Andrew Zonenberg

Security and open source at the hardware/software interface. Embedded sec @ IOActive. Lead dev of ngscopeclient/libscopehal. GHz probe designer. Open source networking hardware. "So others may live"

Toots searchable on tootfinder.

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Last Notes

2026-08-22 23:08:52 UTC

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The design target for this filter was 10.25 GHz Fc and 250 MHz -3 dB BW.
The actual as-fabricated filter seems to be more like 9.92 GHz Fc and 292 MHz -3 dB.
I don't really feel confident making any claims about stopband rejection because of the poor dynamic range of this setup, but the hump around 10.7 GHz is not ideal. I saw some ground plane resonances in the simulation and wasn't sure if they were real, it seems they might be? Once I get more detailed S-parameter data with better dynamic range I'll go back to the simulations and revisit.

2026-08-22 23:06:23 UTC

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It's... definitely a filter. I can say that much.
Not sure what's up with the 0 dB regions at start and end of the sweep, it's clearly a bug (The waveform behavior doesn't match, it's definitely not actually 0 dB)
I'm pushing limits of what I can do as far as dynamic range easily. The Siglent is putting +16 dBm into the doubler (which has an absolute max of +20 so it's safe but not leaving much margin). The doubler is only specced for 10-20 GHz input so 5-10 GHz input and trying to sweep down to 4 GHz on the input means I'm operating out of spec but it seems to mostly work.
The doubler has ~12 dB of conversion loss so I only have about +4 dBm coming out of it, which isn't a ton of stimulus energy when the DUT is this lossy.
I'm not sure why it's coming out as 30 dB IL. My simulations said it would be more like 15, plus copper roughness and ENIG plating losses which I did not expect to add another 15 dB.
I expect the filter rolloff is a lot sharper than what's shown here but the -45 dB loss range is putting me basically at the noise floor of the scope.
I could try to get more dynamic range by adding an amplifier after the doubler, but i'm a bit sketched out about putting big RF PAs on something going into a $10K-to-repair-if-damaged 16 GHz frontend that is rated for +/- 2V p-p.
Probably better to just send the thing to somebody who has a real VNA that can work at these frequencies.
https://files.ioc.exchange/iocexchange/media_attachments/files/117/141/640/506/967/904/original/2c79639af076224a.png

2026-08-22 19:32:14 UTC

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@nprofile…skdr even like an fpga with 1/10 the logic that's "oops all transceivers" would be nice lol

2026-08-22 14:51:28 UTC

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@nprofile…skdr lol that's entirely the point i would want something with a much smaller die that's just a bunch of serdes with a tiny bit of glue between. You don't need a ku3p of compute to do this

2026-08-22 14:34:56 UTC

BRB just daydreaming about being able to buy a JESD204B to PCIe bridge chipset COTS

2026-08-20 12:49:04 UTC

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@nprofile…huwm i looked. According to the sales rep i talked to they do not have any chemical resistant label/ink offerings otherwise they looked attractive

2026-08-20 02:33:34 UTC

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@nprofile…huwm yeah so far nobody has everything i want but i can tolerate windows software in a VM in a pinch.
Brady seems the only option for chemical resistant full color that I've been able to find

2026-08-20 02:31:40 UTC

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@nprofile…huwm doesn't appear to be full CMYK color

2026-08-19 21:44:10 UTC

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@nprofile…huwm I'm currently planning to spend $150 on an eBay J2000 to keep me staggering on a bit longer and burn up the remainder of my (expensive) consumables, then buy a J7300 when i run out

2026-08-19 17:45:23 UTC

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If I go with Brady again, it looks like the next equivalent model would be the J7300, which is $2699 for the base printer.
It's CMY+K inkjet, Windows only although I have a VM. Has Ethernet which is nice, I won't have to place it within USB range of the host (so I can run the Windows software in a VM anywhere).
Cartridges seem to be sold in a 3-pack, 2x CMY + 1 black, for $327.99, or 2x black + 1 CMY for $317.99. Or you can get a black for $115. Weird they don't sell the CMY by itself.
It's not compatible with my existing J2000 labels (that would make way too much sense).
A roll of a thousand die cut chemical resistant 0.375 x 1" labels is $103.99, and a 150 foot continuous roll of 1.125" removable vinyl stock is $195.99.
There's some other interesting oddball offerings like velcro hook or magnet back that I have no immediate need for, but it's good to know they exist. Does not appear to have a heatshrink offering.

2026-08-19 17:36:12 UTC

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Bad news, according to their sales none of the label stock they offer has any level of solvent resistance which is kinda key for stuff I'm using in the fume hood.

2026-08-19 17:18:23 UTC

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The label editor software they provide appears to be windows only though, so I guess i'd be on my own if I ran on Linux. Not sure how that works WRT die-cut labels and continous sheet with cutting etc.

2026-08-19 17:16:04 UTC

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Not seeing anything I like from Brother, and Brady is going to have the same problems WRT locked down windows-only software etc.

