diff --git a/src/Dreamcast.cpp b/src/Dreamcast.cpp
@@ -44,7 +44,7 @@
 static const size_t MEM_SZ = 16 * 1024 * 1024;
 
 static Sh4 cpu;
-static BiosFile *bios;
+static BiosFile bios;
 static struct Memory mem;
 
 static volatile bool is_running;
@@ -85,8 +85,8 @@ void dreamcast_init(char const *bios_path, char const *flash_path) {
     memory_init(&mem, MEM_SZ);
     if (flash_path)
         flash_mem_load(flash_path);
-    bios = new BiosFile(bios_path);
-    memory_map_init(bios, &mem);
+    bios_file_init(&bios, bios_path);
+    memory_map_init(&bios, &mem);
     sh4_init(&cpu);
     spg_init();
 
@@ -119,10 +119,10 @@ void dreamcast_init_direct(char const *path_ip_bin,
     if (flash_path)
         flash_mem_load(flash_path);
     if (bios_path)
-        bios = new BiosFile(bios_path);
+        bios_file_init(&bios, bios_path);
     else
-        bios = new BiosFile();
-    memory_map_init(bios, &mem);
+        bios_file_init_empty(&bios);
+    memory_map_init(&bios, &mem);
 
     file_ip_bin.seekg(0, file_ip_bin.end);
     size_t len_ip_bin = file_ip_bin.tellg();
@@ -186,7 +186,7 @@ void dreamcast_cleanup() {
 #endif
 
     sh4_cleanup(&cpu);
-    delete bios;
+    bios_file_cleanup(&bios);
     memory_cleanup(&mem);
 }
 

diff --git a/src/Dreamcast.hpp b/src/Dreamcast.hpp
@@ -25,7 +25,7 @@
 
 #include <boost/asio.hpp>
 
-#include "BiosFile.hpp"
+#include "BiosFile.h"
 #include "memory.h"
 #include "hw/sh4/sh4.hpp"
 #include "dc_sched.hpp"

diff --git a/src/MemoryMap.cpp b/src/MemoryMap.cpp
@@ -66,7 +66,7 @@ int memory_map_read(void *buf, size_t addr, size_t len) {
             if ((addr + (len - 1)) > ADDR_BIOS_LAST) {
                 goto boundary_cross;
             }
-            return bios->read(buf, addr - ADDR_BIOS_FIRST, len);
+            return bios_file_read(bios, buf, addr - ADDR_BIOS_FIRST, len);
         } else if (addr >= ADDR_FLASH_FIRST && addr <= ADDR_FLASH_LAST) {
             if ((addr + (len - 1) > ADDR_FLASH_LAST) ||
                 (addr < ADDR_FLASH_FIRST)) {

diff --git a/src/MemoryMap.hpp b/src/MemoryMap.hpp
@@ -23,7 +23,7 @@
 #ifndef MEMORYMAP_HPP_
 #define MEMORYMAP_HPP_
 
-#include "BiosFile.hpp"
+#include "BiosFile.h"
 #include "memory.h"
 #include "mem_areas.h"
 

diff --git a/src/error.c b/src/error.c
@@ -124,3 +124,4 @@ DEF_ERROR_STRING_ATTR(feature)
 DEF_ERROR_STRING_ATTR(param_name)
 DEF_ERROR_U32_ATTR(address)
 DEF_ERROR_INT_ATTR(length)
+DEF_ERROR_INT_ATTR(errno_val)
diff --git a/src/error.h b/src/error.h
@@ -42,6 +42,12 @@ enum error_type {
 
     /* memory access failed because the address was out-of-bounds */
     ERROR_MEM_OUT_OF_BOUNDS,
+
+    /* unable to allocate memory */
+    ERROR_FAILED_ALLOC,
+
+    /* error on some file operation */
+    ERROR_FILE_IO
 };
 
 enum error_attr_type {
@@ -147,6 +153,8 @@ ERROR_U32_ATTR(address);
 
 ERROR_INT_ATTR(length);
 
+ERROR_INT_ATTR(errno_val);
+
 #define RAISE_ERROR(tp)                         \
     do {                                        \
         error_set_line(__LINE__);               \

diff --git a/src/flash_memory.cpp b/src/flash_memory.cpp
@@ -23,6 +23,8 @@
 #include <fstream>
 #include <iostream>
 
+#include "BaseException.hpp"
+
 #include "flash_memory.hpp"
 
 static uint8_t flash_mem[FLASH_MEM_SZ];

diff --git a/src/hw/aica/aica_rtc.cpp b/src/hw/aica/aica_rtc.cpp
@@ -25,6 +25,7 @@
 #include <boost/cstdint.hpp>
 
 #include "MemoryMap.hpp"
+#include "BaseException.hpp"
 
 #include "aica_rtc.hpp"
 

diff --git a/src/video/opengl/framebuffer.cpp b/src/video/opengl/framebuffer.cpp
@@ -30,6 +30,7 @@
 #include "hw/pvr2/pvr2_core_reg.hpp"
 #include "hw/pvr2/pvr2_tex_mem.hpp"
 #include "opengl_backend.hpp"
+#include "BaseException.hpp"
 
 #include "framebuffer.hpp"
 

diff --git a/unit_tests/sh4div_test.cpp b/unit_tests/sh4div_test.cpp
@@ -30,11 +30,33 @@
 #include "BaseException.hpp"
 #include "memory.h"
 #include "RandGenerator.hpp"
-#include "BiosFile.hpp"
+#include "BiosFile.h"
 #include "MemoryMap.hpp"
 
 typedef RandGenerator<uint32_t> RandGen32;
 
