5.4. Resolució de problemes del procés d'instal·lació

5.4.1. Reliability of optical media

Sometimes, especially with older drives, the installer may fail to boot from an optical disc. The installer may also — even after booting successfully from such disc — fail to recognize the disc or return errors while reading from it during the installation.

Aquests problemes són deguts a diferents causes. Tan sols podem llistar alguns dels problemes coneguts i donar suggeriments de com podeu tractar-los. La resta és cosa vostra.

Hi ha dues coses molt senzilles que podeu provar.

  • If the disc does not boot, check that it was inserted correctly and that it is not dirty.

  • If the installer fails to recognize the disc, try just running the option Detect and mount installation media a second time. Some DMA related issues with very old CD-ROM drives are known to be resolved in this way.

If this does not work, then try the suggestions in the subsections below. Most, but not all, suggestions discussed there are valid for CD-ROM and DVD.

If you cannot get the installation working from optical disc, try one of the other installation methods that are available.

5.4.1.1. Problemes usuals

  • Algunes unitats de CD-ROM velles no suporten la lectura de discs que es van gravar a altes velocitats utilitzant una gravadora de CD moderna.

  • Algunes unitats de CD-ROM velles no funcionen correctament si està activat l'«accés directe a memòria» (DMA).

5.4.1.2. Com investigar i potser resoldre alguns problemes

If the optical disc fails to boot, try the suggestions listed below.

  • Check that your BIOS actually supports booting from optical disc (only an issue for very old systems) and that booting from such media is enabled in the BIOS.

  • If you downloaded an iso image, check that the md5sum of that image matches the one listed for the image in the MD5SUMS file that should be present in the same location as where you downloaded the image from.

    $ md5sum debian-testing-i386-netinst.iso
    a20391b12f7ff22ef705cee4059c6b92  debian-testing-i386-netinst.iso
    

    Next, check that the md5sum of the burned disc matches as well. The following command should work. It uses the size of the image to read the correct number of bytes from the disc.

    $ dd if=/dev/cdrom | \
    > head -c `stat --format=%s debian-testing-i386-netinst.iso` | \
    > md5sum
    a20391b12f7ff22ef705cee4059c6b92  -
    262668+0 records in
    262668+0 records out
    134486016 bytes (134 MB) copied, 97.474 seconds, 1.4 MB/s
    

If, after the installer has been booted successfully, the disc is not detected, sometimes simply trying again may solve the problem. If you have more than one optical drive, try changing the disc to the other drive. If that does not work or if the disc is recognized but there are errors when reading from it, try the suggestions listed below. Some basic knowledge of Linux is required for this. To execute any of the commands, you should first switch to the second virtual console (VT2) and activate the shell there.

  • Canvieu al VT4 o mireu els continguts del fitxer /var/log/syslog (utilitzeu el nano com a editor) per comprovar qualsevol missatge d'error específic. Després, comproveu la sortida del l'ordre dmesg.

  • Check in the output of dmesg if your optical drive was recognized. You should see something like (the lines do not necessarily have to be consecutive):

    ata1.00: ATAPI: MATSHITADVD-RAM UJ-822S, 1.61, max UDMA/33
    ata1.00: configured for UDMA/33
    scsi 0:0:0:0: CD-ROM            MATSHITA DVD-RAM UJ-822S  1.61 PQ: 0 ANSI: 5
    sr0: scsi3-mmc drive: 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray
    cdrom: Uniform CD-ROM driver Revision: 3.20
    

    If you don't see something like that, chances are the controller your drive is connected to was not recognized or may be not supported at all. If you know what driver is needed for the controller, you can try loading it manually using modprobe.

  • Check that there is a device node for your optical drive under /dev/. In the example above, this would be /dev/sr0. There should also be a /dev/cdrom.

  • Use the mount command to check if the optical disc is already mounted; if not, try mounting it manually:

    $ mount /dev/hdc /cdrom
    

    Check if there are any error messages after that command.

  • Check if DMA is currently enabled:

    $ cd /proc/ide/hdc
    $ grep using_dma settings
    using_dma      1       0       1       rw
    

    A «1» in the first column after using_dma means it is enabled. If it is, try disabling it:

    $ echo -n "using_dma:0" >settings
    

    Make sure that you are in the directory for the device that corresponds to your optical drive.

