Tim Misiak
@timdbg.com
OS/systems engineer, co-founder of Augmend. I used to work on WinDbg at Microsoft. Also on mastodon/fediverse as @tim@dbg.social
Reposted by Tim Misiak
Parents - check your halloween candy carefully. Someone may try to teach your kids the C programming language
October 31, 2025 at 4:29 PM
Parents - check your halloween candy carefully. Someone may try to teach your kids the C programming language
I'm switching to Anthropic for an app I'm building because OpenAI doesn't have an IPv6 endpoint... in 2025.
Sorry, I'm not going to pay $45 a year extra just so I can have an IPv4 address to talk to your API.
Sorry, I'm not going to pay $45 a year extra just so I can have an IPv4 address to talk to your API.
October 18, 2025 at 3:29 AM
I'm switching to Anthropic for an app I'm building because OpenAI doesn't have an IPv6 endpoint... in 2025.
Sorry, I'm not going to pay $45 a year extra just so I can have an IPv4 address to talk to your API.
Sorry, I'm not going to pay $45 a year extra just so I can have an IPv4 address to talk to your API.
If you just heard a really loud sigh, it's because I just saw the library book my son took home. It's about a kid who time travels to the distant past... to the year 1993
October 10, 2025 at 9:50 PM
If you just heard a really loud sigh, it's because I just saw the library book my son took home. It's about a kid who time travels to the distant past... to the year 1993
Reposted by Tim Misiak
🐞 Building a debugger = learning how computers really work.
On today’s #GOTOpodcast, @timdbg.com & @tartanllama.xyz unpack:
🔍 The hidden complexity of stack unwinding & stepping
🖥️ Windows vs Linux debugging
⏳ Time travel debugging & the future
🎧 gotopia.tech/podcast
On today’s #GOTOpodcast, @timdbg.com & @tartanllama.xyz unpack:
🔍 The hidden complexity of stack unwinding & stepping
🖥️ Windows vs Linux debugging
⏳ Time travel debugging & the future
🎧 gotopia.tech/podcast
September 19, 2025 at 12:15 PM
🐞 Building a debugger = learning how computers really work.
On today’s #GOTOpodcast, @timdbg.com & @tartanllama.xyz unpack:
🔍 The hidden complexity of stack unwinding & stepping
🖥️ Windows vs Linux debugging
⏳ Time travel debugging & the future
🎧 gotopia.tech/podcast
On today’s #GOTOpodcast, @timdbg.com & @tartanllama.xyz unpack:
🔍 The hidden complexity of stack unwinding & stepping
🖥️ Windows vs Linux debugging
⏳ Time travel debugging & the future
🎧 gotopia.tech/podcast
Feels strange cancelling my subscription to a VPS I used for some side projects, after being a customer for 20 years.
Now I feel really old.
Now I feel really old.
August 29, 2025 at 5:28 PM
Feels strange cancelling my subscription to a VPS I used for some side projects, after being a customer for 20 years.
Now I feel really old.
Now I feel really old.
Reposted by Tim Misiak
If you're like me and can't remember if it's RCX or R8 for the fourth parameter... Get the Compiler Explorer ABI Mug: actual calling conventions for x86-64 System V, Windows, and ARM64. Support @godbolt.org: grab yours here -> shop.compiler-explorer.com/collections/...
August 17, 2025 at 10:02 PM
If you're like me and can't remember if it's RCX or R8 for the fourth parameter... Get the Compiler Explorer ABI Mug: actual calling conventions for x86-64 System V, Windows, and ARM64. Support @godbolt.org: grab yours here -> shop.compiler-explorer.com/collections/...
Reposted by Tim Misiak
AOL To Discontinue Dial-Up Internet
theonion.com/aol-to-...
theonion.com/aol-to-...
August 13, 2025 at 8:30 PM
AOL To Discontinue Dial-Up Internet
theonion.com/aol-to-...
theonion.com/aol-to-...
Reposted by Tim Misiak
Microsoft:
All-time high valuation
All-time high revenue
All-time high profits
*Still does mass layoffs*
(Sidenote: probably now is the single best time to hire, or try to hire from the company)
All-time high valuation
All-time high revenue
All-time high profits
*Still does mass layoffs*
(Sidenote: probably now is the single best time to hire, or try to hire from the company)
July 10, 2025 at 12:13 PM
Microsoft:
All-time high valuation
All-time high revenue
All-time high profits
*Still does mass layoffs*
(Sidenote: probably now is the single best time to hire, or try to hire from the company)
All-time high valuation
All-time high revenue
All-time high profits
*Still does mass layoffs*
(Sidenote: probably now is the single best time to hire, or try to hire from the company)
Reposted by Tim Misiak
There a gatcha machines for every interest group:
June 26, 2025 at 4:27 AM
There a gatcha machines for every interest group:
Reposted by Tim Misiak
Building a Debugger is now officially released!
It guides you through building a whole native x64 debugger from scratch, dispelling all the magic and teaching you a ton about operating systems as it goes.
Even if you don't care about building a debugger, you can read it to your cat.
It guides you through building a whole native x64 debugger from scratch, dispelling all the magic and teaching you a ton about operating systems as it goes.
Even if you don't care about building a debugger, you can read it to your cat.
June 10, 2025 at 3:59 PM
Building a Debugger is now officially released!
It guides you through building a whole native x64 debugger from scratch, dispelling all the magic and teaching you a ton about operating systems as it goes.
Even if you don't care about building a debugger, you can read it to your cat.
It guides you through building a whole native x64 debugger from scratch, dispelling all the magic and teaching you a ton about operating systems as it goes.
Even if you don't care about building a debugger, you can read it to your cat.
I have a story about this. Arm kernel debugger would run the CPU at 100% when at an exception. Supposedly early WP hardware didn't have sufficient thermal protection so it could literally crash and burn.
I don't know if it ever actually happened, but I was told to be careful when debugging.
I don't know if it ever actually happened, but I was told to be careful when debugging.
In my opinion one of the greatest losses in abandoning Windows Phone was the intense performance and battery focus m it forced into the Windows kernel and experience.
Microsoft's new Xbox full-screen experience will come first to Xbox Ally and Xbox Ally X, but Microsoft says it will update the Ally and Ally X too. "Similar full screen Xbox experiences will be rolling out to other Windows handhelds beginning next year" www.theverge.com/news/682011/...
June 9, 2025 at 8:04 AM
I have a story about this. Arm kernel debugger would run the CPU at 100% when at an exception. Supposedly early WP hardware didn't have sufficient thermal protection so it could literally crash and burn.
I don't know if it ever actually happened, but I was told to be careful when debugging.
I don't know if it ever actually happened, but I was told to be careful when debugging.
100% accurate. I saw Dawson's first law many times working on WinDbg. With a few of them discovered by Dawson. The rest were discovered by the SQL server team using thread/module counts beyond what any sane person would expect.
O(n^2) is the "works on my machine" of algorithmic complexity.
O(n^2) is the "works on my machine" of algorithmic complexity.
I like to call this Dawson’s first law of computing: O(n^2) is the sweet spot of badly scaling algorithms: fast enough to make it into production, but slow enough to make things fall down once it gets there.
June 7, 2025 at 8:25 PM
100% accurate. I saw Dawson's first law many times working on WinDbg. With a few of them discovered by Dawson. The rest were discovered by the SQL server team using thread/module counts beyond what any sane person would expect.
O(n^2) is the "works on my machine" of algorithmic complexity.
O(n^2) is the "works on my machine" of algorithmic complexity.
Looks like Google might be stepping up ad-blocking-blocking on YouTube. And considering they do absolutely nothing every time I report hateful and/or scam adverts, I guess it means I'm done with YouTube. Not that I needed much of a push.
June 5, 2025 at 8:18 PM
Looks like Google might be stepping up ad-blocking-blocking on YouTube. And considering they do absolutely nothing every time I report hateful and/or scam adverts, I guess it means I'm done with YouTube. Not that I needed much of a push.
Thank you, github copilot, for covering up part of the line of code I need to read with an offer to explain it to me, with no way to dismiss or scroll past the button.
May 23, 2025 at 4:20 PM
Thank you, github copilot, for covering up part of the line of code I need to read with an offer to explain it to me, with no way to dismiss or scroll past the button.
Reposted by Tim Misiak
When emulating x86 shr, remember to apply the proper mask:
“the count is masked against 1FH, essentially using only the lowest five bits of the rotation.2 If the REX.W prefix is used, the mask will be 3FH, meaning the maximum shift is 63 bits.”
www.timdbg.com/posts/useles...
Thanks @timdbg.com!
“the count is masked against 1FH, essentially using only the lowest five bits of the rotation.2 If the REX.W prefix is used, the mask will be 3FH, meaning the maximum shift is 63 bits.”
www.timdbg.com/posts/useles...
Thanks @timdbg.com!
Weird things I learned while writing an x86 emulator
If you’ve read my first post about assembly language, you might expect that this is another post on how to understand assembly language. I will write more about that at some point, but this post is no...
www.timdbg.com
May 16, 2025 at 6:54 PM
When emulating x86 shr, remember to apply the proper mask:
“the count is masked against 1FH, essentially using only the lowest five bits of the rotation.2 If the REX.W prefix is used, the mask will be 3FH, meaning the maximum shift is 63 bits.”
www.timdbg.com/posts/useles...
Thanks @timdbg.com!
“the count is masked against 1FH, essentially using only the lowest five bits of the rotation.2 If the REX.W prefix is used, the mask will be 3FH, meaning the maximum shift is 63 bits.”
www.timdbg.com/posts/useles...
Thanks @timdbg.com!
Reposted by Tim Misiak
!!!!!! I have actually physical copies of my book
May 13, 2025 at 1:33 PM
!!!!!! I have actually physical copies of my book
Really enjoyed interviewing @tartanllama.xyz about "Building a Debugger". This is a wonderful book for anyone who wants to learn more about how the OS, compiler, and debugger work together. It's not just for people who want to build a debugger!
