delphij's Chaos

刘纪鹏老师一篇很有意思的 文章，对这个问题有兴趣的同学建议读一读。

Maho今天正式commit了 OpenJDK 的port，表面上看这是一小步，但在我看来这却是一项历史性的进步，因为终于可以不再受到之前那个 click-through 许可证的限制了（也就是说，可以几乎没有任何限制地随光盘，或者通过网站提供可用的jdk源代码和二进制版本了）。

注意：如果您熟悉RAID请不必浪费时间阅读这篇文章。

为什么用RAID-Z/RAID-Z2而不是RAID-5呢？

答案是：RAID-5有一个不可避免的问题，即它必须使用后备电源才能保证写入的正确性。这也是为什么我一直极力反对使用低档RAID卡和软件实现的RAID-5的原因。

1987年，菲律宾前总统访华，谈到南沙主权问题时说：“至少在地理上，那些岛屿离菲律宾更近。”

邓小平抽了口烟，说：“在地理上，菲律宾离中国也很近。”

很久没有shared chaos了，今天来一道小学数学题。

有一个水池，进水的速度恒定，提前接了一定时间的水；水池有若干出水口均在底部，假设所有出水口的出水速度一样（换言之，每多开一个出水口，速度即相应线性提高—-本人注）。同时打开3个出水口，水池水位在80秒后会下降到0；同时打开4个出水口，水池水位在50秒后会下降到0；问：如果同时打开8个出水口，水位需要多长时间下降到0？

其实是个很简单的常识，居然搞了我半个小时……

fgetc()的返回值是int，因为这个值除了返回拿到的字符之外，还兼作错误标志。由于fgetc()允许文件中包含任意内容，所以只好增大返回值的宽度来表达。

WxClassInfo的析构函数（~WxClassInfo）死循环是什么原因？检查发现RTTI的那个链表有个环，但是不太明白这个表（从上下文看是由Register()方法维护的）为什么能出现环？

Pretty interesting project: Haiku.

It looks like that it uses a lot of FreeBSD code by creating glue between FreeBSD and BeOS API, on the other hand they are using MIT license for most of their code, making sharing code easy.

I have taken some time to rewrite memchr(3) to utilize similiar algorithm as my strlen(3) did. Two different formular, however, would have a roughly 1/3 difference.

Currently I have taken an approach that when memchr(3) is trying to match a pattern of 8-bit, then consider the string as 8-bit, which uses the first formular which is expected to have uniform O(n) time complexity by reducing unnecessary branches.

This approach, however, might be bogus since if you find 7-bit character within a 8-bit string, in that case, memchr(3) would perform poorly, if there are a lot of characters having their MSB as 1.

今年 1 月 27 日发表的 《GCC运行环境豁免条款 (英文版)》 再次狠狠地打了苹果的耳光。

原先的豁免条款如下：

// As a special exception, you may use this file as part of a free software
// library without restriction. Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License. This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.