09 2014 档案

how to use the curses library in unix?
摘要：In linux, you can use the ncurses library to use the terminal as a text buffer: move the cursor around, and write text. It can also draw windows and o... 阅读全文
posted @ 2014-09-30 15:42 zmiao 阅读(108) 评论(0) 推荐(0) 编辑
how to write a struct to a file directly?
摘要：Using write and read system call. Following is an example:blk.h:#include #include #include #include #include #include struct data{ char s[20]; i... 阅读全文
posted @ 2014-09-30 13:54 zmiao 阅读(132) 评论(0) 推荐(0) 编辑
删除
摘要：要说明的是，在删除文件的时候，我并没有实现文件块区以及i节点的清除操作，众所周知，那样很耗时，和很多实现一样，我只是记录了一些信息，表示这个文件块或者inode字段是可以随时覆盖的。 阅读全文
posted @ 2014-09-29 06:29 zmiao 阅读(120) 评论(0) 推荐(0) 编辑
unix文件系统
摘要：转自here我一向坚持的原则，那就是任何东西的根本性的，本质上的原理以及背后的思想都是及其简单的，所谓的复杂性都是优化与策略化的扩展带来的，正如TCP一样，UNIX的文件系统也不例外！我们必须知道，什么是最根本的，什么是次要的。对于UNIX文件系统，最根本的就是其布局以及其系统调用接口，一个处在最低... 阅读全文
posted @ 2014-09-28 15:05 zmiao 阅读(269) 评论(0) 推荐(0) 编辑
configure PUTTY to not time out
摘要：To modify an existing session with "keep alives" to maintain your connection follow the steps below:Open the PuTTy application and navigate to theOpti... 阅读全文
posted @ 2014-09-27 04:15 zmiao 阅读(249) 评论(0) 推荐(0) 编辑
how to use tar?
摘要：In UNIX, tar is the most useful tool to compress files (just like zip in Windows.)To compress, input: tar -cvzf file.tar.gz inputfile1 inputfile2to u... 阅读全文
posted @ 2014-09-26 16:51 zmiao 阅读(175) 评论(0) 推荐(0) 编辑
longest increasing subsequence
摘要：problem is like this:Input is an int array: -> 10, 85, 96, 80, 93, 54, 3, 26, 4, 37Output is an integer, in this example, you should return 3 (because... 阅读全文
posted @ 2014-09-26 13:59 zmiao 阅读(133) 评论(0) 推荐(0) 编辑
unlinking
摘要：When a file name is deleted from the directory tree, the file name's connection to the inode number is severed. If the file name is the last "link" to... 阅读全文
posted @ 2014-09-25 13:53 zmiao 阅读(165) 评论(0) 推荐(0) 编辑
first os
摘要：Make your first OS. (MikeOS).check out here 阅读全文
posted @ 2014-09-25 06:29 zmiao 阅读(90) 评论(0) 推荐(0) 编辑
callback in C
摘要：callback is nothing but passing the function pointer to the code from where you want your handler/ callback to be invoked.check here 阅读全文
posted @ 2014-09-23 07:09 zmiao 阅读(118) 评论(0) 推荐(0) 编辑
FUSE
摘要：FUSE is particularly useful for writing [ vritual ] file system. Unlike traditional filesystem that essentially save data to and retrive data from dis... 阅读全文
posted @ 2014-09-20 15:48 zmiao 阅读(125) 评论(0) 推荐(0) 编辑
Java is Pass-by-Value!
摘要：Java is strictly pass-by-value. which means, when you pass a variable to a method, the method will just make a copy of that varible and use that copy,... 阅读全文
posted @ 2014-09-20 08:58 zmiao 阅读(222) 评论(0) 推荐(0) 编辑
swap in java?
摘要：Is it possible to write a swap method in java? these two variables will be primitives.It's not possible, without any objects or arrays. (Java passes s... 阅读全文
posted @ 2014-09-20 08:48 zmiao 阅读(137) 评论(0) 推荐(0) 编辑
tmpfs
摘要：the /tmp folder of linux will be cleaned every time when you reboot.Well, actually, It doesn't "delete on reboot"; it only exists in RAM in the first ... 阅读全文
posted @ 2014-09-20 08:08 zmiao 阅读(152) 评论(0) 推荐(0) 编辑
BFS and Queue
摘要：BFS (Bridth First Search) can be implemented by a queue.Procedure is like this: (Q is Queue)1, Put 1 in Q : ->1 (front) 2, Read the front of Q (which ... 阅读全文
posted @ 2014-09-20 04:07 zmiao 阅读(162) 评论(0) 推荐(0) 编辑
Why isn't sizeof for a struct equal to the sum of sizeof of each member?
摘要：check here.Basically the compiler will insert unused memory into a structure so that data members are optimally aligned for better performance. 阅读全文
posted @ 2014-09-19 04:28 zmiao 阅读(106) 评论(0) 推荐(0) 编辑
复杂
摘要：任何东西的根本性的，本质上的原理以及背后的思想都是及其简单的，所谓的复杂性都是优化与策略化的扩展带来的。 阅读全文
posted @ 2014-09-18 11:25 zmiao 阅读(112) 评论(0) 推荐(0) 编辑
how to add a shared lib in C?
