Ideas for Network Boot of Radio Shack Color Computers

Radio Shack Color Computers

Coco1: 1980: 4K or 16K

Coco2: 1983: 64K

Coco3: 1986: 128K or 512K (with Memory Mapping Unit)

The 6809 CPU sees only a 64K memory space.

Typically 32K for RAM and 32K for ROM:

$0000 - $7FFF RAM
$8000 - $9FFF Extended Color Basic
$A000 - $BFFF Color Basic
$C000 - $DFFF Cartridge 8K ROM (possibly Disk Basic)
$E000 - $FDFF Another 8K ROM (possibly Super Basic(?))

$FE00 - $FEFF Trampoline RAM
$FF00 - $FFFF Device I/O

=====================================

What will fit in 8K Cartridge Rom (on an Ethernet card)?

Write in ASM? C? FORTH?

DHCP for network addresses

or STATIC address assignment?

Unique ID per ROM (hostname for DHCP, Ethernet MAC)

Quickly load the next chunk of code from TFTP

Load bare metal programs

Load other operating systems (NitrOS-9, Flex, Ya-dos, Fuzix)

Debugging Monitor (view memory, registers, run code)

OpenFirmware-ish interpreter (better debugging!)

What would a new "network operating system" look like? ( videotex? chromebook? )

Easter Eggs (simple built-in game? image? screen saver?)

=====================================

Compiled ROM code sizes so far, in bytes, for one test program:

https://github.com/strickyak/frobio/blob/main/frob2/bootrom/polynetboot.c

https://github.com/strickyak/frobio/blob/main/frob2/bootrom/poly-compile.sh

8413 :: cmoc -O0
7951 :: cmoc -O1
7040 :: cmoc -O2
7258 :: gcc -O0
5209 :: gcc -O1
5598 :: gcc -O2
5021 :: gcc -Os
5450 :: gcc -O2 -fomit-frame-pointer
4855 :: gcc -Os -fomit-frame-pointer
4767 :: gcc -O2 -fwhole-program
4690 :: gcc -O2 -fomit-frame-pointer -fwhole-program
4389 :: gcc -Os -fwhole-program
4288 :: gcc -Os -fomit-frame-pointer -fwhole-program

Other problems: gcc for 6809 has bugs in some of these modes.

boot_lemma.bak

https://boyter.org/posts/how-to-start-go-project-2023/#multiple-main-entry-points

https://go.dev/doc/code (how to write Go code)

https://www.mikrocontroller.net/attachment/1483/SPI_74HC595.pdf ( bidir SPI with -165 and -595 ) ( cache: /file SPI_74HC595.pdf )

level shifter: https://www.adafruit.com/product/735