A field guide to the microcomputer era
Computers, from
the instruction up.
Meet the processors that made personal computing possible. Read their stories, follow their architecture, and see the definitions that bring them to life.
Explore the processors8 processors. Readable specifications. Working models.
Drawn directly from the executable specification
Start with the basics
What can eight bits tell you?
Switch bits on and off. See the same number in binary, decimal, and hexadecimal. Start there, or jump to an 8080 or Altair lesson.
Start with bits and numbers Browse all 37 lessonsProcessor guides
A decade on a chip.
From the 8008 to the 68000.
Choose a processor and explore how it works.
Intel 8008
14-bit model address space
Intel 8080
16-bit model address space
Motorola 6800
16-bit model address space
MOS 6502
16-bit model address space
Zilog Z80
16-bit model address space
Motorola 6809
16-bit model address space
Intel 8088
20-bit model address space
Motorola 68000
24-bit model address space
Historical machines
Give the computer a program.
Load your own software and explore the machine behind it.
Altair 8800
Load 4K BASIC from paper tape. Use its terminal and front panel.
Apple II Plus
Boot Applesoft from your ROM. Write a program and draw in sixteen colours.
TRS-80 Color Computer
Run Color BASIC and inspect the processor, keyboard, memory, and video hardware.
IBM PC/XT
Boot the original XT into ROM BASIC, or insert a floppy and run DOS on its CGA screen.
An explanation you can run
Read it.
Understand it.
Run it.
A processor specification can be more than a reference. It can be the source of the emulator itself.
Each guide brings together the chip’s history, its programming model, and formal definitions of its behavior. Dromaios turns those definitions into working processor models. The explanation and the machine share one source.
Start experimenting with bits and numbers, or explore the processor guides. Ready for a whole machine? Load and run BASIC on the Altair 8800, using its historical paper tape.
Build and run Dromaios Read the specification language guide