diff --git a/cli/main.rs b/cli/main.rs
index 700e0a098..3ef3d6774 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -1,12 +1,7 @@
-use anyhow::Result;
 use clap::{Parser, ValueEnum};
 use cli_table::{Cell, Table};
-use lig_core::{Database, DatabaseRef, Value};
+use lig_core::{Database, Value, SyncIO};
 use rustyline::{error::ReadlineError, DefaultEditor};
-use std::cell::RefCell;
-use std::collections::HashMap;
-use std::fs::File;
-use std::io::{Read, Seek};
 use std::path::PathBuf;
 use std::sync::Arc;
 
@@ -35,7 +30,7 @@ struct Opts {
 
 fn main() -> anyhow::Result<()> {
     let opts = Opts::parse();
-    let io = IO::new();
+    let io = SyncIO::new();
     let db = Database::open(Arc::new(io), opts.database.to_str().unwrap())?;
     let conn = db.connect();
     let mut rl = DefaultEditor::new()?;
@@ -108,47 +103,3 @@ fn main() -> anyhow::Result<()> {
     Ok(())
 }
 
-struct IO {
-    inner: RefCell<IOInner>,
-}
-
-struct IOInner {
-    db_refs: usize,
-    db_files: HashMap<DatabaseRef, File>,
-}
-
-impl lig_core::IO for IO {
-    fn open(&self, path: &str) -> Result<DatabaseRef> {
-        let file = std::fs::File::open(path)?;
-        let mut inner = self.inner.borrow_mut();
-        let db_ref = inner.db_refs;
-        inner.db_refs += 1;
-        inner.db_files.insert(db_ref, file);
-        Ok(db_ref)
-    }
-
-    fn get(&self, database_ref: DatabaseRef, page_idx: usize, buf: &mut [u8]) -> Result<()> {
-        let page_size = buf.len();
-        assert!(page_idx > 0);
-        assert!(page_size >= 512);
-        assert!(page_size <= 65536);
-        assert!((page_size & (page_size - 1)) == 0);
-        let mut inner = self.inner.borrow_mut();
-        let file = inner.db_files.get_mut(&database_ref).unwrap();
-        let pos = (page_idx - 1) * page_size;
-        file.seek(std::io::SeekFrom::Start(pos as u64))?;
-        file.read_exact(buf)?;
-        Ok(())
-    }
-}
-
-impl IO {
-    fn new() -> Self {
-        Self {
-            inner: RefCell::new(IOInner {
-                db_refs: 0,
-                db_files: HashMap::new(),
-            }),
-        }
-    }
-}
diff --git a/core/benches/benchmark.rs b/core/benches/benchmark.rs
index 23f3266f9..59b33bd49 100644
--- a/core/benches/benchmark.rs
+++ b/core/benches/benchmark.rs
@@ -1,61 +1,11 @@
-use anyhow::Result;
 use criterion::{criterion_group, criterion_main, Criterion, Throughput};
-use lig_core::{Database, DatabaseRef};
+use lig_core::{Database, SyncIO};
 use pprof::criterion::{Output, PProfProfiler};
-use std::cell::RefCell;
-use std::collections::HashMap;
-use std::fs::File;
-use std::io::{Read, Seek};
 use std::sync::Arc;
 
