This repository contains scripts, patches and build recipes for building a custom BIOS from source for the Monotech NuXT V1 modern PC XT compatible system. It will currently not work on V2. If you would like to help, please look at this issue.
It aggregates the Micro 8088 BIOS, XT-IDE Universal BIOS, GLaBIOS, GLaTICK, Multi-Floppy and IBM Cassette BASIC in order to build a hybrid BIOS consisting of two separate BIOS implementations.
The hybrid BIOS is a 128 KiB image suitable for flashing onto the BIOS EEPROM. The user may select one of the two BIOS'es before booting the machine by the use of DIP switch 4 on the NuXT motherboard.
The first BIOS is active when the switch is OFF, it consists of the Micro 8088 BIOS + XT-IDE for booting the CF Card. The Micro 8088 BIOS supports RTC and all types of floppy drives out of the box. This BIOS does not support IBM BASIC.
The second BIOS is active when the switch is ON, this BIOS is based on GLaBIOS. GLaBIOS relies on option ROM's to provide certain functionality, so this half includes GLaTICK (for RTC support), Multi-Floppy (for supporting drives other than 360 KiB) and XT-IDE (for booting from CF Card). This is essentially the same functionality albeit in a different way. This BIOS includes IBM BASIC so BASICA.COM will work.
Current versions of the different modules are:
| Module | Version |
|---|---|
| Micro 8088 | v0.9.9 |
| GLaBIOS | v0.2.4 |
| XT-IDE Universal BIOS | r625 |
The BIOS images can either be built from source by following the instructions below, or downloaded from the releases page.
svn and dosbox must be available to run from the command line.
On Ubuntu this can be done with apt:
sudo apt install subversion dosbox
To use the helper scripts (not mandatory but makes things easier), just must be installed. It is often found in your distribution's package manager, but if it isn't you may need to follow specific instructions in just's repository. If just is not installed, consult the .justfile and find the relevant recipe when needed.
After first cloning the project, perform just init to retrieve all submodules and dependencies.
All BIOS'es may be built by issuing just build (or make -j). Alternatively a single BIOS can be built by using make.
Micro 8088 builds contain the Micro 8088 main BIOS + XT-IDE.
GLaBIOS builds contain the main GLaBIOS BIOS and XT-IDE + Multi-Floppy + GLaTICK + BASIC.
"Hybrid" builds are 128 KiB images suitable for replacing the whole EEPROM content, other builds can be used to write each EEPROM half independently or to create other "hybrids".
Artifacts built are:
| Name | Content | Size |
|---|---|---|
bios-nuxt-hybrid-universal.bin |
Hybrid universal | 128 KiB |
bios-nuxt-hybrid-V20.bin |
Hybrid V20 optimized | 128 KiB |
bios-nuxt-glabios-universal.bin |
GLaBIOS universal | 64 KiB |
bios-nuxt-glabios-v20.bin |
GLaBIOS V20 optimized | 64 KiB |
bios-nuxt-micro-universal.bin |
Micro 8088 universal 8088 | 64 KiB |
bios-nuxt-micro-v20.bin |
GLaBIOS V20 optimized | 64 KiB |
The Micro 8088 BIOS requires nothing special, it is built and used as-is on the NuXT.
The Multi-Floppy option ROM requires nothing special, it is built and used as-is on the NuXT.
To build on Linux the AS variable is passed to make as AS=nasm.
To build the V20 optimized option USE_NEC_V=1 is passed to make.
GLaBIOS is built using masm 5.0, this is included in the masm5 directory. DOSBox is used to do the build.
Two DOS .BAT files are used to control the build process, GBN8.BAT (for (G)La(B)IOS (N)uXT (8)088) passes /DARCH_TYPE='F' /DCPU_TYPE='8' to masm for targeting Faraday FE2010A and 8088. GBNV.BAT (for (G)La(B)IOS (N)uXT (V)20) passes /DARCH_TYPE='F' /DCPU_TYPE='V' to target V20 instead.
GLaTICK is also built using masm 5.0 through DOSBox.
GLaTICK is patched to target common NuXT hardware RTC's in Makefile using the rtc.patch file.