It started with a thought: to understand people's perspectives on life and its meaning. So I texted folks, "What is life (to you)?". Each of the following list items (-) is a response from a different individual, mostly verbatim.

- A lot

- Everyone has a few universal basic qualities, and some special qualities. To me life is pursuit of exploring world based on those qualities and maturing those qualities as one goes on about exploring world/life with those qualities.
Discovering and enhancing experiences as one goes through them.

- life is endless suffering

- my answer might change daily, but this is what I've noticed and feel recently. Life is a spectrum with two distinct ends: what we control and what we don't. At birth, the spectrum is largely tilted toward control, but throughout our lives, it gradually shifts toward the other side. Ultimately, as we approach death, we lose all control over any aspect of our existence, reaching the other end of the spectrum.
tho this isn't universal, privilege plays a huge part in what you control tho i believe it holds true for the majority
but yeah man, meaning and purpose are dynamic, it's in their nature to change i can give you a different answer this evening itself xD

- Funeral Monologue from Synecdoche, New York. https://www.youtube.com/watch?v=Z9PzSNy3xj0

- Zindagi ek nadiya hai, Aur mujhe tairna nahi aata
(translation - Life is a river, and I don't know how to swim)
On a more serious note, Life is what you make it out for yourself. The only established truth is that it will end. We can never know if there is something after or if there was something before. So try to live a life that you feel aspired by? But this question was beautifully answered by that book which you had about that dying professor
(Me - He was talking about Tuesday's with Morrie)

- My answer is 42

- One, it's living on your own terms, you define everything for yourself, success, normal, whatever. You get to curate your version of it no matter the societal norms.
It's an accumulation of experiences - friends, parents, work, activities, doing shit loads. Sab try karo- travel, zumba, art, music, workout, sports, dil kara ye karna hai karlo. (translation - If your heart wants to do it, just do it.)
Then I think relationships - all that you've nurtured, people forget maintaining people because of work. It takes efforts to keep people in your life, everyone that comes has a place in yours, how well thats stays is upto you. You also get to curate your people, who stays who don't. Family toh hai hi (translation - family is there) but everyone else that comes along can make it pretty good.
So I don't want to be 50 and be like chalo ab kuch apne liye karte hai… (translation - Come on, now let's do something for ourselves) Do whatever shit you want today. Not everything costs money, and if it does get thrifty
But do keep healthy while doing all of that

- Being alive so that my daughter can grow up and i can help raising her kids as well. Raising kids without mother is tough :P

- Definitively, I feel like Life is a by product of proteins and energy working together. But in a more personal sense, Life is a dumb joke played onto us. It's a rat race. But rats exists because of life and then it becomes a chicken-egg problem
Honestly, I don't give good answers to life questions. I'm generally the one asking
Life can be like a box of chocolates, you don't know what you're gonna get untill you experience the chocolate(assuming the chocolates are heterogenous and contains a mix of everything)
Camus once said, "Life is a revolt", and one of his students added more spice to it like "Life is a revolt against the meaninglessness of existence"
I kinda feel like Life is the pursuit of every person's search for meaning

- Imprisonment waiting for execution 😄
I have one more thought while we are on the topic , game with pre defined starting position and predefined destination , path to reach is a maze

- Life to me is to live without regrets and live with freedom.
Life is always unpredictable and this unpredictability makes it more interesting and worth it.

- As of now, for the state of mind that I am in , I think for me life is about subtle struggle, subtle inconveniences and yet moving forward cause that's all I know.
I am not sure if any of this has any meaning, but sometimes I feel I was born of a purpose and that the universe has my back.
For me it's about raising my consciousness, understanding people to their depths, gaining moderate material success and helping people to some extend.
I have tried to seek a grander meaning but I have failed.
Life for me is what I make out it.
In my times of great success i rarely think about life for I am busy enjoying it, whatever you may call that state of mind.

- For me its the little things that you enjoy with YOUR people

- Mere liye (translation - for me) life is staying at my home and studying random economics papers. That's when I enjoy myself the most.

- Very complicated
Some days I wish this life never ended and some time I feel it would be better if it stopped at that moment.
It all depends on the events that happen in the so called "life".
So life to me is a string of events that happen anyway and you get to make some decisions which can turn it in any direction and then you wonder how did that happen.

- To be honest it changed with time! At 19 it was about freedom, wasn't sure what freedom meant but i wanted that! To be free from everything, maybe because parents still controlled a part of my life. Then came 22-24 where i was working, trying to figure out what i want, the meaning changed from freedom to living for myself. To earn more, to be greedy about myself and pursue whatever would help me gain more steps in my career.
Came my mba life, switched my life from doing for myself to trying everything out to have no regrets. Life meaning was just about living with no regrets, invested, gambled, did everything to earn that tag of "yeah, have tried that". Now it has all switched to, it was all just a fake facade. Life turned to having a meaningful life rather than finding meaning in what i am doing. Living for people around me, chhoti chhoti cheezo m khushi (translation - happiness in small things(?)) isn't really a topic of conversation but more of happy thing for me. So it changed, and m quite happy to be honest. Life did show me a lot of failures, but was privileged enough to face those failures. Gained a lot of learnings if not money😂
Hopeful for more learnings and change meaning of life with time

- A task.

- You have different answers at different times You learn different meanings at different times When you are studying, basically it is about job, finding a partner then it becomes, house, car other things based on your income in between, there can be passion too
Free Software was a passion, electoral politics too, but both kind of faded and I want cooperative and user driven development now (prav - something that motivates me every day) and these days learning Chinese and watching Cdrama takes a huge part of my leisure time it is heavily subjective and also influences by previous experiences people around you, how much influence they have on you
it also depends on if they had to struggle in their life or not, for some life did not give much troubles and trouble itself can be relative people who never had to struggle may find even smallest challenges as troubles like if you own a car, your worry is finding a parking slot

- I am too young to think about lyfe

- A ticket to see the show on earth, I guess 😀
I guess life is different depending on the mood. It is a very broad question.
(Me - What is it in this present mood?)
Learning stuff (like I am learning a new language) and being happy but also to regulate emotions in a world where being optimistic is getting harder each day.
Life is also having a unique set of glasses you wear. Both in terms of looking from your eyeballs and your psychological perspective. Both are unique and cannot be replicated.
It is interesting what people on their deathbed think of life. If I know I am dying, my perspective would change a whole lot.
Life is finishing reading books while we are alive 😉
Life is sleeping after a good XMPP chat 😉

- Dukh dard peeda (translation - surrow pain suffering)

- uhh to word it? life is just like a journey from A to somewhere and its all about what paths you take and what line you get on to me, just a series of short adventures that all connect to a larger sequence until you can't have any more adventures-
(Me - eee, THE END. drop dead, like a coin)
yeaaaah- I am not really for spirituality of an afterlife, to me life just ends at some point, after which point there fails to remain a discernable you, and some X time after which, you will be last remembered, try to make that last time a good one I guess?
(Me - no soul?)
uhhh not in the way most people think of it i guess?
theres just a lot of yous, theres the physical you, there is the idea of you, there is the expectation of you, and one of the undefinable you I would label as the soul maybe? like the part thats not physically you, but also certainly you
(Me - can't say I understood part, but I get you in this sense)
mhm- well its about just questioning who you are more so questioning what life is-, I have sadly spent way too much time trying to figure that out

- Making the best of the time you have

- living a full range of experiences and embracing the good ones, seeing all that the world has to offer. In the end we were always just stardust. Might as well enjoy it when we are stardust with a consciousness of our own.

- Life is being fucked by everything and you just have to figure out and try to stick to the things worth being fucked for

Note: Following was transcribed from a audio message.

- There are five conditions to become a life to survive in the environment. I think there's five conditions by the biological definitions and reproduction is one of the factor virus is not considered a life form because it cannot reproduce on its own but technically it's kind of a life because it reproduces using the DNA ability this is the biological definition. Do you want a philosophical definition?
My definition is kind of the same except that you get life experiences along with it as a human. Extra benefits is that you are not an NPC. All other organisms are NPCs. But humans can interpret the world and change it to their liking. That is life in the case of a human. But then many humans are mostly NPCs. But they still can change the life. Okay, fuck this. Where is this even going?
A human is an exception in the case of life, because human is not an NPC. Human can interrupt the world, human can change it to its liking, which is why we are such a successful organism on this planet. That is life to me. That's a human. But all of this is kind of meaningless, because the biological impurity of a human being still exists, so you still have the urges to reproduce, which kind of makes it like just another organism. But then, humans are yet to evolve to overcome that biological imperative.

