X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/7515e526342f6ee07cbe92f5a458f1c2c4a1fcaf..d8d001a6664b88b66524989589fcd809de6d3a92:/lunaix-os/kernel/demos/iotest.c

diff --git a/lunaix-os/kernel/demos/iotest.c b/lunaix-os/kernel/demos/iotest.c
index 2ddeb1a..0cf7cba 100644
--- a/lunaix-os/kernel/demos/iotest.c
+++ b/lunaix-os/kernel/demos/iotest.c
@@ -1,5 +1,6 @@
 #include <lunaix/fctrl.h>
 #include <lunaix/foptions.h>
+#include <lunaix/lunistd.h>
 #include <lunaix/proc.h>
 #include <lunaix/syslog.h>
 
@@ -12,24 +13,30 @@ _iotest_main()
                            "There were two regal sisters who ruled together "
                            "and created harmony for all the land.";
 
-    int fd = open("/dev/sda", 0);  // bd0 设备 - 硬盘
-    int tty = open("/dev/tty", 0); // tty 设备 - 控制台
+    int fd = open("/dev/sda", 0); // sda 设备 - 硬盘
+
+    // tty 设备 - 控制台，使用O_DIRECT打开，即所有IO绕过Lunaix内核的缓存机制
+    int tty = open("/dev/tty", FO_DIRECT);
 
     if (fd < 0 || tty < 0) {
         kprintf(KERROR "fail to open (%d)\n", geterrno());
         return;
     }
 
-    // 移动指针至第二个逻辑扇区（LBA=1），并写入
-    lseek(fd, 1, FSEEK_SET);
+    // 移动指针至512字节，在大多数情况下，这是第二个逻辑扇区的起始处
+    lseek(fd, 512, FSEEK_SET);
+    write(fd, test_sequence, sizeof(test_sequence));
+    lseek(fd, 521, FSEEK_SET);
     write(fd, test_sequence, sizeof(test_sequence));
 
     // 读出我们写的内容
     char read_out[256];
-    lseek(fd, -1, FSEEK_CUR);
+    lseek(fd, 512, FSEEK_SET);
     read(fd, read_out, sizeof(read_out));
 
+    // 将读出的内容直接写入tty设备
     write(tty, read_out, sizeof(read_out));
+    write(tty, "\n", 1);
 
     close(fd);
     close(tty);