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Esta nota de lançamento é um documento com questões conhecidas sobre o Ubuntu 9.04 e suas variantes.

Requisitos do sistema

O requisito mínimo de memória para Ubuntu 9/04 é de 256 MB de memória. Se o seu computador tem apenas a quantidade mínima de memória, o processo de instalação irá demorar mais do que o normal, mas será concluído com êxito e o sistema irá funcionar de forma adequada uma vez instalado.

Sistemas com menos memória podem ser capazes de seleccionar "Instalar o Ubuntu" no menu de inicialização para executar apenas o instalador, em vez de toda a área de trabalho.

Instalação

Pacotes recomendados instalados por padrão

De acordo com o Manual de Políticas Debian (que diz "O domínio 'recomendado' deverá listar os pacotes que podem ser encontrados juntamente nessa e em todos instalações não usuais"), o sistema gestor de pacotes agora instala pacotes listados nas recomendações: domínios de outros pacotes instalados como suas dependências, por padrão. Se você deseja evitar isso para pacotes específicos, utilize apt-get --no-install-recommends; se você deseja fazer isso permanente, estabeleça APT::Install-Recommends "false"; em /etc/apt/apt.conf. Esteja ciente que isso pode resultar em recursos ausentes em alguns programas.

(Essas alterações foram feitas no Ubuntu 8.10.)

Atualização

Usuários do Ubuntu 8.10 podem atualizar para o Ubuntu 9.04 por um conveniente processo automatizado. Usuários de versões mais antigas do Ubuntu necessitam atualizar para o Ubuntu 8.10 primeiro, e então para 9.04. Intruções completas podem ser encontradas em http://www.ubuntu.com/getubuntu/upgrading.

Usuários Kubuntu podem atualizar diretamente do Kubuntu 8.04 para Kubuntu 9.04. Usuários que atualizam desse foram são aconselhados são também aconselhados a ler as notas de versão para Ubuntu 8.10, cujas questões decritas serão também aplicáveis.

Falhas de inicialização em sistemas com placa-mãe Intel D945

Usuários tem relatado a detecção de discos rígidos SATA mais lenta que o nromal em sistemas com placa-mãe Intel D945 no Ubuntu 9.04. Isso pode fazer com que o sistema caia para um shell busybox initramfs na inicialização com um erro "Desistiu-se de esperar pelo dispositivo raiz.". Espere um minuto ou dois a então saia do shell initramfs digitando 'exit'. A inicialização deverá prosseguir normalmente. Se isso não ocorrer, aguarde mais um pouco e tente novamente. Um vez que inicie, edite /boot/grub/menu.lst e adicione rootdelay=90 para a instância kernel do seu atual kernel. (Bug 290153).

Atualizações a partir do beta podem usar LABEL= no /etc/fstab

Systems installed using Jaunty Alpha 5, Jaunty Alpha 6, or the Ubuntu 9.04 beta may use LABEL= syntax in /etc/fstab to identify file systems. This may cause unexpected behaviour later if another disk (such as a USB drive) is added later containing file systems with clashing labels. Unless you are sure that this is what you intend, we recommend that you switch to using universally unique identifiers (UUIDs) instead.

For example, if a file system is identified as LABEL=home in /etc/fstab, you can find the UUID as follows:

blkid -o value -s UUID -l -t LABEL=home

You can then replace LABEL=home with UUID=output, where output is the output of blkid.

Systems installed using the release candidate or final release of Ubuntu 9.04 do not have this problem.

Upgrades from alphas may need re-encryption of encrypted home directories

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 RC 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.

Upgrades from Ubuntu 8.10 may have lilo installed

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. Bug 314004

Setting wireless regulatory domain via module option no longer supported

Ubuntu 9.04 enables the CRDA wireless regulatory framework for controlling which wireless channels are usable and visible in a particular location. If you previously had to use the module option similar to that below in /etc/modprobe.d/options to allow access to certain channels in your locality then you may find that wireless will not function at all:

  • options cfg80211 ieee80211_regdom=EU

You should remove this kernel module option on upgrade to Ubuntu 9.04 and use the iw reg command instead.

Network management applet must be re-added on Kubuntu upgrade

When upgrading from Kubuntu 8.10, the new Network Management applet will need to be added to the panel manually. (Bug 349066)

Click the Plama icon in the bottom right.

Click Add Widget.

Double click on Network Management.

Ctrl-Alt-Backspace disabled by default in Xorg

The Ctrl-Alt-Backspace key combination to force a restart of X is now disabled by default, to eliminate the problem of accidentally triggering the key combination. Users who do want this function can enable it in their xorg.conf, or by running the command dontzap --disable.

Change in notifications of available updates

Ubuntu 9.04 introduces a change to the handling of package updates, launching update-manager directly instead of displaying a notification icon in the GNOME panel. Users will still be notified of security updates on a daily basis, but for updates that are not security-related, users will only be prompted once a week.

Users who wish to continue receiving update notifications in the previous manner can restore the earlier behavior using the following command:

gconftool -s --type bool /apps/update-notifier/auto_launch false

Other known issues

Performance regressions on Intel graphics cards

Users of Intel video chipsets have reported performance regressions in Ubuntu 8.10 compared with previous releases (bug 252094). Many of the issues have been resolved in Ubuntu 9.04, but some remain.

  • Some users have found improved performance by using the "greedy" migration heuristic. This can be done by running "sudo gedit /etc/X11/xorg.conf", and adding Option "MigrationHeuristic" "greedy" to the Device section of your xorg.conf.

  • Alternatively, a new experimental acceleration architecture option, "DRI2/UXA", is available for Intel graphics users which our testing has found provides significant performance improvements in some cases, but has also shown risk of severe stability problems. 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".

    Warning /!\ In some cases this will lead to the graphical environment not starting at all or becoming entirely unusable. In that case, start into rescue mode or press Ctrl+Alt+F2 and log into the text console, and use sudo nano /etc/X11/xorg.conf to revert the UXA option.

  • If none of the above helps, some users reported success with using an older driver version.

Display freezes with Intel graphics cards

Users of Intel video chipsets reported that the display freezes a few minutes after resuming from suspend or hibernate (bug 339091), or under other circumstances. In many cases, switching off desktop effects in System → Preferences → Appearance was reported to help.

If it still happens without desktop effects, you can add Option "DRI" "off" to the Device section of /etc/X11/xorg.conf, as described above. This will disable 3D acceleration and desktop effects, but makes suspend work reliably again and also avoid many types of crashes.

Lock-ups when deleting files from ext4 filesystems

In some cases, deleting files from an ext4 filesystem is reported to cause soft lock-ups in the kernel (330824). Investigation of this problem is ongoing, and it is expected that a fix for this problem will be made available as a post-release update. To avoid this problem, users may wish to install using the default ext3 filesystem and convert their filesystem to ext4 (as documented on the ext4 wiki) once a fix is available.

Switching to ext4 requires manually updating grub

If you choose to upgrade your / or /boot filesystem in place from ext2 or ext3 to ext4 (as documented on the ext4 wiki), then you must also use the grub-install command after upgrading to Ubuntu 9.04 to reinstall your boot loader. If you do not do this, then the version of GRUB installed in your boot sector will not be able to read the kernel from the ext4 filesystem and your system will fail to boot.

Occasional hangs possible on ARM architecture

The ARM port currently does not support the ppoll() & pselect() system syscalls, which will sometimes cause a failure to mount the root filesystem on boot. This is a race condition, and retrying the boot will usually clear the problem. The work to add the syscalls is currently underway and will be delivered as an update to the Ubuntu 9.04 kernel some time after release.