user7352: Does Cardano have a virtual machine? Throughout crypto we hear a lot about EVM but have never heard any reference to a Cardano VM? Is there a need for a VM for Cardano or has the system been architected in away that eliminates the need?

user4302: Ethereum, Solana, and other blockchains that use an accounts-based ledger model can each be thought of as one big box of logical interdependencies, whose state is constantly changing, all replicated, maintained, and updated by many nodes. Keeping track of and executing all these interdependencies requires a "VM" - a sort of universe in which all these logical structures can live in context with one another. This allows for a high degree of flexibility and customizability, but also makes it difficult to model and prevent chaotic side effects.
Bitcoin, Cardano, and other blockchains that use a UTXO-based ledger model are different. Instead of thinking of the blockchain as one big box (as in the previous case), it is better to think of it as a collection, or a set, of many little boxes (a.k.a UTXOs). The whole UTXO set is replicated and constantly changing like any other blockchain, but there are no interdependencies between the UTXOs themselves. Instead, each UTXO contains just enough information it needs to only ever be spent exactly how the creator of the UTXO intended it. There is no notion of a shared "global state", and hence no need for a VM.

7352: <p>Does Cardano have a virtual machine? Throughout crypto we hear a lot about EVM but have never heard any reference to a Cardano VM? Is there a need for a VM for Cardano or has the system been architected in away that eliminates the need?</p>
 4302: <p>Ethereum, Solana, and other blockchains that use an accounts-based ledger model can each be thought of as one big box of logical interdependencies, whose <em>state</em> is constantly changing, all replicated, maintained, and updated by many nodes. Keeping track of and executing all these interdependencies requires a &quot;VM&quot; - a sort of universe in which all these logical structures can live in context with one another. This allows for a high degree of flexibility and customizability, but also makes it difficult to model and prevent chaotic side effects.</p>
<p>Bitcoin, Cardano, and other blockchains that use a UTXO-based ledger model are different. Instead of thinking of the blockchain as one big box (as in the previous case), it is better to think of it as a collection, or a <em>set</em>, of many little boxes (a.k.a UTXOs). The whole UTXO set is replicated and constantly changing like any other blockchain, but <strong>there are no interdependencies between the UTXOs themselves.</strong> Instead, each UTXO contains just enough information it needs to only ever be spent <em>exactly</em> how the creator of the UTXO intended it. There is no notion of a shared &quot;global state&quot;, and hence no need for a VM.</p>
