Virtual Machines

FAQs for Virtual Machines

Note: At this point in time, we are restarting and accelerating the K Ethereum Virtual Machine (KEVM) program only. The IELE program will be coming very soon, but you can learn about IELE's features and benefits in this page.

I’m a Cardano fan

Q. Why are we doing this?

A. To provide the community with an environment to experience the technology for smart contracts that Cardano will deliver as part of the Goguen rollout. We want to establish a conversation with the community and develop an ecosystem to support these features. KEVM and IELE will allow Solidity developers to participate in the Cardano ecosystem. IELE in particular will allow universal compatibility, which means that it will be possible to write smart contracts in several different languages besides Solidity (Python, for example).

Q. Who is the devnet targeted at? Who would be able to use it?

A. The devnet is targeted at smart contract developers who have previously created smart contracts for other blockchains using Solidity. For example, ETC developers, Ethereum, Tron, etc.)

Q. How can one access the devnet?

A. Our dedicated devnet site is now live.

Q. How does Mantis interact with the devnets? Why are we using an ETC codebase for this?

A. The KEVM is 100% compatible with the EVM, so it made sense to plug the VM into Mantis, as Mantis was already compatible with ETC. Finally, we want to initiate a conversation with the community.

Q. How does this relate to native tokens?

A. In the future, smart contracts written in KEVM and IELE will have native tokens exposed as part of the language. This is currently not possible because both work streams (native tokens and VMs) work in parallel and will converge later with the launch of Goguen.

Q. What funcionality can I expect?

A. You can take a smart contract created in Solidity, compile it to run in KEVM or IELE, and deploy it to the test environments.

Q. What’s the user journey of what a developer can do, step by step, using what tools?

A. You can read the Smart Contracts Architecture article, and see how the different pieces work together.

Q. What’s Mallet, and how does it fit into the journey?

A. Mallet, the minimal wallet, is the command line interface used to send transactions, deploy smart contracts, and interact with the IELE and KEVM devnets.

Q. What tools or Integrated Development Environments (IDEs) are we offering?

A. We will initially support Mallet. Support for Truffle is coming soon.

I’m a developer

Q. What is KEVM?

A. KEVM is an implementation of the Ethereum virtual machine (EVM) developed by Runtime Verification. It is derived automatically from the formal semantics of the EVM (i.e., the yellow paper ) thanks to K framework technology.

KEVM has two main advantages over the original EVM:

  1. It is correct by construction, meaning that the user of the VM only needs to read the formal semantics of EVM, which are given in a clear and easy-to-understand declarative form. The user can be sure that the VM will behave precisely as specified, and not in any other way.

  2. By leveraging the K framework technology, it was possible to automatically derive other tools such as a compiler and a fully automated prover.

Q. What is the K Framework?

A. The K Framework is a set of tools used to define programming languages. It has been used in the aerospace and automotive industries, and it is now being used in the blockchain industry. Once the language is defined, tools such as a parser, an interpreter, and even a program verifier are available for it,

Q. What is IELE?

A. IELE consists of two things: the IELE Virtual Machine (VM) and the IELE assembly language, which is executed by that VM.

The IELE VM differs from the KEVM, the original EVM, and other VMs, in that IELE is register-based, rather than stack-based. The VM itself, the compiler, and other tools are all formally verified by the K Framework.

Q. Is IELE its own language?

A. The IELE language is the low-level language executed by the IELE VM. The typical process for creating a smart contract is to write it in Solidity or any other supported high-level language, compile to IELE assembly, and execute the result in the IELE VM.

As an analogy of how Solidity gets compiled to IELE assembly and executed on the IELE VM, think of how Java gets compiled to Java byte code (low level) and executed on the Java virtual machine (JVM).

Q. What is the difference between the KEVM and IELE VM?

A. The KEVM is an implementation of the EVM developed within the K-Framework. The IELE VM is an entirely new VM, inspired by the low-level virtual machine (LLVM). The KEVM is stack-based and can execute the complete Solidity language, while LLVM is register-based, and IELE uses a more restricted subset of the language.

Q. What are the differences between IELE, KEVM, Plutus, and Marlowe?

A. These products are related but are not quite the same. Let's classify them:

  • IELE and KEVM are VMs that execute programs
  • Plutus and Solidity are general purpose languages that operate in blockchains
  • Marlowe is a domain-specific languages targeting financial contracts

A domain-specific language is used to write concise programs about financial concepts such as debt, interest, etc., while general purpose languages like Plutus and Solidity can also implement applications such as Crypto-kitties. All these languages must be compiled to run in a VM (KEVM or IELE).

Q. What is Universal Compatibility?

A. Just like there are many natural languages (English, Spanish, etc.), there are many programming languages (Java, C++, Haskell, etc.). There also are many smart contract programming languages (Plutus, Solidity, Marlowe, etc.). However, each programming language requires one compiler for every processor (Intel, ARM, M1) on which it is going to execute. With a VM such as IELE, only one compiler per language is needed, since all of the programming languages will execute in the same VM. In the future, you will be able to write smart contracts in your favorite language.

Q. How can I reuse a smart contract in KEVM and in IELE?

A. Solidity compiles to both the KEVM and the IELE VMs, so some Solidity contracts can be reused by simply re-compiling them. In comparison to the KEVM, IELE offers increased security by supporting arbitrarily large signed integers (thus getting rid of issues of arithmetic overflow), removing unsafe features like DelegateCall and being register-based (thus avoiding the risk of stack over- or underflows). This means that some Solidity features are not 100% compatible with IELE.

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