+/*
+ * loads a program into the given address.  the InputIterator's
+ * indirect method (overload*) should return a data_tp.
+ */
+static void bios_load_binary(BiosFile *bios, addr32_t where,
+                             Sh4Prog::ByteList::const_iterator start,
+                             Sh4Prog::ByteList::const_iterator end) {
+    size_t bytes_written = 0;
+
+    bios_file_clear(bios);
+
+    for (Sh4Prog::ByteList::const_iterator it = start; it != end; it++) {
+        uint8_t tmp = *it;
+
+        if (bytes_written + sizeof(uint8_t) >= bios->dat_len)
+            BOOST_THROW_EXCEPTION(InvalidParamError());
+
+        memcpy(bios->dat + bytes_written, &tmp, sizeof(tmp));
+        bytes_written += sizeof(tmp);
+    }
+}
+
 /*
  * sh4 program for unsigned division of a 32-bit dividend by a 16-bit divisor
  *
@@ -311,7 +333,7 @@ run_div_test(addr32_t run_until, struct div_test_state *state,
 
     test_prog.add_txt(std::string(prog_asm));
     const Sh4Prog::ByteList& inst = test_prog.get_prog();
-    state->bios.load_binary<uint8_t>(0, inst.begin(), inst.end());
+    bios_load_binary(&state->bios, 0, inst.begin(), inst.end());
 
     sh4_on_hard_reset(&state->sh4);
     sh4_enter(&state->sh4);
@@ -428,7 +450,7 @@ unsigned_div_test_64_32(struct div_test *test, struct div_test_state *state) {
 
     test_prog.add_txt(std::string(div_unsigned_64_32));
     const Sh4Prog::ByteList& inst = test_prog.get_prog();
-    state->bios.load_binary<uint8_t>(0, inst.begin(), inst.end());
+    bios_load_binary(&state->bios, 0, inst.begin(), inst.end());
 
     sh4_on_hard_reset(&state->sh4);
     sh4_enter(&state->sh4);
@@ -466,9 +488,10 @@ int main(int argc, char **argv) {
             seed = atoi(optarg);
     }
 
-    try {
-        struct div_test_state test_state;
+    struct div_test_state test_state;
+    bios_file_init_empty(&test_state.bios);
 
+    try {
         memory_init(&test_state.mem, 16 * 1024 * 1024);
         memory_map_init(&test_state.bios, &test_state.mem);
         sh4_init(&test_state.sh4);
@@ -497,5 +520,7 @@ int main(int argc, char **argv) {
     std::cout << std::dec << n_tests << " run -- " << n_success <<
         " successes." << std::endl;
 
+    bios_file_cleanup(&test_state.bios);
+
     return (n_tests == n_success) ? 0 : 1;
 }
diff --git a/unit_tests/sh4inst_test.cpp b/unit_tests/sh4inst_test.cpp
diff --git a/unit_tests/sh4tmu_test.cpp b/unit_tests/sh4tmu_test.cpp
@@ -34,9 +34,31 @@
 #include "tool/sh4asm/sh4asm.hpp"
 #include "BaseException.hpp"
 #include "memory.h"
-#include "BiosFile.hpp"
+#include "BiosFile.h"
 #include "MemoryMap.hpp"
 
+/*
+ * loads a program into the given address.  the InputIterator's
+ * indirect method (overload*) should return a data_tp.
+ */
+static void bios_load_binary(BiosFile *bios, addr32_t where,
+                             Sh4Prog::ByteList::const_iterator start,
+                             Sh4Prog::ByteList::const_iterator end) {
+    size_t bytes_written = 0;
+
+    bios_file_clear(bios);
+
+    for (Sh4Prog::ByteList::const_iterator it = start; it != end; it++) {
+        uint8_t tmp = *it;
+
+        if (bytes_written + sizeof(uint8_t) >= bios->dat_len)
+            BOOST_THROW_EXCEPTION(InvalidParamError());
+
+        memcpy(bios->dat + bytes_written, &tmp, sizeof(tmp));
+        bytes_written += sizeof(tmp);
+    }
+}
+
 char const prog_asm[] =
     /*
      * the interrupt vector will be at 0x0c000600 (VBR == 0x0c000000)
@@ -193,20 +215,21 @@ char const prog_asm[] =
     "";
 
 int main(int argc, char **argv) {
+    BiosFile bios;
     try {
         Sh4Prog test_prog;
-        BiosFile bios;
         struct Memory mem;
         Sh4 sh4;
         int ret_code = 0;
 
+        bios_file_init_empty(&bios);
         memory_init(&mem, 16 * 1024 * 1024);
         memory_map_init(&bios, &mem);
         sh4_init(&sh4);
 
         test_prog.add_txt(std::string(prog_asm));
         const Sh4Prog::ByteList& inst = test_prog.get_prog();
-        bios.load_binary<uint8_t>(0, inst.begin(), inst.end());
+        bios_load_binary(&bios, 0, inst.begin(), inst.end());
 
         sh4_run_until(&sh4, 0x0c000100);
 
@@ -256,11 +279,13 @@ int main(int argc, char **argv) {
         else
             std::cout << "TEST SUCCESS" << std::endl;
 
+        bios_file_cleanup(&bios);
         sh4_cleanup(&sh4);
 
         return ret_code;
     } catch (BaseException& exc) {
         std::cerr << boost::diagnostic_information(exc);
+        bios_file_cleanup(&bios);
     }
 
     return 1;