I'm grateful for all the replies, outlooks, and subsequent conversations I got to have after this question with everyone. After all, it was a deeply personal question. It does fit in nicely with my definition of life:
"Life is all about experiences and all the transient relationships one gets to have with folks we meets on the way."

16 Apr 2026 5:59pm GMT

It's true - processing data from software defined radios can be a bit complex 👈😏👈 - which tends to keep all but the most grizzled experts and bravest souls from playing with it. While I wouldn't describe myself as either, I will say that I've stuck with it for longer than most would have expected of me. One of the biggest takeaways I have from my adventures with software defined radio is that there's a lot of cool crossover opportunity between RF and nearly every other field of engineering.

Fairly early on, I decided on a very light metadata scheme to track SDR captures, called rfcap. rfcap has withstood my test of time, and I can go back to even my earliest captures and still make sense of what they are - IQ format, capture frequencies, sample rates, etc. A huge part of this was the simplicity of the scheme (fixed-lengh header, byte-aligned to supported capture formats), which made it roughly as easy to work with as a raw file of IQ samples.

However, rfcap has a number of downsides. It's only a single, fixed-length header. If the frequency of operation changed during the capture, that change is not represented in the capture information. It's not possible to easily represent mulit-channel coherent IQ streams, and additional metadata is condemned to adjacent text files.

ARF (Archive of RF)

A few years ago, I needed to finally solve some of these shortcomings and tried to see if a new format would stick. I sat down and wrote out my design goals before I started figuring out what it looked like.

First, whatever I come up with must be capable of being streamed and processed while being streamed. This includes streaming across the network or merely written to disk as it's being created. No post-processing required. This is mostly an artifact of how I've built all my tools and how I intereact with my SDRs. I use them extensively over the network (both locally, as well as remotely by friends across my wider lan). This decision sometimes even prompts me to do some crazy things from time to time.

I need actual, real support for multiple IQ channels from my multi-channel SDRs (Ettus, Kerberos/Kracken SDR, etc) for playing with things like beamforming. My new format must be capable of storing multiple streams in a single capture file, rather than a pile of files in a directory (and hope they're aligned).

Finally, metadata must be capable of being stored in-band. The initial set of metadata I needed to formalize in-stream were Frequency Changes and Discontinuities. Since then, ARF has grown a few more.

After getting all that down, I opted to start at what I thought the simplest container would look like, TLV (tag-length-value) encoded packets. This is a fairly well trodden path, and used by a bunch of existing protocols we all know and love. Each ARF file (or stream) was a set of encoded "packets" (sometimes called data units in other specs). This means that unknown packet types may be skipped (since the length is included) and additional data can be added after the existing fields without breaking existing decoders.

Unlike a "traditional" TLV structure, I opted to add "flags" to the top-level packet. This gives me a bit of wiggle room down the line, and gives me a feature that I like from ASN.1 - a "critical" bit. The critical bit indicates that the packet must be understood fully by implementers, which allows future backward incompatible changes by marking a new packet type as critical. This would only really be done if something meaningfully changed the interpretation of the backwards compatible data to follow.

Within each Packet is a tag field. This tag indicates how the contents of the value field should be interpreted.

In order to help with checking the basic parsing and encoding of this format, the following is an example packet which should parse without error.

 00, // tag (0; no subpacket is 0 yet)
 00, // flags (0; no flags)
 00, 00 // length (0; no data)
 // data would go here, but there is none

Additionally, throughout the rest of the subpackets, there are a few unique and shared datatypes. I document them all more clearly in the draft, but to quickly run through them here too:

UUID

This field represents a globally unique idenfifer, as defined by RFC 9562, as 16 raw bytes.