2026-08-19 17:08:25 UTC

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Epson ColorWorks: looks promising. The CW-C4000 claims Linux support. It's $2500 for the printer, the separate C/M/Y/K cartridges are $39 each. There seems to be a decent collection of aftermarket labels available for them.

2026-08-19 16:49:03 UTC

Anybody have suggestions on a non-enshittified industrial full color label printer? My Brady J2000 has been growing increasingly less reliable lately and I'm starting to think about a replacement.
Looking for a decent selection of chemical and liquid resistant permanent and removeable labels, both die cut and cut-to-length roll stock.

2026-08-15 00:12:16 UTC

You know that gritty pumice filled toothpaste dentists use to polish your teeth?
It really should come in gojo orange instead of mint. They've got the texture down already, why not the flavor?

2026-08-14 10:48:58 UTC

How cursed is it for a PCB to have components at 22.5 degree rotations?

2026-08-13 13:12:05 UTC

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@nprofile…huwm I've talked to the Sonnet people about GPU accelerating their solver as well. It's definitely something I want to think about.
One of the big challenges is consumer GPUs having poor float64 performance, and a lot of scientific computing stuff really needing the extra dynamic range from fp64.

2026-08-12 12:15:57 UTC

Years ago I remember hearing a story of a real-life Shrek who just wanted to live in a swamp and be left alone.
His family had once owned a lot of land, maybe a farm, in the area but most of it had been sold off and was being gradually developed. He still owned a house and a small plot of land though, and couldn't stand the encroaching suburbs and strip malls.
After a bit of exploring he discovered some streams and swamps in a neighboring, vacant lot and contacted the state about it. Before long, that land was legally a protected wetland that would be expensive or impossible to develop, guaranteeing him a buffer against the approaching subdivisions.
But this made the land decrease in value, since no developer would buy it. So he picked up this plot for a fraction of what a buildable plot in the same area would cost.
After a bit of excavation and streambed restoration, he expanded the wetlands right up to the next property line. But this also meant a sizeable chunk of the neighboring lot earned protected wetland status, making *it* unbuildable and reducing its value.
I forget how many times he repeated the process but the end result was him owning a small house surrounded by a large amount of permanently unbuildable wetlands, to be left in its natural state forever. IIRC he was a guy so "bog witch" doesn't really fit, but can you be a bog wizard?

2026-08-11 12:08:04 UTC

Spent a bit of time over the weekend designing this 10.25 GHz hairpin bandpass for high-IF filtering on a future SDR-adjacent project.
280 MHz BW (I was aiming for around 250 so this is probably good enough).
Tthe insertion loss of about -9.3 dB is a little higher than I would ideally want, although probably within acceptable limits. I think this might be pretty unavoidable, because loose coupling translates to higher losses and I think loose coupling is necessary to get narrow bandwidth.
Anyone have tips on how to tweak this or things I obviously did wrong? The impedance match seems pretty decent in the passband (-27 dB S11 at 10.25 GHz) so I think I'm just seeing high coupling losses. I guess that means the un-coupled energy is being radiated, and I'll want an RF absorber in whatever shield I put around this?
The filter is quite small, 15.6 mm x 4.275 mm not counting feedlines. Targets the OSHPark 4-layer stackup with ground on layer 2, although I'm simulating with RO4350B here because that's what the final board will use. The Dk is close enough I might have a small Fc shift but it should be close enough since my synthesizers are tunable.
https://files.ioc.exchange/iocexchange/media_attachments/files/117/076/753/247/813/794/original/40517859def9f178.png
https://files.ioc.exchange/iocexchange/media_attachments/files/117/076/753/247/311/195/original/7e409975d26b7c89.png
https://files.ioc.exchange/iocexchange/media_attachments/files/117/076/753/247/080/938/original/0d1439375371784c.png
https://files.ioc.exchange/iocexchange/media_attachments/files/117/076/766/836/928/953/original/75c3cae0246df95c.png

2026-08-08 00:55:55 UTC

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I also have a few small microatx tower systems that aren't set up with anything special hardware wise but I could probably slap a cheap single slot 3070 in. Need to check if they have enough pcie for a gpu plus the TS.

2026-08-08 00:52:35 UTC

Thinking about traveling demo setups for ngscopeclient and thunderscope.
Requirements:
* Smaller is better
* PCIe gen2 x4 or thunderbolt 3 host port for TS
* Decent internal GPU or free pcie slot for an nvidia card
Open to laptop, mini pc, SBC, or any other form factor but ideally it should fit in a carryon sized pelican case along with whatever else I'm demoing it attached to.
What is the lowest cost/smallest form factor minimum viable setup if i don't care about GPU performance but need functional vulkan? What about if I want something decently powerful?
I have a base model M4 mac mini that is functional but needs an external keyboard/mouse/monitor and the GPU is somewhat wimpy compared to higher end apple silicon.
I also have a spare RTX 2080 Ti but nothing to house it in.

