Dave Plummer on Lex Fridman: How Task Manager got shipped

1. 0:00 – 1:22

   Introduction

   1. LFLex Fridman0:00

      The following is a conversation with Dave Plummer, programmer and an old school Microsoft software engineer who helped work on Windows 95, NT, and XP, building a lot of incredible tools, some of which have been continuously used by hundreds of millions of people, like the famed Windows Task Manager. Yes, the Windows Task Manager. And the zip/unzip compression support in Windows. And he ported the code for Space Cadet Pinball, AKA 3D Pinball to Windows. Today, he's loved by many programmers and engineers for his amazing YouTube channel called Dave's Garage that you should definitely go check out. Also, he wrote a book on autism and about his life story called Secrets of the Autistic Millionaire, where he gives really interesting insights about how to navigate relationships, career, and day-to-day life with autism. All this taken together, this was a super fun conversation about the history and future of programming, computing, technology, and just building cool stuff in the proverbial garage. This is the Lex Fridman Podcast. To support it, please check out our sponsors in the description, and now, dear friends, here's Dave Plummer.

2. 1:22 – 7:00

   First computer

   1. LFLex Fridman1:23

      Tell me about your first computer. Do you remember?

   2. DPDave Plummer1:25

      I do. I didn't own my first computer for a long time, but the first computer I ever used was a TRS-80 Model 1, Level 1, 4K machine, and I rode my bike in fifth or sixth grade, so I was about 11, to the local RadioShack. And, you know, they, they had the standard component stereo systems, everything else RadioShack had, but they had a stack of boxes that was labeled computer, and so I was asking the people that worked there about it, and they said they just got it and they hadn't set it up yet. And so I was rather precocious and I figured, "Well, I'll set it up for you," and they said, "Okay, have a shot." (laughs)

   3. LFLex Fridman1:53

      Did you know what you were doing?

   4. DPDave Plummer1:54

      Absolutely not. I mean, it's no worse than a component stereo, the only thing is that Tandy in their infinite wisdom used the same five pin DIN connector for power, video, and I think cassettes, so they were all identical, and if you plugged them in wrong, you'd blow it up. So I read the label and, uh, got it working and wound up playing with it and not knowing anything about computers, so I'm typing English commands into it and, you know, PRINT 2+2 works perfectly, yet more s- simple English that you enter into a basic Level 1 interpreter is not gonna get you very far.

   5. LFLex Fridman2:23

      So you're trying to talk to it in English?

   6. DPDave Plummer2:25

      Yeah.

   7. LFLex Fridman2:26

      (laughs)

   8. DPDave Plummer2:26

      Didn't know any better. And I still have an old foolscap that I wrote in sixth grade of a, of a program that's kind of illogically correct, but has no chance of working on any interpreter that existed at the time, so it took me a while to figure out what was actually going on with them. But, uh, I rode my bike down there every Thursday and Saturday, and they were gracious to let me use the machine.

   9. LFLex Fridman2:45

      When was this?

   10. DPDave Plummer2:46

       '79, '80.

   11. LFLex Fridman2:47

       Okay. What was the state of the art of computing back then? So what are we talking about?

   12. DPDave Plummer2:50

       Well, the big three had come out. There was the TRS-80 Model 1, there was the PET 2001, and the Apple II came out roughly simultaneously.

   13. LFLex Fridman2:59

       Apple II. Would you say that's the greatest computer ever built?

   14. DPDave Plummer3:02

       Probably in retrospect. Well, I would probably give that to the Commodore 64.

   15. LFLex Fridman3:06

       Yeah. You and I agree on this, that that was my first computer probably many years after it was released, but yeah, Commodore 64's incredible. But yes, Apple II had a huge impact on the history of personal computers.

   16. DPDave Plummer3:18

       Right. It's hard to gauge the long-term impact, but I think the 64 itself probably influenced more people, so that's my reason for picking that one.

   17. LFLex Fridman3:26

       You think so?

   18. DPDave Plummer3:26

       The sales were certainly higher.

   19. LFLex Fridman3:28

       So Commodore 64 sold a lot?

   20. DPDave Plummer3:30

       Yeah. I mean, the numbers are hard to believe. It depends which numbers you believe, but even the medium estimates were pretty high.

   21. LFLex Fridman3:36

       All right, cool. So you eventually graduated to the Commodore 64. Uh, like, tell me about that machine. What did you do on the, on the Commodore 64?

   22. DPDave Plummer3:45

       Well, the first thing I did was overheat the floppy drive on it, which was unfortunate because it wasn't a warranty machine we had. My parents didn't have a lot of money so we bought it from Computer House as opposed to one of the major retailers, which meant when it died, it had to go back to Germany or something to be fixed. So I was left with no floppy and so I had a cassette deck, which was the best you could do at the time, and so I was writing small things, and I had a machine language monitor that you could load from cassette. Didn't have an assembler built in, but it had a dissembler so you could enter the op codes in 6502 in hex, and if you were careful about planning, you'd be able to write some basic programs, so that's kind of how I learned. And, uh, the first thing I ever wrote on it was a clone of Galaga. Now, it's a bad clone of Galaga, but it has the major enemies that attack over time and it's all written in hand-coded machine language and you can't relocate 6502, so if you need to add code in the middle, you need to manually insert a jump to somewhere else, do your work, jump back to where you were. It's just hideous spaghetti code. But it all worked eventually. And I went to make a backup of it to preserve it for future scholars or whatever the hell I was doing.

   23. LFLex Fridman4:45

       (laughs) Okay.

   24. DPDave Plummer4:46

       And, uh, I copied my blank floppy onto my data floppy. So that was my first experience with data management.

   25. LFLex Fridman4:53

       Oh, no.

   26. DPDave Plummer4:53

       So I don't have a copy of my first program anymore.

   27. LFLex Fridman4:55

       What was that feeling like? Do you remember, of, of, uh, just doing something, um, i- if I may say so, like stupid, you know, which is a part of the programming experience?

   28. DPDave Plummer5:04

       Yeah, there was a huge amount of guilt because right, you destroyed several weeks of work-

   29. LFLex Fridman5:08

       Yeah.

   30. DPDave Plummer5:08

       ... and you know it was because you rushed or you did-
3. 7:00 – 14:41

   Dropping out of high-school

   1. LFLex Fridman7:01

   2. DPDave Plummer7:01

      Yeah.

   3. LFLex Fridman7:01

      All right. You dropped out of high school.

   4. DPDave Plummer7:02

      Yeah. Not the smartest move.

   5. LFLex Fridman7:03

      Okay. But you ended up going back to school and being very successful at school and just, in general, successful as a programmer, as a developer, as a creator of software. Uh, how were you able to find your way? Can you tell that journey of dropping out and then-

   6. DPDave Plummer7:20

      Yeah.

   7. LFLex Fridman7:20

      ... finding your way back?

   8. DPDave Plummer7:21

      There's no moment when I dropped out. You just go less and less and less until you realize it's going to be embarrassing if I show up 'cause I haven't been there in a long time, and then pretty soon, you're just not going, and that's how you drop out of high school. So if you find yourself on that path, stop doing that. Um, but that's precisely what I did. And so now, I'm not at school and I have to get a job, so I'm working at 7-Eleven and a paint warehouse and stuff like that. And 7-Eleven is actually kind of an interesting job because it's a job, I think they keep rotating for people that are smart enough to do the night shift with all the accounting and the administration stuff they make the night shift do, but that have reasons personally that they need to work at 7-Eleven. Um, and I was one of those people 'cause I had no high school diploma.

   9. LFLex Fridman8:00

      What are some memorable moments from that time at 7-Eleven? Uh, w- well, maybe what do you, uh, appreciate about the difficulty of that job?

   10. DPDave Plummer8:09

       Probably the worst moment for me, I mean, I got held up at knife-point and stuff, and that's all entertaining, but the worst (laughs) , the most, the, the suckiest part for me was doing the gas dips. We've got a long, it's like a 15 or 20-foot wooden stick and it's measured in gradients of inches and feet, and you drop it into the gasoline tanks and then you bring it up and you measure where the gasoline sits 'cause there's no electronic sensor.

