diff --git a/src/.gitignore b/src/.gitignore
index 331b6e1cf73646379484d1f2fe8fe168894d3a72..bb9caa138e939a38767fd94b6b9cb65b42761ca7 100644
--- a/src/.gitignore
+++ b/src/.gitignore
@@ -4,60 +4,12 @@
 
 # Object files
 *.o
-*.ko
 *.obj
-*.elf
-*.disasm
-
-# Linker output
-*.ilk
-*.map
-*.exp
-
-# Precompiled Headers
-*.gch
-*.pch
-
-# Libraries
-*.lib
-*.a
-*.la
-*.lo
-
-# Shared objects (inc. Windows DLLs)
-*.dll
-*.so
-*.so.*
-*.dylib
-
-# Executables
-*.exe
-*.out
-*.app
-*.i*86
-*.x86_64
-*.hex
-
-# Image
-*.iso
-*.vhd
-*.bin
-
-# Debug files
-*.dSYM/
-*.su
-*.idb
-*.pdb
-*.dump
 
 # Kernel Module Compile Results
 *.cmd
-.tmp_versions/
-modules.order
-Module.symvers
-Mkfile.old
-dkms.conf
 
+# kernel special
 fixdep
 init/rootfs.c
 build
diff --git a/src/arch/riscv64/port/clock.c b/src/arch/riscv64/port/clock.c
index c7b7c562bbe4c368da469245a3b450f3c4a4d1d7..9280a4e6d84cc3ca54dda4d7765844cd0383a6c5 100644
--- a/src/arch/riscv64/port/clock.c
+++ b/src/arch/riscv64/port/clock.c
@@ -37,6 +37,7 @@
 #endif
 
 NX_PRIVATE NX_U64 tickDelta = NX_TIMER_CLK_FREQ / NX_TICKS_PER_SECOND;
+NX_PRIVATE volatile NX_U64 tickNext = 0;
 
 NX_PRIVATE NX_U64 GetTimerCounter()
 {
@@ -45,20 +46,57 @@ NX_PRIVATE NX_U64 GetTimerCounter()
     return ret;
 }
 
+NX_U64 NX_ClockGetMicrosecond(void)
+{
+    NX_U64 us = 0;
+
+    NX_U64 counter = GetTimerCounter() % tickDelta;
+    
+    /**
+     * us in per ms
+     */
+    us = (NX_DIV_ROUND_UP(counter, (tickDelta / 1000))) % 1000;
+
+    /**
+     * us in time
+     */
+    us += NX_ClockGetMillisecond() * 1000;
+    return us;
+}
+
 void NX_HalClockHandler(void)
 {
-    NX_ClockTickGo();
+    NX_U64 counter;
+
     /* update timer */
-    sbi_set_timer(GetTimerCounter() + tickDelta);
+    counter = GetTimerCounter();
+    if (counter - tickNext >= tickDelta)
+    {
+        tickNext = counter + tickDelta;
+    }
+    else
+    {
+        tickNext += tickDelta;
+    }
+    sbi_set_timer(tickNext);
+    
+    NX_ClockTickGo();
 }
 
 NX_INTERFACE NX_Error NX_HalInitClock(void)
 {
+    NX_U64 counter;
     /* Clear the Supervisor-Timer bit in SIE */
     ClearCSR(sie, SIE_STIE);
 
     /* Set timer */
-    sbi_set_timer(GetTimerCounter() + tickDelta);
+    tickNext = tickDelta;
+    counter = GetTimerCounter();
+    if (counter > tickNext)
+    {
+        tickNext = NX_DIV_ROUND_UP(counter, tickDelta) * tickDelta;
+    }
+    sbi_set_timer(tickNext);
 
     /* Enable the Supervisor-Timer bit in SIE */
     SetCSR(sie, SIE_STIE);
diff --git a/src/arch/x86/port/clock.c b/src/arch/x86/port/clock.c
index 0a996641812f5159cef0669bb1af1665a9782e1f..015af46776cf7d54b89bd6e796ba977e720fb79f 100644
--- a/src/arch/x86/port/clock.c
+++ b/src/arch/x86/port/clock.c
@@ -134,6 +134,14 @@ enum ctrl_mode_bits
 #define TIMER_FREQ     1193180  /* clock frequency */
 #define COUNTER0_VALUE  (TIMER_FREQ / NX_TICKS_PER_SECOND)
 
+/**
+ * FIXME: support this
+ */
+NX_U64 NX_ClockGetMicrosecond(void)
+{
+    return 0;
+}
+
 NX_PRIVATE NX_Error ClockHandler(NX_U32 irq, void *arg)
 {
     NX_ClockTickGo();
diff --git a/src/include/base/clock.h b/src/include/base/clock.h
index 396d7753cf8c9c0456142e06d39c36ba1e3667af..37aa1a5970fec90e71a3367a3a6e0381ae73163b 100644
--- a/src/include/base/clock.h
+++ b/src/include/base/clock.h
@@ -37,6 +37,9 @@ void NX_ClockTickGo(void);
 
 NX_Error NX_ClockTickDelay(NX_ClockTick ticks);
 
+NX_U64 NX_ClockGetMicrosecond(void);
+NX_Error NX_DelayMicrosecond(NX_TimeVal us);
+
 NX_INLINE NX_TimeVal NX_ClockTickToMillisecond(NX_ClockTick tick)
 {
     return NX_TICKS_TO_MILLISECOND(tick);
diff --git a/src/platform/d1/defconfig b/src/platform/d1/defconfig
index 5883ee967411a4803dff71d8718f3f7332e63a1d..3c1b29af62375811d679ea58cde5522fd694d5c1 100644
--- a/src/platform/d1/defconfig
+++ b/src/platform/d1/defconfig
@@ -32,7 +32,7 @@ CONFIG_NX_THREAD_STACK_SIZE=8192
 CONFIG_NX_ENABLE_SCHED=y
 CONFIG_NX_THREAD_MAX_PRIORITY_NR=16
 CONFIG_NX_PORCESS_ENV_ARGS=1024
-CONFIG_NX_TICKS_PER_SECOND=100
+CONFIG_NX_TICKS_PER_SECOND=1000
 # end of OS Kernel
 
 #
@@ -47,7 +47,6 @@ CONFIG_NX_PLATFORM_D1=y
 CONFIG_NX_DRIVER_CONSOLE=y
 CONFIG_NX_PRINT_BUF_LEN=256
 CONFIG_NX_DRIVER_ROMDISK=y
-CONFIG_NX_DRIVER_ROMDISK_HOSTOS_PATH="../../romdisk.cpio"
 # CONFIG_NX_DRIVER_DUMMY is not set
 CONFIG_NX_DRIVER_NULL=y
 CONFIG_NX_DRIVER_ZERO=y
diff --git a/src/platform/d1/include/nx_configure.h b/src/platform/d1/include/nx_configure.h
index 7d30342e0ed8d64472f26ec246f07c7cc5d078a6..5df72d80abc5659a89e8930e0a750e4545d9c32b 100644
--- a/src/platform/d1/include/nx_configure.h
+++ b/src/platform/d1/include/nx_configure.h
@@ -17,12 +17,11 @@
 #define CONFIG_NX_ENABLE_SCHED 1
 #define CONFIG_NX_THREAD_MAX_PRIORITY_NR 16
 #define CONFIG_NX_PORCESS_ENV_ARGS 1024
-#define CONFIG_NX_TICKS_PER_SECOND 100
+#define CONFIG_NX_TICKS_PER_SECOND 1000
 #define CONFIG_NX_PLATFORM_D1 1
 #define CONFIG_NX_DRIVER_CONSOLE 1
 #define CONFIG_NX_PRINT_BUF_LEN 256
 #define CONFIG_NX_DRIVER_ROMDISK 1
-#define CONFIG_NX_DRIVER_ROMDISK_HOSTOS_PATH "../../romdisk.cpio"
 #define CONFIG_NX_DRIVER_NULL 1
 #define CONFIG_NX_DRIVER_ZERO 1
 #define CONFIG_NX_DRIVER_MEMINFO 1
diff --git a/src/platform/f133/defconfig b/src/platform/f133/defconfig
index cbdd5300c3bab54dd7822c3b151695ab8ab68d0e..d80166ee16ace53035c265273d5204e0ce9398c6 100644
--- a/src/platform/f133/defconfig
+++ b/src/platform/f133/defconfig
@@ -32,7 +32,7 @@ CONFIG_NX_THREAD_STACK_SIZE=8192
 CONFIG_NX_ENABLE_SCHED=y
 CONFIG_NX_THREAD_MAX_PRIORITY_NR=16
 CONFIG_NX_PORCESS_ENV_ARGS=1024
-CONFIG_NX_TICKS_PER_SECOND=100
+CONFIG_NX_TICKS_PER_SECOND=1000
 # end of OS Kernel
 