2026-08-07 14:38:42 UTC

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@nprofile…cllx @nprofile…huwm my problem is getting data in and out the narrow channel that is VRAM lol. Almost all of my shaders are saturating the memory subsystem so the only major optimizations possible are to do less loads/stores or order them more efficiently for better coalescing or cache hit rates.
Which is why I'm beginning to look at kernel fusion for things like FFT + windowing so I can keep temporaries in registers and never touch the memory subsystem at all

2026-08-07 12:41:02 UTC

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And sure enough the other big shader in the same filter had a huge optimization possible too, 3.75 -> 0.78 ms for the shader and 8.8 -> 6.8 for the whole filter.
Not too bad considering it took 11.2 on the same workload a few hours ago, that's a 65% speedup overall

2026-08-07 09:07:51 UTC

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It feels like every time I look at something in ngscopeclient and go "hmm, this is too slow" and bang on it for a few hours I get a significant speedup out of somewhere.

2026-08-06 09:53:13 UTC

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@nprofile…9ylh So you never got your suitcase back? :(

2026-08-06 08:44:49 UTC

Silly idea: has anyone ever made an embedded device that can run HDLC over serial console for initial provisioning or OOB management or something? Like for when you want the ability to do file transfers and more fancy things than you can do with a simple shell, but don't want to burn the area and power/BOM cost of an ethernet phy

2026-08-06 08:16:08 UTC

I'm offering my oscilloscope probing class in Europe for the first time! If you're in or near the Netherlands, consider signing up. Space is limited to 10 students to ensure everyone has enough lab time; two spaces are already taken.
https://www.eventbrite.com/e/oscilloscope-probing-training-tickets-1996971622881?aff=oddtdtcreator

2026-08-06 02:37:34 UTC

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Lab air filtration is holding strong though, approaching three orders of magnitude lower particle counts than outside.
AQI in the lab is still off scale low (technically 1 because the EPA scale doesn't go any lower, but...), while in the living room it's up to 12.
https://files.ioc.exchange/iocexchange/media_attachments/files/117/046/227/137/350/160/original/830f99fafb5aa509.png

2026-08-05 01:32:32 UTC

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@nprofile…hjhu i have an 18 in the lab now and it's running constantly sooo

2026-08-05 00:32:34 UTC

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@nprofile…hjhu I'm burning power dumping that heat outside then more power to suck it back into the house

2026-08-05 00:21:22 UTC

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@nprofile…hjhu my current water heater is electric resistance and i want a heat pump one.
But putting the 4 kW of waste lab heat to work elsewhere in the house in the winter is the bigger priority.

2026-08-05 00:05:03 UTC

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@nprofile…hjhu Lol. I'm all electric, separate heat pumps for house and lab (a separate issue, I want energy harvesting to heat the house with waste heat from the lab). The lab underpressurizes by enough to need another 20ish pounds to open the door when the fan is running. That's about the right delta P imo, but it should be in the other direction so I'm not sucking contaminants in.

2026-08-04 23:56:28 UTC

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@nprofile…hjhu The problem with my current setup is that it is exhaust only, and the filter on the intake is high enough resistance that it underpressures the lab and sucks unfiltered air in through cracks around doors etc. If I had pressurized intake, I think that would work better. I'd rather positive pressure the lab.
Something I want to think about getting fixed down the road.

2026-08-04 23:51:32 UTC

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@nprofile…hjhu I've wanted an ERV for a while, especially in the lab, but it would need *good* filtration to be usable in this weather. The house is ventilated by passive diffusion if we don't have windows open, and the lab has an exhaust fan system but the filters there are only like MERV 13 or so and the fit around the edge is leaky so when I run it, lots of outside particulate gets in

2026-08-04 23:38:52 UTC

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Having the house all buttoned up is keeping the particular levels low, but not good for the CO2 concentrations.
I've been working at my desk and not in the lab much, but when I opened the door to get something from it a few minutes ago you can see a sudden step change as house air mixed with the lower concentration air there.
https://files.ioc.exchange/iocexchange/media_attachments/files/117/039/866/953/302/885/original/1a29f069a945175b.png

2026-08-04 23:24:26 UTC

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Aaand now we're north of 150 which is "unhealthy".
Lab readings are still in the ISO 7 cleanroom range, and the rest of the house is good, but both are notably elevated above baseline.
https://files.ioc.exchange/iocexchange/media_attachments/files/117/039/811/661/807/272/original/5857a03b3af9c877.png
https://files.ioc.exchange/iocexchange/media_attachments/files/117/039/811/662/417/981/original/8cd881525b8630f3.png
https://files.ioc.exchange/iocexchange/media_attachments/files/117/039/811/661/046/326/original/28d455223e5444a8.png

2026-08-04 02:54:40 UTC

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@nprofile…ptud is it bad that I know it's a 3m 6000 series instantly?

2026-08-03 13:47:43 UTC

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@nprofile…cy5p I do not understand $$$$ sneakers.
If I'm gonna pay several hundred bucks for shoes they better be like hard shell insulated mountaineering boots or super comfortable composite toe safety shoes or otherwise really special.
Not "slightly fancy decorated versions of a cheap basketball shoe with some dude's name printed on them"

2026-07-31 08:25:08 UTC

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@nprofile…q57v Ooooh fresh stroopwafels? I was in Den Haag a few years ago hoping to find a bakery that made them fresh but was unsuccessful and just got some at a supermarket. That's a definite destination.