   11. LFLex Fridman8:28

       Mm-hmm.

   12. DPDave Plummer8:29

       So I'm doing that, and the first time I do it, I drop the pole and I regrab it. Well, that's about a thousand splinters of wood into your hands and it's 40 below out, and that really sucked.

   13. LFLex Fridman8:38

       Oh, wow.

   14. DPDave Plummer8:39

       Um (laughs) , and I realized, "I don't want to do this for a whole life." I knew that, so...

   15. LFLex Fridman8:44

       Okay. So you stand there frozen with splinters in your hand.

   16. DPDave Plummer8:47

       And at some point, I have a revelation about my life that next time, I'm going to do it differently. And then how ludicrous that is hits me about three seconds later, right? And I think that was really the moment for me where I realized that I've got to do something different. And so even though I was 21, I went and I talked to the, uh, principal of my local high school, and I was like, "Can you let me back in?" And he's, "No, you're too old and we don't have room," was his main reason. And I said, "Well, between now and then, somebody's going to drop out. So you'll have room. So let's assume you have room. Can I come back?" And he was gracious and let me come back. And so I did the three or four classes that I needed.

   17. LFLex Fridman9:24

       Yeah. You know, just if we can linger on that, the slow dropping out. That's a weird thing that you can do with your brain. You realize to yourself that you don't have to do the thing that everybody else is doing. And that's a dangerous realization because, like, you kind of have to- to be part of society to do certain things.

   18. DPDave Plummer9:44

       Right.

   19. LFLex Fridman9:44

       And if you realize, like, you don't have to do what everybody else is doing, uh, you can either (laughs) have an incredible life or a really difficult life.

   20. DPDave Plummer9:54

       Well, the problem with that process is you're making a much smaller decision. "I'm just not going to go to class today."

   21. LFLex Fridman9:58

       Yeah.

   22. DPDave Plummer9:59

       And that's all you're deciding. But you do that enough times, you're making a much bigger decision.

   23. LFLex Fridman10:02

       Mm-hmm.

   24. DPDave Plummer10:03

       And that's the problem.

   25. LFLex Fridman10:04

       So it's better to make... If you want to live life in a non-standard way, it's better to make the big decision explicitly, and then you can stop going.

   26. DPDave Plummer10:12

       Yeah.

   27. LFLex Fridman10:13

       Uh, don't allow yourself to make the- the- the ... slip mistake.

   28. DPDave Plummer10:15

       It'll be made for you eventually.

   29. LFLex Fridman10:17

       (laughs) Yeah. Okay. Well, you got back and you e- eventually went to college and were very successful as a student, and you weren't that good of a student before.

   30. DPDave Plummer10:24

       No, I was a terrible student in high school, and even my first semester of college, I still wasn't taking it quite serious because I got mercy passed in Geometry 90, which is, like, the makeup class for the geometry 12th grade class that I didn't have. And that scared me 'cause I realized, by 1% or the grace of the prof- professor who let me through, I just about ended my entire university career here. So fortunately, those marks don't count on your transcript 'cause they're remedial classes. And so I got kind of a fresh start the next semester and did it for real, and I did it for me, and that made all the difference.
4. 14:41 – 16:53

   Joining Microsoft

   1. DPDave Plummer14:41

   2. LFLex Fridman14:41

      Let's go to that time. It's such an interesting time with Bill Gates and Microsoft. Why do you think Microsoft was dominating the software and the personal computing space at that time and, and really for many, many, many years after?

   3. DPDave Plummer14:52

      At the time, it was the single most potent assemblage of smart people that I've ever been a part of, and I've been in academia and I've been in industry to a certain extent, and... You know that when you're working at a regular computer company, the one guy who actually knows what he's doing, his smarter friend? He probably works at Microsoft. So when you get there, you're the big cheese from your small town, you think you know a lot, and all of a sudden, you're just in an environment where, like, "Uh-oh, I'm just not gonna speak 'cause I don't want to look stupid."

   4. LFLex Fridman15:20

      Mm-hmm. Okay. Uh, what are, what about Bill Gates himself? What are some qualities of Bill Gates that you think contribute to the success of Microsoft?

   5. DPDave Plummer15:28

      I think he was relentless in the pursuit of his one dream, which was his old slogan of a computer in every home and a computer in every desk. It was his special interest, and he was a smart guy, super determined, and he hired people that were as smart or smarter than him to help him execute it. And he built an almost unstoppable machine of intellect to go forth and make, let's say, very simple products. MS-DOS is not a complicated product by any stretch, but it's exactly what the market needed at that time.

   6. LFLex Fridman15:56

      Yeah, I mean, MS-DOS changed the game, and, uh, that's actually the team you joined, the MS-DOS team, and I think you joined before Windows 95-

   7. DPDave Plummer16:06

      Yeah.

   8. LFLex Fridman16:06

      ... was released. Uh, so tell me about the story of MS-DOS. Its, uh, success of MS-DOS is probably pivotal to the success of Microsoft.

   9. DPDave Plummer16:18

      Yeah, before DOS, they were largely a language company. So they had made BASIC for a lot of computers, and they had a Fortran compiler and a Pascal compiler, that kind of thing, but their deal to have MS-DOS included with every version of, or every instance of the PC effectively, set them as a standard, uh, that they were ale- able to leverage for decades going forward. And to a certain extent, they lucked into that, and on a- another hand, they were smart to have done it, so... 'Cause I, they didn't charge IBM a lot of money for it, but making it a standard really played out to their advantage over time.

   10. LFLex Fridman16:51

       Uh, so at that time, MS-DOS,

5. 16:53 – 20:05

   MS-DOS

   1. LFLex Fridman16:53

      no graphical interface. Can you just speak to what the heck MS-DOS is?

   2. DPDave Plummer16:57

      It's largely a command launcher. So you type in a name of a command, it looks it up to see if that's in the current directory or on a special path of folders, and it loads it into memory and executes it if it's there. And that's 90% of what MS-DOS does. Now, it has environment variables and some complexity and a small scripting language built in, but it is basically just an operating system shell that allows you to, uh, use the resources of the computer, like the hard drive or the CPU, and it doesn't allow you to multitask. There's no graphical interface. Now, Microsoft did a- add a text-based graphical interface for things like an editor and QuickBASIC in DOS 5.0, I believe, and there was a DOS shell, which was sort of a graphical file manager in MS-DOS 4.0. So they experimented with it, but it's largely a command prompt.

   3. LFLex Fridman17:41

      Did- does it have ability to communicate with, uh, external devices, so drivers and all that kind of stuff? Like, how expansive of an operating system was MS-DOS?

   4. DPDave Plummer17:52

      Well, it was limited by the original x86 instruction set, which limited it to 640K.

   5. LFLex Fridman17:57

      Right.

   6. DPDave Plummer17:57

      And then there were various Band-Aids on top of that to do high mem and then extended memory beyond that, and, uh, a lot of hoops have to be jumped through to make anything work without consuming base RAM.

   7. LFLex Fridman18:10

      Yeah, I mean, you, so you programmed on MS-DOS. What- what's it like? What are some interesting details there? Like you said, there's the memory constraints of s-... 640, uh, kilobytes?

   8. DPDave Plummer18:20

      Yeah. 640K is the maximum that's ever going to be available, so it's not what's available to you as an operating system developer, because whatever you use is what the user won't get. So if you use 10K needlessly, you're going to... Every machine in the world now has 10K less, so it's kind of a big responsibility.

   9. LFLex Fridman18:35

      Is that a true quote from Bill Gates, where he said-

   10. DPDave Plummer18:39

       Nobody will ever need more than 640K?

   11. LFLex Fridman18:40

       Yeah.

   12. DPDave Plummer18:40

       Yeah. No. It's not him.

   13. LFLex Fridman18:41

       Okay.

   14. DPDave Plummer18:42

       It's been attributed to him, but not real.

   15. LFLex Fridman18:43

       Uh, okay. So, I mean, w- what are some interesting aspects of w- that you were able to do as an intern and when you joined on MS-DOS and beyond?

   16. DPDave Plummer18:51

       Well, one of the first things I did was to take SmartDrive, the disk cache, because I had familiarity with disk caches-

   17. LFLex Fridman18:56

       Mm-hmm.

