PETdisk MAX Kit


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

Out of stock



Dec 2, 2021: I ran out of PETdisk MAX boards, having difficultly reordering at the moment due to the chip shortage (AVR microcontrollers out of stock). Hopefully it will be available again soon, if you are interested please let me know with the form below and I will let you know as soon as it is available again.

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 coming very soon.

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.

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 ESP8266 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: