OpenSolaris:
-開放原始碼
-有龐大的社群支援
-可以散播
-License採CDDL方式
-每六個月版本更新週期
-一般比Solaris版本要新,可以說是體驗版,不保證穩定度
-自己study, try & error,加入社群

Solaris:
-非開放原始碼
-個人使用免費
-由SunMicrosystem提供的技術支援與專業服務,及教育訓練
-有應用軟體廠商的認證
-屬於穩定版本才會release,因此版本更新較慢

基本上它就是Solaris
但是一些新功能都會先透過Open版本釋出,等到穩定後,才會放入商業版
至於維護則是只針對商業版,Open版本就透過社群熱心人士為之

關於考 SCSA 的部份，我是在使用 OpenSolaris 當我的筆記型電腦的作業系統(以前是用 Linux)約一年後去考的。有幾點要注意的是：

1. 有些功能是在 OpenSolaris 上才有的，千萬別記錯。
2. 可以在 OpenSolaris 上安裝 xVM VirtualBox。如此您可以同時享受 OpenSoalris 的新功能並測試 Solaris 10。
3. 建議還是要有考試相關的學習教材或參加學習課程。

若要免費測試一下：
Sun's Free Proficiency Assessment System

若是對 OpenSolaris 有興趣，推薦您以下幾個網址：
OpenSolaris.org - OpenSolaris 開發社群
OpenSolaris.com - OpenSolaris 使用社群
OpenSolaris 使用者社群
OpenSolaris Indiana
鳥哥的新手討論區
太陽能(Solar Power)

1. Put this way, OpenSolaris is like Fedora for RHEL (Redhat Enterprise Linux), OpenSuse for Suse Enterprise. OpenSolaris is a community OS for collabrative and new functions purpose instead of stable Production environment OS. It may be buggy and not stable since it not focused on professional Support and maintenance & OS QA.
2. Learned from different ways, SxNY Asia has decided to move all of Solaris OS ( 8, 9, 10) from Sun Box to Linux platform in HP Proliant servers ( about 200 units ). Panxsonic also decomm all of Sun Box into RHEL boxes ( 150 units ).
3. Compared with Linux and Solaris10, you will find out Solaris Volume Manager is very difficult to be configured which compares with Linux LVM. Most of production Solaris boxes have to buy Vertias Volume Manager which is an extra cost.
4. Good time of Sun Microsystem is no more. In May, Sun retrenched 2,400 staff. In November, it will retrench 6,000 head count due to poor server performance and wrong business approach.
5. In fact, compared with less downtime in Unix/Linux/Windows environment:
   AIX > Suse > HP-UX > Solaris > Redhat > Windows 2003 > Windows 2000, Suse is better than Solaris