Implementing a debugger teaches deep systems knowledge! @timdbg.com and @tartanllama.xyz explore fundamentals, stack unwinding complexity, and the future with time-travel debugging.
Building a Debugger • Sy Brand & Tim Misiak • GOTO 2025
This interview was recorded for the GOTO Book Club. #GOTOcon #GOTObookclubhttp://gotopia.tech/bookclubRead the full transcription of the interview here:https...
youtu.be
May 8, 2025 at 4:35 PM
Really enjoyed interviewing @tartanllama.xyz about "Building a Debugger". This is a wonderful book for anyone who wants to learn more about how the OS, compiler, and debugger work together. It's not just for people who want to build a debugger!
Reposted by Tim Misiak
Implementing a debugger teaches deep systems knowledge! @timdbg.com and @tartanllama.xyz explore fundamentals, stack unwinding complexity, and the future with time-travel debugging.
Building a Debugger • Sy Brand & Tim Misiak • GOTO 2025
This interview was recorded for the GOTO Book Club. #GOTOcon #GOTObookclubhttp://gotopia.tech/bookclubRead the full transcription of the interview here:https...
youtu.be
May 8, 2025 at 12:01 PM
Implementing a debugger teaches deep systems knowledge! @timdbg.com and @tartanllama.xyz explore fundamentals, stack unwinding complexity, and the future with time-travel debugging.
Weird to see the logo I "helped" design pop up on a news site. But weirder to see why it popped up.
Ai+windbg makes sense, but probably the biggest boost for most people is just fixing arcane interactions rather than deep insights.
www.tomshardware.com/tech-industr...
Ai+windbg makes sense, but probably the biggest boost for most people is just fixing arcane interactions rather than deep insights.
www.tomshardware.com/tech-industr...
AI taught to analyze Windows crash dumps, released to open source — 'like going from hunting with a stone spear to using a guided missile'
Brings crash dump analysis into the AI era by integrating GitHub Copilot with WinDBG.
www.tomshardware.com
May 8, 2025 at 6:01 AM
Weird to see the logo I "helped" design pop up on a news site. But weirder to see why it popped up.
Ai+windbg makes sense, but probably the biggest boost for most people is just fixing arcane interactions rather than deep insights.
www.tomshardware.com/tech-industr...
Ai+windbg makes sense, but probably the biggest boost for most people is just fixing arcane interactions rather than deep insights.
www.tomshardware.com/tech-industr...
Description of the PR that broke everything: "This PR should be noop."
April 30, 2025 at 6:08 AM
Description of the PR that broke everything: "This PR should be noop."
I'm about ready to switch from chatgpt to claude just to escape the new overly enthusiastic emoji-ridden responses. Just answer my question and stop acting like an sycophant.
April 27, 2025 at 1:23 AM
I'm about ready to switch from chatgpt to claude just to escape the new overly enthusiastic emoji-ridden responses. Just answer my question and stop acting like an sycophant.
I always thought this door handle was weirdly warm to the touch... Guess I wasn't imagining it.
April 21, 2025 at 8:50 PM
I always thought this door handle was weirdly warm to the touch... Guess I wasn't imagining it.
Reposted by Tim Misiak
Uncle Sam abruptly turns off funding for CVE program. Yes, that CVE program
Uncle Sam abruptly turns off funding for CVE program. Yes, that CVE program
Because vulnerability management has nothing to do with national security, right?
US government funding for the world's CVE program – the centralized Common Vulnerabilities and Exposures database of product security flaws – ends Wednesday.…
dlvr.it
April 16, 2025 at 12:06 AM
Uncle Sam abruptly turns off funding for CVE program. Yes, that CVE program
Why yes, I *did* spend a few hours today writing a mod for Valheim that forwards player metrics to a Datadog dashboard.
April 7, 2025 at 5:52 AM
Why yes, I *did* spend a few hours today writing a mod for Valheim that forwards player metrics to a Datadog dashboard.
Reposted by Tim Misiak
Last week I pushed a bunch of documentation updates that have been on my to-do list for a while.
Most of the EH Rtl functions were documented in a hurry during the consent decree dark period. Hopefully you can the see the difference with how I documented the new learn.microsoft.com/en-us/window...
Most of the EH Rtl functions were documented in a hurry during the consent decree dark period. Hopefully you can the see the difference with how I documented the new learn.microsoft.com/en-us/window...
RtlVirtualUnwind2 function (Wdm.h) - Win32 apps
Given a representation of the CPU context within a function, calculates CPU context representing the parent (caller) stack frame.
learn.microsoft.com
April 4, 2025 at 2:38 AM
Last week I pushed a bunch of documentation updates that have been on my to-do list for a while.
Most of the EH Rtl functions were documented in a hurry during the consent decree dark period. Hopefully you can the see the difference with how I documented the new learn.microsoft.com/en-us/window...
Most of the EH Rtl functions were documented in a hurry during the consent decree dark period. Hopefully you can the see the difference with how I documented the new learn.microsoft.com/en-us/window...