   18. DPDave Plummer18:56

       ... and to add CD-ROM caching to it, because that was new. (laughs) CD-ROMs were just, just coming out. Microsoft Bookshelf is one of the few products you could run for it. And as you can imagine, caching a CD speeds it up by dozens of times if you're smart about it. So it, it was a big performance win and a nice thing to work on. Um, a bigger part of that was moving a bunch of SmartDrive and eventually the double-space compression engine up into what's known as high memory.

   19. LFLex Fridman19:19

       Mm-hmm.

   20. DPDave Plummer19:19

       And without rat holing on the technical aspect of it, on the x86, there's something, I believe, called the A20 line. And I probably have this backwards or I got a 50/50 shot at it, but if you've got the A20 line asserted, then your memory pointers wrap at the one megabyte mark.

   21. LFLex Fridman19:33

       Mm-hmm.

   22. DPDave Plummer19:34

       And if not, they don't, so you continue going up in memory. So you can rewrite memory above by combining your segment and offset registers to a number bigger than one megabyte, and you get an extra 64K. And you put your code in there, and then you just put stubs to jump to it from low memory. And so you can get another 64K out of the machine that way, and we did that for a couple other products, and that's... I had no idea what high mem was because I was an Amiga programmer, and I'd never written any x86 code before I got there, so.

   23. LFLex Fridman20:02

       So that was, like, a cool optimization that you got to be a part of.

   24. DPDave Plummer20:04

       Yeah.

6. 20:05 – 26:52

   Windows 95

   1. DPDave Plummer20:05

   2. LFLex Fridman20:05

      So what about Windows? There was a parallel development of Windows 95, right, at that time? Did you get, d- did you get a chance to interact with those folks?

   3. DPDave Plummer20:12

      I actually worked on Windows 95 for about three or four months. I was on the COM/OLA team doing their presentation cache, which is when you insert a, say, a Word or an Excel spreadsheet or chart into a Word document. You don't want Excel to have to be loaded to render it every time, so there's a presentation cache of enhanced metafiles, and I was working on that. So that shipped in Windows 95, but I moved to the shell team about six months after getting to Microsoft, and so I worked on NT from there forward.

   4. LFLex Fridman20:38

      Okay, and what's 95? What's NT?

   5. DPDave Plummer20:40

      Uh, Windows 95 is an evolution of the original 16-bit Windows 3.1, which was the very first popular version of Windows-

   6. LFLex Fridman20:47

      Mm-hmm.

   7. DPDave Plummer20:47

      ... and it adds 32-bit support and then VXD drivers and a bunch of new technology and an entirely new user interface. And it's something that, at the time, was revolutionary. The people lined up at night to, uh, wait in line to buy the thing.

   8. LFLex Fridman21:00

      Can you just take us back to that time and describe why 95 was such a big leap from 3.1? So Apple already had a graphical interface. Uh, Windows 3.1 had a graphical interface. W- why was Windows 95 such a gigantic leap?

   9. DPDave Plummer21:17

      I don't want to make it as basic as the Start menu, but I think-

   10. LFLex Fridman21:19

       (laughs)

   11. DPDave Plummer21:20

       ... it's a big part of it. I know when I first saw it-

   12. LFLex Fridman21:22

       Yeah.

   13. DPDave Plummer21:22

       ... I couldn't quantify what about it was different and awesome, but I realized that I wanted to be a part of it. And that's why I started writing a shell extension, which became, uh, zip folders at some point.

   14. LFLex Fridman21:31

       Mm-hmm.

   15. DPDave Plummer21:32

       But I was just fascinated by the new shell, and that's why I wound up working on the team that brought that shell over to the NT and what's Windows today.

   16. LFLex Fridman21:39

       Would you say that's the greatest operating system ever? What's the most im- impactful operating system ever?

   17. DPDave Plummer21:46

       Windows 95 would be number two for me. I think OS/360 is going to be number one.

   18. LFLex Fridman21:50

       Okay, interesting.

   19. DPDave Plummer21:51

       Because you could take a machine and write a COBOL program for it in 1962, jump in your time machine, go to Poughkeepsie, and boot up an IBM z17 mainframe and run it today. And they've been doing it for however many years, that is. And it's all on the business side, so we as consumers don't have much access to it, but I think it was probably as influential in the commercial side as Windows 95 was in the home side. And then probably Linux would be number three for me. I put Linux b- as bigger than Unix, which doesn't work because you can't have one without the other. But the impact of Unix, BSD, and so forth is largely in the academic space. It's by programmers for programmers.

   20. LFLex Fridman22:29

       So yeah. Linux created... I mean, it was the embodiment of the open-source spirit at its largest scale, right? So it almost created a community, and it, it created a spirit of programming that, uh, propagates to this day. That's true. That's true. Like, scale matters.

   21. DPDave Plummer22:51

       Yeah. And its penetration on the server side of things now is... I don't know if it's equivalent to what System/360 achieved, but it's almost ubiquitous, so.

   22. LFLex Fridman22:59

       Yeah. The world... (laughs) I mean, s- this is the quiet secret of the universe, is it runs on Linux. Okay, so, uh, tell, t- tell me about the days, uh, your workdays. W- what were they like back then, back, uh, back in the MS-DOS and Windows 95 days? Take me through a productive day.

   23. DPDave Plummer23:17

       Well, your day starts coming in, and you got to download the address book, (laughs) which is... Microsoft has between 10 and 15,000 employees at this point, and we're all on MS Mail. We're just getting off of the PDP-11 called Miss Piggy, which ran Whizmail, and, uh, we're running MS Mail. But MS Mail has a fixed address book that every user must download every morning, and when there's 10,000 people downloading 10,000 people, it gets pretty messy. And I think we're on 10 megabit networking at the time. So your first hour is downloading the address book, which was always frustrating. But you'd use that time to look at the crashes that would have happened overnight from a process we called Stress, which is in NT, all the machines that are unused run tests all night long, and they try to crash themselves. And if they manage to crash themselves, it will drop into a debugger with a serial cable to another machine, and you can connect to that other machine and remotely debug the crashed machine. So you come in, and they will have triaged bugs. You know, there was a crash in the Start menu, so we'll assign that to Dave. And so you come in, and that's your first thing, is to connect, because you got to get that machine back to the guy that owns it and unlock the machine, so...... that's your first hour of your day, is basically triage for bugs that have come up from stress overnight. And then at that point, it's probably back to coding, which, unfortunately, 80% of the time is fixing bugs, especially in my career. It was porting code and fixing bugs. I wasn't writing a lot of new code. And there were exceptions. I wrote a lot of new code on the side to get it out of my system-

   24. LFLex Fridman24:39

       Mm-hmm.

   25. DPDave Plummer24:39

       ... from a day, day-to-day grind of always fixing bugs in other people's code, which is amazing learning experience.

   26. LFLex Fridman24:46

       So you did a lot of the... At Microsoft, you did a lot of the porting of, uh, what is it? Windows 95 code to NT?

   27. DPDave Plummer24:53

       Yeah. We took the entire Windows 95 user interface and we ported it to NT, which me- meant making it Unicode for one thing. So everything that was eight bits is now 16 bits, so pointers... It's, it's quite a mess when you switch the code over, as you can imagine.

   28. LFLex Fridman25:07

       Can you give us insights in what is involved in porting?

   29. DPDave Plummer25:12

       It's like breaking into somebody's house and going through all their stuff and seeing the stuff in their drawers that they didn't want you to see.

   30. LFLex Fridman25:17

       Yeah.
7. 26:52 – 31:48

   The man behind Windows

   1. DPDave Plummer26:52

      to start with.

   2. LFLex Fridman26:53

      You said that Dave Cutler is the man, the mind behind Windows. Can you, uh, can you explain?

   3. DPDave Plummer26:59

      So Dave Cutler is the architect of the kernel. So he is Linus in the Linux world. It's Dave C in the Windows world.

   4. LFLex Fridman27:06

      Dave C, okay.

