Glossary

Rome-specific and Solana terms used throughout this documentation.

A

ATA (Associated Token Account) — A deterministic token account for a given wallet + mint pair on Solana. Derived from the wallet pubkey, token mint, and ATA program.

Atomic Execution (VmAt) — EVM transaction mode where the entire execution completes within a single Solana transaction. Default mode for most operations.

B

BN254 — An elliptic curve used for ZK proof verification. Rome supports ecAdd (0x06), ecMul (0x07), and ecPairing (0x08) precompiles.

Borsh — Binary Object Representation Serializer for Hashing. Solana's standard serialization format. Little-endian byte ordering.

C

Chain ID — A unique identifier for each EVM environment on Rome. Each application gets its own chain ID.

CPI (Cross-Program Invocation) — One Solana program calling another within the same transaction. How Rome EVM contracts interact with Solana programs.

Compute Units (CU) — Solana's equivalent of Ethereum gas. Each transaction has a compute budget; operations consume CU.

E

ERC20SPL — An ERC-20 wrapper contract that reads balances from the underlying SPL token account on Solana. No separate state — the ERC-20 IS the SPL token.

ERC20SPLFactory — A factory contract that deploys ERC20SPL wrappers for any SPL token mint.

H

Hercules — The block indexer service. Monitors Rome EVM events on Solana and produces Ethereum-compatible block data.

Holder Account — An on-chain buffer (max 80 KB) that stores large EVM transactions exceeding Solana's 1,232-byte transaction limit.

I

Iterative Execution (VmIt) — EVM transaction mode that splits execution across multiple Solana transactions, executing ~500 opcodes per step. Used for compute-intensive operations.

L

Lamports — Smallest unit of SOL. 1 SOL = 10^9 lamports.

M

Meta-Hook Router — Token-2022 Transfer Hook multiplexer. Sits in a mint's single hook slot and dispatches to up to 8 sub-hooks.

Mollusk SVM — Off-chain Solana VM emulator used by Rome Proxy for eth_call and gas estimation. Can execute arbitrary BPF programs.

O

Oracle Gateway — Adapter contracts exposing Pyth and Switchboard price feeds through Chainlink's AggregatorV3Interface.

OP-Geth — Modified Go-Ethereum client providing full Ethereum RPC compatibility. Optional — used in OP-Geth deployment mode.

P

Payer — A Solana keypair that signs and pays for Solana transactions on behalf of EVM users. Managed by the Proxy.

PDA (Program Derived Address) — A deterministic Solana address derived from seeds and a program ID. No private key — the program "owns" the PDA.

Proxy — The Rome JSON-RPC server (port 9090) that translates Ethereum API calls into Solana transactions.

R

RSOL — The default gas token on Rome EVM chains (wrapped SOL as ERC-20).

Rhea — The mempool bridge that relays transactions from OP-Geth to Solana. Only used in OP-Geth mode.

RheaTx — A single EVM transaction on one rollup.

RemusTx — Multiple EVM transactions across rollups, executed atomically.

RomulusTx — EVM transactions + native Solana instructions, executed atomically.

ResourceFactory — SDK component that pools Solana keypairs and holder account indices for parallel transaction submission.

S

Single-State Mode — Deployment mode where users connect directly to Rome Proxy. No OP-Geth layer.

SPL Token — Solana's standard token program. All fungible tokens on Solana (USDC, SOL, etc.) are SPL tokens.

StateHolder — An on-chain account that stores serialized VM state between iterative execution steps.

T

Token-2022 — Next-generation SPL token program with extensions (Transfer Hooks, Confidential Transfers, Permanent Delegates).

Transfer Hook — Token-2022 extension that invokes a program on every transfer_checked call.

TxBuilder — SDK component that builds Solana instructions from EVM transactions.