diff --git a/am/am.h b/am/am.h
index e6b43951..3e2ce844 100644
--- a/am/am.h
+++ b/am/am.h
@@ -36,15 +36,6 @@ typedef struct _Area {
   void *start, *end;
 } _Area; 
 
-// A device (@id, @name) with @read/@write support
-// See <amdev.h> for device descriptions
-typedef struct _Device {
-  uint32_t id;
-  const char *name;
-  size_t (*read) (uintptr_t reg, void *buf, size_t size);
-  size_t (*write)(uintptr_t reg, void *buf, size_t size);
-} _Device;
-
 // An event of type @event, caused by @cause of pointer @ref
 typedef struct _Event {
   int event;
@@ -70,7 +61,6 @@ void _halt(int code) __attribute__((__noreturn__));
 // ======================= I/O Extension (IOE) =======================
 
 int _ioe_init();
-_Device *_device(int n);
 size_t _io_read(uint32_t dev, uintptr_t reg, void *buf, size_t size);
 size_t _io_write(uint32_t dev, uintptr_t reg, void *buf, size_t size);
 
diff --git a/am/arch/x86-qemu/src/ioe.c b/am/arch/x86-qemu/src/ioe.c
index d9e03386..2c93de56 100644
--- a/am/arch/x86-qemu/src/ioe.c
+++ b/am/arch/x86-qemu/src/ioe.c
@@ -3,36 +3,37 @@
 void vga_init();
 void timer_init();
 
-#define DEVOP_DEF(dev, op) \
-  size_t dev##_##op(uintptr_t reg, void *buf, size_t size);
+#define DEF_DEVOP(fn) \
+  size_t fn(uintptr_t reg, void *buf, size_t size);
 
-#define DEVOPS(_) \
-  _(input, read) \
-  _(timer, read) \
-  _(video, read)   _(video, write) \
-  _(pciconf, read) _(pciconf, write) \
-  _(hd, read)      _(hd, write)
+DEF_DEVOP(input_read);
+DEF_DEVOP(timer_read);
+DEF_DEVOP(video_read);
+DEF_DEVOP(video_write);
+DEF_DEVOP(pciconf_read);
+DEF_DEVOP(pciconf_write);
 
-DEVOPS(DEVOP_DEF)
+size_t _io_read(uint32_t dev, uintptr_t reg, void *buf, size_t size) {
+  switch (dev) {
+    case _DEV_INPUT: return input_read(reg, buf, size);
+    case _DEV_TIMER: return timer_read(reg, buf, size);
+    case _DEV_VIDEO: return video_read(reg, buf, size);
+    case _DEV_PCICONF: return pciconf_read(reg, buf, size);
+  }
+  return 0;
+}
 
-static _Device x86_dev[] = {
-  {_DEV_INPUT,   "8279 Keyboard Controller", input_read, NULL},
-  {_DEV_TIMER,   "RDTSC Timer / CMOS RTC",   timer_read, NULL},
-  {_DEV_VIDEO,   "Standard VGA Controller",  video_read, video_write},
-  {_DEV_PCICONF, "PCI Configuration",        pciconf_read, pciconf_write},
-};
+size_t _io_write(uint32_t dev, uintptr_t reg, void *buf, size_t size) {
+  switch (dev) {
+    case _DEV_VIDEO: return video_write(reg, buf, size);
+    case _DEV_PCICONF: return pciconf_write(reg, buf, size);
+  }
+  return 0;
+}
 
 int _ioe_init() {
   if (_cpu() != 0) panic("init IOE in non-bootstrap CPU");
   timer_init();
   vga_init();
   return 0;
-}
-
-_Device *_device(int n) {
-  if (n >= 1 && n <= sizeof(x86_dev) / sizeof(x86_dev[0])) {
-    return &x86_dev[n - 1];
-  } else {
-    return NULL;
-  }
-}
+}
\ No newline at end of file
diff --git a/libs/klib/src/io.c b/libs/klib/src/io.c
index 20553a23..29bae729 100644
--- a/libs/klib/src/io.c
+++ b/libs/klib/src/io.c
@@ -1,77 +1,49 @@
 #include <klib.h>
 #include <amdev.h>
 