   5. DPDave Plummer27:07

      And, uh, it's not that there weren't other people that contributed, of course, huge pieces to it. But, uh, I think he's the driving force behind it and always largely has been, and he still... I think he's 85 now, and he still codes every day. He's a Microsoft Fellow. He's, as far as I know, still goes into work, so.

   6. LFLex Fridman27:21

      Uh, can you speak to the genius of that guy? Like, what's, what's interesting about his mind, having, having worked with him, having interacted with Dave Cutler?

   7. DPDave Plummer27:30

      Well, the dude's wicked smart, but he's also like a farmer. He's like the guy that will follow you around and make sure that stuff gets done and gets done right to make sure that you're not checking any crap into his operating system.

   8. LFLex Fridman27:42

      Mm-hmm.

   9. DPDave Plummer27:42

      And he won't tolerate it. And he's a real taskmaster in that regard, but I think it really paid off 'cause it was a very big paradigm shift for Microsoft developers to be subjected to the Dave Cutler Digital Equipment style of leadership.

   10. LFLex Fridman27:55

       Uh, what did you learn from that about, uh, successful software teams where there's a large number of people collaborating? Because Microsoft had a lot of brilliant engineers back then, and like you said, Dave Cutler. They had to, uh, they had to create completely new systems, many of which we still use today. What have you learned about great software engineering teams from that time?

   11. DPDave Plummer28:21

       Tools are everything, I think, for one. A- and people are everything, we'll, uh, give that as a granted, but the tool set is a huge fact. If we went ahead Git, it would have been immensely easier. We were using Diff and, you know, manual Deltas-

   12. LFLex Fridman28:35

       Mm-hmm.

   13. DPDave Plummer28:35

       ... to do the supporting and stuff. So being able to fork a branch of source code would be a luxury that is new to me.

   14. LFLex Fridman28:41

       (laughs)

   15. DPDave Plummer28:42

       So at the time, it would've been really handy.

   16. LFLex Fridman28:44

       What were some memorable conversations from that time when you walked over next door?

   17. DPDave Plummer28:49

       Uh, well, what-

   18. LFLex Fridman28:50

       Talked to some of these folks.

   19. DPDave Plummer28:50

       ... I was not present for was, somebody was complaining, a new hire came into the team and was working on what I believe was called Cairo. And Cairo was going to be the next future operating system, was going to be beautiful, and have a whole new user interface newer than Windows 95, and it never materialized. But while they were working on it, one of the guys who was working on Cairo was kind of flaming on the open NT dev alias, which is thousands of people, how shitty the NT boot experience was. And (laughs) the response that came back was, uh, an epic flame that I wish I would have saved, and I won't name the guy who wrote it. He knows who he is, but, uh-

   20. LFLex Fridman29:23

       (laughs)

   21. DPDave Plummer29:24

       ... it was a work of art of angry flame mail, kind of like the ones you see Linus send every now and then about kernel stuff. So it's a very similar sentiment.

   22. LFLex Fridman29:32

       Were there, like, kind of intellectual debates, like-

   23. DPDave Plummer29:35

       Oh yeah.

   24. LFLex Fridman29:35

       ... there was some, some heated stuff with the engineers?

   25. DPDave Plummer29:38

       It was... Yeah, it got contentious. So you've got intellects competing, and eventually the technical merits for some people are secondary and it's about besting the other person in that argument, and it's no longer productive at that point half the time, but there was a fair bit of that.

   26. LFLex Fridman29:53

       Yeah, I've- I've seen those kind of debates in, uh, like, programming language design communities like Guido van Rossum, the leaders of those communities, it can wear them down 'cause people get... You almost, like, forget the mission you're on and start being very nitpicky about the details. And e- engineering minds get together and you s- just go to war over the stupidest, like, syntax subtlety.

   27. DPDave Plummer30:20

       Right.

   28. LFLex Fridman30:20

       Well, it's- I shouldn't say stupid, but it's a small-... syntax subtlety. Now, for it, that's for programming language. I'm sure there's internal battles about specific kernel components.

   29. DPDave Plummer30:32

       Yeah, I mean, there was one that I lost that still bugs me to this day, I think.

   30. LFLex Fridman30:36

       Yeah?
8. 31:48 – 37:05

   Debugging

   1. DPDave Plummer31:48

   2. LFLex Fridman31:49

      Yeah. So, uh, yeah, I mean, you mentioned MIPS and RISC. How deeply did you have to understand the lowest level, sort of the lowest level of the software and even the hardware with the stuff you were building? Like, w- what are the layers of the abstractions you had to understand to be successful with all the stuff you're doing with NT, and before that, with MS-DOS?

   3. DPDave Plummer32:12

      Well, about half your day is going to be spent debugging, and h- and most of that time is going to be spent in call stacks that are in pure assembly language, 'cause there's no source level debugging.

   4. LFLex Fridman32:20

      Mm-hmm.

   5. DPDave Plummer32:21

      So it's not like we're in Visual Studio and you hit a break point and it pops up and there's the source code. You can go look at the source code, but you're looking at the raw assembly dump from the machine at all times.

   6. LFLex Fridman32:29

      So even if you're programming in C, the debugging is in assembly?

   7. DPDave Plummer32:33

      Yeah, 100%.

   8. LFLex Fridman32:34

      Oh, man.

   9. DPDave Plummer32:35

      So it's a little cumbersome.

   10. LFLex Fridman32:36

       (laughs) Oh.

   11. DPDave Plummer32:37

       And better yet, we're doing four instruction sets, 'cause we're doing Intel, uh, MIPS, Alpha, and PowerPC, so depending on which machine it crashes on, you've got an entirely different instruction set-

   12. LFLex Fridman32:46

       Yeah.

   13. DPDave Plummer32:46

       ... and registers and... So you get reasonably adept at debugging all four, but, uh, I had more experience in MIPS, so MIPS stuff would come my way.

   14. LFLex Fridman32:54

       That's a real endurance event. I mean, can you speak to that? The, the torture that is debugging, especially that kind of debugging, without the, without the tooling associated with it? I mean, that's, you know, programming... (laughs) Kids these days. (laughs) Uh, programming isn't all about creating beautiful things, right? It's, uh, also about fixing things.

   15. DPDave Plummer33:18

       Yeah, I would say that 20% of my professional life has been creating and 80% has been debugging and fixing.

   16. LFLex Fridman33:23

       Yeah.

   17. DPDave Plummer33:24

       And, I mean, I got a bit of a reputation as somebody who could fix stuff, and so stuff like that would flow to me, and so I would spend more time doing that. I wasn't renowned as a creative UI genius where I'm flowering all these new ideas, so I got to fix ugly stuff. But you get really good at that, so... I don't mind it until it's one of those things where you've been chasing it for so long that you don't know what to do next, and you can't understand why it doesn't work or how it ever worked or whatever situation you happen to be in. And, uh, you know, after a day of it, it can get pretty trying.

   18. LFLex Fridman33:52

       Yeah, debugging can be real torture. It's, can be really, really difficult. There's a psychological, I think, component, I think, of perseverance.

   19. DPDave Plummer34:00

       I think the ones that l- you know, take you a day? They resolve one of two ways. Either it's like, "Oh, extra semicolon," and then you finally see it. (laughs)

   20. LFLex Fridman34:08

       Yeah.

   21. DPDave Plummer34:08

       Or it's some horrible manifestation of cross-threaded apartment nonsense that was really hard. But it can go both ways. Um, I had a bug, uh, it wasn't my bug actually, but it was a manifestation of a bug in Task Manager, where every now and then, it would say, "Greater than 100% total CPU usage." And this looks pretty silly for a task manager, so... I had tried to resolve it for a long time, and I'd talked to the kernel guys about my issue and they were unsympathetic, let's say, 'cause the kernel guys are a special breed and they weren't interested in my user land problems. It's probably some issue in my code, right? And they're probably right, but it wasn't in this case, and I was sure of it, and so I kept adding asserts all through the code to make sure that the, that the preparatory steps of adding the stuff together were never more than 100, and that the final sum was never more than 100, and finally, it never asserted. But occasionally we would get this bug where people would still see it, and so I put, finally put my phone number in the assert. And I was like, "If you see this message, call Dave PL at 425-836, my phone number." (laughs)

   22. LFLex Fridman35:09

       (laughs)

   23. DPDave Plummer35:09

       Um, and finally we did get a catch in the actual stress debugger that I was talking about earlier where it happened to somebody with a debugger connected. We were able to go through and it was actually a kernel accounting issue and it wasn't a task manager issue so they just fixed it in the kernel once I was able to prove that it was, in fact, a kernel issue. And, uh, you'd think we would then remove my phone number, but we just commented it out. So it's shipped and it's in all the damn source code leaks for NT that are out there, so-

   24. LFLex Fridman35:32

       (laughs) That's awesome.

   25. DPDave Plummer35:32

       That's how I find task manager code is I search for my phone number on Google and it will reverse find-

   26. LFLex Fridman35:37

       Oh, that's fascinating.

   27. DPDave Plummer35:38

       ... the NT source code.

   28. LFLex Fridman35:39

       Can you speak to the assert thing? By the way, I saw, I think you tweeted or you said somewhere that if you want to take your asserts really seriously, you add your, your home phone number, uh, in there.

   29. DPDave Plummer35:48

       Yeah.

   30. LFLex Fridman35:48

       It's true. It's true.
9. 37:05 – 42:14

   Task Manager

   1. DPDave Plummer37:05

   2. LFLex Fridman37:05

      You mentioned Task Manager. Obviously, we have to talk about this, the legendary program that you created, the Windows Task Manager. Tell me every detail of how you built it. What is Windows Task Manager?

   3. DPDave Plummer37:18

      So Windows Task Manager is a way to go in and find out which apps on your system are using the computer, using the hardware, using the CPU, using the memory, and which ones might be using too much or locked up or going crazy and it gives you the ability to terminate and kill those ones. So it's an inspection and a fixing tool.

   4. LFLex Fridman37:34

      Yeah, it lists all the processes. I mean, it's a legendary piece of software. It's crazy. We, you just take it for granted. It's like the Start menu, right?

   5. DPDave Plummer37:42

      Yeah.

   6. LFLex Fridman37:42

      It's, like, genius.

   7. DPDave Plummer37:44

      Well, I had the great fortune of working on a lot of things that people are familiar with and Task Manager is one of those side projects that I started as something that I wanted for myself and eventually came in-house. So I started writing it at home and I got kind of the basics up and running and I was using, I think it's HKey Current Perform- or HKey Performance in the registry to get the stats because I didn't have access to the internal APIs because I was working from home and I don't call those as if I'm working from home.

   8. LFLex Fridman38:07

      Mm-hmm.

   9. DPDave Plummer38:08

      And, uh, when I brought it in-house, then I was able to call things like NT Query System Information or NT Query Process Information and get the real answers very quickly, which enabled it to become a very fast and responsive app. So, people have come to rely on it because I wrote it to be as reliable as possible. I wasn't worried about the features. There was a basic set of functionality that I wanted in there and I got everything I wanted, but I wanted it to be really robust. And so that, and small. And the original was like 87K.

   10. LFLex Fridman38:35

       Okay. Can you speak to what it takes to build a piece of software like that that doesn't freeze?

   11. DPDave Plummer38:40

       Uh, you don't assume much, right? If you're going to call the shell to run an app, well, that could be a network path that's on a TCP/IP share that takes 90 seconds to time out. So any time you do any kind of APL, API call like that, that could take time, you're gonna wind up doing it on a separate thread. And so the app becomes a little more complex because everything's multi-threaded.

   12. LFLex Fridman38:59

       Okay. So what programming language were you working in?

   13. DPDave Plummer39:01

       C.

   14. LFLex Fridman39:02

       So this was for Windows N- NT?

   15. DPDave Plummer39:04

       Yes.

   16. LFLex Fridman39:05

       Okay.

   17. DPDave Plummer39:05

       So this shipped initially in NT 4.0.

   18. LFLex Fridman39:07

       Okay. So what are some interesting details about this program? Because you have to get it as simple as possible, but also as robust as possible. Uh, what are some interesting optimizations, for example, you had to implement?

   19. DPDave Plummer39:20

       There's a couple of things I, that are a little hardcore now, I'm surprised I did. Like I didn't want to link to the C runtimes at all, so I made sure never to call a runtime call and I didn't link to them and that saved me whatever the C runtime is, 96K or something. So, you know, it almost doubled the size of the app if you just touched any C call. So I was careful not to do that. But then I was actually writing in C++, which is r- C with objects more than anything. But, uh, in order to get it to work, I had to go through and call all the object constructors manually from the dispatch table and stuff because you don't have the runtimes to do it for you. So you're working with a compiler that doesn't have its runtime and I don't want to rat hole on the technical issues, but it's a lot of extra work to get it to work. But when you do, it's incredibly small and tight.

   20. LFLex Fridman40:00

       That's about the size-

   21. DPDave Plummer40:02

       Yeah.

   22. LFLex Fridman40:02

       ... of the program. Um, what are some interesting aspects of tracking down, like, every, every process and how much CPU usage in that process?

   23. DPDave Plummer40:10

       One of the cooler things that I saw is, I don't want to say I invented Hamming code, but I kind of invented Hamming code without (laughs) knowing Hamming code existed. So every column and every row in Task Manager has a bit on whether it's become dirty or not and then I can look basically the same way Hamming code looks in your X and Y columns to find out which rows have changed, go through and find out which ones actually need to be repainted. So Task Manager is super efficient and it works in concert with the ListView control, which provides that functionality to go through and repaint as little as an individual cell that changes from frame to frame. So it could paint very fast, it could resize very smoothly and resizing was probably my biggest, uh, personal goal with that app so you can size it to any size and it still works. And even if you have 32 CPUs, which wasn't possible in the day, it will draw I think only eight graphs and then it wraps but, uh, it still works today. So I'm kind of proud of that.

   24. LFLex Fridman41:06

       It is incredible. Um, you've gotten the chance to sort of observe the evolution of Task Manager. In some ways, it really hasn't changed much. Maybe there's some prettier aspects to it that fit into the whatever version of Windows it's in but it's really basically the same thing.

   25. DPDave Plummer41:23

       The functionality is very same. Um, the reporting is more because they've added GPU and thermals and things like that, which is really nice to have. And we didn't have that ability in the day, so.

   26. LFLex Fridman41:32

       I mean, what can you say? Do you know about, w- like, uh, was there any refactoring done or is it basically the same code? (laughs)

   27. DPDave Plummer41:37

       Uh, as far as I know, the original code's still mostly all there. So there are layers of drawing code and dark mode code and whatever else, XML, schema code that goes on top of that that makes it four megabytes instead of 87K, but that's the world we live in, so.

   28. LFLex Fridman41:51

       Yeah. It's one of those pieces of software you create and just s- stay o- once it's there. It's just really like the Start menu and then I'm sure if you remove it, people would just lose their mind. (laughs)

   29. DPDave Plummer42:02

       Yeah, it might be locked in for a while and that one might be good.

   30. LFLex Fridman42:06

       Yeah. I thought that would be true for Clippy but, uh, Clippy will make it back one day. All right. What are, what are

10. 42:14 – 47:13

    3D Pinball: Space Cadet

    1. LFLex Fridman42:14

       some, uh, other pieces of software you created at the time that are legendary? So you were part of Space Cadet Pinball, at least porting.

    2. DPDave Plummer42:22

       Yeah. So they came into my office and said, "Hey, what are you doing?" And I said, told them what I was doing and they said, "Well, how do you want to spend your next three months?" I said, "I have no idea." And he said, "Do you want to port Pinball?"... and I had, I'd seen Space Cadet Pinball as a game standalone for the Win95 platform, and it had a couple of different tables and it was a cool game. So, I was kind of excited, and what they wanted was some visual splash for NT, to show that NT can do, for then, high speed graphics, and, or at least responsive graphics. And so I took a shot and unfortunately, a lot of the code was in Assembly, and I was on the MIPS so I had to rewrite the code in C so I could then port it to all the different platforms. And at the heart of the game is a huge state engine. And it's like a giant switch statement with, if I remember, like 50 entries in it.

    3. LFLex Fridman43:06

       Yeah.

