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8. Diafores plhrofories kai apanthseis

8.1 Pws programmatizw to XYZ sto Linux

Diabaste ta biblia odhgiwn xrhshs (manuals), h ena kalo biblio gia to Unix. Oi selides boh8eias (manpages) (plhktrologhste man man) einai synh8ws mia kalh phgh anaforas plhroforiwn gia ton akribh tropo xrhshs mias sygkekrimenhs entolhs h mias synarthshs Yparxei epishs kai pollh enhmerwtikh bibliografia GNU h opoia einai syxna pio xrhsimh ws ekpaideysh-ejaskhsh (tutorial). Trejte ton Emacs kai plhktrologhste C-h i, h plhktrologhste info info an den exete h den sas aresei o Emacs. Shmeiwste oti oi plhrofories toy Emacs gia ton libc (Emacs libc node) den perigrafoyn akribws thn libc toy Linux (h opoia einai perissotero san mia libc paradosiakou Unix , xwris na exei kapoies apo tis idiaiterothtes toy GNU), alla einai arketa kalh gia mia ekpaideysh sto programmatismo ths C gia Unix. H teleytaia ekdosh twn selidwn boh8eias (manpages) gia to Linux kai mia syllogh xrhsimhs bibliografias GNU kai diafores alles plhrofories sxetikes me ton programmatismo se Linux mporoun na bre8oun sto sunsite.unc.edu sto /pub/Linux/docs/man-pages.

8.2 Ti einai ayta gia to ELF;

Deite to ELF HOWTO apo ton Daniel Barlow - shmeiwsh, ayto den einai to arxeio allajte se elf, to opoio einai ena bhma pros bhma ma8hma gia to pws na anaba8misete se ELF monoi sas. To Linux allazei se diaforetikh morfh gia ta ektelesima, ta antikeimena kai tis biblio8hkes antikeimenwn, gnwsth ws `ELF' (h palia morfh legetai `a.out'). Ayth h morfh 8a exei polla pleonekthmata, symperilambanomenhs kaluterhs yposthrijhs gia diamoirazomenes biblio8hkes (shared libraries) kai dynamikh sundesh (dynamic linking). Kai oi duo morfes dyadikwn, h a.out kai h ELF mporoun na synyparxoyn se ena susthma. Wstoso, xrhsimopoioun diaforetikes diamoirazomenes biblio8hkes C, poy 8a prepei na einai kai oi duo egkatesthmenes. An 8elete na ma8ete an ton susthma sas mporei na ektelesei dyadika arxeia ELF, koitajte sto /lib gia ena arxeio me onoma libc.so.5. An ayto yparxei, pi8anotata mporei. An 8elete na ma8ete an h egkatastash sas einai ELF mporeite na dialejete ena antiproswpeytiko programma, san to ls, kai na trejte to file se ayto:

   -chiark:~> file /bin/ls
   /bin/ls: Linux/i386 impure executable (OMAGIC) - stripped

   valour:~> file /bin/ls
   /bin/ls: ELF 32-bit LSB executable, Intel 80386, version 1, stripped

Yparxei ena dior8wtiko (patch) gia na kanete ton pyrhna 1.2.x na metaglwttizei xrhsimopoiwntas toys metaglwttistes (compilers) ELF kai na paragei ELF coredumps, sto tsx-11.mit.edu sto /pub/packages/GCC. Den xreiazeste ayto to dior8wtiko gia na trexete ELF ektelesima. O pyrhnas 1.3.x kai metagenesteroi den xreiazontai ka8oloy dior8wtiko.

8.3 Ti einai ena arxeio .gz ; Kai ena .tgz ; Kai ... ;

Ta .gz (kai .z) arxeia exoyn sympiestei xrhsimopoiwntas to GNU gzip. Prepei na xrhsimopoihsete sto gunzip (to opoio einai enas symbolikos sundesmos sthn entolh gzip poy symperilambanetai me tis perissoteres egkatastaseis Linux ) gia na aposympiesete to arxeio. Ta .taz kai .tz einai arxeia kasetas (poy ftiaxthkan me to Unix tar) sympiesmena xrhsimopoiwntas thn entolh toy Unix compress. Ta .tgz (h .tpz) einai arxeia kasetas sympiesmena me to gzip. To .lsm einai ena stoixeio Xarth Logismikou Linux (Linux Software Map entry), se morfh enos syntomoy arxeioy keimenoy. Plhrofories gia ta LSM kai o idios o xarths einai dia8esima ston ypokatalogo docs sto sunsite.unc.edu. To .deb einai ena dyadiko paketo Debian - h morfh dyadikwn paketwn poy xrhsimopoieitai apo th dianomh Debian GNU/Linux. Xrhsimopoieitai me to dpkg kai to dpkg-deb (dia8esima sta systhmata Debian kai apo to ftp.debian.org). To .rpm einai ena paketo Red Hat, to opoio xrhsimopoieitai apo tis dianomes Red Hat. Ayta briskontai sto ftp.redhat.com. H entolh file mporei syxna na sas pei ti einai ena arxeio An blepete oti to gzip paraponietai otan prospa8eite na aposympiesete ena gzipped arxeio, mallon to katebasate (downloaded) se morfh ASCII kata la8os. Prepei na katebazete ta perissotera arxeia se dyadikh morfh (binary) - na 8ymaste na plhktrologeite thn entolh binary sto FTP prin xrhsimopoieite to get gia na katebasete to arxeio.

