VCF EAST MENU — Speakers FAQ — Speakers Registration — Roundtables
Talks List
50 years of Z80 – Jeff Jonas
Oh Z80, how do I love thee? Let me count the ways! The software compatibility, the operating system, the Lego-like peripheral chips led to thousands of designs. Still operating undercover as an embedded processor in TI calculators, the Z80 never really went away.
Cassette BASIC: The Forgotten Operating System of the IBM PC – William (Milli) Hicks
Before floppy disks became standard, the original IBM PC could load and run programs directly from audio cassette. This talk explores IBM’s little-known Cassette BASIC: how it worked, how it compared to cassette systems on other 8-bit computers, and why IBM included it in the first place.
We’ll look at the technical design, the user experience, and why this approach was quickly abandoned as the PC ecosystem evolved — leaving behind a fascinating snapshot of computing at the moment it crossed from hobbyist to mainstream.
COSMAC 1802 Control Logic Unit: How to Program with a Soldering Iron – Joyce Weisbecker
See how the flow chart for a machine language instruction can be used to create a logic diagram & a TTL circuit that executes that instruction. A hand-drawn wiring diagram of Joe Weisbecker’s FRED CPU (prototype for 1802) is used as an example of this “programming with a soldering iron” approach to control logic design for an 8-bit CPU.
FPGA-based PDP-11 I/O board – Mike Reiker
Design and implementation of an FPGA-based PDP-11/34 Unibus board for I/O and memory.
Once Upon a Time in ComputerLand – My first 46 Years selling microcomputers – Bob Roswell
46 Years of selling microcomputers
PDP-8 meets Python and POSIX — Curating old Software with modern tools. – William Catey
So much of vintage computing rests on “found objects” — whatever software happened to survive on museum-piece hardware. SIMH and other emulators expanded our ability to experience these platforms, and notable efforts like the PiDP-10 have shown what active curation can achieve. This talk describes similar work for the PDP-8 and OS/8 ecosystem: a Python-based toolchain that brings source control, automated builds, dependency management, regression testing, and collaborative workflows to software that has been frozen in time for decades.
The talk covers three scripting languages for automation — os8-run for complex OS/8 operations, os8pkg for source-level dependency management and bootable media creation, and os8-progtest for regression testing under SIMH — and demonstrates how they enable reproducible builds of the OS/8 Combined Kit and other software onto tu56 and rk05 images for both simulators and original hardware. A self-contained collaboration platform, fossil, ties it all together, making it as easy as possible for new contributors to participate.
The proof of concept is pdp8-alive, a demonstration curation environment built around PDP-8 Adventure — tracking down every published version, establishing a historical timeline, and in the process finding and fixing a bug present since the first release in 1979. The goal is not only to show what has been done, but to inspire similar approaches and bring more collaborators on board.
Why Ohio Scientific was Great (and why have you never heard of it?) – Crawford Griffith
In celebration of the 50th anniversary of Ohio Scientific Inc, we review the history of this engineering-focused company. While not as well known or successful as IMSAI, Commodore or Apple, OSI made some groundbreaking and innovative products. Various OSI exhibits will show these products at VCF East this year.