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FreeDOS Running. Lots More Work Needed.
I now have FreeDOS running on my 286 build. In this running post, I'll add information about incremental updates I am doing. In the...
rehsd
Jun 12, 20231 min read
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80286 System Roadmap (updated June 2023)
Back in January of this year, I posted a list of potential roadmap items for my 26 build. See 80286 System Roadmap (rehsdonline.com). As...
rehsd
Jun 5, 20231 min read
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Troubleshooting FreeDOS Boot on my 286 System - Hangs on execrh() Call in Kernel
As I continue to work towards getting FreeDOS running on my 286 homebrew build, I am encountering a new issue. During boot, the FreeDOS...
rehsd
May 5, 20235 min read
189 views
2 comments

Troubleshooting CPU Flags Register Between BIOS and FreeDOS
I am running into an issue getting expected CPU flags register values back from interrupt calls made in FreeDOS to my BIOS on my 286...
rehsd
Apr 30, 20233 min read
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FreeDOS Development Environment
In this post, I will share a bit about the development environment I am using to build FreeDOS (and possibly other DOS applications). I...
rehsd
Apr 17, 20235 min read
177 views
2 comments


Booting FreeDOS
At this stage of my homebrew 286 system build, I have an IDE interface to a compact flash (CF) card. I have begun implementing disk...
rehsd
Apr 16, 20233 min read
135 views
2 comments


IDE Interface
I am currently working to see if I can boot to an IDE storage device (specifically, a CF Card) and get FreeDOS's kernel loaded. I'll use...
rehsd
Apr 14, 20231 min read
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286 Build - Six Months In
I am nearly six months into my 286 project. While I started on breadboards, I am now at a nice stage where I have an ATX form-factor...
rehsd
Apr 2, 20231 min read
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Interrupts and More Interrupts
I am starting to implement support for additional interrupts on my 286 system. This includes BIOS interrupts and DOS interrupts. Relevant...
rehsd
Mar 10, 20231 min read
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Working with AY-3-8910, YM2149 Programmable Sound Generators
Sample code at x86/Audio/20230308 at main · rehsd/x86 (github.com).
rehsd
Mar 9, 20231 min read
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Using C/C++ with my 286
Up to this point, all code running on my 286 system has been x86 assembly (real mode). I am hoping to learn how to compile C or C++ code...
rehsd
Feb 24, 20235 min read
188 views
3 comments


286: Onboard ROM Updates
A helpful feature that I am looking to add to my 286 system is onboard flash ROM updates, where I do not need to remove the flash ROMs to...
rehsd
Feb 20, 20232 min read
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Sound Card for my 286 System
For my sound card, I plan to leverage previous work that I did for my 65816 system build. I will refactor the sound card to support my...
rehsd
Feb 17, 20231 min read
2,265 views
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Mouse for my 80286 System (SPI to PS/2)
My 286 system does not have built-in mouse support (yet). I have been experimenting with a few options. Back on my 6502 system, I added...
rehsd
Feb 15, 20232 min read
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VGA 640x480 ISA Card
As a follow-up to VGA Next: 640x480 ISA Card, I now have a functional version of an ISA VGA card working. The card supports 640x480 with...
rehsd
Feb 9, 20232 min read
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Using PSoCs for Rapid Prototyping
While working on my 6502 back in 2021, u/Enlightenment777 had suggested I look into Programmable System-on-Chips (PSoCs). It took me...
rehsd
Feb 5, 20231 min read
135 views
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80286 System Roadmap
Last October (2022), I started my learning journey to develop a 286 system. See Start to an 80286 System. As of this writing, I have a...
rehsd
Jan 25, 20233 min read
242 views
3 comments

VGA Next: 640x480 ISA Card
One of my goals for my 286 system is to run MS-DOS at some point (ideally, 6.22). To get to that stage, I have some heavy lifting to do....
rehsd
Dec 31, 20223 min read
642 views
5 comments


VGA for my 80286
As a follow-up to Brainstorming... Video Card for 286 System, I am now working to get my VGA card working in my 80286 system. Initial...
rehsd
Dec 18, 20223 min read
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Transitioning 80286 from Breadboard to PCB
Over the past couple of months, I have been working to build out a breadboard-based 80286 system. See /blog/categories/x86. I plan to...
rehsd
Dec 13, 20222 min read
336 views
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