2026-07-31 05:18:57 UTC

It looks like I'm going to have some downtime in The Netherlands in late September / early October due to airline pricing (staying an extra two days after the event I'm attending saves $1200 on airfare, cutting the ticket price by more than half and more than justifying the extra meal/hotel cost)
Anyone interested in a get-together Monday Sep 28th, Friday Oct 2, or Saturday Oct 3? Or have suggestions on things to do in the greater Gouda / Den Haag / Rotterdam area?

2026-07-31 00:45:55 UTC

I need something bigger than a pair of 24" 1080p display on my lab bench.
Big GPU profiling traces just don't fit in 1080 scanlines when you are looking at double digit numbers of threads and lots of Vulkan queues.
I can't fit any more width, but maybe I'd benefit from like a 30-something inch 4K in portrait mode?
https://files.ioc.exchange/iocexchange/media_attachments/files/117/011/819/280/268/026/original/10269b4dd00c2df1.png

2026-07-30 20:57:31 UTC

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@nprofile…skdr It is a huge pain in the butt to configure and I really don't like the architecture. They're also close to $100 in low volume and lack a bunch of features the STM32s have that I consider key for useful embedded stuff ,most notably a hard TRNG and AES accelerator

2026-07-30 19:12:47 UTC

Once again daydreaming about a "baby zynq" microcontroller with a STM32H7 class processor and memory subsystem attached to a few kluts of low power FPGA with hard APB/AHB/AXI (depending on how big they want to make it) ports, a bunch of dedicated or muxable GPIOs, etc.
ST apparently has an FPGA-esque peripheral in some STM32s but it's *sixteen* LEs which is a joke. You can't do any kind of useful custom peripheral in that.
Ideally i would want to be able to implement my own peripherals for a weird bus the MCU doesn't include natively and even have native DMA to/from them. Which means having full MMIO capabilities (no need to put a DMA in the FPGA, you can use the hard DMA IP and just read/write registers in the FPGA).

2026-07-30 10:27:37 UTC

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@nprofile…7k5d there's a reason i stopped buying consumer hardware ~15 years ago lol.
well ok mostly it was I wanted ECC RAM (and a lot of it) but tons of PCIe lanes also come in handy for the things I do. I can't imagine having only 24 lanes in a workstation, a 100G NIC and a GPU is 32 before you even add anything else like SSDs

2026-07-30 10:22:09 UTC

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@nprofile…7k5d my storage cluster nodes are supermicro x11spa-tf based, one with a xeon 4116 and the other two with 4208s.
The socket has three gen3 x16 pipes off it... one goes to the bifurcation card, one goes to the four m.2 ports on the mobo, and the remaining one goes into a PEX8747 that splits off to the remaining pcie slots which serve the NIC and have a few empty slots for expansion in the future.
I've iterated a few times with what goes in which slot to try to get the most pcie bandwidth but also cram as much NVMe into the nodes as possible without having to upgrade the mobos and processors. I can still add another 2ish SSDs per ndoe pretty comfortably without running into bandwidth limits so I'm confident in my original goal of keeping the cluster running into the 2030s without a chassis/mobo swap.

2026-07-30 10:12:17 UTC

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@nprofile…7k5d some of my storage servers actually have little bifurcation cards in them that hold four m.2 22110, two on each side, in a x16 slot. If your host supports bifurcation they work well

2026-07-30 10:11:38 UTC

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@nprofile…7k5d like if i have 64 lanes and use one for an x16 nic, i have 48 left which is enough for 12 x4 devices and i can't fit 13 cards in a normal 4U chassis or e-atx mobo lol

2026-07-30 10:07:30 UTC

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@nprofile…7k5d don't we all, lol.
I also need more *slots* I want to fit a lot of x4 devices in a chassis and they dont all fit

2026-07-29 18:55:54 UTC

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@nprofile…y6u5 @nprofile…eew3 My feeling for a long time has been that purpose-built neural networks designed to do one thing can be useful.
They may not be the best or most efficient solution to a problem, but if you have no idea how something works and a lot of data, and can tolerate some errors, throwing some kind of boolean classifier at it is not an unreasonable move. And if it was trained on data you or a trusted organization vetted and curated you have increased trust in the ethics and accuracy of the model.
Things like "how likely is this drug to bind to that receptor" are a perfect use case because you're gonna do a ton of molecular dynamics and lab testing on the ones it likes so you don't need perfect accuracy, you just want to whittle trillions of candidates down to few enough that you can spend significant resources on. And you can't test every possible molecule so if it rejects some promising options by mistake, it's not the end of the world - you already left a ton on the table by not even evaluating them.
Trying to make a single "god model" that can do everything is never the right move even if you could somehow ethically train and operate it. Even if decades or millennia down the road we somehow do create an AGI, it will be so compute heavy that a purpose built NN - or classical tool - will always be able to solve any given problem far less expensively.

