This blog post from 2004 recounts the author's experience troubleshooting a customer's USB floppy drive issue. The customer reported their A: drive constantly seeking, even with no floppy inserted. After remote debugging revealed no software problems, the author deduced the issue stemmed from the drive itself. USB floppy drives, unlike internal ones, lack a physical switch to detect the presence of a disk. Instead, they rely on a light sensor which can malfunction, causing the drive to perpetually search for a non-existent disk. Replacing the faulty drive solved the problem, highlighting a subtle difference between USB and internal floppy drive technologies.
Raymond Chen, a Microsoft developer, recounts a perplexing technical support case involving external USB floppy disk drives from the year 2004. The user reported an issue where their computer would freeze intermittently when using one of these drives. The bewildering aspect of this problem was its seemingly random nature and the fact that it only occurred with some USB floppy drives, while others functioned perfectly on the same machine.
Chen meticulously details the troubleshooting process, emphasizing the challenges in diagnosing hardware-related issues that lack clear, reproducible steps. Initially, the support team suspected a faulty driver, given the relative newness of USB floppy drives at the time. However, replacing the driver yielded no improvement. Further investigation revealed that the problem wasn't universal to all USB floppy drives; some worked flawlessly. This observation shifted the focus from the software to the hardware itself.
The crucial clue emerged when examining the problematic drives. These drives were equipped with a unique power-saving feature: they would spin down the floppy disk motor after a period of inactivity to conserve power. While seemingly innocuous, this power-saving mechanism turned out to be the culprit. The act of spinning down the motor and then spinning it back up upon accessing the drive introduced a timing quirk. The system, during its enumeration and identification of USB devices, would sometimes encounter this spin-down process. The intricate interplay between the drive spinning down, the USB enumeration, and the device driver interacting with this transition created a race condition. This race condition manifested as a system freeze, where the computer would become unresponsive due to conflicting instructions and timing mismatches.
Drives that lacked this power-saving feature functioned without issue because the spin-down/spin-up cycle—and its associated timing complications—never occurred. Ultimately, the solution was to disable the power-saving feature on the problematic USB floppy drives, effectively eliminating the source of the race condition. This resolved the freezing issue and allowed the user to access their floppy disks without system instability. Chen concludes by highlighting the complexity of hardware-software interactions, especially when dealing with relatively new technologies and power-saving mechanisms, and how seemingly minor features can introduce unexpected and difficult-to-diagnose issues.
Summary of Comments ( 38 )
https://news.ycombinator.com/item?id=43002426
HN users discuss various aspects of USB floppy drives and the linked blog post. Some express nostalgia for the era of floppies and the challenges of driver compatibility. Several commenters delve into the technical details of how USB storage devices work, including the translation layers required for legacy devices like floppy drives and the differences between the "fixed" storage model of floppies versus other removable media. The complexities of the USB Mass Storage Class Bulk-Only Transport protocol are also mentioned. One compelling comment thread explores the idea that Microsoft's attempt to enforce the use of a particular class driver may have stifled innovation and created difficulties for users who needed specific functionality from their USB floppy drives. Another interesting point raised is how different vendors implemented USB floppy drives, with some integrating the controller into the drive and others requiring a separate controller in the cable.
The Hacker News post titled "A story about USB floppy drives (2004)" links to Raymond Chen's "The Old New Thing" blog post from 2004. The discussion on Hacker News is relatively brief, with only a handful of comments, and doesn't delve into deep technical analysis.
One commenter points out the irony of the original post's age, noting that in 2004, USB floppy drives were considered a potential solution to failing internal floppy drives, whereas today, both technologies are largely obsolete. This comment highlights the rapid pace of technological advancement.
Another comment reflects on the common practice of using floppy disks to transfer small files, even when networking was available, due to the perceived difficulty or inconvenience of setting up file sharing. This commenter suggests that this habit contributed to the persistence of floppy disks even as their technical limitations became increasingly apparent.
A third comment briefly mentions the Y2038 problem, a potential time-keeping error in computer systems that could occur in the year 2038, triggered by the comment's timestamp. This is only tangentially related to the main topic and serves more as a meta-commentary on the passage of time.
The remaining comments are very short and offer little substantive discussion. One simply expresses appreciation for Raymond Chen's blog, while another remarks on the age of the linked article. There's no real in-depth analysis of the technical aspects of USB floppy drives or their history. The conversation is more a reflection on the pace of technological change and the quirks of computing practices in the early 2000s.