Introduction

Why is Solana so different from Ethereum?

By far the biggest reason the development experience between Solana and Ethereum is so different is due to their account model designs. Before we dig into those, it’s helpful to understand why Solana’s account model was designed so differently from Ethereum. Unlike Ethereum, which is designed to run on consumer grade hardware, Solana was designed to optimize transaction throughput on high-end multi-core machines. The Solana team noticed a trend that the number of cores in computers is growing exponentially. In order to take advantage of all these cores and future-proof the protocol, the Solana team designed transactions to be easily parallelized with each other.

Account model design

So what is actually meant by the “account model” of a blockchain? Well, when an on-chain program is called on a blockchain like Solana or Ethereum, the smart contract needs a way to track certain state like token balances, who owns an NFT, or who the current highest bidder in auction is. All of this state is stored inside accounts on the blockchain and is replicated perfectly across all the nodes in a cluster.

On Ethereum, each smart contract is an account which has its own storage. The smart contract’s code specifies how to make sense of that storage.

On Solana, an on-chain program is a completely immutable account and its storage is only used to store executable byte code.

So where do Solana programs store state? In other non-executable accounts! In fact, each Solana account specifies a program owner which is the only program allowed to make modifications to the account.

By forcing programs to store data inside other accounts, Solana allows developers to design their smart contracts to be parallelizable. Developers are encouraged to split their smart contract state across many different accounts that can be used in parallel transactions without data conflicts.

Transaction Parallelization

Each Solana transaction must list all of the accounts that it will read from, write to, and invoke as a program. With all this information listed up front, Solana validators know which transactions can be processed at the same time without conflicting with each other before those transactions are run. To fully take advantage of this parallelization, on-chain programs themselves can split their state across many accounts so that they can be parallelized too. For example, the Serum Dex program has separate storage accounts for each new market pair and so transactions on the USDC/ETH market won’t slow down transactions on the USDC/SOL market because the state is totally separate and they can all be run in parallel.

Design Constraints

Solana’s design and constraints force developers to carefully consider the design of their own on-chain programs. Learning how to write Solana programs has an arguably steeper learning curve than Solidity smart contracts. But don’t forget the upside! By doing a bit more work upfront, Solana transactions can be processed very efficiently. This results in both higher throughput and lower fees. But this isn’t to say Solana is always the solution. As developers, we make tradeoffs all the time when choosing our tools. The development experience with Solidity on the EVM is much more flexible than on Solana without all the overhead of figuring out which accounts will be accessed and which contracts will be called.