2026-07-26 13:34:17 UTC

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@nprofile…vnlz @nprofile…ds0l I dont know if there is an expiration date or it's a lifetime ban but we had a secretary/admin type guy at $dayjob a decade ago who often attended conferences and events to do logistics support for client meetings and the like, and I was told that he couldn't do so for events in Canada because his DUI conviction was a disqualifier

2026-07-26 13:31:57 UTC

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@nprofile…vnlz @nprofile…ds0l Makes sense. There are definitely specific offenses that are disqualifiers, IIRC you can't even get into Canada as a visitor much less immigrate if you have a conviction for DUI.

2026-07-26 02:06:59 UTC

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@nprofile…yclf @nprofile…3fsz is this a dryer exhaust vent? They make flappers that spring closed when there's no pressure and open up when air is coming out.
But I'm not sure how hard they are to pry open from the outside

2026-07-24 20:16:11 UTC

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@nprofile…e965 My general opinion on this sort of thing is, it's a tool for when you'd rather take the charge for destruction of evidence instead of the charge for whatever they'd find otherwise is.

2026-07-24 00:27:42 UTC

Traffic in Seattle is so bad i just outran an ambulance with lights and sirens on.
On a bicycle.

2026-07-23 05:11:12 UTC

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@nprofile…3tsk also i think you have to add -c:v libx264 before the -x509

2026-07-23 05:10:09 UTC

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@nprofile…3tsk shitposts for a very specific audience

2026-07-22 18:40:49 UTC

Random thought: is there a placebo pharmaceutical manufacturing factory somewhere?
Like, say you're running a double-blind clinical trial and you need a tablet or gel cap or whatever made of a specific formulation with no active ingredient that's visually indistinguishable from the active test subject and contains the same binders and excipients etc.
Or you're a film producer shooting a scene involving an actor taking some sort of drug that needs to look like a well-known medication (or some real or fictional narcotic).
Can you just put an order in for a dozen 4.2mm long capsules with light green on one side, silver on the other, a black cat face printed on the light green side, and filled with a 50/50 mixture of dextrose and microcrystalline cellulose?

2026-07-22 18:22:44 UTC

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@nprofile…pk25 @nprofile…xahp As far as the constraint flow works, have you looked at SolveSpace's keyboard/UX flow?
It's very critical that common operations around constraints like adding a "points coincident" or a dimension be accessible via keyboard shortcuts and not constant shifting back and forth between the board editor and properties dialogs.
Also, is there support for construction geometry (not rendered in copper or gerber layers, but something you can attach constraints to)? This is also a critical need for this sort of thing

2026-07-22 17:52:53 UTC

aand apparently I'm on Analog Device's WA list now too. Lovely.

2026-07-22 17:43:23 UTC

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@nprofile…pk25 @nprofile…xahp I don't use blind/buried vias much (yet) so not sure I can be a ton of help, i've only used them a handful of times.
What *would* be good is a way to design impedance-matched, reproducible layer transitions for high-speed signals. Like a combination of signal vias for both legs of a diffpair, the fanout geometry from the closely spaced pair to the vias, return path vias nearby, maybe a void in the ground plane, etc.
Or for single ended, a signal via with 2 or 4 surrounding return path vias and again perhaps controlled clearance to the plane that's separate from the usual plain clearance.
And once you've designed these and associated them with a net/netclass somehow, every time you add a via it drops the whole transition instead

2026-07-22 17:29:46 UTC

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@nprofile…pk25 @nprofile…xahp Finally! I've been dreaming of this for years but never had the time to do it myself, glad someone else built it.

2026-07-22 16:39:09 UTC

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@nprofile…7g5c Again, my argument is not that we should be adding deliberate vulnerabilities, only that the existence of physical attack vectors - which are somewhat inherent, digital data has to be stored in the physical world somehow and that includes keys - is not necessarily a bad thing.
The nature of this sort of physical attack is that while the reverse engineering only has to be done once, the lab work to prepare each sample for imaging and extract the key is time consuming, requires millions of dollars of equipment, and has a significant chance of going wrong and destroying the sample.
The whole reason I'm saying it's a stable MAD state within the arms race is that *it doesn't scale*. There aren't enough trained operators to do this sort of thing at high volume (semiconductor deprocessing is more of an art than a science and takes years to get good at) and even if the budget was available for more equipment, and you generally can't run multiple samples at once on the tools. And the device is literally vaporized in the process so there's no way you can do it to someone's phone without them knowing.

