diff --git a/src/core/sanboot.c b/src/core/sanboot.c
new file mode 100644
index 00000000..da1b68b5
--- /dev/null
+++ b/src/core/sanboot.c
@@ -0,0 +1,563 @@
+/*
+ * Copyright (C) 2017 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/**
+ * @file
+ *
+ * SAN booting
+ *
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <assert.h>
+#include <ipxe/xfer.h>
+#include <ipxe/open.h>
+#include <ipxe/timer.h>
+#include <ipxe/process.h>
+#include <ipxe/iso9660.h>
+#include <ipxe/sanboot.h>
+
+/**
+ * Timeout for block device commands (in ticks)
+ *
+ * Underlying devices should ideally never become totally stuck.
+ * However, if they do, then the blocking SAN APIs provide no means
+ * for the caller to cancel the operation, and the machine appears to
+ * hang.  Use an overall timeout for all commands to avoid this
+ * problem and bounce timeout failures to the caller.
+ */
+#define SAN_COMMAND_TIMEOUT ( 15 * TICKS_PER_SEC )
+
+/** List of SAN devices */
+LIST_HEAD ( san_devices );
+
+/**
+ * Find SAN device by drive number
+ *
+ * @v drive		Drive number
+ * @ret sandev		SAN device, or NULL
+ */
+struct san_device * sandev_find ( unsigned int drive ) {
+	struct san_device *sandev;
+
+	list_for_each_entry ( sandev, &san_devices, list ) {
+		if ( sandev->drive == drive )
+			return sandev;
+	}
+	return NULL;
+}
+
+/**
+ * Free SAN device
+ *
+ * @v refcnt		Reference count
+ */
+static void sandev_free ( struct refcnt *refcnt ) {
+	struct san_device *sandev =
+		container_of ( refcnt, struct san_device, refcnt );
+
+	assert ( ! timer_running ( &sandev->timer ) );
+	uri_put ( sandev->uri );
+	free ( sandev );
+}
+
+/**
+ * Close SAN device command
+ *
+ * @v sandev		SAN device
+ * @v rc		Reason for close
+ */
+static void sandev_command_close ( struct san_device *sandev, int rc ) {
+
+	/* Stop timer */
+	stop_timer ( &sandev->timer );
+
+	/* Restart interface */
+	intf_restart ( &sandev->command, rc );
+
+	/* Record command status */
+	sandev->command_rc = rc;
+}
+
+/**
+ * Record SAN device capacity
+ *
+ * @v sandev		SAN device
+ * @v capacity		SAN device capacity
+ */
+static void sandev_command_capacity ( struct san_device *sandev,
+				      struct block_device_capacity *capacity ) {
+
+	/* Record raw capacity information */
+	memcpy ( &sandev->capacity, capacity, sizeof ( sandev->capacity ) );
+}
+
+/** SAN device command interface operations */
+static struct interface_operation sandev_command_op[] = {
+	INTF_OP ( intf_close, struct san_device *, sandev_command_close ),
+	INTF_OP ( block_capacity, struct san_device *,
+		  sandev_command_capacity ),
+};
+
+/** SAN device command interface descriptor */
+static struct interface_descriptor sandev_command_desc =
+	INTF_DESC ( struct san_device, command, sandev_command_op );
+
+/**
+ * Handle SAN device command timeout
+ *
+ * @v retry		Retry timer
+ */
+static void sandev_command_expired ( struct retry_timer *timer,
+				     int over __unused ) {
+	struct san_device *sandev =
+		container_of ( timer, struct san_device, timer );
+
+	sandev_command_close ( sandev, -ETIMEDOUT );
+}
+
+/**
+ * Restart SAN device interface
+ *
+ * @v sandev		SAN device
+ * @v rc		Reason for restart
+ */
+static void sandev_restart ( struct san_device *sandev, int rc ) {
+
+	/* Restart block device interface */
+	intf_nullify ( &sandev->command ); /* avoid potential loops */
+	intf_restart ( &sandev->block, rc );
+
+	/* Close any outstanding command */
+	sandev_command_close ( sandev, rc );
+
+	/* Record device error */
+	sandev->block_rc = rc;
+}
+
+/**
+ * (Re)open SAN device
+ *
+ * @v sandev		SAN device
+ * @ret rc		Return status code
+ *
+ * This function will block until the device is available.
+ */
+int sandev_reopen ( struct san_device *sandev ) {
+	int rc;
+
+	/* Close any outstanding command and restart interface */
+	sandev_restart ( sandev, -ECONNRESET );
+
+	/* Mark device as being not yet open */
+	sandev->block_rc = -EINPROGRESS;
+
+	/* Open block device interface */
+	if ( ( rc = xfer_open_uri ( &sandev->block, sandev->uri ) ) != 0 ) {
+		DBGC ( sandev, "SAN %#02x could not (re)open URI: %s\n",
+		       sandev->drive, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Wait for device to become available */
+	while ( sandev->block_rc == -EINPROGRESS ) {
+		step();
+		if ( xfer_window ( &sandev->block ) != 0 ) {
+			sandev->block_rc = 0;
+			return 0;
+		}
+	}
+
+	DBGC ( sandev, "SAN %#02x never became available: %s\n",
+	       sandev->drive, strerror ( sandev->block_rc ) );
+	return sandev->block_rc;
+}
+
+/**
+ * Handle closure of underlying block device interface
+ *
+ * @v sandev		SAN device
+ * @ret rc		Reason for close
+ */
+static void sandev_block_close ( struct san_device *sandev, int rc ) {
+
+	/* Any closure is an error from our point of view */
+	if ( rc == 0 )
+		rc = -ENOTCONN;
+	DBGC ( sandev, "SAN %#02x went away: %s\n",
+	       sandev->drive, strerror ( rc ) );
+
+	/* Close any outstanding command and restart interface */
+	sandev_restart ( sandev, rc );
+}
+
+/**
+ * Check SAN device flow control window
+ *
+ * @v sandev		SAN device
+ */
+static size_t sandev_block_window ( struct san_device *sandev __unused ) {
+
+	/* We are never ready to receive data via this interface.
+	 * This prevents objects that support both block and stream
+	 * interfaces from attempting to send us stream data.
+	 */
+	return 0;
+}
+
+/** SAN device block interface operations */
+static struct interface_operation sandev_block_op[] = {
+	INTF_OP ( intf_close, struct san_device *, sandev_block_close ),
+	INTF_OP ( xfer_window, struct san_device *, sandev_block_window ),
+};
+
+/** SAN device block interface descriptor */
+static struct interface_descriptor sandev_block_desc =
+	INTF_DESC ( struct san_device, block, sandev_block_op );
+
+/** SAN device read/write command parameters */
+struct san_command_rw_params {
+	/** SAN device read/write operation */
+	int ( * block_rw ) ( struct interface *control, struct interface *data,
+			     uint64_t lba, unsigned int count,
+			     userptr_t buffer, size_t len );
+	/** Data buffer */
+	userptr_t buffer;
+	/** Starting LBA */
+	uint64_t lba;
+	/** Block count */
+	unsigned int count;
+};
+
+/** SAN device command parameters */
+union san_command_params {
+	/** Read/write command parameters */
+	struct san_command_rw_params rw;
+};
+
+/**
+ * Initiate SAN device read/write command
+ *
+ * @v sandev		SAN device
+ * @v params		Command parameters
+ * @ret rc		Return status code
+ */
+static int sandev_command_rw ( struct san_device *sandev,
+			       const union san_command_params *params ) {
+	size_t len = ( params->rw.count * sandev->capacity.blksize );
+	int rc;
+
+	/* Initiate read/write command */
+	if ( ( rc = params->rw.block_rw ( &sandev->block, &sandev->command,
+					  params->rw.lba, params->rw.count,
+					  params->rw.buffer, len ) ) != 0 ) {
+		DBGC ( sandev, "SAN %#02x could not initiate read/write: "
+		       "%s\n", sandev->drive, strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * Initiate SAN device read capacity command
+ *
+ * @v sandev		SAN device
+ * @v params		Command parameters
+ * @ret rc		Return status code
+ */
+static int
+sandev_command_read_capacity ( struct san_device *sandev,
+			       const union san_command_params *params __unused){
+	int rc;
+
+	/* Initiate read capacity command */