-struct IO {
-    inner: RefCell<IOInner>,
-}
-
-struct IOInner {
-    db_refs: usize,
-    db_files: HashMap<DatabaseRef, File>,
-}
-
-impl lig_core::IO for IO {
-    fn open(&self, path: &str) -> Result<DatabaseRef> {
-        println!("Opening database file {}", path);
-        let file = std::fs::File::open(path)?;
-        let mut inner = self.inner.borrow_mut();
-        let db_ref = inner.db_refs;
-        inner.db_refs += 1;
-        inner.db_files.insert(db_ref, file);
-        Ok(db_ref)
-    }
-
-    fn get(&self, database_ref: DatabaseRef, page_idx: usize, buf: &mut [u8]) -> Result<()> {
-        let page_size = buf.len();
-        assert!(page_idx > 0);
-        assert!(page_size >= 512);
-        assert!(page_size <= 65536);
-        assert!((page_size & (page_size - 1)) == 0);
-        let mut inner = self.inner.borrow_mut();
-        let file = inner.db_files.get_mut(&database_ref).unwrap();
-        let pos = (page_idx - 1) * page_size;
-        file.seek(std::io::SeekFrom::Start(pos as u64))?;
-        file.read_exact(buf)?;
-        Ok(())
-    }
-}
-
-impl IO {
-    fn new() -> Self {
-        Self {
-            inner: RefCell::new(IOInner {
-                db_refs: 0,
-                db_files: HashMap::new(),
-            }),
-        }
-    }
-}
 
 fn bench_db() -> Database {
-    let io = IO::new();
+    let io = SyncIO::new();
     Database::open(Arc::new(io), "../testing/hello.db").unwrap()
 }
 
diff --git a/core/io/mod.rs b/core/io/mod.rs
new file mode 100644
index 000000000..5678c41b5
--- /dev/null
+++ b/core/io/mod.rs
@@ -0,0 +1 @@
+pub(crate) mod sync_io;
diff --git a/core/io/sync_io.rs b/core/io/sync_io.rs
new file mode 100644
index 000000000..385dd96c0
--- /dev/null
+++ b/core/io/sync_io.rs
@@ -0,0 +1,53 @@
+use crate::{DatabaseRef, IO};
+
+use std::io::{Read, Seek};
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::fs::File;
+use anyhow::Result;
+
+/// Synchronous I/O using traditional read() and write() system calls.
+pub struct SyncIO {
+    inner: RefCell<SyncIOInner>,
+}
+
+struct SyncIOInner {
+    db_refs: usize,
+    db_files: HashMap<DatabaseRef, File>,
+}
+
+impl IO for SyncIO {
+    fn open(&self, path: &str) -> Result<DatabaseRef> {
+        let file = std::fs::File::open(path)?;
+        let mut inner = self.inner.borrow_mut();
+        let db_ref = inner.db_refs;
+        inner.db_refs += 1;
+        inner.db_files.insert(db_ref, file);
+        Ok(db_ref)
+    }
+
+    fn get(&self, database_ref: DatabaseRef, page_idx: usize, buf: &mut [u8]) -> Result<()> {
+        let page_size = buf.len();
+        assert!(page_idx > 0);
+        assert!(page_size >= 512);
+        assert!(page_size <= 65536);
+        assert!((page_size & (page_size - 1)) == 0);
+        let mut inner = self.inner.borrow_mut();
+        let file = inner.db_files.get_mut(&database_ref).unwrap();
+        let pos = (page_idx - 1) * page_size;
+        file.seek(std::io::SeekFrom::Start(pos as u64))?;
+        file.read_exact(buf)?;
+        Ok(())
+    }
+}
+
+impl SyncIO {
+    pub fn new() -> Self {
+        Self {
+            inner: RefCell::new(SyncIOInner {
+                db_refs: 0,
+                db_files: HashMap::new(),
+            }),
+        }
+    }
+}
diff --git a/core/lib.rs b/core/lib.rs
index 0781c52ee..3ebf67b34 100644
--- a/core/lib.rs
+++ b/core/lib.rs
@@ -5,6 +5,7 @@ mod schema;
 mod sqlite3_ondisk;
 mod types;
 mod vdbe;
+mod io;
 
 use mimalloc::MiMalloc;
 
@@ -18,6 +19,7 @@ use schema::Schema;
 use sqlite3_parser::{ast::Cmd, lexer::sql::Parser};
 use std::{borrow::BorrowMut, sync::Arc};
 
+pub use io::sync_io::SyncIO;
 pub use types::Value;
 
 pub struct Database {