2026-07-22 15:35:43 UTC

For decades there's been a conflict between governments wanting to get access to people's private data and people trying to keep them out.
Over the years I've gradually come to the conclusion that the stable "Goldilocks zone", where there's the least likelihood of a major swing that makes things worse for everyone, is *not* the privacy utopia where devices are invulnerable, or a police state where anyone with a badge who asks can root through all your data, or a fictional engineered cryptographic backdoor that''s somehow only exploitable by "the good guys".
Instead, it's the state where devices (especially phones) are breakable, but only through attack vectors that require physical access, have a high per-device cost, and are not 100% reliable. Things like "solder to an internal layer trace on the logic board to glitch it" or "FIB a per-device key out of the SoC".
I'm not saying we should be adding deliberate backdoors - quite the opposite, since these are very likely to make entry *too* easy.
But if devices become completely invulnerable, I expect we will see something like chat control turned up to 11 where the pressure to find some way in becomes unbearable and we end up with CALEA-style entry points that turn devices into total spyware with no privacy at all.
So IMO the ideal balance is where there is no viable remote attack vector, trivial drive-by USB etc attacks a la Cellebrite are blocked, but if a government has a phone off a body and are willing to spend $100K+ of lab time to have a >50% chance of breaking into *that one device*, destroying it in the process, without it easily scaling to the next, they can do so.
And this level of difficulty is juuust easy enough that they aren't spending the same money lobbying politicians to make it easy to break into every device belonging to an opposition party or something. They still try of course, they always want more, but they can't claim to congress that the guy who shot senator X will never be caught because they couldn't break the phone they found at the scene.
You know your device was confiscated (or are dead and not around to complain), it's not viable to do to everyone crossing a border or who was in a certain geofenced area, etc. There's no practical way to scale physical attacks to mass surveillance.

2026-07-22 00:18:16 UTC

There's plenty of mapping tools that tell you how to get from point A to point B and how long it will take.
But what about for more exploratory mapping? Say, I live/work at point A and want a job/house no more than an hour away by X mode of transit. Is there any way to plot travel time isosurfaces so I can see a polygon of locations an hour or less from home?
Or say I want to go for a 2 hour bike ride. What are potential destinations leaving from a given starting point?

2026-07-21 22:43:01 UTC

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I'm used to thinking of fedi as a friendly "old internet" space where barring an instance shutdown or something, useful information doesn't just vanish because someone paywalled it or EOL'd the product it was talking about or whatever.
And auto deletion really messes with that.

2026-07-21 22:40:43 UTC

Auto post deletion leads to some really weird dynamics sometimes.
Like having a tab open with a post that I saved wanting to come back and refer to a suggestion someone gave me or something, only to realize it's gone.
Or having someone favorite or boost a reply I made a year ago, but completely out of context because the original post was deleted.

2026-07-21 04:58:58 UTC

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Oh actually you can see the mountains I just wasn't in the right spot.
There's so many pretty views all over the place here. I really need to get out and explore more. Got tired of sitting on my butt and decided to just go for a bike ride nowhere in particular trying out a new route, first time riding on this side of town although I've driven through the area before.
Late evening to the wee hours of the morning, in summer, is my favorite time to ride. No sun, no rain, not too many cars, not too hot, not too cold.
https://files.ioc.exchange/iocexchange/media_attachments/files/116/956/189/315/622/548/original/ff23412475eb37be.jpg

2026-07-21 04:50:36 UTC

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A little hazy to see the mountains in the distance but I'm still not complaining
https://files.ioc.exchange/iocexchange/media_attachments/files/116/956/160/013/986/635/original/3aef64732c82aa51.jpg

2026-07-21 04:38:43 UTC

Beautiful PNW summer night
https://files.ioc.exchange/iocexchange/media_attachments/files/116/956/113/805/237/434/original/02361a7f0206cd3e.jpg

2026-07-20 15:43:04 UTC

woo i'm blocked by the cisa.gov WAF

2026-07-20 05:45:13 UTC

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@nprofile…6ljk It's a cleanishroom.
There's no specific target other than that it's full of optics and equipment with fans and heatsinks that don't like dust. The less the better, but I don't want to have to wear a bunny suit and gloves and hair net every time I go in there to use an oscilloscope.
So the real goal is "as clean as I can make it while being able to walk in wearing ordinary clothes I wear around the house". Which I think I've hit.

2026-07-20 05:30:03 UTC

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Comparing to ISO cleanroom thresholds, although this isn't a certified/traceable meter so I can't officially say I qualify, I'm comfortably below the ISO 7 (class 10000) thresholds at the moment (outside air intake fan off, me not actively in there stirring up dust):
* > 0.5um: measurement 46K, threshold 352K
* >1um: measurement 1K, threshold 83.2K
* >5um: measurement 0, threshold 2.93K
This generally tracks with the rough data I made with my older, cheaper Plantower sensor but the data was a lot noisier there due to low count values and poor sensitivity. The Sensirion seems to be more consistent although it's too soon to make firm judgments.
I'll let it sit overnight to get a good baseline then spend some time working in the lab tomorrow with the ventilation fan on and see how much worse it gets when I'm sucking in outside air and moving around using equipment rather than just recirculating through the filters over and over. If past data is any hint, I will probably end up in the ISO 8 range under those conditions.

2026-07-20 05:23:53 UTC

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Looking at the particles larger-than-threshold per m^3, as used in cleanroom air standards, tells a similar story:
> 0.5 um: lab is 46K vs living room 1.1M (23x dirtier), office 1.87M (40x dirtier), outside 2.33M (50x dirtier)
>1um: lab is 1K vs living room 32K, office 59K, outside 78K. You can do the math here.
> 2.5um: lab is off scale low (no counts within the most recent 300-second integration window), living room 2.3K, office 3K, outside 6.6K.

