Ubuntu的下一個版本Ubuntu 9.04(Jaunty Jackalope)，已經發行Beta 公開版本，Ubuntu 9.04正式版則預計在2009年4月23日發行。
Ubuntu Linux簡介
Ubuntu是一個免費的Linux作業系統發行版，提供桌面版、伺服器版、多媒體平台版等各種版本，每半年改版更新一次，免費更新，功能大多數都超越Windows平台產品，安全性、穩定性與系統資源的善用程度也較佳。
開機一段時間後，這個有使用Compiz 3D桌面的系統，基本用掉的記憶體大約只有200MB上下不等。而我另一台沒使用Compiz的電腦，開機後的記憶體使用量只有165MB左右。
即便是在終端機下指令free -m來做比較，系統實際使用的記憶體也和Gnome系統監控叫出來的差異不大，還是比Windows少非常非常多，其記憶體管理效率也較佳。
開啟了Pidgin(MSN)、Firefox 3、OpenOffice.org 3.0.1開啟excel檔案後，系統記憶體增加到350MB左右。我在大多數情況下用了5、6個小時，Firefox分頁開到20幾個，工作用的doc檔、xls檔，開啟影像處理圖檔、Pidgin等訊息後，記憶體的使用亮也約莫在600MB左右，並不會很耗系統資源，與Windows的速度緩慢有很大的差異。
Ubuntu是由南非富商Mark Shuttleworth創辦的Canonical公司，以及許多全球性的開源社群，大小公司一起打造的Linux作業系統發行版，不只是個人用，也提供給企業使用。
Ubuntu 9.04重要特點
Ubuntu 9.04的開機時間改善加快，具備更好的燒錄軟體、改善的螢幕顯示與解析度調整，並支援了EXT4檔案系統(安裝時可選ext4，Gparted也可ext4格式化)，X.Org server 1.6、支援雲端運算、Turn-key郵件伺服器、新的字體大小最佳化與新的桌面訊息通知系統與通知樣式等等。
開機時間我以在公司用的電腦為例測試，/boot為ext3磁區，其他則是xfs磁區，開機完成的時間只要27秒，開機檔案傳輸最高達97MB/s。如果是改用ext4磁區，開機速度會更快。
接著，上面這張圖是家中的AMD雙核心處理器電腦，使用的是EXT4檔案系統，開機時間只要18秒，比前一張圖快了9秒左右，滿驚人的改進。
Ubuntu 9.04目前使用的Linux核心版本是Linux Kernel 2.6.28-11.38 kernel (基於Linux核心2.6.28.8) 。GNOME桌面環境已經更新到2.26。
Ubuntu 9.04正式發行日期
預計Ubuntu Linux 9.04 RC版則是4月16日，Ubuntu Linux 9.04正式版則在4月23日公開釋出。
歡迎想試試看新一代Linux桌面系統的人，建議是對Linux有經驗，且有興趣的使用者，碰到問題時，比較容易從網路上找到解決方法。
Ubuntu 9.04更新與下載
從Ubuntu 8.10升級上來到9.04很簡單，只要按下Alt+F2，輸入update-manager -d後，按下Enter，按照指示進行即可。
以下是Ubunt 9.04 Beta各個版本的iso檔下載，燒錄成光碟或利用工具usb-creator寫到USB隨身碟後，就可以用光碟片或USB隨身碟開機進行安裝。
一般來說，請下載(Ubuntu Desktop and Server) ubuntu-9.04-beta-desktop-i386.iso這個檔案來使用。
http://releases.ubuntu.com/releases/9.04/ (Ubuntu Desktop and Server)
http://releases.ubuntu.com/releases/edubuntu/9.04/ (Ubuntu Education Edition)
http://releases.ubuntu.com/releases/kubuntu/9.04/ (Kubuntu)
http://cdimage.ubuntu.com/releases/9.04/beta/ (Ubuntu Netbook Remix and Ubuntu MID)
http://cdimage.ubuntu.com/xubuntu/releases/9.04/beta/ (Xubuntu)
http://cdimage.ubuntu.com/ubuntustudio/releases/9.04/beta/ (UbuntuStudio)
http://cdimage.ubuntu.com/mythbuntu/releases/9.04/beta/ (Mythbuntu)
http://cdimage.ubuntu.com/netboot/9.04/beta/ (Ubuntu ARM)
延伸閱讀：
Ubuntu Linux vs Windows Vista vs Windows 7部份項目大評比
Ubuntu 9.04(Jaunty Jackalope) Alpha 4使用初感
Ubuntu 9.04(Jaunty Jackalope) Alpha 4開放下載，支援ext4安裝
Ubuntu 9.04(Jaunty Jackalope) Alpha 5釋出，越來越穩定
Ubuntu 9.04(Jaunty Jackalope) Alpha 6釋出
目前Ubuntu 9.04 Beta 已知問題：
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A bug in an Ubuntu-specific patch to X server logging code will cause X sessions to crash after they have been running for longer than a day. Users encountering this bug should upgrade to the latest version of the xserver-xorg-core package, which will be available immediately after the beta release. 328035.