Frequency

Data encoded in a Frequency field is stored as microhz (1 Hz is stored as 1000000, 2 Hz is stored as 2000000) as an unsigned 64 bit integer. This has a minimum value of 0 Hz, and a maximum value of 18446744073709551615 uHz, or just above 18.4 THz. This is a bit of a tradeoff, but it's a set of issues that I would gladly contend with rather than deal with the related issues with storing frequency data as a floating point value downstream. Not a huge factor, but as an aside, this is also how my current generation SDR processing code (sparky) stores Frequency data internally, which makes conversion between the two natural.

IQ samples

ARF supports IQ samples in a number of different formats. Part of the idea here is I want it to be easy for capturing programs to encode ARF for a specific radio without mandating a single iq format representation. For IQ types with a scalar value which takes more than a single byte, this is always paired with a Byte Order field, to indicate if the IQ scalar values are little or big endian.

Header

Each ARF file must start with a specific Header packet. The header contains information about the ARF stream writ large to follow. Header packets are always marked as "critical".

In order to help with checking the basic parsing and encoding of this format, the following is an example header subpacket (when encoded or decoded this will be found inside an ARF packet as described above) which should parse without error, with known values.

00, 00, 00, fa, de, dc, ab, 1e, // magic
00, 00, 00, 00, 00, 00, 00, 00, // flags
18, 27, a6, c0, b5, 3b, 06, 07, // start time (1740543127)

// guid (fb47f2f0-957f-4545-94b3-75bc4018dd4b)
fb, 47, f2, f0, 95, 7f, 45, 45,
94, b3, 75, bc, 40, 18, dd, 4b,

// site_id (ba07c5ce-352b-4b20-a8ac-782628e805ca)
ba, 07, c5, ce, 35, 2b, 4b, 20,
a8, ac, 78, 26, 28, e8, 05, ca

Stream Header

Immediately after the arf Header, some number of Stream Headers follow. There must be exactly the same number of Stream Header packets as are indicated by the num streams field of the Header. This has the nice effect of enabling clients to read all the stream headers without requiring buffering of "unread" packets from the stream.

In order to help with checking the basic parsing and encoding of this format, the following is an example stream header subpacket (when encoded or decoded this will be found inside an ARF packet as described above) which should parse without error, with known values.

00, 01, // id (1)
00, 00, 00, 00, 00, 00, 00, 00, // flags
01, // format (float32)
01, // byte order (Little Endian)
00, 00, 01, d1, a9, 4a, 20, 00, // rate (2 MHz)
00, 00, 5a, f3, 10, 7a, 40, 00, // frequency (100 MHz)

// guid (7b98019d-694e-417a-8f18-167e2052be4d)
7b, 98, 01, 9d, 69, 4e, 41, 7a,
8f, 18, 16, 7e, 20, 52, be, 4d,

// site_id (98c98dc7-c3c6-47fe-bc05-05fb37b2e0db)
98, c9, 8d, c7, c3, c6, 47, fe,
bc, 05, 05, fb, 37, b2, e0, db,

Samples

Block of IQ samples in the format indicated by this stream's format and byte_order field sent in the related Stream Header.

In order to help with checking the basic parsing and encoding of this format, the following is an samples subpacket (when encoded or decoded this will be found inside an ARF packet as described above). The IQ values here are notional (and are either 2 8 bit samples, or 1 16 bit sample, depending on what the related Stream Header was).

01, // id
ab, cd, ab, cd, // iq samples

Frequency Change

The center frequency of the IQ stream has changed since the Stream Header or last Frequency Change has been sent. This is useful to capture IQ streams that are jumping around in frequency during the duration of the capture, rather than starting and stopping them.

In order to help with checking the basic parsing and encoding of this format, the following is a frequency change subpacket (when encoded or decoded this will be found inside an ARF packet as described above).

01, // id
00, 00, b5, e6, 20, f4, 80, 00 // frequency (200 MHz)

Discontinuity

Since the last Samples packet for this stream, samples have been dropped or not encoded to this stream. This can be used for a stream that has dropped samples for some reason, a large gap (radio was needed for something else), or communicating "iq snippits".

In order to help with checking the basic parsing and encoding of this format, the following is a discontinuity subpacket (when encoded or decoded this will be found inside an ARF packet as described above).

