diff --git a/io_async.h b/io_async.h
deleted file mode 100644
index 4c397d5..0000000
--- a/io_async.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
-    SPDX-License-Identifier: GPL-2.0-or-later
-
-    UMKa - User-Mode KolibriOS developer tools
-    io_async - input/output platform specific code
-
-    Copyright (C) 2023  Ivan Baravy <dunkaist@gmail.com>
-*/
-
-#ifndef IO_ASYNC_H_INCLUDED
-#define IO_ASYNC_H_INCLUDED
-
-#include <stddef.h>
-
-void *
-io_async_init();
-
-void
-io_async_close(void *arg);
-
-ssize_t
-io_async_read(int fd, void *buf, size_t count, void *arg);
-
-ssize_t
-io_async_write(int fd, const void *buf, size_t count, void *arg);
-
-#endif  // IO_ASYNC_H_INCLUDED
diff --git a/linux/io_async.c b/linux/io_async.c
deleted file mode 100644
index 1b0246f..0000000
--- a/linux/io_async.c
+++ /dev/null
@@ -1,212 +0,0 @@
-/*
-    SPDX-License-Identifier: GPL-2.0-or-later
-
-    UMKa - User-Mode KolibriOS developer tools
-    io_async - input/output platform specific code
-
-    Copyright (C) 2023  Ivan Baravy <dunkaist@gmail.com>
-*/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <inttypes.h>
-#include <sys/mman.h>
-#include <sys/syscall.h>
-#include <linux/io_uring.h>
-#include "../umka.h"
-
-#define QUEUE_DEPTH 1
-
-#define read_barrier()  __asm__ __volatile__("":::"memory")
-#define write_barrier() __asm__ __volatile__("":::"memory")
-
-#define MAX(x, y) ((x) >= (y) ? (x) : (y))
-
-struct io_uring_queue {
-    int fd;
-    void *base;
-    size_t base_mmap_len;
-    struct io_uring_params p;
-    uint32_t *array;
-    struct io_uring_sqe *sqes;
-    size_t sqes_mmap_len;
-    uint32_t *sq_head, *sq_tail;
-    uint32_t sq_mask;
-    struct io_uring_cqe *cqes;
-    uint32_t *cq_head, *cq_tail;
-    uint32_t cq_mask;
-};
-
-static int
-io_uring_setup(unsigned entries, struct io_uring_params *p) {
-    return (int) syscall(__NR_io_uring_setup, entries, p);
-}
-
-static int
-io_uring_enter(int ring_fd, unsigned int to_submit, unsigned int min_complete,
-               unsigned int flags) {
-    return (int) syscall(__NR_io_uring_enter, ring_fd, to_submit, min_complete,
-                   flags, NULL, 0);
-}
-
-/*
-static void
-dump_scht(char *prefix, struct io_uring_queue *q) {
-fprintf(stderr, "# async %s: %p %p\n", prefix, (void*)q, q->base);
-    size_t head, tail, mask;
-    read_barrier();
-    mask = q->sq_mask;
-    mask = *(uint32_t*)(((uintptr_t)q->base) + q->p.sq_off.ring_mask);
-    head = *q->sq_head & mask;
-    tail = *q->sq_tail & mask;
-fprintf(stderr, "######### %s ######### sq %u:%u 0x%x\n", prefix, head, tail, mask);
-    mask = q->cq_mask;
-    mask = *(uint32_t*)(((uintptr_t)q->base) + q->p.cq_off.ring_mask);
-    head = *q->cq_head & mask;
-    tail = *q->cq_tail & mask;
-fprintf(stderr, "######### %s ######### cq %u:%u 0x%x\n", prefix, head, tail, mask);
-}
-*/
-
-int
-cq_has_data(struct io_uring_queue *q) {
-    size_t head, tail;
-    read_barrier();
-    head = *q->cq_head & q->cq_mask;
-    tail = *q->cq_tail & q->cq_mask;
-    return head != tail;
-}
-
-static void
-build_op_read(struct io_uring_sqe *sqe, int fd, void *data, size_t size,
-              off_t offset) {
-    sqe->fd = fd;
-    sqe->flags = 0;
-    sqe->opcode = IORING_OP_READ;
-    sqe->addr = (uintptr_t)data;
-    sqe->len = size;
-    sqe->off = offset;
-    sqe->user_data = 0;
-}
-
-static int
-read_from_cq(struct io_uring_queue *q) {
-    size_t head, tail;
-    struct io_uring_cqe *cqe;
-    do {
-        read_barrier();
-        head = *q->cq_head & q->cq_mask;
-        tail = *q->cq_tail & q->cq_mask;
-        if (head == tail)
-            break;
-
-        /* Get the entry */
-        cqe = q->cqes + head;
-        if (cqe->res < 0) {
-            fprintf(stderr, "Read error: %s\n", strerror(abs(cqe->res)));
