Tuesday, February 24, 2009

Zoho Creator AppEngine Extension

Zoho Creator is a powerful Web application development tool. It can export project to Google AppEngine also. But you will be disappointed if you want to do any real task with the exported code, because there are some IMPORTANT LIMITS besides the ones mentioned officially:

* Some important actions against records are removed, including DELETE, UPDATE and SEARCH
* Data access is executed in a very expensive way, and has a limitation of 1000 record for each table
* No support for 1:N mapping between tables

There are some minor issues also:

* Values of input fields are not escaped

But as a developer without good skill of UI, I still prefer to create prototypes with Zoho Creator for RAD. It's not difficult to hack the exported code with Python, HTML and Javascript. But, the interacted development with Zoho Creator and local development tools is still a big challenge. So I started to develop a toolkit with can be used with this type of project:

* One-way update from Zoho Creator to local project
* Minimized changes to code generated by Zoho Creator
* Implementations of the missed features and fixes of known bugs of generated code
* A framework for further development

Following are some tools and skills I will use:

* jQuery powered JS library for Web page hack(minimizing the changes to generated source code)
* Regexp based code converting tools to apply changes to the generated code
* Diff for one-way update

Of cause, Zoho won't like my hacks, they want to keep user playing with their hosting service rather than exporting projects to Google AppEngine. But, we all know there will be some RAD tools for AppEngine soon or later. So, why don't Zoho take the chances of becoming a leader of this trend?

Update: Now, I don't think the AppEngine code generated with Zoho Creator is a serious implementation. I prefer to hang it up before it can handle a real task.

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Sunday, February 22, 2009

家用文件服务器

这两天开始考虑攒个文件服务器了。总的来说作了以下几个方面权衡:

* 备选功能
** 文件服务
** 网络应用服务
** VM Host
** 视频播放,不要求支持 HD
** DVD Burning
* 系统架构
** Atom
** Athlon BE,据说(http://www.pcpop.com/doc/0/373/373434_4.shtml) AMD 功耗更低
* FS, RAID 策略, 有同学(http://www.tummy.com/journals/entries/jafo_20080705_130814)报告说 FUSE ZFS 能用,还说 RAID-Z 好
* 功耗和噪音,貌似(http://bbs.pcpop.com/070101/781254-1.html)硬盘(3到5块)将是大头
* 机箱,要够大
* 电源,为了硬盘,需要提供至少 200W 的电源
* HDD, 初期至少 SATA x 2 + IDE x 1 (我那闲置了大半年的 600G), 还得要个硬盘架
* DVD-RW,要光雕的


配置 品牌型号 数量 单价 选用
*CPU
AMD Athlon64 X2 BE-2300(散) 1 ¥ 260
*主板
梅捷 SY-N73V-RL 1 ¥ 280
*内存
金士顿 2GB DDR2 800(窄板) ¥ 120
*硬盘
日立 1TB 7200转 7K1000 ¥ 650
显卡

声卡
1 ¥
光驱
LG 22速光雕锁码刻GH22LP20 1 ¥ 195
网卡
1 ¥
CRT
1 ¥
LCD
1 ¥
*机箱
技展 9011 1 ¥ 398
电源
先马 腾雾辉煌版(静音型)ATX-325-6 1 ¥ 148
鼠标
1 ¥
键盘
1 ¥
键鼠装
1 ¥
音箱
1 ¥
散热器
1 ¥
操作系统
1 ¥
办公软件
1 ¥
合计金额:2701 元

硬盘架,带热插拔的 400+,不带的 100+。

看来钱都是花在存储上了。机箱电源还要好好学习一下,据说单相电源省电,但那彪悍的硬盘组恐怕是要三相伺候的。

3000 RMB 的 File Server ,算是够有诚意了吧。要是放办公室,我就弄个 4U 的机箱,管他多大声呢。

Update:
* 有人说日立那块硬盘功率才 9W,那么我用 100W 的电源就够了?
* 有小朋友在讨论双路电源

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