    4. DPDave Plummer43:06

       And it's got an Easter egg built in. And decoding the state, it's like running a neural network through this thing as you hit it with different states, and I just put it aside and treated it as a black box. And so my code runs on top of that and does the drawing and the sound and everything else. But the original game is still running. And somebody recently asked me, uh, why is it slightly different, the physics are slightly different from Windows 95 version, but it should be the same code, because I'm trying very hard to preserve that. But what it is, is I had a bug where I will draw as many frames per second as I can, which on a modern computer could be 5,000 frames a second for pinball because it's a pretty basic game. And so all your physics are interpolated 5,000 times per second instead of 30 times a second, or whatever you would have gotten on the old ones. You're getting arguably better, or at least different physics. But they fixed that since, so...

    5. LFLex Fridman43:57

       Wh- why is that game so awesome?

    6. DPDave Plummer43:59

       I think it's a great design. I mean, I take no credit for that. That's all totally the guys at Cinematronics. But the original game is a great design. It's very similar to Black Knight 2000, which I own as an actual physical pinball machine, and the layout is actually very similar. I don't know if it was inspired by it or not. So, it's a good game.

    7. LFLex Fridman44:15

       Yeah. Sometimes I think about like Tetris, about certain games with pretty primitive graphics that captivate the, uh, the excitement of a large number of people. And m- maybe it's the excitement of a large number of people that contributes to the awesomeness of the game. So when a l- when many people together get excited and talk about it, that sort of gets implanted into your head. But that's one of the great games. I mean even s- even like Solitaire and Minesweeper. I mean, there's just a generation of people that have gone to war on Minesweeper, right? (laughs)

    8. DPDave Plummer44:48

       Well, those things were included in the OS not as games, but as educational tools to get you to use a mouse.

    9. LFLex Fridman44:53

       Oh, interesting.

    10. DPDave Plummer44:54

        So Solitaire is there to show you how to do drag and drop.

    11. LFLex Fridman44:56

        Yeah.

    12. DPDave Plummer44:57

        And Minesweeper's probably right click. I think you put a right, a flag or some item.

    13. LFLex Fridman45:00

        Yeah.

    14. DPDave Plummer45:00

        I'm not a Minesweeper guy, but so each one of them teaches you something.

    15. LFLex Fridman45:03

        (laughs) Minesweeper guy. That's funny. (laughs) Yeah. Wow. I didn't know that. That's interesting. And that's true, but I don't know how many hours I've spent on these games. And like millions of people have spent millions of hours on these games.

    16. DPDave Plummer45:16

        I used to volunteer teaching computer science at my kids' school, you know, for the third graders and stuff. So it's more like logging in than computer science, but uh, the kids of course, all their dads work at Microsoft so nobody's impressed by anything you do. But so one of the kids found out I worked on Pinball and then they were like, "Whoa, you worked on Pinball?" Because they all knew that in those days. Now the kids are probably aged out, they don't know it anymore, but for a brief period.

    17. LFLex Fridman45:38

        Uh, you're behind the Windows activation.

    18. DPDave Plummer45:42

        You say it like it's a bad thing.

    19. LFLex Fridman45:44

        (laughs) Um, everything's a matter of perspective. So tell the story of that. What's Windows activation? What, uh, how'd you get involved?

    20. DPDave Plummer45:53

        So they came to me late in the XP ship process. I don't know if the beta had gone out, I don't think the beta had gone out yet, but they had intended to take the Office activation code and then adapt it to Windows and add activation to Windows. But whoever was responsible for doing it had slipped it enough times that it wasn't gonna happen, and so I had kind of a reputation for being able to fix things quickly, so they came to me and said, "Can you get this done in time for XP?" "I don't know, but I'll try." So with the help of the guys who were doing the DRM stuff on the DRM side, and the research guys doing the math for the product keys and everything else, we cranked it out in time for XP. And I don't know what it, actual impact is for revenue, but I imagine it's substantial when you start enforcing license keys.

    21. LFLex Fridman46:35

        I wonder what it is.

    22. DPDave Plummer46:36

        I don't know.

    23. LFLex Fridman46:36

        Because it's also annoying.

    24. DPDave Plummer46:39

        It is, especially if you have to phone activate. And that was just the case that we had to carry with us as a albatross around our neck where you've got to pass data up to the clearinghouse, the backend systems that are going to approve your key. You've got to tell it all your hardware parameters, like how much memory and hard drive space and the various things the hardware key is bound to, as well as the product key. And you've got it encoded in letters and numbers that somebody is willing to read in over a phone. And if you think doing product activation is painful over the phone, could you imagine being the person that worked on the other end of that line? I mean, that's just got to be a mind numbing job to listen to product keys for eight hours

11. 47:13 – 58:12

    Start menu and taskbar

    1. DPDave Plummer47:13

       a day.

    2. LFLex Fridman47:13

       Yeah, one of the challenges with Windows, and it's been a frustration point for me, but I, I understand from a design perspective it's very difficult, is so many different kinds of people use Windows. But, uh, it's been frustrating how over time Windows has more and more leaned into the direction of like the not, not the power user, I should say, which is why sort of Linux has always been really wonderful. But from, from an activation perspective or from any kind of configuration, it's been, it's been a, it's been a source of a lot of frustration.

    3. DPDave Plummer47:49

       Yeah. One of my more popular episodes of late has been why you can't move the Windows taskbar.

    4. LFLex Fridman47:54

       Yeah.

    5. DPDave Plummer47:54

       And I had no idea, but the outrage is palpable amongst people that you just put it on the left or top and you can't any more, and it is an affront to their existence. And I understand it to a certain extent.

    6. LFLex Fridman48:02

       Well, it's one of the main reasons I really just dislike Win- There's a lot of aspects about Windows 11 I dislike, one of which is like you can't customize things as much about the position of the taskbar, just basic customization. Can we just configure stuff? Because there's going to be a small contingent of power users that are just gonna enjoy the hell out of this operating system if you just give them that option, it costs you nothing, just give them that freedom.

    7. DPDave Plummer48:28

       Well, it does cost, right? Because the, uh, freedom to put the start menu on the left or the top or the right-... really increases the complexity of the code that renders the Start menu and lays out the tabs and does all the things. And now it's a much larger surface for bugs, and it's a much larger piece of code to maintain. So you probably need more developers or another developer or some portion of a developer's time. So the question becomes, at what point is it still worth it to satisfy the niche needs of a small set of users? And I, I just not- those decisions weren't mine to make, but I could see it from both sides.

    8. LFLex Fridman49:04

       I think just like the people who make movies and insert very nuanced details that only a small number of people will realize are there, that's gonna really pay off. There's a kind of reputation that builds over time that has a very powerful ripple effect. Uh, that I think i- it has- it, (laughs) it has so many benefits, including for hiring great software engineers. (laughs) It's like you create this aura of a place, uh, that puts love into every detail, that puts- that really takes care of the power users, that takes care of the developers. And I think Microsoft has more and more moved in that direction with GitHub and acquiring GitHub and just taking care of the developers. But on the Windows interface side, come on, some customization. With, you know, with VS Code, you can customize everything. Why, why can't we customize the Start menu, right? Anyway, uh, uh, and the taskbar, um, and really every aspect of the Windows interface. I don't, I don't- I... Maybe you're right, maybe it in- increases the complexity of the code. I suspect that's just not the case.

    9. DPDave Plummer50:25

       I bet it was. I bet it was a scheduling decision when they rewrote the Start menu. I think they rewrote it because it's different than the old taskbar.

    10. LFLex Fridman50:30

        Mm-hmm.

    11. DPDave Plummer50:31

        And somebody was tasked with, "You've got to deliver this set of functionality, and if I cut out putting it on the left and the top and the right and two rows of tabs and all the other cool features, I can deliver it four months sooner." And I'm not saying that's the right decision, but I'm guessing that might be the kind of thing that motivates it. And they're on such a different release schedule now. It used to be... Y- you won't see much craftsmanship unless somebody owns a component for a long time and it settles to a point that then you can work on polishing, right? But if it's always churning and the UI is changing every release, it's never gonna get that level of polish. Although I think the UI is pretty nice, but...