2026-07-20 05:20:37 UTC

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And here's early particle count data.
I think I am going to need to break out the lab into its own graph or use a log scale or something. It's multiple orders of magnitude cleaner than the house or outside.
Not going to describe all of the data in the sea of plots in alt text, but here's the important bits...
PM10.0 counts per m^3 range from 17.7M on the deck (outside air) to 14.1M in the office (indoors but nearby air cleaner is switched off currently) to 8.4M in the living room (air cleaner running, but some windows open to cool the house down) to 318K in the lab (fully sealed from the house and outside except via an exhaust fan with a high MERV-filtered outlet and intake, and with two large air cleaners).
PM2.5 levels are pretty close to the PM10 levels, indicating almost all airborne particulate is small.
https://files.ioc.exchange/iocexchange/media_attachments/files/116/950/582/583/018/951/original/04b8e9ae61026cee.png
https://files.ioc.exchange/iocexchange/media_attachments/files/116/950/582/589/220/962/original/dd18d6d973e67a07.png
https://files.ioc.exchange/iocexchange/media_attachments/files/116/950/582/589/996/737/original/484bc0bec073819a.png
https://files.ioc.exchange/iocexchange/media_attachments/files/116/950/582/585/741/008/original/cbaa05e984c2a334.png

2026-07-20 05:13:28 UTC

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@nprofile…aejz no that has much worse performance lol. I'm going full manual under a stereo microscope at like 30-40x magnification and watching the workpiece start to move as I turn the handwheel to take up backlash.
I've hit Z axis tolerances down to <10um when I was hitting a visually obvious layer in the sample (i.e. exposing but not perforating a ~17um copper foil, fairly consistently)

2026-07-20 05:03:11 UTC

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@nprofile…aejz backlash and resolution of the leadscrews has been a much bigger problem for me to date than flexure of the axes

2026-07-20 05:02:40 UTC

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@nprofile…aejz And again, I am never going to be applying more than like a few millinewtons of shear load to the axis during a machining operation when i'm making a cut whose depth is measured in the low tens of microns

2026-07-20 04:46:47 UTC

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@nprofile…aejz probably lol. But I don't want a machine the size of a car so it's gonna be tricky to figure out how to improve

2026-07-20 01:07:38 UTC

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@nprofile…kuux I'm eyeing some fancy spindles from nsk nakanishi that hit tens of krpm but they cost several times what i paid for the mill so I'm wondering if I'd be better off just getting a better machine lol

2026-07-20 01:06:14 UTC

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@nprofile…kuux my sherline tops our at 2800 rpm so I'm never anywhere near optimal speeds and feeds.
With my 250 um endmills I'm usually doing like 5-25 un depth of cut in fr4/copper

2026-07-20 01:02:29 UTC

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@nprofile…kuux oh you mean 50um depth of cut?

2026-07-20 00:59:41 UTC

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@nprofile…3q9y pixel 9 pro and i see clouds

2026-07-19 22:51:20 UTC

TIL you can buy through hole U.FL connectors. I wonder who would ever use that??

2026-07-19 20:51:03 UTC

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@nprofile…clxj I don't buy *full* MREs for a couple of reasons.
1) I can be a bit picky with what I like and don't. Buying full meals means I would end up with a lot of things I don't like
2) Most of this stuff is being used as on-duty rations for SAR deployments, when I need to keep my pack loaded with two days of food 24/7 and be ready to run out the door on zero notice, but it might sit around for a while.
When I'm on a mission, I might have just had a big dinner at home, or I might be running out the door before breakfast. What I actually consume on a mission varies a lot. Full meal pouches are not a good fit to this.
3) MREs are expensive. I use MRE components when there is no satisfactory equivalent on the civilian market, but e.g. clif bars and beef jerky are cheap at Safeway.
4) On a mission I'm generally spending a lot of time hiking and not a whole lot sitting around (except in base, where there's sometimes tastier food available if e.g. someone brought in pizza or the Soup Ladies came).
So I specifically bias my food loads towards snacks and things I can eat on the move - the pocket sandwiches/pastries, pound cakes, etc feature prominently, while I might bring one of the big entree pouches per day and only actually eat maybe 1-2 a year outside of training weekends since it's so rare I have time to stop, pull out a spoon, and make a hot meal.
I prefer something I can tear open, take a bite of, fold the foil back over, and shove it in my chest rig until next time I stop to shout our missing person's name or wait for someone slogging through a patch of heavy brush to catch up or something.

2026-07-19 20:40:16 UTC

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@nprofile…clxj fresh, early 2025 manufacture
https://files.ioc.exchange/iocexchange/media_attachments/files/116/948/572/631/539/217/original/2b79a60be5951cda.jpg

2026-07-19 20:39:01 UTC

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@nprofile…clxj Sometimes it's stamped/laser engraved and hard to see other times it's inked and more obvious

2026-07-19 20:38:36 UTC

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@nprofile…clxj I think some vendors have started using a longer, less ambiguous code of YYDDD with a two-digit year but everything I have in my inventory is the 4-digit format

2026-07-19 20:38:08 UTC

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@nprofile…clxj The actual date codes on the individual components are perhaps more useful. They're formatted as YDDD where Y is the last digit of the year and DDD is days since January 1st.
So 3201 would mean manufactured on the 201st day of a year ending in 3 (hopefully 2023, unless you're getting ripped off by someone selling stuff that's been sitting around since 2013).