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Some users of Intel i8x5 video chipsets are unable to load X, getting an error message of "Fatal server error: Couldn’t bind memory for BO front buffer". As a workaround, use the VESA driver by logging into a text console, running "sudo nano /etc/X11/xorg.conf", and adding the line Driver "vesa" to the Device section. An alternative (experimental) workaround is to use the UXA acceleration method (see below). If in doubt, please do not upgrade to Ubuntu 9.04 Beta yet. 304871
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Users of Intel video chipsets have reported performance regressions in Ubuntu 8.10 compared with previous releases. (252094) Although these performance issues have not been resolved by default in Ubuntu 9.04, a new experimental acceleration architecture option, DRI2/UXA, is available for Intel graphics users. Our testing has found this provides significant performance improvements for many users, but has also shown risk of severe stability problems, thus we are not yet providing to the general public. You can opt-in to enable this by running "sudo gedit /etc/X11/xorg.conf", and adding Option "AccelMethod" "UXA" to the Device section of your xorg.conf. Users wishing to maximize stability should stay with the standard default acceleration method, "EXA".
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Ctrl-Alt-Backspace is now disabled, to reduce issues experienced by users who accidentally trigger the key combo. Users who do want this function can enable it in their xorg.conf, or via the command dontzap –disable.
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Ubuntu 8.10 systems installed from the desktop CD mistakenly had the lilo package installed as well as grub, although grub was used for booting. If you use the recommended Update Manager upgrade method, then the lilo package will be removed if it does not appear to be used. If you upgrade using some other method and are sure that you only use the GRUB boot loader, then we recommend that you remove the lilo package manually. 314004
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On the timezone map in the desktop CD installer, the markers for cities are displaced from their correct locations. Users should be aware of this issue when selecting their timezone. This bug will be resolved for daily builds immediately after the 9.04 Beta. 334284
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If any filesystems are mounted when starting the desktop CD installer, then a dialog labelled "Unmount partitions that are in use?" will be presented. Unfortunately, the buttons on this dialog box are poorly named: "Continue" attempts to unmount filesystems and then repeats, which will often just display the same dialog box again, while "Go Back" ignores this condition and continues. This will be corrected for the final release. 346589
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On desktop installations from USB disks, such as typical Ubuntu Netbook Remix installations, the installer displays a warning about the fact that the installation medium itself (often /dev/sdb) is mounted. This warning is unnecessary, because the fact that it is mounted is completely normal, and does not interfere with the user’s ability to install the system to devices other than the USB disk itself. You should ignore this warning; note that in order to do so you will need to select "Go Back", due to the issue above. 347916
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In some cases, the "Prepare Disk Space" screen in the desktop installer displays obviously incorrect partition sizes in its graphical disk previews. This is only an error in the preview and does not reflect a problem with the partitioning changes that will actually be applied. 336203
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The mythtv frontend in mythbuntu fails to render fonts correctly when using video drivers other than the Intel or closed-source nVidia drivers. This issue is expected to be resolved for the final 9.04 release. 341898
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When installing to a system with another OS previously installed, the migration assistant will offer to migrate settings and documents even when the entire disk is being overwritten. The migration assistant will not be able to preserve documents when using the entire disk for installation. 339898
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Users who were running eCryptfs on the Jaunty Alpha milestones are advised to re-encrypt any encrypted files. An upstream 2.6.28 kernel bug caused random kernel memory to be written to eCryptfs encrypted file headers. The fix has been applied and deployed to Ubuntu users in the Jaunty Beta kernel. Ubuntu eCryptfs users running this kernel should re-encrypt each encrypted file using /usr/bin/ecryptfs-rewrite-file. For more information, please see ecryptfs-rewrite-file(1). See 345544.
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Users of Compaq Smart Array controllers will be unable to remove existing LVM volumes using the partitioner in the installer. 341928
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The mdadm package in Ubuntu 9.04 Beta will fail to assemble RAID10 arrays on boot. Other types of RAID are not affected; investigation of this issue is ongoing. 316670
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Booting degraded RAID may fail in virtual-machine setups where the host is running with cpu frequency scaling enabled, due to a non-deterministic race condition, 334994. Booting degraded RAID on physical hardware should not be affected, since the cpu frequency is constant through the hard disk detection process.
- Upgrading a desktop system using an ATI video chipset with the fglrx binary-only driver may result in a warning that the driver needs to be replaced. There is a bug in the driver replacement logic, so if you see this prompt, please cancel the upgrade until this is fixed, which will happen immediately after the beta release.