8.4 Ti shmainoyn ta arxika VFS;

Eikoniko susthma arxeiwn (Virtual File System). Einai to afairetiko epipedo anamesa sto xrhsth kai to pragmatiko susthma arxeiwn opws ta ext2, minix kai msdos. Metaju allwn h doyleia toy einai na adeiazei thn proswrinh endiamesh mnhmh (buffer) anagnwshs otan antilambanetai allagh diskoy se ena odhgo eukampths disketas:

   VFS: Disk change detected on device 2/0

8.5 Ti einai to BogoMip;

To `BogoMips' einai mia parafrash toy `Bogus MIPS'. MIPS shmainei (analoga me ton poion akoute) Ekatommuria Entolwn ana Deyterolepto -Millions of Instructions per Second-, h Anousia Endeijh Taxuthtas toy Epejergasth -Meaningless Indication of Processor Speed-. O ari8mos poy emfanizetai kata thn ekkinhsh einai to apotelesma mias ba8monomishs sygxronismou toy pyrhna, poy xrhsimopoieitai gia polu suntomoys brogxoys ka8ysterhshs apo orismenoys odhgous syskeywn. Xontrika to BogoMips 8a einai peripoy:

     386SX              clock * 0.14
     386DX              clock * 0.18
     486Cyrix/IBM       clock * 0.33
     486SX/DX/DX2       clock * 0.50
     586                clock * 0.39
An o ari8mos poy blepete einai polu xamhloteros apo ayton, isws exete piesei to koympi Turbo h exete ry8misei thn taxuthta ths CPU la8os, h exete kapoio problhma lan8anoysas mnhmhs [opws perigrafetai sto Q6.5 `When I add more memory it slows to a crawl.'.]

Gia times poy exoyn dei an8rwpoi me alloys, spanioteroys epejergastes deite to BogoMips Mini-HOWTO, sto sunsite.unc.edu sto /pub/Linux/docs/howto/mini/BogoMips.

8.6 Ti einai to Linux Journal kai poy mporw na to brw

To Linux Journal einai ena mhniaio periodiko (entypo) poy diati8etai sta periptera (!) (newsstands) kai mesw syndromwn se olo ton kosmo. Steilte ena e-mail sto linux@ssc.com gia leptomereies.

8.7 Posoi an8rwpoi xrhsimopoioun Linux

To Linux diati8etai dwrean kai kaneis den einai ypoxrewmenos na katagracei ta antigrafa poy katexei se kapoia kentrikh yphresia, etsi einai duskolo na jeroyme. Polles epixeirhseis epibiwnoyn apokleistika apo pwlhsh kai yposthrijh Linux, kai polu ligoi xrhstes toys Linux xrhsimopoioun aytes tis epixeirhseis, kat' analogia. Ta newsgroups gia to Linux einai apo ta pio polydiabasmena sto diktyo, etsi o ari8mos einai mallon stis ekatontades xiliadwn, alla swsta stoixeia einai duskolo na bre8oun. Wstoso, enas gennaios tupos, o Harald T. Alvestrand Harald.T.Alvestrand@uninett.no, apofasise na prospa8hsei, kai zhtaei na toy steilete ena mhnyma sto linux-counter@uninett.no an xrhsimopoieite Linux, me ena apo ta akoloy8a 8emata: `I use Linux at home' (xrhsimopoiw to Linux sto spiti), `I use Linux at work' (xrhsimopoiw to Linux sth doyleia), h `I use Linux at home and at work' (xrhsimopoiw to Linux sto spiti kai sth doyleia). Epishs dexetai kataxwrhseis apo alloys - rwthste ton gia plhrofories. ask him for details. Enallaktika mporeite na kataxwrh8eite xrhsimopoiwntas tis formes WWW sto http://domen.uninett.no/ hta/linux/counter.html. Stelnei tis metrhseis toy sto comp.os.linux.misc ka8e mhna, enallaktika koitajte sto aun.uninett.no sto /pub/misc/linux-counter h sthn proanafer8eisa web selida.

8.8 Pws 8a eprepe na proferw to Linux

Ayto sigoyra einai ena 8ema "8rhskeytikou polemoy"! An 8elete na akousete ton Linus na leei pws to proferei katebaste to english.au h to swedish.au apo ftp.funet.fi (sto /pub/OS/Linux/PEOPLE/Linus/SillySounds). An exete karta hxoy h ton odhgo gia to megafwnaki toy PC mporeite na toys akousete plhktrologwntas:

   cat english.au >/dev/audio
H diafora den einai sthn profora toy Linux alla sthn glwssa sthn opoia o Linus leei hello. H agglikh ekdosh exei diakwmwdh8ei polu kala apo ton Jin Choi ws "Hi, my name is Leenoos Torvahlds and I pronounce Leenooks as Leenooks." Gia esas poy den exete ta aparaithta gia na to akousete: O Linus proferei to Linux sxedon san Leenus, opoy to ee einai opws sto feet alla mallon braxutero kai to u einai mia polu braxuterh ekdosh toy eu sto peur (an to proferete opws to u sto put mallon pernaei). 1/4tan o Ian Jackson milaei agglika to proferei Lie-nucks (u opws sto bucket) -- ayth einai mia agglopoihmenh profora poy basizetai sthn analogia me to onoma toy Linus, to opoio sta agglika proferetai ws Lie-nus (u opws sto put). Einai fysika paradekto kai synh8ismeno na metatrepetai h profora kapoias lejhs otan allazei glwsses. O Ian Jackson nomizei oti h profora Linnucks (braxu i opws sto pit, braxu u opws sto bucket) einai la8os sta agglika, ka8ws den einai h prwtotyph soyhdikh profora, den einai mia logikh agglikopoihshs ayths kai den sthrizetai sthn agglopoihmenh morfh toy onomatos toy Linus.


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