  • If there are any problems during the installation, try checking the integrity of the installation media using the option near the bottom of the installer's main menu. This option can also be used as a general test if the disc can be read reliably.

5.4.2. Configuració de l'arrencada

Si teniu problemes i el nucli es penja durant l'arrencada, no reconeix els perifèrics o les unitats no es reconeixen com cal, primer de tot comprovau els paràmetres d'arrencada, tal com s'indica a Secció 5.3, «Paràmetres d'arrencada».

En molts casos, el funcionament incorrecte por ésser causat per què el dispositiu no disposa de microprogramari («firmware») (llegiu Secció 2.2, «Dispositius que requereixen microprogramari» i Secció 6.4, «Carregar microprogramari no inclòs a l'instal·lador»).

5.4.3. Com interpretar els missatges del nucli durant l'arrencada

Durant la seqüència d'arrencada, podeu veure nombrosos missatges del tipus can't find quelcom, o quelcom not present, can't initialize quelcom, o fins i tot this driver release depends on quelcom. No us heu de preocupar per la majoria d'aquests missatges. Els veieu perquè el nucli del sistema d'instal·lació s'ha fet perquè funcione a ordinadors amb molts dispositius perifèrics diferents. Òbviament, cap ordinador té tots els dispositius possibles, per tant el sistema operatiu potser es queixarà en cercar perifèrics que no hi ha. Potser veureu també que el sistema fa una pausa momentània. Això ocorre quan s'espera la resposta d'un dispositiu i aquest no hi és. Si trobeu que hi triga massa, podeu fer-vos després un nucli a mida (vegeu Secció 8.5, «Compilar un nou nucli»).

5.4.4. Informar d'errors d'instal·lació

If you get through the initial boot phase but cannot complete the install, the menu option Save debug logs may be helpful. It lets you store system error logs and configuration information from the installer on a storage medium, or download them using a web browser. This information may provide clues as to what went wrong and how to fix it. If you are submitting a bug report, you may want to attach this information to the bug report.

Podeu trobar altres missatges d'instal·lació pertinents a /var/log/ durant la instal·lació, i a /var/log/installer/ després que l'ordinador s'haja arrencat en el sistema ja instal·lat.

5.4.5. Emissió d'informes d'error

Si encara teniu problemes, podeu enviar un informe d'instal·lació. Us animem a enviar també informes en cas que la instal·lació haja reeixit, per poder disposar de la major quantitat d'informació possible sobre el major nombre de configuracions de maquinari.

Fixeu-vos que el vostre informe d'instal·lació es publicarà al Sistema de seguiment d'errors de Debian (BTS) i s'enviarà a una llista de correu pública. Assegureu-vos d'utilitzar una adreça de correu que no us importe fer pública.

Si teniu un sistema Debian en funcionament, la manera més fàcil d'emetre un informe d'instal·lació és instal·lar els paquets installation-report i reportbug (apt-get install installation-report reportbug) i configurar reportbug tal com s'explica a Secció 8.4.2, «Enviar correus fora del sistema», executant l'ordre reportbug installation-reports.

Alternatively you can use this template when filling out installation reports, and file the report as a bug report against the installation-reports pseudo package, by sending it to .

Package: installation-reports

Boot method: <How did you boot the installer? CD/DVD? USB stick? Network?>
Image version: <Full URL to image you downloaded is best>
Date: <Date and time of the install>

Machine: <Description of machine (eg, IBM Thinkpad R32)>
Processor:
Memory:
Partitions: <df -Tl will do; the raw partition table is preferred>

Output of lspci -knn (or lspci -nn):

Base System Installation Checklist:
[O] = OK, [E] = Error (please elaborate below), [ ] = didn't try it

Initial boot:           [ ]
Detect network card:    [ ]
Configure network:      [ ]
Detect media:           [ ]
Load installer modules: [ ]
Detect hard drives:     [ ]
Partition hard drives:  [ ]
Install base system:    [ ]
Clock/timezone setup:   [ ]
User/password setup:    [ ]
Install tasks:          [ ]
Install boot loader:    [ ]
Overall install:        [ ]

Comments/Problems:

<Description of the install, in prose, and any thoughts, comments
      and ideas you had during the initial install.>

In the bug report, describe what the problem is, including the last visible kernel messages in the event of a kernel hang. Describe the steps that you did which brought the system into the problem state.