Today's http://onchainchecker.xyz listing is a special one in many ways:

PETARP by the late @nopsta 

PETARP is the precessor of much more popular collection ORAAND. Although not fully on-chain like ORAAND, PETARP stores the executable Commodore 64 programs on-chain

writing onchain programs for the Commodore 64

1/

In PETARP, the artwork is accessible from the chain through getTokenPRG calls. With parameter unmodified=false, the returned binary corresponds to art as seen on marketplaces

Cryptoartist focusing on dynamic and fully on-chain artworks.

Tweets are not financial advice.

Pronouns: they/them

2/

The binary is composed from 3 layers

The base layer of the binary is basePRGData that contains the template of the PETARP Commodore 64 program

3/

On top of that, each token has a set of token-specific parameters that are retrieved through getTokenParams call. These parameters are applied on top of base PRG file to alter the program to be unique for that particular token

5/

The binary data returned from getTokenPRG can be converted easily into a binary program for instance with a simple bash command combo:

echo "0x01080b...00" | xxd -r -p > petarp.prg

This file can then be executed in any C64 emulator or even real hardware!

6/

Although PETARP utilizes off-chain emulator, nopsta also managed to deploy on-chain version of his emulator to Ethereum as part of ORAAND. Demonstrating it would be possible to write a wrapper that makes also PETARP tokens fully on-chain!

https://etherscan.io/address/0x40307D57da1BEdF31967dC9fa186c1026b496AB2#code

7/

Given that PETARP tokens depends on centralized server (http://nopsta.com), the tokens are rated as 3/5 by On-Chain Checker. Although the core program is fully on-chain, marketplaces and dapps depend on http://nopsta.com being online if no wrapper is created

8/  In short term, the best that could be done was to launch a preservation effort. For the eventual case of nopsta.com going offline, @0xfff started an archival project I also contributed to, available at:

8/  In short term, the best that could be done was to launch a preservation effort. For the eventual case of nopsta.com going offline, @0xfff started an archival project I also contributed to, available at:

https://github.com/0xfffxfff/nopsta

9/ Finally:

PETARP is an interesting artwork from nopsta. It can be treated as a prototype for many of the technical feats also seen in ORAAND. Its not fully on-chain, but is on-chain in Commodore 64 executable PRG format.

And hence, deserve to be On-Chain Checker listed

Such a good write up for such a talented artist

Thank you for continuing to share all of these amazing works. Petarp and Oraand really are special. Thank you for your preservation efforts. 

Onchainchecker.xyz really is the home page of the new internet. Iykyk. 163 $degen

memes. bald. based. cypherpunk. 

If you need a reminder:

https://activism.net/cypherpunk/manifesto.html

https://activism.net/cypherpunk/crypto-anarchy.html