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4. ±`°Ý°ÝÃD¤Îµª®×

4.1 "¿N¿ýµ{§Ç¦³¦h±Ó·P"

µª®×¡G³o´N­n¬Ý§Aªº¿N¿ý¾¹¤F¡C³q±`¸û·sªº«¬¸¹³£·|¦³ 1MB ©Î§ó¦h¡A³o¼Ë¥¦«K¥i¥H ¤ä«ù 1-2 ¬í¨S¦³¸ê®Æ¡C¦pªG§A·Q±o¨ì§ó¦hªº¸ê®Æ§A¥i¥H°Ý¥Í²£°Ó©Î¬Ý¬ÝµwÅé¤â¥U¡C

¤£ºÞ¨º¨Ç¸ê®Æ½w½Ä¾¹ªº¤j¤p¦p¦ó§A³£»Ý­n«OÃÒ¤@­Óªø®É¶¡ 300 kb/s ©Î 600 kb/s ªº¸g±` ¿é¥X¡C

¤@¨ÇµwºÐ±K¶°ªº¤u§@¨Ò¦p§ó·s locate-¸ê®Æ®w¡C ´î§C maxium flow rate ´NªÖ©w·|·lÃa§Aªº¥úºÐ¡F§A³Ì¦n¦b¿N¿ý¥úºÐ«e¥Î cron¡A at ©Î anacron ¨ÓÀˬd¤@¤U§A¦³§_°õ¦æ³o¨Ç¤u§@¡C

¥t¤@¤è­±¡A¦³¨Ç¤H»¡¥L­Ì¯à¤@­±½sĶ®Ö¤ß¤@­±¿N¿ý¥úºÐ³£¨S¦³¥ô¦ó°ÝÃD¡C ªº½T§A­n¤@³¡«Ü§Öªº¾÷¾¹¤~¯à°µ³o­Ó¹êÅç¡C

4.2 "fragmentation ·|§_¼vÅT¿é¥X©O¡H"

Fragmentation ³q±`³£¤£·|¼vÅT¿é¥X¡C¤£¹L§A¥i¥H«Ü®e©ö¨î³y pathological cases of fragmentation ¨Ó´î§C§AªºµwºÐ¿é¥X¤j¬ù 100 kbyte/second¡C©Ò¥H¤d¸U¤£­n³o¼Ë°µ¡C:-)

¬Oªº¡A§AªºµwºÐ·| fragmented ¸g¹L¸g¦~ªº¨Ï¥Î¡C¦pªG¶V§Öfragmented¡A¨ºÀɮרt²Î«K¶V º¡¡C¸g±`«O«ù 10% ©Î 20% ªºªÅ¶¡¡A³o¼Ë¿N¿ý¥úºÐ«K¨S¦³°ÝÃD¤F¡C

¦pªG§A¤£ªÖ©wªº¸Ü§A¥i¥H¬Ý¬Ý±Ò°Ê®Éªº°T®§¡A§A´N¥i¥H¬Ý¨ì§AªºÀɮרt²Î¦³´X¦hºÏºÐªÅ¶¡ fragmentation ªº¦Ê¥÷¤ñ¡C§A¥i¥H¥Î¤@­Ó«D±`¦MÀIªº«ü¥O

shell> e2fsck -n  /dev/sda5        # '-n' is important!
[stuff deleted - ignore any errors]
/dev/sda5: 73/12288 files (12.3% non-contiguous)

¦b³o­Ó½d¨Ò¤¤ºÏºÐªÅ¶¡¦ü¥G«D±`ÃP´² ¢w ¤£¹L³oùØ¥u¦³ 73 ­Ó«D±`¤pªºÀɮצb³o ­ÓÀɮרt²Î¤¤¡A©Ò¥H³o­Ó¥u¤£¹L¬O¤@­Ó«Ü¤Öªº­È¡C

