jr-IDE is an open-source kit designed by Alan Hightower from retrotronics.org for the IBM model 4860 PCjr. Included are the following features on a side-car board:
- 40-pin Parallel ATA IDE interface
- 1MB of static RAM
- 512KB of flash ROM
- A real-time clock
- A Power On Self Test (POST) display
- Bus activity indicator LED
The board includes pass-through mounting holes allowing it to fit into a standard IBM side-car enclosure. The IBM PCjr side-car bus connectors (AMP 532773-2 & 532771-2) are very hard to find parts, but already installed on our pre-built board. You may supply a donor shell from another side-car, or alternately, use it stand-alone. Many people use the parallel port side-car commonly found on eBay. The process is completely reversible if you decide to remove the jr-IDE from your system and return the shell to it’s donor card.
Alan developed this board and sold them in kits and assembled them for many years now, but the time has come for him to hang up his soldering iron on this project. We decided it would be a perfect product to add to our existing PCjr lineup. A special device is required to program the Atmel CPLDs and in the side-car connectors can proof very difficult, if not impossible to purchase in single quantities. It seems the vast majority of units Alan sold were preassembled, as such we decided to only sell them fully assembled and tested.
The PCjr is a fun little computer, and the jr-IDE makes it much more fun to use without sourcing increasingly expensive original parts. You may use a 40 pin IDE to compact flash card adapter to use a standard CF card as a hard drive. Many older IDE hard drives may function as well. Your experience may vary and experimentation could be required to find an optimal device to use as a hard drive. As always, we recommend the SanDisk Ultra II cards.
Main site for the jr-IDE – https://www.retrotronics.org/home-page/jride/
Clock set / reset utility – https://www.retrotronics.org/download/jr-ide-clock-utility/?wpdmdl=1545
The project genesis happened on Mike’s terrific PCjr forums in this thread – http://www.brutman.com/forums/viewtopic.php?f=1&t=180
Information on how to use later DOS versions on PCjr – https://www.brutman.com/forums/viewtopic.php?f=3&t=224