+	if ( ( rc = block_read_capacity ( &sandev->block,
+					  &sandev->command ) ) != 0 ) {
+		DBGC ( sandev, "SAN %#02x could not initiate read capacity: "
+		       "%s\n", sandev->drive, strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * Execute a single SAN device command and wait for completion
+ *
+ * @v sandev		SAN device
+ * @v command		Command
+ * @v params		Command parameters (if required)
+ * @ret rc		Return status code
+ */
+static int
+sandev_command ( struct san_device *sandev,
+		 int ( * command ) ( struct san_device *sandev,
+				     const union san_command_params *params ),
+		 const union san_command_params *params ) {
+	int rc;
+
+	/* Sanity check */
+	assert ( ! timer_running ( &sandev->timer ) );
+
+	/* Reopen block device if applicable */
+	if ( sandev_needs_reopen ( sandev ) &&
+	     ( ( rc = sandev_reopen ( sandev ) ) != 0 ) ) {
+	     goto err_reopen;
+	}
+
+	/* Start expiry timer */
+	start_timer_fixed ( &sandev->timer, SAN_COMMAND_TIMEOUT );
+
+	/* Initiate command */
+	if ( ( rc = command ( sandev, params ) ) != 0 )
+		goto err_op;
+
+	/* Wait for command to complete */
+	while ( timer_running ( &sandev->timer ) )
+		step();
+
+	/* Collect return status */
+	rc = sandev->command_rc;
+
+	return rc;
+
+ err_op:
+	stop_timer ( &sandev->timer );
+ err_reopen:
+	return rc;
+}
+
+/**
+ * Reset SAN device
+ *
+ * @v sandev		SAN device
+ * @ret rc		Return status code
+ */
+int sandev_reset ( struct san_device *sandev ) {
+	int rc;
+
+	DBGC ( sandev, "SAN %#02x reset\n", sandev->drive );
+
+	/* Close and reopen underlying block device */
+	if ( ( rc = sandev_reopen ( sandev ) ) != 0 )
+		return rc;
+
+	return 0;
+}
+
+/**
+ * Read from or write to SAN device
+ *
+ * @v sandev		SAN device
+ * @v lba		Starting logical block address
+ * @v count		Number of logical blocks
+ * @v buffer		Data buffer
+ * @v block_rw		Block read/write method
+ * @ret rc		Return status code
+ */
+int sandev_rw ( struct san_device *sandev, uint64_t lba,
+		unsigned int count, userptr_t buffer,
+		int ( * block_rw ) ( struct interface *control,
+				     struct interface *data,
+				     uint64_t lba, unsigned int count,
+				     userptr_t buffer, size_t len ) ) {
+	union san_command_params params;
+	unsigned int remaining;
+	size_t frag_len;
+	int rc;
+
+	/* Initialise command parameters */
+	params.rw.block_rw = block_rw;
+	params.rw.buffer = buffer;
+	params.rw.lba = ( lba << sandev->blksize_shift );
+	params.rw.count = sandev->capacity.max_count;
+	remaining = ( count << sandev->blksize_shift );
+
+	/* Read/write fragments */
+	while ( remaining ) {
+
+		/* Determine fragment length */
+		if ( params.rw.count > remaining )
+			params.rw.count = remaining;
+
+		/* Execute command */
+		if ( ( rc = sandev_command ( sandev, sandev_command_rw,
+					     &params ) ) != 0 )
+			return rc;
+
+		/* Move to next fragment */
+		frag_len = ( sandev->capacity.blksize * params.rw.count );
+		params.rw.buffer = userptr_add ( params.rw.buffer, frag_len );
+		params.rw.lba += params.rw.count;
+		remaining -= params.rw.count;
+	}
+
+	return 0;
+}
+
+/**
+ * Configure SAN device as a CD-ROM, if applicable
+ *
+ * @v sandev		SAN device
+ * @ret rc		Return status code
+ *
+ * Both BIOS and UEFI require SAN devices to be accessed with a block
+ * size of 2048.  While we could require the user to configure the
+ * block size appropriately, this is non-trivial and would impose a
+ * substantial learning effort on the user.  Instead, we check for the
+ * presence of the ISO9660 primary volume descriptor and, if found,
+ * then we force a block size of 2048 and map read/write requests
+ * appropriately.
