yangjingxu-优快云博客

原创 PrintStream vs PrintWriter (MEMO)

http://stackoverflow.com/questions/2822005/java-difference-between-printstream-and-printwriterhttp://stackoverflow.com/questions/11372546/printstream-vs-printwriter

2014-07-11 18:01:59 232

原创 Division and modulo in C/C++, Java and Python

[quote]a is an integer, n is a positive integer.C/C++=====quotient is rounded towards zero. a mod n = a - n (a/n)Python======Same as defined by CRLS.[/quote]

2013-12-19 12:58:08 247

原创 Hacking Assembly Code Generated by G++

For the following C++ code: class person { public: person() {} person(const person& rhs) {}};void func(person p) {}int main(int argc, const char *argv[]) { person y...

2013-06-09 15:31:59 309

原创 Synchronous vs. Asynchronous (systems)

In a synchronous system, there are bounds on:- Time of computation- Time of message deliver An asynchronous system is one that is not synchronous.

2013-06-05 16:38:33 299

IBM HACMP

Standby configurationsStandby configurations are the traditional redundant hardware configurations where one or more standby nodes stand idle, waiting for a server node to leave the cluster.Takeo...

2013-06-04 21:17:45 145

How do unsynchronized values get updated in Java?

Section Visibility in http://gee.cs.oswego.edu/dl/cpj/jmm.html answesr this question.

2013-05-27 17:59:58 192

Nework

Full Duplex:http://www.intel.com/support/express/switches/sb/CS-014409.htm

2013-05-02 09:55:19 174

Hard Disk

One disk drive has only one actuator arm.Every plate has 2 surfaces to store data.Throughput: 100MB/sSeek time: 10msec (100 seeks/s)

2013-04-26 17:35:05 137

About Binary Tree

CLRS-----1) full binary tree: an ordered tree in which each internal node has degree 22) A complete k-ary tree: k-ary tree in which all leaves have the same depth and all internal nodes h...

2013-04-18 14:56:25 118

PageRank in Pig

https://github.com/yaojingguo/data-mining/tree/master/PageRank

2013-04-13 15:01:07 157

Sequential Consistency Paper Reading

Lamport 1979 paper is often cited when talking about sequential consistency [1]. But the paper context is outdated. Robert Morris gives the following requirements which are together equivalent ...

2013-04-12 21:39:50 137

An Application of Bubble Sort

This problem is inspired by the discussion about ordering specification, BSort in the paper "Aurora: a new model and architecture for data stream management" Problem: There is an array A who...

2013-04-11 21:03:51 109

原创 Oracle Logging

Oracle uses STEAL NO-FORCE logging. The following content is just my conjecture which is not proved. A log record has 2 parts: undo and redo. For Oracle, undo is treated differently. Undo data ...

2013-04-10 13:53:25 203

Secondary Sort in Hadoop

I write this stuff since it confused me a lot.First, the input Iterable values for reduce method is not sorted in any order. It is mentioned on Page 277 in Hadoop: The Definitive Guide, Third ...

2013-03-26 16:08:17 114

原创 How to read a reseach paper

1) Have a precise understanding of the key points.2) Try to recite the main idea.3) Make simple mental experiments.4) Read other referenced papers and search google.5) If too hard, stop. Do ...

2013-03-13 17:12:24 194

Canned SQL (MEMO)

http://www.simple-talk.com/sql/t-sql-programming/a-case-for-canned-sql/

2012-12-24 10:15:27 140

原创 SSH Agent Forwarding

https://help.github.com/articles/using-ssh-agent-forwardinghttp://www.unixwiz.net/techtips/ssh-agent-forwarding.html

2012-09-15 18:09:50 210

Bash extglob shell option

To list .h and .ccp files, use: ls *.@(h|cc)

2012-07-16 14:15:43 189

原创 C++ inline

http://www.parashift.com/c++-faq-lite/inline-member-fns.html

2012-07-10 13:41:10 142

Clone a web site

Clone http://www.abc.com/refererence. Only follow links in directory /reference. wget -k -m -I /reference http://www.abc.com/refererence.

2012-07-06 15:00:31 136

Check the final definition of a typedef

Refer to http://stackoverflow.com/questions/471248/what-is-ultimately-a-time-t-typedef-to. Read Quassnoi's answer.