-        }
-        (*q->cq_head)++;
-    } while (head == tail);
-    write_barrier();
-    return cqe->res;
-}
-
-struct io_uring_queue *
-io_async_init() {
-    struct io_uring_queue *q = calloc(1, sizeof(struct io_uring_queue));
-    q->fd = io_uring_setup(QUEUE_DEPTH, &q->p);
-    if (q->fd < 0) {
-        perror("io_uring_setup");
-        return NULL;
-    }
-
-    size_t sring_size = q->p.sq_off.array + q->p.sq_entries * sizeof(unsigned);
-    size_t cring_size = q->p.cq_off.cqes
-                      + q->p.cq_entries * sizeof(struct io_uring_cqe);
-    size_t rings_size = MAX(sring_size, cring_size);
-    q->base_mmap_len = rings_size;
-
-    if (!(q->p.features & IORING_FEAT_SINGLE_MMAP)) {
-        fprintf(stderr, "[io.uring] Your kernel doesn't support"
-                " IORING_FEAT_SINGLE_MMAP, upgrade to Linux 5.4\n");
-        return NULL;
-    }
-
-    q->base = mmap(0, rings_size, PROT_READ | PROT_WRITE, MAP_SHARED
-                   | MAP_POPULATE, q->fd, IORING_OFF_SQ_RING);
-    if (q->base == MAP_FAILED) {
-        perror("[io.uring] Can't mmap io_uring rings");
-        return NULL;
-    }
-
-    q->sqes_mmap_len = q->p.sq_entries * sizeof(struct io_uring_sqe);
-    q->sqes = mmap(0, q->sqes_mmap_len, PROT_READ | PROT_WRITE, MAP_SHARED
-                   | MAP_POPULATE, q->fd, IORING_OFF_SQES);
-    if (q->sqes == MAP_FAILED) {
-        perror("[io.uring] Can't mmap io_uring SQEs");
-        return NULL;
-    }
-
-    q->cqes = (struct io_uring_cqe*)((uintptr_t)q->base + q->p.cq_off.cqes);
-    q->array = (uint32_t*)((uintptr_t)q->base + q->p.sq_off.array);
-    q->sq_head = (uint32_t*)((uintptr_t)q->base + q->p.sq_off.head);
-    q->sq_tail = (uint32_t*)((uintptr_t)q->base + q->p.sq_off.tail);
-    q->sq_mask = *(uint32_t*)((uintptr_t)q->base + q->p.sq_off.ring_mask);
-    q->cq_head = (uint32_t*)((uintptr_t)q->base + q->p.cq_off.head);
-    q->cq_tail = (uint32_t*)((uintptr_t)q->base + q->p.cq_off.tail);
-    q->cq_mask = *(uint32_t*)((uintptr_t)q->base + q->p.cq_off.ring_mask);
-
-    return q;
-}
-
-void
-io_async_close(void *arg) {
-    struct io_uring_queue *q = arg;
-    munmap(q->base, q->base_mmap_len);
-    munmap(q->sqes, q->sqes_mmap_len);
-    close(q->fd);
-    free(q);
-}
-
-static uint32_t
-io_uring_wait_test() {
-    appdata_t *app;
-    __asm__ __volatile__ ("":"=b"(app)::);
-    struct io_uring_queue *q = app->wait_param;
-    int done = cq_has_data(q);
-    return done;
-}
-
-ssize_t
-io_async_read(int fd, void *buf, size_t count, void *arg) {
-    struct io_uring_queue *q = arg;
-    read_barrier();
-    size_t tail = *q->sq_tail & q->sq_mask;
-    struct io_uring_sqe *sqe = q->sqes + tail;
-    build_op_read(sqe, fd, buf, count, -1);
-    q->array[tail] = tail;
-    (*q->sq_tail)++;
-
-    int ret =  io_uring_enter(q->fd, 1, 0, IORING_ENTER_GETEVENTS);
-    if(ret < 0) {
-        perror("io_uring_enter");
-        return 1;
-    }
-
-    kos_wait_events(io_uring_wait_test, q);
-
-    ssize_t res = read_from_cq(q);
-
-    return res;
-}
-
-ssize_t
-io_async_write(int fd, const void *buf, size_t count, void *arg) {
-    (void)fd;
-    (void)buf;
-    (void)count;
-    (void)arg;
-    return -1;
-}
diff --git a/makefile b/makefile
index 9495bed..d1633e4 100644
--- a/makefile
+++ b/makefile
@@ -58,19 +58,18 @@ test: umka_shell
 umka_shell: umka_shell.o umka.o shell.o trace.o trace_lbr.o vdisk.o \
             vdisk/raw.o vdisk/qcow2.o vdisk/miniz/miniz.a vnet.o \
             $(HOST)/vnet/tap.o vnet/file.o lodepng.o $(HOST)/pci.o \
-            $(HOST)/thread.o umkaio.o $(HOST)/io_async.o umkart.o optparse32.o \
-            bestline32.o
+            $(HOST)/thread.o umkaio.o umkart.o optparse32.o bestline32.o
 	$(CC) $(LDFLAGS_32) $^ -o $@ -T umka.ld
 
 umka_fuse: umka_fuse.o umka.o trace.o trace_lbr.o vdisk.o vdisk/raw.o \
            vdisk/qcow2.o vdisk/miniz/miniz.a $(HOST)/pci.o $(HOST)/thread.o \
-           umkaio.o $(HOST)/io_async.o
+           umkaio.o
 	$(CC) $(LDFLAGS_32) $^ -o $@ `pkg-config fuse3 --libs` -T umka.ld
 
 umka_os: umka_os.o umka.o shell.o lodepng.o vdisk.o vdisk/raw.o vdisk/qcow2.o \
          vdisk/miniz/miniz.a vnet.o $(HOST)/vnet/tap.o vnet/file.o trace.o \
-         trace_lbr.o $(HOST)/pci.o $(HOST)/thread.o umkaio.o \
-         $(HOST)/io_async.o umkart.o bestline32.o optparse32.o
+         trace_lbr.o $(HOST)/pci.o $(HOST)/thread.o umkaio.o umkart.o \
+         bestline32.o optparse32.o
 	$(CC) $(LDFLAGS_32) `sdl2-config --libs` $^ -o $@ -T umka.ld
 
 umka_gen_devices_dat: umka_gen_devices_dat.o umka.o $(HOST)/pci.o \
@@ -86,9 +85,6 @@ shell.o: shell.c lodepng.h
 umkaio.o: umkaio.c umkaio.h
 	$(CC) $(CFLAGS_32) -D_DEFAULT_SOURCE -c $< -o $@
 
-$(HOST)/io_async.o: $(HOST)/io_async.c io_async.h
-	$(CC) $(CFLAGS_32) -D_DEFAULT_SOURCE -c $< -o $@
-
 $(HOST)/thread.o: $(HOST)/thread.c
 	$(CC) $(CFLAGS_32) -c $< -o $@
 
diff --git a/shell.c b/shell.c
index f996515..d344888 100644
--- a/shell.c
+++ b/shell.c
@@ -75,6 +75,11 @@ umka_run_cmd_sync(struct shell_ctx *ctx) {
                            c->hscroll);
         break;
         }
+    case UMKA_CMD_SYS_LFN: {
+        struct cmd_sys_lfn *c = &cmd->arg.sys_lfn;
+        umka_sys_lfn(c->bufptr, c->r, c->f70or80);
+        break;
+        }
     default:
         fprintf(ctx->fout, "[!] unknown command: %u\n", cmd->type);
         break;
@@ -2353,9 +2358,21 @@ ls_all(struct shell_ctx *ctx, f7080s1arg_t *fX0, f70or80_t f70or80) {
     size_t bdfe_len = (fX0->encoding == CP866) ? BDFE_LEN_CP866 :
                                                  BDFE_LEN_UNICODE;
     while (true) {
+        struct umka_cmd *cmd = umka_cmd_buf;
+        struct cmd_sys_lfn *c = &cmd->arg.sys_lfn;
+        cmd->type = UMKA_CMD_SYS_LFN;
+        c->f70or80 = f70or80;
+        c->bufptr = fX0;
+        c->r = &r;
+
+        atomic_store_explicit(&cmd->status, UMKA_CMD_STATUS_READY,
+                              memory_order_release);
         COVERAGE_ON();
-        umka_sys_lfn(fX0, &r, f70or80);
+//        umka_sys_lfn(fX0, &r, f70or80);
+        umka_run_cmd(ctx);
         COVERAGE_OFF();
+        atomic_store_explicit(&cmd->status, UMKA_CMD_STATUS_EMPTY,
+                              memory_order_release);
         print_f70_status(ctx, &r, 1);
         assert((r.status == ERROR_SUCCESS && r.count == fX0->size)
               || (r.status == ERROR_END_OF_FILE && r.count < fX0->size));
diff --git a/umka.h b/umka.h
index a2a0e86..339b455 100644
--- a/umka.h
+++ b/umka.h
@@ -2401,6 +2401,7 @@ enum {
     UMKA_CMD_SET_MOUSE_DATA,
     UMKA_CMD_SYS_PROCESS_INFO,
     UMKA_CMD_SYS_GET_MOUSE_POS_SCREEN,
+    UMKA_CMD_SYS_LFN,
 };
 
 enum {
@@ -2417,6 +2418,16 @@ struct cmd_set_mouse_data {
     int32_t hscroll;
 };
 
+struct cmd_sys_lfn {
+    f70or80_t f70or80;
+    f7080s1arg_t *bufptr;
+    f7080ret_t *r;
+};
+
+struct cmd_ret_sys_lfn {
+    f7080ret_t status;
+};
+
 struct cmd_sys_process_info {
     int32_t pid;
     void *param;
@@ -2431,9 +2442,11 @@ struct umka_cmd {
     uint32_t type;
     union {
         struct cmd_set_mouse_data set_mouse_data;
+        struct cmd_sys_lfn sys_lfn;
     } arg;
     union {
         struct cmd_ret_sys_get_mouse_pos_screen sys_get_mouse_pos_screen;
+        struct cmd_ret_sys_lfn sys_lfn;
     } ret;
 };
 
diff --git a/umka_shell.c b/umka_shell.c
index e439646..6c177b1 100644
--- a/umka_shell.c
+++ b/umka_shell.c
@@ -35,7 +35,7 @@ struct umka_shell_ctx *
 umka_shell_init(int reproducible, FILE *fin, FILE *fout) {
     struct umka_shell_ctx *ctx = malloc(sizeof(struct umka_shell_ctx));
     ctx->umka = umka_init();
-    ctx->io = io_init(&ctx->umka->running);
+    ctx->io = io_init(NULL);
     ctx->shell = shell_init(reproducible, history_filename, ctx->umka, ctx->io,
                             fin, fout, &ctx->umka->running);
     return ctx;
diff --git a/umkaio.c b/umkaio.c
index 8deb696..38161b1 100644
--- a/umkaio.c
+++ b/umkaio.c
@@ -7,35 +7,127 @@
     Copyright (C) 2023  Ivan Baravy <dunkaist@gmail.com>
 */
 
+#include <stdatomic.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <inttypes.h>
+#include "umka.h"
 #include "umkaio.h"
-#include "io_async.h"
+
+#define IOT_QUEUE_DEPTH 1
+
+struct iot_cmd iot_cmd_buf[IOT_QUEUE_DEPTH];
+
+static void *
+thread_io(void *arg) {
+    (void)arg;
+    for (size_t i = 0; i < IOT_QUEUE_DEPTH; i++) {
+        iot_cmd_buf[i].status = UMKA_CMD_STATUS_EMPTY;
+        iot_cmd_buf[i].type = 0;
+        pthread_cond_init(&iot_cmd_buf[i].iot_cond, NULL);
+        pthread_mutex_init(&iot_cmd_buf[i].iot_mutex, NULL);
+        pthread_mutex_lock(&iot_cmd_buf[i].iot_mutex);
+        pthread_mutex_init(&iot_cmd_buf[i].mutex, NULL);
+    }
+
+    struct iot_cmd *cmd = iot_cmd_buf;
+    ssize_t ret;
+    while (1) {
+        pthread_cond_wait(&cmd->iot_cond, &cmd->iot_mutex);
+        // status must be ready
+        switch (cmd->type) {
+        case IOT_CMD_TYPE_READ:
+            ret = read(cmd->read.arg.fd, cmd->read.arg.buf, cmd->read.arg.count);
+            atomic_store_explicit(&cmd->read.ret.val, ret, memory_order_release);
+            break;
+        case IOT_CMD_TYPE_WRITE:
+            cmd->read.ret.val = write(cmd->read.arg.fd, cmd->read.arg.buf,
+                                      cmd->read.arg.count);
+            break;
+        default:
+            break;
+        }
+
+    atomic_store_explicit(&cmd->status, UMKA_CMD_STATUS_DONE, memory_order_release);
+    }
+
+    return NULL;
+}
+
+static uint32_t
+io_async_submit_wait_test() {
+//    appdata_t *app;
+//    __asm__ __volatile__ ("":"=b"(app)::);
+//    struct io_uring_queue *q = app->wait_param;
+    int done = pthread_mutex_trylock(&iot_cmd_buf[0].mutex);
+    return done;
+}
+
+static uint32_t
+io_async_complete_wait_test() {
+//    appdata_t *app;
+//    __asm__ __volatile__ ("":"=b"(app)::);
+//    struct io_uring_queue *q = app->wait_param;
+    int status = atomic_load_explicit(&iot_cmd_buf[0].status, memory_order_acquire);
+    return status == UMKA_CMD_STATUS_DONE;
+}
+
+ssize_t
+io_async_read(int fd, void *buf, size_t count, void *arg) {
+    (void)arg;
+
+    kos_wait_events(io_async_submit_wait_test, NULL);
+    // status must be empty
+    struct iot_cmd *cmd = iot_cmd_buf;
+    cmd->read.arg.fd = fd;
+    cmd->read.arg.buf = buf;
+    cmd->read.arg.count = count;
+    atomic_store_explicit(&cmd->status, UMKA_CMD_STATUS_READY, memory_order_release);
+    
+    pthread_cond_signal(&cmd->iot_cond);
+    kos_wait_events(io_async_complete_wait_test, NULL);
+
+    ssize_t res = atomic_load_explicit(&cmd->read.ret.val, memory_order_acquire);
+
+    atomic_store_explicit(&cmd->status, UMKA_CMD_STATUS_EMPTY, memory_order_release);
+    pthread_mutex_unlock(&cmd->mutex);
+
+    return res;
+}
+
+ssize_t
+io_async_write(int fd, const void *buf, size_t count, void *arg) {
+    (void)fd;
+    (void)buf;
+    (void)count;
+    (void)arg;
+    return -1;
+}
 
 struct umka_io *
 io_init(int *running) {
     struct umka_io *io = malloc(sizeof(struct umka_io));
     io->running = running;
-    io->async = io_async_init();
+    if (running) {
+        pthread_create(&io->iot, NULL, thread_io, NULL);
+    }
     return io;
 }
 
 void
 io_close(struct umka_io *io) {
-    io_async_close(io->async);
     free(io);
 }
 
 ssize_t
 io_read(int fd, void *buf, size_t count, struct umka_io *io) {
     ssize_t res;
-    if (!*io->running) {
+    if (!io->running || !*io->running) {
         res = read(fd, buf, count);
     } else {
-        res = io_async_read(fd, buf, count, io->async);
+        res = io_async_read(fd, buf, count, NULL);
     }
     return res;
 }
@@ -43,10 +135,10 @@ io_read(int fd, void *buf, size_t count, struct umka_io *io) {
 ssize_t
 io_write(int fd, const void *buf, size_t count, struct umka_io *io) {
     ssize_t res;
-    if (!*io->running) {
+    if (!io->running || !*io->running) {
         res = write(fd, buf, count);
     } else {
-        res = io_async_write(fd, buf, count, io->async);
+        res = io_async_write(fd, buf, count, NULL);
     }
     return res;
 }
diff --git a/umkaio.h b/umkaio.h
index fd687bd..dc70b79 100644
--- a/umkaio.h
+++ b/umkaio.h
@@ -10,11 +10,59 @@
 #ifndef UMKAIO_H_INCLUDED
 #define UMKAIO_H_INCLUDED
 
-#include <unistd.h>
+#include <stddef.h>
+#include <pthread.h>
 
 struct umka_io {
     const int *running;
-    void *async;    // platform specific
+    pthread_t iot;
+};
+
+struct iot_cmd_read_arg {
+    int fd;
+    void *buf;
+    size_t count;
+};
+
+struct iot_cmd_read_ret {
+    ssize_t val;
+};
+
+union iot_cmd_read {
+    struct iot_cmd_read_arg arg;
+    struct iot_cmd_read_ret ret;
+};
+
+struct iot_cmd_write_arg {
+    int fd;
+    void *buf;
+    size_t count;
+};
+
+struct iot_cmd_write_ret {
+    ssize_t val;
+};
+
+union iot_cmd_write {
+    struct iot_cmd_write_arg arg;
+    struct iot_cmd_write_ret ret;
+};
+
+enum {
+    IOT_CMD_TYPE_READ,
+    IOT_CMD_TYPE_WRITE,
+};
+
+struct iot_cmd {
+    pthread_cond_t iot_cond;
+    pthread_mutex_t iot_mutex;
+    pthread_mutex_t mutex;
+    int status;
+    int type;
+    union {
+        union iot_cmd_read read;
+        union iot_cmd_write write;
+    };
 };
 
 struct umka_io *