Note: This derived from the example filesystem repo. The difference is that this repo does not compile/assemble anything. It is intended to be used to copy all the .COM files in the com directory into a disk image that can be burned onto an SD card.

The intended use for this is to REPLACE every file on a disk image. Not to merge files into an existing one.

For example, if you are on the standard Raspberry PI setup then to download some games from linuxplayground and copy them to the SD card slot for drive E: so you run them on your Retro, you can do this:

git clone https://github.com/Z80-Retro/Z80-Retro-disk-maker.git
cd Z80-Retro-disk-maker
wget https://github.com/linuxplayground/nabu-games/releases/download/v3.3/nabu-games-z80retro-v3.3.tgz
tar zxvf nabu-games-z80retro-v3.3.tgz -C apps
make
make burn

To change the drive slot number, create a Make.local as discussed in the Make.default file.

Note that this will build a disk image that has no operating system on it.

See the Z80 Retro! CP/M repo for information on how to format an SD card and install a bootable image into drive A which we normally refer to as "slot zero".

The image created by this Makefile is intended to be stored into any slot OTHER than slot zero.

Below is a discussion of how and where things are stored on an SD card suitable for use in a Z80 Retro! system. By default, the Makefile has been configured to function out-of-the-box if you are using a Raspberry PI as your development platform as seen in the Z80 Retro! Playlist on the John's Basement YouTube channel.

If you are using a different system, you will want to create a Make.local file to override the defaults as needed by your platform. You should not have to alter any of the other Make* files unless you are adding or removing programs from the filesystem.

If you find this to be untrue then you are either doing it wrong or there is an error in how this project has been prepared. Please post comments to let the maintainers know!

We use the cpmtools package to do this. On a Debian-derived linux system we can install it like this:

sudo apt install cpmtools

It is not documented, but a diskdefs file in the current directory will be searched my the cpmtools commands for the given -f format:

mkfs.cpm -f generic-8k-8m retro.img

Note that the above will save 0xe5 bytes into the directory are of the disk and accomplish nothing more.

Once a filesystem has been initialized by the mkfs.cpm command, files can be added to it like this:

cpmcp -f generic-8k-8m retro.img myprog.com 0:

We can also look at what files are on the CP/M filesystem with the cpmls command like this:

cpmls -f generic-8k-8m retro.img

We consider the one SD partition as a series of 8 megabyte slots.
The goal is to write one disk image (filesystem) to each slot on the disk partition using the dd command by specifying where on the SD card to put each one.

We consider the slots to be numbered 0-15.

Each slot is 16384 blocks in size (0x4000). seek=01x16384 - 16384 in decimal is the start of the second disk slot.

To change the slot number used by the Makefile, you can create a Make.local file to override the default slot number that can be found in the Make.default file.

For example, one way to create a new Make.local file and/or delete any existing one and replace it with one line to change the slot number to 5 (for drive F:), you could do this:

echo "DISK_SLOT=5" >> Make.local

For more apps that can run on your Retro! board, search the Internet for variations of cp/m software downloads and 'cp/m game download' etc.

Some big archives that might keep you busy for a while can be found here:

http://cpmarchives.classiccmp.org/
https://ifarchive.org/indexes/if-archiveXgamesXcpm.html
https://deramp.com/downloads/mfe_archive/040-Software/Digital%20Research/CPM%20Implementations/COMPUPRO/GAMES/

If you want something to cook on your CPU and test every instruction, you can try zexall.com and zexdoc.com files found in the CPM.zip file located here:

https://mdfs.net/Software/Z80/Exerciser/