2012-07-04 10:43:59 109

Customize NERD Commenter

NERD_commenter.vim: \ 'c': { 'left': '// ', 'leftAlt': '/*', 'rightAlt': '*/' }, \ 'cpp': { 'left': '// ', 'leftAlt': '/*', 'rightAlt': '*/' },

2012-05-21 14:07:59 202

Turing machine

A computer architecture can be seen as a turing machine. But how to express interrupt in turing machine? I think that we can see interrupt a the flowing condition statement. This statement get exe...

2012-05-11 14:41:54 191

Usage of grep

Find error or exception in a log file: grep -i -E '((error)|(exception))' log

2012-05-07 10:05:10 98

C symbol table

C source code: #include <stdio.h>void sub(int x) {}void xiao() { static int x = 10; sub(x);}void yu(){ static int x = 20; sub(x);}int main(int argc, co...

2012-05-06 10:38:55 489

GCC options: -ffunction-sections and -fdata-sections

C code: struct person { int age; int no;};int plus_one(int no){ return no + 1;}int minus_one(int no){ return no - 1;} Run 'gcc -S -ffunction-sections -fdata-sect...

2012-05-05 11:21:16 158

Source code change effect on object code

C code: #include <stdio.h>// change no's type from int to long longlong long func(long long no) { return no + 1; }int main(int argc, const char *argv[]) { int i; i = 100...

2012-05-05 11:15:01 124

gcov tutorial

tmp.c#include <stdio.h>int main(int argc, const char *argv[]) { int i, j; for (i = 0; i < 10; i++) if (i > 100) j += 3; else j += 2; return 0;} S...

2012-05-03 21:01:43 131

x86 64 assembly tutorial (MEMO)

Refer to http://os-blog.com/x86-64-assembly-programming-hello-world/. Check /usr/include/unistd.h for system call numbers. Note that syscall numbers may be different for the same system call on 32...

2012-04-24 15:50:01 171

Multiline String in a Bash Script

#!/bin/bashTEST1=$(cat <<_EOF_Dogs and catsliving togetherThe worldUpside down_EOF_)echo "$TEST1"

2012-04-20 14:23:26 176

原创 The New C: X Macros (memo)

The code:#include <stdio.h>#define COLOR_TABLE \X(red, "red") \X(green, "green") \X(blue, "blue")#define X(a, b) a,enum COLOR { COLOR_TABLE};#undef X#defi...

2012-04-20 10:42:23 145

svn diff

Diff between differerent revisions. Example: svn diff -r 13401:13747 bi/data-integrator/src/clojure/di/di.clj Colordiff: http://www.zalas.eu/viewing-svn-diff-result-in-colors

2012-04-19 13:26:05 116

Assembly code for stack array initialization

I develop the code with x86 gcc. The C code: #include <stdio.h>void test() { int i; int array[3] = {0}; for (i = 0; i < 3; i++) printf("array[%d] = %d\n", i, arr...

2012-04-14 10:28:02 134

C array initialization

For fewer initializers, refer to 4.9 Initialization in K&R and 6.7.8 Initialization in C99 standard. #include <stdio.h>// in bss section. static storage. initialized to 0int ...

2012-04-14 10:18:35 174

Example of snprintf

#include <stdio.h>int main(int argc, const char *argv[]) { int count; int i; char buf[10]; for (i = 0; i < 10; i++) buf[i] = 1; count = snprintf(buf, 10, "%s", "abc");...

2012-04-09 18:18:33 119

Array and its first element

#include <stdio.h>struct rx_desc { int len; int status;};struct rx_desc rx_ring[2];int main(int argc, const char *argv[]) { struct rx_desc* rx; // Intialization rx_r...

2012-04-09 17:46:01 119

Struct array member

C code:#include <stdio.h>// This struct does not store jp_data: // +-+-+-+-+ // 0+-+-+-+-+ jp_len // 3 2 1 0struct zero_size_array_struct { int jp_len; ch...

2012-04-08 10:59:49 141

Relationship between union and its members

Code:#include <stdio.h>struct Nsreq_accept { int req_s;};struct Nsreq_shutdown { int req_s; int req_how;};union Nsipc { struct Nsreq_accept accept; struct Nsreq_sh...

2012-04-08 09:42:42 151

#if and #ifdef in C

#include <stdio.h>#define debug 0int main(int argc, const char *argv[]) {#if debug printf("#if\n");#endif#ifdef debug printf("#ifdef\n");#endif}

2012-04-06 22:19:12 297

Optional comma in C initialization

#include <stdio.h>struct person { int sex; int no;};int main(int argc, const char *argv[]) { int array_1[3] = {1, 2, 3}; int array_2[3] = {1, 2, 3,}; struct person xiao_y...

2012-04-06 14:09:51 112