摘要：http://www.cprogramming.com/tutorial/shared-libraries-linux-gcc.htmlBasically, 2 steps: 1) make the lib. 2) put the lib in /usr/lib and ldconfig (upda... 阅读全文
posted @ 2014-09-17 07:39 zmiao 阅读(95) 评论(0) 推荐(0) 编辑
ArrayList implementation
摘要：check here.tip: 当使用remove方法时，index后边的元素要自动前移。Nothing special. 阅读全文
posted @ 2014-09-16 16:26 zmiao 阅读(81) 评论(0) 推荐(0) 编辑
how to increase an regular array length in java?
摘要：Arrays in Java are of fixed size that is specified when they are declared. To increase the size of the array you have to create a new array with a lar... 阅读全文
posted @ 2014-09-16 16:20 zmiao 阅读(134) 评论(0) 推荐(0) 编辑
malloc without free, what happens?
摘要：It's per-process. Once your process exits, the allocated memory is returned to the OS for use by other processes (new or existing).To answer your edit... 阅读全文
posted @ 2014-09-16 06:56 zmiao 阅读(126) 评论(0) 推荐(0) 编辑
differences between null pointer and void pointer.
摘要：These are two different concepts, you cannot compare them. What the difference between the skunk and the moonlight?Null pointer is a special reserved ... 阅读全文
posted @ 2014-09-16 05:28 zmiao 阅读(180) 评论(0) 推荐(0) 编辑
what a malloc has to do
摘要：1) Allocate a chunk of memory big enough to satisfy the request, and return a pointer to it.2) Remember which chunks of ram are in use and which aren'... 阅读全文
posted @ 2014-09-15 13:49 zmiao 阅读(107) 评论(0) 推荐(0) 编辑
FUSE and File System
摘要：FUSE: File system in USErspace.So what is a file system?A file system maps file paths to file contents and metadata.Metadata includes modification tim... 阅读全文
posted @ 2014-09-11 14:18 zmiao 阅读(162) 评论(0) 推荐(0) 编辑
how computer boot up?
摘要：The power button activates the power supply in the PC, sending power to the motherboard and other components.The PC performs a power-on self-test (POS... 阅读全文
posted @ 2014-09-11 08:47 zmiao 阅读(272) 评论(0) 推荐(0) 编辑
repeat a string in java
摘要：if I want to repeat "hello" four times as a new string-> "hellohellohellohello". I can:return new String(new char[4]).replace("\0", "hello") 阅读全文
posted @ 2014-09-10 17:59 zmiao 阅读(487) 评论(0) 推荐(0) 编辑
force reboot for Chromebook
摘要：Refresh + Power 阅读全文
posted @ 2014-09-10 10:41 zmiao 阅读(135) 评论(0) 推荐(0) 编辑
implement a system call in minix
摘要：http://www.papervisions.com/implementing-system-call-in-minix-os/ 阅读全文
posted @ 2014-09-09 09:15 zmiao 阅读(118) 评论(0) 推荐(0) 编辑
read file in a single line
摘要：String text=new Scanner(File('input.txt')).useDelimiter("\\A").next();java version! 阅读全文
posted @ 2014-09-07 14:12 zmiao 阅读(136) 评论(0) 推荐(0) 编辑
why TCP guarentee delivery?
摘要：Simple idea: just use a TIMEOUT, if no answer after a certain seconds, just re-deliver! 阅读全文
posted @ 2014-09-06 15:00 zmiao 阅读(121) 评论(0) 推荐(0) 编辑
reincarnation server
摘要：- parent of all the drivers and servers- when a driver or server dies, RS collects it.- RS checks a table for action to take, e.g: restart it.- RS als... 阅读全文
posted @ 2014-09-06 14:57 zmiao 阅读(197) 评论(0) 推荐(0) 编辑
greatest common divisor
摘要：One efficient way to compute the GCD of two numbers is to use Euclid's algorithm, which states the following: GCD(A, B) = GCD(B, A % B) GC... 阅读全文
posted @ 2014-09-05 10:17 zmiao 阅读(142) 评论(0) 推荐(0) 编辑
java FLOAT
摘要：System.out.println(""+ 1/2);得不到0.5，只能得到0.要想打印出浮点数，必须除数和被除数至少有一个是浮点数，像这样：System.out.println(""+ 1/2.0);就可以了。 阅读全文
posted @ 2014-09-04 16:29 zmiao 阅读(186) 评论(0) 推荐(0) 编辑
diff and patch
摘要：A patch captures the changes of two different files (oldfile and newfile). Given the oldfile and the patch, one can use the patch program to create th... 阅读全文
posted @ 2014-09-03 03:44 zmiao 阅读(219) 评论(0) 推荐(1) 编辑
philosophy
摘要：Even though the UNIX system introduces a number of innovative programs and techniques, no single program or idea makes it work well. Instead, what mak... 阅读全文
posted @ 2014-09-01 17:22 zmiao 阅读(184) 评论(0) 推荐(0) 编辑
inode
摘要：使用 vi 来编辑一个文件。当您键入 vi 时，在 inode 表中找到 inode 编号之后，才允许您打开该 inode 。在 vi 的编辑会话期间，更改了该 inode 中的某些属性，当您完成操作并键入 :wq 时，将关闭并释放该 inode 。通过这种方式，如果两个用户试图对同一个文件进行编... 阅读全文
posted @ 2014-09-01 11:32 zmiao 阅读(132) 评论(0) 推荐(0) 编辑