    12. LFLex Fridman51:05

        I- Y- yeah, i- it is nice, but I think there- I think it's- I just don't think it's a scheduling thing, I think it's a, I think it's a craftsmanship thing. Just like you with a- with a task manager. If there's a guy or a girl in there who take ownership of it, who have a, like passionate- like for them, it's a thing that they take pride in, uh, over a period of time, they can like by themselves in a short amount of time create something truly wonderful.

    13. DPDave Plummer51:33

        Right.

    14. LFLex Fridman51:34

        And like, I- I think if you have large software engineering teams with managers and sch- scheduling of meetings and all this kind of stuff, yeah, okay, then, then your argument applies. But if there- if you allow the flourishing of individuals that create cool shit and like their own sort of the side project, which Google is very good at-

    15. DPDave Plummer51:55

        They've tried that, right? Google, yeah.

    16. LFLex Fridman51:56

        Yeah, like have fun with it, like do some crazy stuff and then we'll integrate it. We'll, we'll try to integrate it into the whole ecosystem. I don't know. I don't know. Uh, uh, cause like to me, (laughs) there's- it's such a great joy from an individual developer to create something like customization of the Start menu or the taskbar, because you know that millions of people are going to use it, uh, the, the taskbar. And then you know that thousands, tens of thousands of developers might be using to customize even little subtle aspects of the taskbar. You know how much joy you create, you give to people to customize, to have some kind of JSON thing where you customize something about the taskbar?

    17. DPDave Plummer52:37

        Okay, but how do you respond to the Steve Jobs aspect of giving you customization implies that we couldn't figure out the right answer for you? Or maybe there is no right answer and all four answers are equally right, I have no idea, but-

    18. LFLex Fridman52:51

        Right. Uh, I think I've always- the- I- I'm glad Apple exists, it's a beautiful thing and that idea of love design is wonderful, but I always thought that their- that Windows creates the contrast. Like the point of Windows is to be the operating system that works on all kinds of devices, that just is mu- it's supposed to be much more open. And they've moved towards that direction more and more with Windows Subsystems for Linux. It's just this whole developer-friendly ecosystem. It, it- the interface should be in the spirit of that, I think.

    19. DPDave Plummer53:21

        Right.

    20. LFLex Fridman53:21

        But, but I do think that there could also be security vulnerabilities that created with that. It's not just the complexity of the code, because Windows is just under attack.

    21. DPDave Plummer53:29

        Yeah.

    22. LFLex Fridman53:30

        (laughs) It's very difficult to keep it secure. Anyway, taking that, that tangent, you also developed a zip file support for Windows, uh, creating Visual ZIP, like you mentioned, zip folders that eventually evolved into zip folders. Tell the story of that.

    23. DPDave Plummer53:44

        So that was a piece of software that I, I wrote at home again. And, uh, what happened was I was out with my wife and I think it was a Sunday afternoon, we're driving around, this is 1993 and we're living in our apartment and we're just seeing what the housing market is like out there. And there's a guy, he's got this beautiful three-bedroom house and a Corvette convertible, 93 red, torch red, parked in the driveway and the house is for sale and it's like 300K I think, and there's no chance I'm coming up with 300K at that point, or even the down payment on that. So, um, I took the flyer and I cut the picture of the house out and I taped it to my monitor. And that was my incentive to just write something at night because when I came home, I was doing two things. I was, one, expressing a creativity that I couldn't get out at work when I was just fixing bugs, and I was trying to make some extra money. And so I wrote a Shell extension before I actually went to the Shell team, I started it, and that's what led to my interest in going to the Shell team based on an MSDN sample or MSJ at the time, MSJ sample that I saw on how to like-... bring up a folder. Now, once I had the very basic bring-up-a-folder template, adding zip file support to it was just incremental all the way. And, uh, I released it as a shareware product. I think it was 19.95 or 29.95, and I sold, whatever, a couple of hundreds or thousands of copies. And one day, I'm getting ready for work and I get a call, and it's a lady, and she says, "Are you Dave Plummer?" And I said, "Yeah." And she said, "Are you the guy that wrote VisualZip?" And I said, "Yeah." And she said, "Well, this is Betsy from Microsoft, and we'd like you to come by and come in and talk about an acquisition of it." And I said, "Okay, what building are you in?" And she's like, "What do you mean?" And I said, "Well, I'll come by." And she said, "Well, no, you gotta talk to travel and you gotta talk to legal, and this all has to be set up." And I'm like, "I don't get it. We both work at the same place. Why can't I just stop by?" I don't know if I said that literally-

    24. LFLex Fridman55:24

        Yeah.

    25. DPDave Plummer55:24

        ... but it was a few minutes of back and forth where we both realized that she didn't know I worked there.

    26. LFLex Fridman55:28

        Yeah (laughs) . That's funny.

    27. DPDave Plummer55:29

        They had just cold-called the author and then found out that it was me.

    28. LFLex Fridman55:32

        Yeah. That's funny.

    29. DPDave Plummer55:32

        And, uh, so they made me an offer on it. And it's the kind of thing where if I don't accept the offer, w- now my choices are, I can keep selling my own version and quit Microsoft, or I can stop selling my own version and work for Microsoft. Neither of those is great. I mean, I'd like to keep my job, of course, but I'd like to h- still have this income stream. And the other option was accept their offer, which is what I did. So then I bought a used '93 red Corvette and...

    30. LFLex Fridman55:57

        (laughs) And you got to continue building it internally?
12. 58:12 – 1:00:21

    Blue Screen of Death

    1. DPDave Plummer58:12

       so.

    2. LFLex Fridman58:13

       Tell me the story of the infamous blue screen of death.

    3. DPDave Plummer58:17

       What it is, is when Windows has no other option, when the kernel gets into a state where something illegal has happened... So let's say a device driver is trying to write to a piece of memory it doesn't own, or it's trying to free a memory, piece of memory twice, something that just cannot happen. And the kernel has no other option. It will shut the machine down to save your work.

    4. LFLex Fridman58:34

       Mm-hmm.

    5. DPDave Plummer58:35

       And... Well, not save, but prevent further damage. And it puts up a blue screen and it, uh, prints out the stack information. Depending how your settings are, sometimes it's just a sad face-

    6. LFLex Fridman58:45

       (laughs)

    7. DPDave Plummer58:45

       ... (laughs) in the current Windows.

    8. LFLex Fridman58:46

       Yeah, I wonder what the first version of Windows where the blue screen came to be.

    9. DPDave Plummer58:51

       So, Windows 3 had a blue screen-

    10. LFLex Fridman58:54

        Mm-hmm.

    11. DPDave Plummer58:54

        ... but it's completely unrelated to the blue screen in Windows NT. And I talked to the guy who wrote the blue screen in Windows NT. His name's Jon Virt. And, uh, the reason he picked white on blue, I had thought... I'd always heard it was 'cause w- in the labs, you could walk through a lab where we have 50 PCs all running stress. "Oh, that one's got a blue screen. It's crashed."

    12. LFLex Fridman59:12

        Mm-hmm.

    13. DPDave Plummer59:12

        It wasn't that simple. It was just the MIPS firmware that he was building it on was blue on white, and s- VisualSlickEdit that he was using as an editor was also the same color scheme. And so you could code, boot, crash, and reboot, all in the same color scheme.

    14. LFLex Fridman59:25

        Why do you think so many problems with computers can be solved by turning it off and turning it on back again?

    15. DPDave Plummer59:34

        I think there's two major things that happen with computers as you run them over time. One is memory gets used and not freed.

    16. LFLex Fridman59:40

        Yeah.

    17. DPDave Plummer59:40

        And so it accumulates on a heap or in the swap file or wherever, and things get sluggish. And the other is, code gets into a state that the developers didn't anticipate or didn't test very well.

    18. LFLex Fridman59:50

        Mm-hmm.

    19. DPDave Plummer59:51

        And maybe that's a rare state, but now that Notepad or Word or Excel is in that state, your system is goofy. So if you just reboot the thing or shut it down or restart it, you're getting a fresh state and there's no memory leaks, so it covers a lot of sins, basically.

    20. LFLex Fridman1:00:03

        And, uh, the intricate ways that several pieces of software in a goofy state interact with each other creates sort of a meta goofy state (laughs) that just kinda ha- j- just the entire system starts acting a little weird.