+ */
+static int sandev_parse_iso9660 ( struct san_device *sandev ) {
+	static const struct iso9660_primary_descriptor_fixed primary_check = {
+		.type = ISO9660_TYPE_PRIMARY,
+		.id = ISO9660_ID,
+	};
+	struct iso9660_primary_descriptor *primary;
+	unsigned int blksize;
+	unsigned int blksize_shift;
+	unsigned int lba;
+	unsigned int count;
+	int rc;
+
+	/* Calculate required blocksize shift for potential CD-ROM access */
+	blksize = sandev->capacity.blksize;
+	blksize_shift = 0;
+	while ( blksize < ISO9660_BLKSIZE ) {
+		blksize <<= 1;
+		blksize_shift++;
+	}
+	if ( blksize > ISO9660_BLKSIZE ) {
+		/* Cannot be a CD-ROM.  This is not an error. */
+		rc = 0;
+		goto invalid_blksize;
+	}
+	lba = ( ISO9660_PRIMARY_LBA << blksize_shift );
+	count = ( 1 << blksize_shift );
+
+	/* Allocate scratch area */
+	primary = malloc ( ISO9660_BLKSIZE );
+	if ( ! primary ) {
+		rc = -ENOMEM;
+		goto err_alloc;
+	}
+
+	/* Read primary volume descriptor */
+	if ( ( rc = sandev_rw ( sandev, lba, count, virt_to_user ( primary ),
+				block_read ) ) != 0 ) {
+		DBGC ( sandev, "SAN %#02x could not read ISO9660 primary"
+		       "volume descriptor: %s\n",
+		       sandev->drive, strerror ( rc ) );
+		goto err_rw;
+	}
+
+	/* Configure as CD-ROM if applicable */
+	if ( memcmp ( primary, &primary_check, sizeof ( primary_check ) ) == 0){
+		DBGC ( sandev, "SAN %#02x contains an ISO9660 filesystem; "
+		       "treating as CD-ROM\n", sandev->drive );
+		sandev->blksize_shift = blksize_shift;
+		sandev->is_cdrom = 1;
+	}
+
+ err_rw:
+	free ( primary );
+ err_alloc:
+ invalid_blksize:
+	return rc;
+}
+
+/**
+ * Allocate SAN device
+ *
+ * @ret sandev		SAN device, or NULL
+ */
+struct san_device * alloc_sandev ( struct uri *uri, size_t priv_size ) {
+	struct san_device *sandev;
+
+	/* Allocate and initialise structure */
+	sandev = zalloc ( sizeof ( *sandev ) + priv_size );
+	if ( ! sandev )
+		return NULL;
+	ref_init ( &sandev->refcnt, sandev_free );
+	sandev->uri = uri_get ( uri );
+	intf_init ( &sandev->block, &sandev_block_desc, &sandev->refcnt );
+	sandev->block_rc = -EINPROGRESS;
+	intf_init ( &sandev->command, &sandev_command_desc, &sandev->refcnt );
+	timer_init ( &sandev->timer, sandev_command_expired, &sandev->refcnt );
+	sandev->priv = ( ( ( void * ) sandev ) + sizeof ( *sandev ) );
+
+	return sandev;
+}
+
+/**
+ * Register SAN device
+ *
+ * @v sandev		SAN device
+ * @ret rc		Return status code
+ */
+int register_sandev ( struct san_device *sandev ) {
+	int rc;
+
+	/* Check that drive number is not in use */
+	if ( sandev_find ( sandev->drive ) != NULL ) {
+		DBGC ( sandev, "SAN %#02x is already in use\n", sandev->drive );
+		return -EADDRINUSE;
+	}
+
+	/* Read device capacity */
+	if ( ( rc = sandev_command ( sandev, sandev_command_read_capacity,
+				     NULL ) ) != 0 )
+		return rc;
+
+	/* Configure as a CD-ROM, if applicable */
+	if ( ( rc = sandev_parse_iso9660 ( sandev ) ) != 0 )
+		return rc;
+
+	/* Add to list of SAN devices */
+	list_add_tail ( &sandev->list, &san_devices );
+
+	return 0;
+}
+
+/**
+ * Unregister SAN device
+ *
+ * @v sandev		SAN device
+ */
+void unregister_sandev ( struct san_device *sandev ) {
+
+	/* Sanity check */
+	assert ( ! timer_running ( &sandev->timer ) );
+
+	/* Shut down interfaces */
+	intfs_shutdown ( 0, &sandev->block, &sandev->command, NULL );
+
+	/* Remove from list of SAN devices */
+	list_del ( &sandev->list );
+}
diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h
index 1a037b10..cd5c1959 100644
--- a/src/include/ipxe/errfile.h
+++ b/src/include/ipxe/errfile.h
@@ -72,6 +72,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ERRFILE_blocktrans	       ( ERRFILE_CORE | 0x00200000 )
 #define ERRFILE_pixbuf		       ( ERRFILE_CORE | 0x00210000 )
 #define ERRFILE_efi_block	       ( ERRFILE_CORE | 0x00220000 )
+#define ERRFILE_sanboot		       ( ERRFILE_CORE | 0x00230000 )
 