²{¦b¦³¤@­Ó¹êÅç©Êªº¤u¨ã³n¥ó¥s°µ e2defrag ¥¦¥i¥H¥Î¨Ó defragment extended-2 Àɮרt²Î¡C¤£¹L²{¦bªºª©¥»¦b¨p¤HÀô¹Ò¤¤ÁÙ¬O¤£°÷í©w¡C¦pªG§A¯u·Q defragment §A ªºÀɮרt²Î¡A½Ð¥ý³Æ¥÷ (³Ì¦n¡G¨â¥÷)¡A¹Á¸Õ restore ³Æ¥÷¡AµM«á«Ø¥ß¤@­Ó·sªºÀɮרt ²Î (·|¯}Ãa¦³ªº) ³Ì«á¦A restore ³Æ¥÷¡CÁ`¤§³o¬O³Ì¦w¥þªº§Þ¥©¡C

4.3 "¬O§_¥i¥H±N¥úºÐ¼v¹³ÀÉÀx¦s¦b UMSDOS Àɮרt²Î¤¤©O¡H "

¥i¥H¡C¥u¦³¤@­ÓÀɮרt²Î¬O¤£¯à¥i¾a©M§Ö³t¨Ó¿N¿ý¥úºÐªº¡A³o´N¬O network filesystem (NFS)¡C

§Ú²{¦b¬O¦b¤@³¡ (486/66) PC ¤¤¨Ï¥Î UMSDOS ¨ÓÅýLinux ©M DOS/Win ¦@¨ÉºÏºÐ ªÅ¶¡¡A¦Ó³o³¡ 486 ¬O±Mªù¨Ó¿N¿ý¥úºÐ¥Îªº¡C

4.4 "¦³µL¤èªk¥i¥H§JªA iso9660 ªº­­¨î¡H"

¥i¥H¡C§A¥i¥H¥Î¥ô¦ó¤@­ÓÀɮרt²Î¨Ó¿N¿ý¥úºÐ¡C¤£¹L§A¤£¯à¦b¨ä¥Lªº¾Þ§@¨t²Î¤¤¨Ï ¥Î³o°¦¥úºÐ¡C

¥Î³o­Ó¤èªk´N¦æ¤F¡G

¦p§x§A·Q¦b/etc/fstab ¥[¤@­Ó¥X¤J¤fµ¹¨º°¦¥úºÐªº¸Ü¡A§A«K»Ý­n¨ú®ø¹ï¨º°¦¥ú ºÐªºÀˬd¡A¨Ò¦p¡G

/dev/cdrom  /cdrom  ext2  defaults,ro  0 0

²Ä¤@­Ó¹s¥Nªí "¤£­n¥]§t¦b dumps" ¡A²Ä¤G­Ó¹s¥Nªí "¦b±Ò°Ê®É¤£­nÀË¿ù»~" ( fsck ±N¤£·|Àˬd¥úºÐ¤ºªº¿ù³B ) ¡C

4.5 "«ç¼ËŪ¨ú¤Î¼g¤J­µ¼Ö¥úºÐ¡H"