 #
diff --git a/src/platform/f133/include/nx_configure.h b/src/platform/f133/include/nx_configure.h
index dfc7ab14396cb434c75451baae68f535a7bc9fd7..ca65608a34128d4dc192284db478dc543ee6b7db 100644
--- a/src/platform/f133/include/nx_configure.h
+++ b/src/platform/f133/include/nx_configure.h
@@ -17,7 +17,7 @@
 #define CONFIG_NX_ENABLE_SCHED 1
 #define CONFIG_NX_THREAD_MAX_PRIORITY_NR 16
 #define CONFIG_NX_PORCESS_ENV_ARGS 1024
-#define CONFIG_NX_TICKS_PER_SECOND 100
+#define CONFIG_NX_TICKS_PER_SECOND 1000
 #define CONFIG_NX_PLATFORM_F133 1
 #define CONFIG_SOC_SUN20IW1 1
 #define CONFIG_DRIVERS_CCMU 1
diff --git a/src/platform/f133/tools/SBI/opensbi-f133.bin b/src/platform/f133/tools/SBI/opensbi-f133.bin
new file mode 100644
index 0000000000000000000000000000000000000000..5b672910aa26cb7fc301368e684e382bcbf264e5
Binary files /dev/null and b/src/platform/f133/tools/SBI/opensbi-f133.bin differ
diff --git a/src/platform/qemu_riscv64/defconfig b/src/platform/qemu_riscv64/defconfig
index 6f8d415411a16a2debf9214204e6e174075c6dd4..68ce7ba35236240880a5071d7cd76dd322bdac29 100644
--- a/src/platform/qemu_riscv64/defconfig
+++ b/src/platform/qemu_riscv64/defconfig
@@ -32,7 +32,7 @@ CONFIG_NX_THREAD_STACK_SIZE=8192
 CONFIG_NX_ENABLE_SCHED=y
 CONFIG_NX_THREAD_MAX_PRIORITY_NR=16
 CONFIG_NX_PORCESS_ENV_ARGS=1024
-CONFIG_NX_TICKS_PER_SECOND=100
+CONFIG_NX_TICKS_PER_SECOND=1000
 # end of OS Kernel
 
 #
@@ -48,7 +48,6 @@ CONFIG_NX_UART0_FROM_SBI=y
 CONFIG_NX_DRIVER_CONSOLE=y
 CONFIG_NX_PRINT_BUF_LEN=256
 CONFIG_NX_DRIVER_ROMDISK=y
-CONFIG_NX_DRIVER_ROMDISK_HOSTOS_PATH="../../romdisk.cpio"
 # CONFIG_NX_DRIVER_DUMMY is not set
 CONFIG_NX_DRIVER_NULL=y
 CONFIG_NX_DRIVER_ZERO=y
diff --git a/src/platform/qemu_riscv64/include/nx_configure.h b/src/platform/qemu_riscv64/include/nx_configure.h
index 6ff566c916e22ff22d8a20d34d1dc7ccf8f80b59..f6ad433e24978518cbc8321093f3abc49cd354f5 100644
--- a/src/platform/qemu_riscv64/include/nx_configure.h
+++ b/src/platform/qemu_riscv64/include/nx_configure.h
@@ -17,13 +17,12 @@
 #define CONFIG_NX_ENABLE_SCHED 1
 #define CONFIG_NX_THREAD_MAX_PRIORITY_NR 16
 #define CONFIG_NX_PORCESS_ENV_ARGS 1024
-#define CONFIG_NX_TICKS_PER_SECOND 100
+#define CONFIG_NX_TICKS_PER_SECOND 1000
 #define CONFIG_NX_PLATFORM_RISCV64_QEMU 1
 #define CONFIG_NX_UART0_FROM_SBI 1
 #define CONFIG_NX_DRIVER_CONSOLE 1
 #define CONFIG_NX_PRINT_BUF_LEN 256
 #define CONFIG_NX_DRIVER_ROMDISK 1
-#define CONFIG_NX_DRIVER_ROMDISK_HOSTOS_PATH "../../romdisk.cpio"
 #define CONFIG_NX_DRIVER_NULL 1
 #define CONFIG_NX_DRIVER_ZERO 1
 #define CONFIG_NX_DRIVER_MEMINFO 1
diff --git a/src/time/clock.c b/src/time/clock.c
index 21a966fe4ca509b1705fca6ca978867fcbb3e97c..c29af47dedb14336f33d54806c72e16d92c48562 100644
--- a/src/time/clock.c
+++ b/src/time/clock.c
@@ -82,6 +82,16 @@ NX_Error NX_ClockTickDelay(NX_ClockTick ticks)
     return NX_EOK; 
 }
 
+NX_Error NX_DelayMicrosecond(NX_TimeVal us)
+{
+    NX_TimeVal start = NX_ClockGetMicrosecond();
+    while (NX_ClockGetMicrosecond() < start + us)
+    {
+        /* do nothing to delay */
+    }
+    return NX_EOK; 
+}
+
 NX_PRIVATE void NX_TimerIrqHandler(void *arg)
 {
     NX_TimerGo();