Recent content by retrohimpi

Anyone else see this blog post? Python's not a language I've had much to do with, but there's probably enough info in the post to enable a port to Java for my OSI Challenger emulator (see my blog). At the moment, my emulation's cassette ports read/write directly to text files on the host...

Damn! It was a corrupted boot disk image all along. After tracing BASIC execution through interpretation of the first statement without finding anything obviously amiss I tried booting from a different disk image and, bingo, I got a menu of games from its BEXEC* program. I could play Hangman and...

This article was in the magazine section of my paper today. I'd no idea that blank cassettes are now worth a small fortune. Does anyone else still have their old cassette collection? I keep meaning to digitise those I couldn't replace with CDs, but haven't got round to it yet.

After some fun and games working out how to use Emacs to edit individual bytes in a binary file, I managed to change both the I/O distributor bytes in the disk image to $02 and rebooted my emulator. About 3 seconds later, I got this:- As you can see, it now has a pair of floppy drives as well...

I'm trying to write my own Java emulation of a dual floppy Ohio Scientific Challenger 1P and I've been blogging here about my problems with getting it to boot from a disk image. I'm not sure how to link to my blog posts, but you can access them via my profile page. If anyone has a real C1P and...

Well, I've made some progress in understanding the problem, even if I'm no nearer a solution. I set a breakpoint in OS65D's generic character output subroutine, rebooted and wrote down the ASCII value in the accumulator each time it was called. I saw banners from OS65D and OSI 9 digit BASIC, a...

My first home computer, way back in 1979, was an Ohio Scientific Inc (OSI) Challenger 1P (a SuperBoard in a metal case with 1Mhz 6502, 8Kb RAM, PSU and TV modulator) and I'm currently trying to emulate it in Java. As usual, I had no idea how hard all this was going to be when I started, or I'd...

Hi everyone, I'm a recently retired software engineer, living in the ancient market town of Saffron Walden, Essex in the UK and currently emulating my first single-board computer (Ohio Scientific Challenger 1P) in Java. I've managed to more or less recreate the 1Mhz, 8Kb RAM, cassette-based...