 #define ERRFILE_eisa		     ( ERRFILE_DRIVER | 0x00000000 )
 #define ERRFILE_isa		     ( ERRFILE_DRIVER | 0x00010000 )
diff --git a/src/include/ipxe/sanboot.h b/src/include/ipxe/sanboot.h
index 1c68a58c..420d4dbe 100644
--- a/src/include/ipxe/sanboot.h
+++ b/src/include/ipxe/sanboot.h
@@ -12,9 +12,52 @@
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 #include <ipxe/api.h>
+#include <ipxe/refcnt.h>
+#include <ipxe/list.h>
+#include <ipxe/uri.h>
+#include <ipxe/retry.h>
+#include <ipxe/blockdev.h>
 #include <config/sanboot.h>
 
-struct uri;
+/** A SAN device */
+struct san_device {
+	/** Reference count */
+	struct refcnt refcnt;
+	/** List of SAN devices */
+	struct list_head list;
+
+	/** SAN device URI */
+	struct uri *uri;
+	/** Drive number */
+	unsigned int drive;
+
+	/** Underlying block device interface */
+	struct interface block;
+	/** Current device status */
+	int block_rc;
+
+	/** Command interface */
+	struct interface command;
+	/** Command timeout timer */
+	struct retry_timer timer;
+	/** Command status */
+	int command_rc;
+
+	/** Raw block device capacity */
+	struct block_device_capacity capacity;
+	/** Block size shift
+	 *
+	 * To allow for emulation of CD-ROM access, this represents
+	 * the left-shift required to translate from exposed logical
+	 * I/O blocks to underlying blocks.
+	 */
+	unsigned int blksize_shift;
+	/** Drive is a CD-ROM */
+	int is_cdrom;
+
+	/** Driver private data */
+	void *priv;
+};
 
 /**
  * Calculate static inline sanboot API function name
@@ -91,4 +134,83 @@ int san_boot ( unsigned int drive );
  */
 int san_describe ( unsigned int drive );
 
+extern struct list_head san_devices;
+
+/** Iterate over all SAN devices */
+#define for_each_sandev( sandev ) \
+	list_for_each_entry ( (sandev), &san_devices, list )
+
+/** There exist some SAN devices
+ *
+ * @ret existence	Existence of SAN devices
+ */
+static inline int have_sandevs ( void ) {
+	return ( ! list_empty ( &san_devices ) );
+}
+
+/**
+ * Get reference to SAN device
+ *
+ * @v sandev		SAN device
+ * @ret sandev		SAN device
+ */
+static inline __attribute__ (( always_inline )) struct san_device *
+sandev_get ( struct san_device *sandev ) {
+	ref_get ( &sandev->refcnt );
+	return sandev;
+}
+
+/**
+ * Drop reference to SAN device
+ *
+ * @v sandev		SAN device
+ */
+static inline __attribute__ (( always_inline )) void
+sandev_put ( struct san_device *sandev ) {
+	ref_put ( &sandev->refcnt );
+}
+
+/**
+ * Calculate SAN device block size
+ *
+ * @v sandev		SAN device
+ * @ret blksize		Sector size
+ */
+static inline size_t sandev_blksize ( struct san_device *sandev ) {
+	return ( sandev->capacity.blksize << sandev->blksize_shift );
+}
+
+/**
+ * Calculate SAN device capacity
+ *
+ * @v sandev		SAN device
+ * @ret blocks		Number of blocks
+ */
+static inline uint64_t sandev_capacity ( struct san_device *sandev ) {
+	return ( sandev->capacity.blocks >> sandev->blksize_shift );
+}
+
+/**
+ * Check if SAN device needs to be reopened
+ *
+ * @v sandev		SAN device
+ * @ret needs_reopen	SAN device needs to be reopened
+ */
+static inline int sandev_needs_reopen ( struct san_device *sandev ) {
+	return ( sandev->block_rc != 0 );
+}
+
+extern struct san_device * sandev_find ( unsigned int drive );
+extern int sandev_reopen ( struct san_device *sandev );
+extern int sandev_reset ( struct san_device *sandev );
+extern int sandev_rw ( struct san_device *sandev, uint64_t lba,
+		       unsigned int count, userptr_t buffer,
+		       int ( * block_rw ) ( struct interface *control,
+					    struct interface *data,
+					    uint64_t lba, unsigned int count,
+					    userptr_t buffer, size_t len ) );
+extern struct san_device * alloc_sandev ( struct uri *uri, size_t priv_size );
+extern int register_sandev ( struct san_device *sandev );
+extern void unregister_sandev ( struct san_device *sandev );
+
 #endif /* _IPXE_SANBOOT_H */