PiCore - A Raspberry Pi Port of Tiny Core Linux

piCore is a Tiny Core Linux port for the Raspberry Pi, tailored for custom systems and embedded devices with a very small footprint and up-to-date kernel and app configuration.

The core philosophy is to run entirely from RAM. After boot, the SD card's boot partition is never rewritten, and the default operating mode is Cloud Mode. In this mode, extension applications are downloaded from internet repositories for use, and the filesystem is kept in RAM. On reboot, changes are lost, so the system always starts in a clean state.

In Mounted Mode, a separate ext4 LINUX partition is used as persistent storage.

• Downloaded extension files can be saved to the SD card.
• Changes are not saved automatically; backups are done manually or via script.
• Backed-up files are automatically restored by the system.
• Using /home or /var as persistent storage is also possible, but Mounted Mode is typically used.

Installation is relatively simple. Write the raw SD card image inside the .zip using dd or Win32 Disk Imager on Windows. The base system works offline as well, but a wired internet connection is recommended for accurate system time, package installation, and SSH access.

The SD card layout is also clear.

• First VFAT partition: contains the base system and the Raspberry Pi bootloader, firmware, and support files.
• This partition becomes unmounted after boot, and is neither used nor written to by the system.
• Second ext4 partition for Mounted Mode: stores extension files and backups.

Some images already include the extension partition. For example, images like piCore-5.x-SSH and piCore-5.x-X include a second ext4 partition, but its size may need to be increased for additional extensions and backups. In that case, delete the partition with fdisk, recreate it starting at the same position, and after rebooting, expand the filesystem with resize2fs /dev/mmcblk0p2.

Swap is provided by default as zlib compressed swap in RAM, automatically sized to 25% of RAM. It can be disabled with the NOZSWAP boot code. If a larger swap is needed, create a swap partition with fdisk and format it with mkswap. A small capacity may be sufficient for general use, but heavier tasks such as building large programs may require 512MB or more.

Boot options include general Linux boot codes as well as Tiny Core Linux-specific options, specified in cmdline.txt. The default user account is tc with no password. On piCore-5.x-SSH, the password for tc is piCore. Root login is not allowed.

Support is community-based, and the Tiny Core Linux forums and the Into the Core book are recommended as references. This distribution is tailored for users who want to use the Raspberry Pi as a lightweight, controllable system through its small size, fast boot, and RAM-centric operation.