PETdisk MAX v2 Kit


PETdisk MAX – SD and internet storage device for the Commodore PET

8 in stock (can be backordered)



Apr 7, 2022: The PETdisk MAX v2 is here! Production boards for the new version are here, and the PETdisk MAX is available again. Now using an ESP32 microcontroller in place of the v1’s ATMega1284.

Mar 16, 2022: Sorry for the wait, the first batch of the PETdisk MAX v2 will be available within the next few days. The new version now uses an ESP32 microcontroller instead of the ATMega1284, which has been out of stock everywhere for months. V2 has all of the same features as V1, and future firmware updates could allow some additional features such as FTP and HTTPS support for the network drive. I will update the page as soon as I have some V2 units ready, and more will be coming after that as well.

Oct 2, 2021: The PETdisk MAX is now available in kit form. Assembly of the kit takes about 15 minutes and requires only through-hole soldering, all surface mount parts are pre-assembled. Assembly instructions in the form of a video, linked below.

It’s ready! The PETdisk MAX, the successor to the original PETdisk I made several years ago, is a storage device for the Commodore PET which uses microSD cards as well as accessing PET software over the internet.

You can use FAT32 formatted microSD cards to hold as much PET software as you like. It supports both directly loading .PRG and .SEQ files from the filesystem of the card, and also supports mounting .D64 disk images.

In addition to this you can access PET software hosted on standard web servers as if it was a locally attached drive.

The PETdisk MAX is powered internally from one of the PET’s ROM sockets, so there is no cable hanging out the back of the machine. The device is very low profile and doesn’t extend far out the back of the PET, so you can just leave it attached without worrying about it crashing into something. It also has a passthrough edge connector so you can continue to use other IEEE-488 devices such as printers and other disk drives while the MAX is attached.

The PETdisk MAX comes as a kit, which requires only simple through-hole soldering. All surface mount parts are pre-assembled. Assembly takes approximately 15 minutes, please see the assembly video below. Requires a soldering iron, solder, and a pair of wire clippers.

Assembly and operation instructions for the PETdisk v2 here:
PETdisk MAX v2: Assembly and Operation

Instructions for the PETdisk V1:
PETdisk MAX Kit Assembly

Please note: The current firmware on the PETdisk MAX does not yet support PETs running Basic 1.0 ROMs. This includes early non-upgraded 2001 models. I hope to support this in the near future. PETs running these roms can use the MAX by switching to later basic roms using the ROMulator:

Also note that the WiFi module which the PETdisk MAX uses only supports connection to 2.4GHz wireless networks, or those capable of switching between 5 and 2.4GHz. 5GHz wifi is not supported.

The PETdisk firmware is open source. Code, schematics, and documentation can be found at: