Submission + - Working Palm OS Virus Rediscovered After 25 Years (linkedin.com)

Submitted by ardiri on Saturday October 17, 2026 @06:15AM

ardiri writes: Palm OS developer Aaron Ardiri has rediscovered the original source code of a working, self-replicating Palm OS virus he developed and tested in June 2001, months before the planned PalmSource developer conference in San Jose.

Named "Virii," the virus intercepted Palm OS system calls to progressively infect legitimate applications while preserving their original functionality. Infected applications could then spread between handheld devices through infrared beaming, potentially allowing an infection to propagate among hundreds of developers exchanging software at the conference.

The virus also included a date-triggered payload designed to interfere with system time reporting between October 23 and 27, 2001, potentially causing erratic clocks, unreliable alarms, and missed appointments. Following the September 11 terrorist attacks, PalmSource 2001 was postponed until February 2002, and the experiment never went ahead. The virus was never publicly released.

In 2016, Ardiri mentioned the experiment in a retrospective about his involvement in the infamous Palm OS Liberty Trojan incident, believing the original source code had been lost. In October 2026, he rediscovered the complete implementation on a CompactFlash card containing files dated June 2001.

The newly published retrospective documents the original infection mechanism, potential conference-wide propagation, and historical context. The functional source code and binaries will remain private.

Submission + - 25 Years Later, a Palm OS Developer Opens His Development Archive (github.com)

Submitted by ardiri on Thursday October 15, 2026 @10:05AM

ardiri writes: Palm OS developer Aaron Ardiri (slashdot.org/~ardiri) has released approximately 1 GB of historical Palm OS development resources, accumulated during the early days of handheld computing and preserved on hard drive backups for more than 25 years. The collection includes historical SDKs, developer conference presentations, technical documentation, programming examples, limited source code, and development utilities. ROM images, commercial applications, and simulator binaries have deliberately been excluded.

Ardiri previously published the source code for his Palm OS and VTOS projects, including work exploring the capabilities of early handheld devices. This latest release expands those preservation efforts beyond his own software, making a broader collection of development resources available to the retrocomputing community. The archive is available at https://github.com/ardiri/dev-... and is intended for historical preservation, education, and research, particularly as enthusiasts continue working to maintain, emulate, and revive the platform (available at https://www.ardiri.com./

Ardiri has also written an auto-biography and shas started explored the engineering principles behind these systems in his books, including Inside the Machine, which examines computer architecture from fundamental logic through modern computing systems. At a time when much of the early mobile development ecosystem has disappeared into defunct websites and aging backups, this collection offers another opportunity to preserve the tools and knowledge that helped define an important era of personal computing.

Submission + - From Palm OS to Foldable Phones (linkedin.com)

Submitted by ardiri on Thursday September 10, 2026 @02:55AM

ardiri writes: Long-time Slashdot reader Aaron Ardiri, whose Palm OS work has appeared here a few times over the years, has revisited a mobile architecture he developed more than 20 years ago after this week's renewed attention on fold-able phones.

MedHand International began developing medical reference software for Palm OS in 2000, eventually supporting Palm OS, Windows Mobile, Windows and Mac OS X. Because medical publishers supplied content in wildly different formats, MedHand developed its own canonical XML representation—“MedHand XML”—and separated structured content from its presentation.

That work resulted in a patent filed in 2005 describing components, containers, a layout manager, hierarchical information and display-dependent presentation. Its diagrams explicitly show the same information hierarchy being presented differently on a mobile phone, PDA and desktop display.

The interesting comparison isn't that MedHand somehow “invented the foldable phone”—it didn't—but that modern foldables create essentially the architectural problem the software was designed to handle: the underlying information remains unchanged while the available display environment changes substantially, requiring the presentation and visible information hierarchy to adapt.

Ardiri has written a retrospective comparing the 2005 architecture with modern adaptive mobile interfaces. There's also an amusing historical circle: MedHand International built its own XML publishing pipeline before EPUB became an industry standard, while Ardiri has just released his autobiography and Inside the Machine as EPUBs—including on Apple Books.

So how many supposedly “new” computing problems are really old architectural problems waiting for the hardware to catch up?

Submission + - Palm OS developer releases source to classic games, 20+ years after release (github.com) 1

Submitted by ardiri on Wednesday May 18, 2022 @02:11AM

ardiri writes: Before the iOS and Android entered the scene; heck, even before the smartphone concept was the handheld personal digital assistant, with the likes of Newton, Palm OS, Windows Mobile and Symbian. Palm OS had a thriving gaming scene; with the likes of emulators and implementations/clones of classics such as LodeRunner, Lemmings, and the classic Game and Watch. written mainlyin C and optimizations in assembler — maybe these games will make their way to the various Arduino like micro-controllers out there; designed for low memory, low processing power environments they would port perfectly.

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