Dave Plummer Archives

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June 18, 2026

Microsoft once used its own brand of ‘Lego’ to optimize Windows

Former Microsoft engineer Dave Plummer reflected on software performance challenges during the '90s, specifically the limitations of machines with 12 MB of RAM. He discussed the Basic Block Tool (BBT), which optimized software binaries by reorganizing their structures to enhance execution speed. A typical binary contained around 10 MB of code, but only about 300 KB was necessary for startup. If this essential code was scattered, it led to performance degradation due to excessive page access. BBT defragmented binaries, grouping related code to streamline access and improve user experience, particularly for large products like Windows and Office. Modern tools like BOLT and HP's Dynamo continue to optimize binary layouts and runtime code, but Plummer cautioned about the risks of manipulating binaries. He noted that while computational power has increased, modern software faces similar performance challenges, with larger binaries and complex dependency graphs. He emphasized the importance of locality in software design, advising to keep hot data and code together to enhance performance.

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April 22, 2026

I just found out the creator of Windows Task Manager accidentally left his phone number inside the app

Dave Plummer, the creator of the original Task Manager at Microsoft in the 1990s, encountered an issue where CPU utilization readings occasionally exceeded 100%, which he suspected was a bug in the kernel. Despite being a user interface designer and facing skepticism from the kernel team, he implemented 'asserts' in the code to diagnose the problem. One assertion specified that CPU usage should not exceed 100%, and he embedded his name and home phone number in the code for anyone who might encounter the issue. No one ever contacted him about the bug, and it remained unresolved until the kernel developers identified and fixed it later.

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April 22, 2026

‘A performance tool that requires a graduate seminar before breakfast has already lost the room’: Why Windows Task Manager looks like it’s getting CPU usage wrong

Users have expressed frustration with Windows 11's Task Manager CPU usage reporting, believing it relies only on base clock speeds. Dave Plummer, the original architect of Task Manager, indicated that discrepancies may arise from average calculations and inherent compromises in the metrics. In response, Microsoft announced a fix in a recent Preview build, stating that Task Manager will now use standard metrics for CPU utilization across all pages to align with industry standards. Plummer also suggested a distinct Windows mode for power users to enhance flexibility.

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April 20, 2026

Original Task Manager creator explains why it lies to you about CPU usage — former Microsoft engineer shows unique solution to a seemingly simple, but actually complicated, task

Dave Plummer, a former Microsoft engineer and architect of the original Task Manager, explained the complexities of measuring CPU usage. He noted that the process is not as simple as it seems, as CPU activity can vary across different cores and the timing of measurements can influence results. The Task Manager accounts for various states of CPU activity, including user mode, kernel mode, interrupt time, deferred procedure calls, and idle loops, making the measurement of CPU utilization a complex task rather than a straightforward one.

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April 16, 2026

FAT32 breaks free from its outdated limitation in latest Windows update

The FAT32 file system, historically limited to a 32GB partition size due to a design choice by Microsoft engineer Dave Plummer, can inherently support volumes up to 2TB with a 512-byte sector size and theoretically up to 16TB with 4KB sectors. While Windows maintained this 32GB limit, motherboard manufacturers had already developed firmware to utilize larger FAT32 drives. Tools like Rufus and GUIFormat were used to format high-capacity media, as Windows did not allow direct FAT32 formatting for drives larger than 32GB. However, with the introduction of Windows 11 Insider Preview Builds 26220.8165 and 26300.8170, users can now format large flash drives and external volumes as FAT32 directly from the Command Prompt without third-party software.

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April 14, 2026

Veteran Windows dev shows off AI running on 47-year-old PDP11 with 6 MHz CPU and 64KB of RAM — ‘gloriously absurd’ project runs transformer model written in PDP-11 assembly language

Veteran Windows developer Dave Plummer is using a 47-year-old PDP-11 system with a 6 MHz CPU and 64KB of RAM to train a neural network called ‘Attention 11,’ developed in PDP-11 assembly language. The model is tasked with reversing a sequence of eight digits, requiring it to understand structural rules similar to those used in contemporary large language models like ChatGPT. Plummer emphasizes the importance of optimizing for the system's constraints, stating that constraints drive creative engineering. The model operates with 1,216 parameters and uses fixed-point math with 8-bit precision. After approximately 350 training steps, the model achieved 100% accuracy in the number-reversing task in about 3.5 minutes. Plummer argues that modern AI operates on the same mechanical principles as this vintage machine, just at a much larger scale, and suggests that companies focusing on efficiency and optimization may gain an advantage in the AI landscape.

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April 13, 2026

Windows 11 is finally removing the 32GB FAT32 capacity limit

Microsoft has released new test builds for Windows Insiders, specifically Dev Build 26300.8170 and Beta Build 26220.8165, which remove the 32GB limit on FAT32 formatting for external drives. Users can now format external drives up to 2TB using FAT32 through the Command Prompt. This change, which has been anticipated by users, is a shift from the long-standing restriction that required third-party applications or specialized commands for larger drives. The enhancement applies only to the Command Prompt, as the graphical interface remains unchanged, and the 4GB file size limit for individual files on FAT32 drives still applies. This feature is currently available only in preview versions for Windows Insiders, with a broader rollout planned for future standard Windows 11 updates.

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April 12, 2026

Original Windows Task Manager Was Just 80 KB, Says Microsoft Engineer

The original Windows Task Manager was 80 KB in size, while its current version is 4 MB. Dave Plummer designed it to remain operational during system freezes, emphasizing that every line of code has a cost. The Task Manager could manage multiple instances by sending private messages to existing ones and launching new instances if the original was unresponsive. It utilized global strings and direct access to the kernel’s process table for speed and efficiency. Users have noted that modern systems consume more resources for similar tasks compared to older versions like Windows 7.

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February 21, 2026

Creator of Window’s Task Manager shows off ‘probably what Task Manager would look like if I were still around’ — Tempest AI’s retro-futuristic dashboard code shared to Github

Dave Plummer is developing a dashboard for an AI to play the Atari game Tempest and has shared it on X and GitHub. The reimagined Task Manager features a retro-futuristic design with RGB accents and speedometer-style dials, differing from the minimalist Windows 11 Task Manager. Users have reported issues with recent Windows updates, including problems with the Windows Recovery Environment and BitLocker. The dashboard is not meant for regular use and consumes about 75% of the GPU at 30 frames per second on Plummer's M2 Mac Pro. Plummer's work on the Task Manager began in his leisure time and led to its integration into Windows NT, with significant features introduced in Windows 2000. Microsoft updated the Task Manager in May 2024 to change RAM speed measurements and redesigned it for Windows 11 in 2022.

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January 5, 2026

Windows Task Manager Creator Dave Plummer Calls for Halt to New Windows 11 AI Features for Better Stability

Dave Plummer, the creator of the Windows Task Manager and Pinball game, has expressed concerns about Windows 11, criticizing Microsoft's focus on integrating new artificial intelligence features at the expense of system stability. He argues that stable releases should prioritize fixing critical bugs over adding new functionalities. Plummer references the period around Windows XP Service Pack 2, when Microsoft halted new feature introductions to enhance security and stability in response to major security threats. He advocates for a similar approach for Windows 11, urging Microsoft to pause feature additions until the system is stabilized and existing issues are resolved. Plummer emphasizes the need for Microsoft to focus on improving user experience by prioritizing fixes over new features, particularly for power users.