a thousand ASNs I blackhole at this point... Mine is a daily bash cronjob that fetches a text-based database and uses grep to build an nftables-apply script with all
39.
by jcalvinowens 6mo ago
I had to block meta's ASN on my personal cgit server a few weeks ago because they were ignoring robots.txt and torching it. Like hundreds of megabytes of access logs just from them, spread around different network blocks to clearly try
40.
by jcalvinowens 6mo ago
If you use the GPIO-based PPS on RT Linux, the kernel will soon get a nice improvement in jitter: https://lore.kernel.org/all/A0383FF7-267A-4D4C-9B74-F80B9908... I've been testing it and it is noticeably better, b
41.
by jcalvinowens 6mo ago
> Kernel LPEs are not rare. This was a particularly simple and portable one, but the underlying raw capability is a CNE commodity. I absolutely 100% agree with this and I'm glad to see somebody saying it. Any system that is one LPE
42.
by jcalvinowens 6mo ago
Never throw anything away. I'm constantly amazed how often even very trivial little programs end up being useful again many years later.
43.
by jcalvinowens 6mo ago
>> [...] and thread 2’s time may be earlier than thread 1’s > If it does plain RDTSC, it may not be fine. I'm a little surprised how easily it happens with plain rdtsc on my hardware: https://gist.github.com/jc
44.
by jcalvinowens 6mo ago
> Threads have gotten so fast that paying the async function coloring price makes very little sense for most software. I agree with this 100%. If you're getting paid to bin pack jobs that do lots of concurrent I/O into a server
45.
by jcalvinowens 6mo ago
I doubt it too, but I was hoping to hear from someone who'd tried it. I don't care about peripherals, even booting it without the storage with a serial getty would be useful for me.
46.
by jcalvinowens 6mo ago
Is anybody running Linux headlessly on the m4 mac minis successfully? I'm seeing them flying around used now at tempting prices...
47.
by jcalvinowens 6mo ago
I also appreciate the 10/100 support. I recently needed it for some old voip equipment, and it was shockingly difficult to find an SFP+ module that worked in my 10G switch and supported 100mbps.
48.
by jcalvinowens 6mo ago
I used to drink a small amount of blisteringly strong coffee in the morning and after lunch, but nowadays I drink a massive amount of relatively weak coffee throughout the entire day. Weaker than you'd ever get from a shop or in an off
49.
by jcalvinowens 6mo ago
Honestly, my recent experience with this was really positive: the doctor actually said the technical stuff out loud to me for the first time in my life, in a way I could easily ask polite questions about and discuss with them. In my case it
50.
by jcalvinowens 6mo ago
If you just want to see patterns, and don't actually need to see the values, you can go a step further and simply visualize the data as a bitmap, e.g. dd if=/dev/urandom bs=$[256*256] count=1 | display -size 256x256 -de
51.
by jcalvinowens 6mo ago
The experience I'm describing was two weeks ago. Yes, what we see coming out of the bottom of funnel is now is a little better. But it's sort of like reading day trading blogs: nobody shares their negative results, which in my dir
52.
by jcalvinowens 6mo ago
My experience with these tools is that they generate absolutely enormous amounts of insidiously wrong false positives, and it actually takes a decent amount of skill to work through the 99% which is garbage with any velocity. Of course some
53.
by jcalvinowens 6mo ago
> I generally believe that 256-bit “security levels” are somewhere between a comfort blanket and numerology [...] AES-256 was unfortunately defined to perform more rounds than AES-128, making it needlessly slower. Obviously if you benchm
54.
by jcalvinowens 6mo ago
Yeah, I had the same question. But I'd guess they probably disable IA32 completely.
55.
by jcalvinowens 6mo ago
That could never work, my entire ISP is a /32
56.
by jcalvinowens 6mo ago
The "reputation" concept has to be applied to network blocks in IPv6, because of privacy addresses, and they very clearly aren't doing that for whatever reason. I get at least one captcha a day from a stock Android phone th
57.
by jcalvinowens 6mo ago
For releases! But have a flag to disable it: don't make people edit -Werror out while hacking, that's really annoying.
58.
by jcalvinowens 6mo ago
This could make real sense for ssh host keys, since they need to be used without presence and they're generally tied to the lifetime of the machine anyway. I saw a write up where someone successfully got sshd to use a host key from a f
59.
by jcalvinowens 6mo ago
The "party trick" is more general than just xor, for example: void swap(unsigned* a, unsigned* b) { *a = *a + *b; *b = *a - *b; *a = *a - *b; } GCC still sees through it with restrict: htt
60.
by jcalvinowens 6mo ago
I consistently get 100x as many captchas from google over V6 as over V4, on many different networks: it is obnoxious and obviously broken on their end.

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