Monday, June 28, 2010

PX-8 Virtual Drive, take 2

The Epson PX-8 is a circa 1984 laptop computer, running the CP/M operating system (ROM based). Last I checked, you can still purchase new PX-8 systems from Star Technology. However, the PF-10 3.5" portable disk drive for the PX-8 is a very rare beast - the ones I've seen on eBay I've never been able to afford.

Communications between the PX-8 and PF-10 are over an RS-232 compatible connection at 38400 baud. The protocol is documented, and there are a couple of software packages - one for Linux, and one for DOS - that emulate the drive. I would like to extend the work that's already been done in this field, and create a portable, battery-operated virtual disk drive for the PX-8.

I'm hoping to be able to use a Propeller microcontroller chip as the "brains" of the virtual drive. The Propeller is cool - 8 parallel cores or "cogs" typically running at 80 MHz nominal clock speed. There are hardware/software solutions for interfacing with external storage, including SD cards.

Like last year, I've entered the Retrochallenge contest with the goal of producing a first pass at a virtual drive prototype. Unlike last year, this year I hope to achieve the goal!

More postings as I go. Look for details on this blog, with the tag label "retrochallenge".

Sunday, June 27, 2010

Learning assembly on the C64

I'm jumping back in to learning assembly on the Commodore 64. I'm going to start by making another pass through Jim Butterfield's Machine Language for the Commodore 64, 128 and other Commodore Computers. After that, I'll be looking to level-up to advanced stuff. This time, I really want to go deep on the guts of the C64 and C128. I've got an idea for a couple of projects, and I'm excited to get moving again.

Saturday, June 19, 2010

Retrochallenge 2010 starts in two weeks!

Hi all,

The Retrochallenge 2010 contest begins in about two weeks! If you've got a fun idea for a retrocomputing activity or project, head on over now!

Thursday, June 17, 2010


Hi there retrocomputing fans...

Welcome to the Retrobits Podcast blog!  Here you'll find my periodic musing on the vintage computing world, and also an occasional personal diversion.

- Earl