2026-07-19 20:18:47 UTC

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@nprofile…clxj assuming you're trolling but if you're legitimately unfamiliar with how they're labeled, that's not the date they *were* inspected.
That's the date they're *due* for inspection (3 years from manufacture)

2026-07-17 03:35:34 UTC

Not too long ago, a neighbor's kid was watching TV with the family and two female characters in the show got married.
She looked over incredulous asking "wait, what? two girls can get married?"
... to her moms.

2026-07-16 06:05:08 UTC

FPGA / ASIC people: How likely are synthesis tools, ranging from Yosys to Design Compiler to Quartus, to complain about SystemVerilog parameters with hundreds, thousands, or tens of thousands of bits? Is this likely to run into some secret hard coded limit somewhere?

2026-07-15 22:51:24 UTC

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@nprofile…94p0 HBM is mounted to the chip substrate not the PCB, it's not really possible to rework practically unless you're making your own silicon interposer and even if you did I'm not sure how you'd extract it without destroying it.
If you can reuse the whole chip package including the HBM and whatever it's attached to different story. But you can't like put it on a DIMM or something.

2026-07-14 16:34:52 UTC

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And slow clock domains are actually very beneficial for ILA work.
If you're debugging a SPI register interface or something, running in a 200 MHz clock domain with one interesting event every 10+ clock cycles means your capture buffer is mostly empty space and you're burning a ton of block RAM to see anything interesting. I2C is even worse.
Using a divided PLL output to run the slow logic, even temporarily during debug, allows you to oversample much less and see more with the same buffer. So it's very much a use case to care about.

2026-07-14 16:30:03 UTC

One of the big benefits of my homebrew ILA IP, BTW, is that it works just fine with any clocking relationship between the debug-bridge clock and the capture domain clock.
For some reason that I do not understand - I don't even know how I would implement such a restriction - the Vivado ILA does not work if the capture-domain clock is too slow. It needs to be at least 2x, IIRC, the JTAG TCK frequency.
So if you're running JTAG at say 30 MHz and you want to capture in a 20 MHz domain you're SOL.

2026-07-14 02:48:49 UTC

If you're ever looking for an Italian restaurant and don't have a phone or map, but do have a gamma spectrometer, just look for 511 keV annihilation lines and follow them to their source. If you find them from multiple restaurants, the weaker line is the one to eat at.
No matter how well they try to clean cooking utensils between making pasta and antipasto, some mixing is unavoidable.
A smaller annihilation peak is a good sign of more thorough cleaning and better general food safety practices.

2026-07-14 01:17:52 UTC

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@nprofile…ngkv I don't need it *yet* but my vm server is getting pretty full of pcie devices and I don't have a lot of slots left (but many are underutilized) so I'm thinking ahead

2026-07-14 01:14:50 UTC

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@nprofile…ngkv ooh I'll have to give it a detailed look but certainly seems like what I'm thinking of at a glance

2026-07-14 01:08:45 UTC

Is anyone aware of a rack mountable enclosure + backplane that connects to a PCIe host by cables, and has its own power supply and cooling fans etc?
Use case: server mainboard with a bunch of bifurcation capable x16 slots that I want to hook a ton of x4 devices to

2026-07-13 21:36:14 UTC

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@nprofile…q57v Just getting data into the application doesn't need a ton of power. With anything but a thunderscope you'll be limited by instrument firmware, not your PC.
We have a not-formally-published-but-public-if-you-have-the-URL google spreadsheet with a somewhat out of date table of instrument makes, models, memory depths, and observed trigger rates.
After data is on your computer, performance is extremely dependent on the filter graph.
More video RAM is better if you want to work with deep memory doing complex processing, especially the CDR PLL and PAM4 edge detector blocks are very memory heavy (I want to play with optimizing them a bit but as of now if you go beyond low tens of megapoints memory depth you'll need a pretty high end GPU just for the scratch buffers to fit).
But like, there's a huge difference in speed between say doing a very sharp rolloff FIR filter with 500+ taps on deep memory, and just measuring the frequency of a squarewave. Different filter graph configurations can easily create multiple order of magnitude variations in processing speed. It's not like a game where the workloads are predictable, or a CAD tool where you can mostly just bound by the number of triangles in your model or something. Ngscopeclient is really more of a toolbox, how you put the tools together very much determines how much compute you need.
If you're using only/mostly the 40ish filter blocks out of 200ish that are GPU accelerated, things will run faster, but performance will become very GPU dependent. If you're using CPU-side processing blocks, performance will be broadly worse but also CPU dependent.
I'll definitely try and throw together some benchmark examples in the not-too-distant future, that would probably be good to have, but they're single point measurements on a specific hardware configuration with a specific filter graph and a specific commit of ngscopeclient in a very multidimensional space.