²{¦b¦³¦h­Ó³n¥ó¡C³Ì·sªº¥s§@ "cdpranoia" ¥¦¥i¥H¦b¥H¤U¦a¤è¤U¸ü

http://www.mit.edu/afs/sipb/user/xiphmont/cdparanoia/index.html

©ÎªÌ§A¥i¥H¹Á¸Õ "cdda2wav" ©M "sox" ªº²Õ¦X¡A¥i¥H¦b sunsite ©M¥¦ªº mirror ¤¤¨ú±o

ftp://sunsite.unc.edu/pub/Linux/apps/sound/cdrom/cdda2wav0.71.src.tar.gz

ftp://sunsite.unc.edu/pub/Linux/apps/sound/convert/sox-11gamma-cb3.tar.gz

cdda2wav ¥O§A¥i¥H¥Ñ¥úºÐ¤¤§ì¨ú¨ì¤@¬q¯S©wªº(©Î¤@¾ã±ø)­µ­yµM«á¥i¥H ±N¥¦Âର .wav ÀɮסC sox ¥i¥H±N wav ÀÉ®×Âà¦^­µ¼Ö¥úºÐªºcdda ®æ¦¡¡A µM«á¥i¥H¥Î cdwrite ±N¥¦¿N¿ý¦b¥úºÐ¤W¡C ¦pªG§A¬O¨Ï¥Î³Ì·sª©¥»ªºcdrecord ¡A§A«K¤£»Ý­n¨Ï¥Î sox ¦]¬° cdrecord ¤w¤º¸m¤ä´© .au ©M .wav ÀɮסC

4.6 "±Ò°Ê¨t²Î«á«ç¼Ë§ä´MSCSI-devices?"

drivers/scsi/scsi.c ¦³©Ò»Ý­nªº¸ê®Æ¡C

/*
 * Usage: echo "scsi add-single-device 0 1 2 3" >/proc/scsi/scsi
 * with  "0 1 2 3" replaced by your "Host Channel Id Lun".
 * Consider this feature BETA.
 *     CAUTION: This is not for hotplugging your peripherals. As
 *     SCSI was not designed for this you could damage your
 *     hardware !
 * However perhaps it is legal to switch on an
 * already connected device. It is perhaps not
 * guaranteed this device doesn't corrupt an ongoing data transfer.
 */

Please note that this should only be used if your add SCSI-devices at the end of the chain. Inserting new SCSI-devices into an existing chain disturbs the naming of devices (directory /dev) and may destroy the complete content of your harddisk.

4.7 "¥i¥H¶i¦æ¤@¹ï¤@ªº¥úºÐ½Æ»s¡H"

¥i¥H¡C¤£¹L§A­nª`·Nªº¬O¦pªG·íŪ¨ú¥úºÐ®É¦³¥ô¦óªº¿ù»~µo¥Í¡A³£¥i¯à¥OªW¼g¥¢±Ñ¡C

²Ä¤@­Ó±¡ªp¡G§A¦³¤@­Ó¥i¼g¥úºÐ¾÷©M¤@­Ó°ßŪ¥úºÐ¾÷¡C§A¥i¥H¥Î¥H¤Uªº«ü¥O

cdwrite -v -D /dev/sgc --pad -b  $(isosize  /dev/scd0) /dev/scd0
or
cdrecord -v dev=3,0 speed=2 -isosize /dev/scd0

§A¥i¥H±q/dev/scd0 Ū¨ú¸ê®Æ¬yµM«áª½±µ¸g¥Ñ/dev/sgc ¼g¤J¥úºÐ¤¤¡C

²Ä¤G­Ó±¡ªp¡G§A¨S¦³¥t¤@­Ó°ßŪ¥úºÐ¡C§A«K»Ý­n¥Î¥i¼g¥úºÐ¾÷¨ÓŪ¨ú¥úºÐ¡G

dd if=/dev/scd0 of=cdimage bs=1c count=`isosize  /dev/scd0`

³o­Ó«ü¥Oµ¥¦P©ó mkisofs ¡A©Ò¥H§A¥i¥H¥Î²Ä¤T³¹©Ò´£¤Îªº¤èªkÄ~Äò ¾l¤Uªº¤u§@¡C½Ðª`·N³o­Ó¤èªk¬O¤£¾A¥Î©ó­µ¼Ö¥úºÐ¡C

4.8 "Linux ¥i¤£¥i¥HŪ¨ú Joliet ¥úºÐ¡H"

¥i¥H¡C³Ì·sªº®Ö¤ß (2.0.36 ©M¥H«á) ¤w¤º¸m¤ä´© joliet ®æ¦¡¡C½Ð°OµÛ§A­n¦b /etc/fstab ¤¤¨Ï¥Î iso9660 ©M joliet ¨â­Ó¿ï¶µ¡C­n¨ú±o§ó¦h¸ê®Æ¡A§A¥i¥H¬Ý http://www-plateau.cs.berkeley.edu/people/chaffee/joliet.html.