-static _Device *getdev(_Device **ptr, uint32_t id) {
-  if (*ptr) return *ptr;
-  for (int n = 1; ; n ++) {
-    _Device *cur = _device(n);
-    if (cur->id == id) {
-      *ptr = cur;
-      return cur;
-    }
-    if (!cur) break;
-  }
-  assert(0);
-  return NULL;
-}
-
-static _Device *input_dev;
-static _Device *video_dev;
-static _Device *timer_dev;
-
 uint32_t uptime() {
   _DEV_TIMER_UPTIME_t uptime;
-  _Device *dev = getdev(&timer_dev, _DEV_TIMER);
-  dev->read(_DEVREG_TIMER_UPTIME, &uptime, sizeof(uptime));
+  _io_read(_DEV_TIMER, _DEVREG_TIMER_UPTIME, &uptime, sizeof(uptime));
   return uptime.lo;
 }
 
 void get_timeofday(void *rtc) {
-  _Device *dev = getdev(&timer_dev, _DEV_TIMER);
-  dev->read(_DEVREG_TIMER_DATE, rtc, sizeof(_DEV_TIMER_DATE_t));
+  _io_read(_DEV_TIMER, _DEVREG_TIMER_DATE, rtc, sizeof(_DEV_TIMER_DATE_t));
 }
 
 int read_key() {
-  _Device *dev = getdev(&input_dev, _DEV_INPUT);
   _DEV_INPUT_KBD_t key;
-  dev->read(_DEVREG_INPUT_KBD, &key, sizeof(_DEV_INPUT_KBD_t));
+  _io_read(_DEV_INPUT, _DEVREG_INPUT_KBD, &key, sizeof(_DEV_INPUT_KBD_t));
   int ret = key.keycode;
   if (key.keydown) ret |= 0x8000;
   return ret;
 }
 
 void draw_rect(uint32_t *pixels, int x, int y, int w, int h) {
-  _Device *dev = getdev(&video_dev, _DEV_VIDEO);
-  _DEV_VIDEO_FBCTL_t ctl;
-  ctl.pixels = pixels;
-  ctl.x = x;
-  ctl.y = y;
-  ctl.w = w;
-  ctl.h = h;
-  ctl.sync = 0;
-  dev->write(_DEVREG_VIDEO_FBCTL, &ctl, sizeof(ctl));
+  _DEV_VIDEO_FBCTL_t ctl = (_DEV_VIDEO_FBCTL_t) {
+    .pixels = pixels,
+    .x = x, .y = y, .w = w, .h = h,
+    .sync = 0,
+  };
+  _io_write(_DEV_VIDEO, _DEVREG_VIDEO_FBCTL, &ctl, sizeof(ctl));
 }
 
 void draw_sync() {
-  _Device *dev = getdev(&video_dev, _DEV_VIDEO);
   _DEV_VIDEO_FBCTL_t ctl;
   ctl.pixels = NULL;
   ctl.x = ctl.y = ctl.w = ctl.h = 0;
   ctl.sync = 1;
-  dev->write(_DEVREG_VIDEO_FBCTL, &ctl, sizeof(ctl));
+  _io_write(_DEV_VIDEO, _DEVREG_VIDEO_FBCTL, &ctl, sizeof(ctl));
 }
 
 int screen_width() {
-  _Device *dev = getdev(&video_dev, _DEV_VIDEO);
   _DEV_VIDEO_INFO_t info;
-  dev->read(_DEVREG_VIDEO_INFO, &info, sizeof(info));
+  _io_read(_DEV_VIDEO, _DEVREG_VIDEO_INFO, &info, sizeof(info));
   return info.width;
 }
 
 int screen_height() {
-  _Device *dev = getdev(&video_dev, _DEV_VIDEO);
   _DEV_VIDEO_INFO_t info;
-  dev->read(_DEVREG_VIDEO_INFO, &info, sizeof(info));
+  _io_read(_DEV_VIDEO, _DEVREG_VIDEO_INFO, &info, sizeof(info));
   return info.height;
 }
-