    21. DPDave Plummer1:00:18

        Yeah.

    22. LFLex Fridman1:00:19

        And then somehow fixes it.

13. 1:00:21 – 1:08:22

    Best programmers

    1. LFLex Fridman1:00:21

       What's, uh, what's some of the best and the worst code you've seen during that time at Microsoft? What's some beautiful code and what's some ugly code that pops to memory?

    2. DPDave Plummer1:00:31

       In terms of beautiful code, there's two that stand out for me. One is the kernel in general. When you get down into the Windows kernel-

    3. LFLex Fridman1:00:38

       Mm-hmm.

    4. DPDave Plummer1:00:38

       ... and the actual NT APIs and stuff, it's very well written. And it's written to a standard that you don't see on the user side, or at least is uncommon on the user side.... on the user side, probably the coolest code I remember seeing was a guy named Bob Day wrote a named pipe implementation to eliminate the use of shared memory. So Windows 95 had a big shared segment amongst all the shell processes where it would store stuff that's common to all the shells. We didn't want to do that. Shared memory is a bad idea on NT and at an industrial level. So he came up with a way to do it with named pipes. And, uh, I remember doing a code review on it, and it was very impressive to walk through the code. It was one of those things where it was like, "Oh, I don't think I could have done that if I was trying."

    5. LFLex Fridman1:01:19

       Who's the greatest programmer you've ever encountered?

    6. DPDave Plummer1:01:22

       You know what? I don't think there is any one. I, I've met a number of great programmers. But I'll tell you one story that impressed me a lot, was when I was brand new at the company, I'd been there like six weeks, and I'm working on this OLE Presentation Cache that I'd mentioned earlier. And I'm on Windows 95, and I've got Excel inserted into Word, and I'm in the kernel debugger, and something's going wrong in the scheduler. And I've been there, you know, I've barely written any x86 code and I'm looking at the Windows Scheduler trying to figure out why my thing is deadlocked. And eventually, I get stuck, so I'm kind of out of my element and I send an email to the Windows 95 kernel team and say, "Could you send somebody by?" And so about 10 minutes later, this developer strolls in and they're just holding a null modem cable, which is to connect my two machines together so they can debug one with the other in case I didn't have it, but it was already set up. And so they sit down and they're using WinDbg, which is just a horrible debugger. It's just, it's accursed.

    7. LFLex Fridman1:02:10

       (laughs)

    8. DPDave Plummer1:02:10

       But, uh, they're very, very competent with it and they are just blasting through the call stacks and they're checking all these objects in the kernel and trying to find out who's waiting on what and why things are deadlocked and what things are signaled and what's not. And it's just this quicksilver ballet of call stacks flying by and I'm watching this and I'm pretty blown away because I'm a good programmer, but this person is an amazing debugger and I've never seen a performance like this. And, uh, about five minutes in, I just hear, "Oh, I see." And then they disconnected and got up and left. And that was Laura Butler who became a distinguished engineer at Microsoft. I think she may still be. I'm not sure if she's retired or not, but... So she kind of set my template for, you know, what Microsoft developers were like when they're debugging and what kernel developers were like, and even what female developers were like, because I had such a small sample set. Um, but it was a very high standard, so...

    9. LFLex Fridman1:03:02

       There's a few things I love in life more than people who are ultra-competent at anything really, but the lower level, the better, in the engineering space. They're able to, for example, like, run or maintain the infrastructure, the computer infra- infrastructure. So not the individual computer, but the computers communicating together and working together. Those people are just magicians.

    10. DPDave Plummer1:03:22

        Right.

    11. LFLex Fridman1:03:23

        It's so inspiring to make... It's like watching a great carpenter or...

    12. DPDave Plummer1:03:28

        I love anything done really, really well.

    13. LFLex Fridman1:03:30

        Yeah. It's beautiful to see. It's beautiful to see that humans are able to accomplish that. Even in, in civil engineering space, when I look at, like, bridges, it's like, the number of people that had to come together to build that, and now millions of people use it every single day. With software sometimes you don't get to see visually just the number of people impacted by a thing. So imagine how many people are impacted by Linux and all the different open sources, open source systems that make up Linux. It's incredible. And Task Manager is an example of a piece of software. Just how many people have used that over the years and how many times? It's crazy. It's probably, it's like billions, billions have u- used that.

    14. DPDave Plummer1:04:12

        Yeah, two billion a month or something.

    15. LFLex Fridman1:04:13

        Two billion? (laughs)

    16. DPDave Plummer1:04:14

        Something like that. I, I've seen the metrics and it's up there.

    17. LFLex Fridman1:04:16

        Oh. Crazy to you?

    18. DPDave Plummer1:04:18

        It is. What I love about it though, and I'm sure you've had this experience where sometimes you design a piece of software and it's complex and you get it working in your head and you get the plumbing working and you know how it's going to run and flow and then eventually you write the code and the code does that thing that you had pictured in your head.

    19. LFLex Fridman1:04:32

        Mm-hmm.

    20. DPDave Plummer1:04:33

        And now there are billions of copies of that thing that I had in my head running on millions of peop- or billions of peoples of machines, and that in itself is really cool to me. It's not a vanity thing so much as a, uh, I'm impressed by it, I guess.

    21. LFLex Fridman1:04:46

        Uh, how's your programming evolved over the years?

    22. DPDave Plummer1:04:50

        I take a lot more care and complexity these days. So it used to be you would write code and just keep writing code, writing code, and then at some point go back and clean it up. Well, I write the other way now. I try to write really clean initial skeletal code and then flesh it out because I have been involved in too many projects of my own and of other people's makings where things get so messed up that they're just not fixable. And so sometimes the work you put in upfront pays off, you know?

    23. LFLex Fridman1:05:18

        What programming languages have you used over the years? What's been your main go-tos?

    24. DPDave Plummer1:05:22

        For me it's been C++ and Assembly language.

    25. LFLex Fridman1:05:25

        And still to this day, C++ is really what you lean on?

    26. DPDave Plummer1:05:28

        Yeah. Right now I'm a 100% Lua and Python, but that's just side project I'm working on, so...

    27. LFLex Fridman1:05:33

        Can you speak to the Lua and the Python detour that you took, and, uh, what do you love about C++?

    28. DPDave Plummer1:05:40

        What I'm doing is I wanted to build an AI to play the game Tempest. That's the old Atari game, Tempest. And, uh, this is a game that I actually hold the world record on. And, uh...

    29. LFLex Fridman1:05:49

        Can you take me to this Atari game, Tempest? Okay. Atari Tempest. What kind of game is this?

    30. DPDave Plummer1:05:55

        So it's a 3D vector game from 1980.
14. 1:08:22 – 1:15:50

    Scariest time of Dave's life

    1. DPDave Plummer1:08:22

       try to do both.

    2. LFLex Fridman1:08:23

       Let me ask you about the whole stretch of time that we kind of skipped over. Uh, you built a lot of software over the years after Microsoft, on the side while at Microsoft, and afterwards, uh, a lot of successful pieces of software. Uh, one of your companies was Software Online and it got into trouble for nagging users too much, I guess-

    3. DPDave Plummer1:08:44

       Yep.

    4. LFLex Fridman1:08:44

       ... to upgrade. That's what I saw. What was all that about? And, uh, what did you learn from that experience?

    5. DPDave Plummer1:08:49

       That was... other than, like, family health scares, you know, when kids are sick, that was the scariest time of my life, and the period leading up to it was one of the most invigorating and exciting because what had happened was while I was at Microsoft, I had written all these shareware utilities and I was selling them on the side and sold one to Microsoft, as we talked about, and they started to do really well, and then I discovered banner advertising online. And so I signed up with my credit card for a site, I think it was called Fast Click, and you could say, "I will pay this much for a banner ad impression. Here's my banner," and it would rotate it in, and I didn't set a cap on it. I came back on Monday and I saw I had spent like $10,000 in banner ads. I was like, "Holy crap." (laughs) "How am I going to explain this to my wife? This is a bug, it's a mistake, it was my fault."

Episode duration: 1:50:28