4.9 "«ç¼Ë¥Î¥i¼g¥úºÐ¾÷Ū¨ú¥úºÐ¡H"

´N¦p¦P§A¨Ï¥Î´¶³q°ßŪ¥úºÐ¾÷¤@¼Ë¡C¨S¦³¥ô¦óªº¯S§O¡Cª`·N§A­n¨Ï¥Îscd-devices (°ßŪ¥úºÐ¾÷) ¨ÓŪ¨ú¥úºÐ¡C¥H¤U«K¬O¦b/etc/fstab ¤¤ªº½d¨Ò¡G

/dev/scd0  /cdrom  iso9660  ro,user,noauto  0  0

4.10 "«ç¼Ë©ñ¦h¨Ç¸ê®Æ¨ì¥úºÐ¤¤¡H"

¥Î bzip2 ¥H¨ú¥N¨ä¥LªºÀ£ÁY¾¹¦n¹³ gzip ©Î pkzip¡C³o·|¸`¬Ù30%ªººÏºÐªÅ¶¡¡C§A¥i¥H¦b¥H¤U¦a¤è¤U¸ü

http://www.muraroa.demon.co.uk/

Instead of writing a true audio-CD, you can optionally convert your wav-audio-files into mp3-audio-files and store them on a ISO-9660 filesystem as regular files. Usually MPEG III gives you a compression of 1:10.

Of course, most CD-players are not able to read files... this is the drawback. On the other hand, why not running the music for your next party from harddisk? 18 Gbyte are enough for 3000-4000 titles. :-)

A software MPEG III-encoder is available from

http://www.stud.ifi.uio.no/~larsi/other/8hz-mp3-cheng.tar.gz

A MPEG III-player is available from

http://homepages.uni-tuebingen.de/student/michael.hipp/mpg123/

For recorded speech, you may want to try to reduce its size using shorten or "GSM lossy speech compression":

ftp://svr-ftp.eng.cam.ac.uk/pub/comp.speech/

http://kbs.cs.tu-berlin.de/~jutta/toast.html

4.11 "How to make bootable CD-ROMs?"

You must have an 1.44 MB bootable floppy-disk. Create an exact image of this floppy-disk by issuing the command

dd if=/dev/fd0 of=boot.img bs=18k

Place this floppy-image into the directory holding the collection of your files (or into a subdirectory of it, just as you like). Tell mkisofs about this file with the option '-b' and also use '-c'. For details read the file README.eltorito in the mkisofs-distribution.

An interesting application for a custom bootable CD is as a virus-safe DOS- or Windows-system. It saves you the money for the harddisks (if you have a network and use samba to put the user-data on a fileserver). However, this is purely theoretical as nobody reported an actual recipe to me.

Some details about the bootable RedHat CD-ROM is available from http://www.channel1.com/users/rodsmith/rhjol-technical.html.

4.12 "How to make CD-ROMs writable somehow?"

There is an overlay-filesystem available for Linux, which is mounted over the CD-ROM and intercepts all writing operations. New and modified files are stored elsewhere, but for the user it looks like the CD-ROM is modified. For more information, see http://home.att.net/~artnaseef/ovlfs/ovlfs.html.

If that is not enough for your needs: wait for the UDF-filesystem to be supported by Linux or help developing it (see http://trylinux.com/projects/udf/.

4.13 "Is it possible to use several writers at once?"

Yes. However, it has been only tested with two writers yet. And you need a kernel patch for more buffers in the SCSI-generic driver ( ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/alpha).

4.14 "Which media is the best?"

The german computer magazine "c't" had a list of tips regarding the blank CD-Rs in their november 1996 issue:


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