01, // id

Location

Up-to-date location as of this moment of the IQ stream, usually from a GPS. This allows for in-band geospatial information to be marked in the IQ stream. This can be used for all sorts of things (detected IQ packet snippits aligned with a time and location or a survey of rf noise in an area)

The sys field indicates the Geodetic system to be used for the provided latitude, longitude and elevation fields. The full list of supported geodetic systems is currently just WGS84, but in case something meaningfully changes in the future, it'd be nice to migrate forward.

Unfortunately, being a bit of a coward here, the accuracy field is a bit of a cop-out. I'd really rather it be what we see out of kinematic state estimation tools like a kalman filter, or at minimum, some sort of ellipsoid. This is neither of those - it's a perfect sphere of error where we pick the largest error in any direction and use that. Truthfully, I can't be bothered to model this accurately, and I don't want to contort myself into half-assing something I know I will half-ass just because I know better.

In order to help with checking the basic parsing and encoding of this format, the following is a location subpacket (when encoded or decoded this will be found inside an ARF packet as described above).

00, 00, 00, 00, 00, 00, 00, 00, // flags
01, // system (wgs84)
3f, f3, be, 76, c8, b4, 39, 58, // latitude (1.234)
40, 02, c2, 8f, 5c, 28, f5, c3, // longitude (2.345)
40, 59, 00, 00, 00, 00, 00, 00, // elevation (100)
40, 24, 00, 00, 00, 00, 00, 00 // accuracy (10)

Vendor Extension

In addition to the fields I put in the spec, I expect that I may need custom packet types I can't think of now. There's all sorts of useful data that could be encoded into the stream, so I'd rather there be an officially sanctioned mechanism that allows future work on the spec without constraining myself.

Just an example, I've used a custom subpacket to create test vectors, the data is encoded into a Vendor Extension, followed by the IQ for the modulated packet. If the demodulated data and in-band original data don't match, we've regressed. You could imagine in-band speech-to-text, antenna rotator azimuth information, or demodulated digital sideband data (like FM HDR data) too. Or even things I can't even think of!

In order to help with checking the basic parsing and encoding of this format, the following is a vendor extension subpacket (when encoded or decoded this will be found inside an ARF packet as described above).

// extension id (b24305f6-ff73-4b7a-ae99-7a6b37a5d5cd)
b2, 43, 05, f6, ff, 73, 4b, 7a,
ae, 99, 7a, 6b, 37, a5, d5, cd,

// data (0x01, 0x02, 0x03, 0x04, 0x05)
01, 02, 03, 04, 05

Tradeoffs

The biggest tradeoff that I'm not entirely happy with is limiting the length of a packet to u16 - 65535 bytes. Given the u8 sample header, this limits us to 8191 32 bit sample pairs at a time. I wound up believing that the overhead in terms of additional packet framing is worth it - because always encoding 4 byte lengths felt like overkill, and a dynamic length scheme ballooned codepaths in the decoder that I was trying to keep as easy to change as possible as I worked with the format.

15 Apr 2026 3:43pm GMT

The nineteenth release of the qlcal package arrivied at CRAN just now, and has already been built for r2u. This version synchronises with QuantLib 1.42 released this week.

qlcal delivers the calendaring parts of QuantLib. It is provided (for the R package) as a set of included files, so the package is self-contained and does not depend on an external QuantLib library (which can be demanding to build). qlcal covers over sixty country / market calendars and can compute holiday lists, its complement (i.e. business day lists) and much more. Examples are in the README at the repository, the package page, and course at the CRAN package page.

This releases updates to the 2025 holidays for China, Singapore, and Taiwan.

The full details from NEWS.Rd follow.

Changes in version 0.1.1 (2026-04-15)

• Synchronized with QuantLib 1.42 released two days ago

• Calendar updates for China, Singapore, Taiwan

Courtesy of my CRANberries, there is a diffstat report for this release. See the project page and package documentation for more details, and more examples.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. If you like this or other open-source work I do, you can sponsor me at GitHub. You can also sponsor my Tour de Shore 2026 ride in support of the Maywood Fine Arts Center.

15 Apr 2026 1:07pm GMT