11. To orio toy Linux IDE twn 8 GiB

O Linux IDE odhgos pairnei th gewmetria kai xwrhtikothta toy diskoy (kai alla polla) xrhsimopoiwntas thn klhsh ATA IDENTIFY. Mexri prosfata, o odhgos de 8a pisteye thn epistrefomenh timh ths lba xwrhtikothtas (lba_capacity), an htan panw apo 10% apo thn ypologizomenh me C*H*S. Parola ayta, oi kataskeyastes, se megaloys IDE diskoys (me perissoteroys apo 16514064 tomeis) epistrefoyn ta C=16383, H=16, S=63, gia ena sunolo 16514064 tomewn (7.8 GB), anejarthtws toy pragmatikou toys mege8oys, alla dinoyn thn pragmatikh xwrhtikothta ws lba.

Oi prosfatoi pyrhnes (2.0.34, 2.1.90) to jeroyn ayto kai to dior8wnoyn. An exete palaiotero pyrhna kai de 8elete na anaba8misteite, kai o pyrhnas blepei mono 8 GiB se enan polu megalutero disko, dokimaste na allajete th roytina lba_capacity_is_ok sto /usr/src/linux/drivers/block/ide.c se kati san

static int lba_capacity_is_ok (struct hd_driveid *id) {
        id->cyls = id->lba_capacity / (id->heads * id->sectors);
        return 1;
}

11.1 BIOS epiplokes

Opws molis anefera, oi megaloi diskoi epistrefoyn C=16383, H=16, S=63 anejarthta apo to pragmatiko toys mege8os, enw to pragmatiko mege8os epistrefetai ws LBAcapacity. Merika BIOS den to anagnwrizoyn ayto kai metafrazoyn to 16383/16/63 se kati me ligoteroys kylindroys kai perissoteres kefales, p.x. 1024/255/63 h 1027/255/63. Etsi, o pyrhnas de mporei na anagnwrisei th gewmetria 16383/16/63, alla kai tis mperdemenes ekdoseis ths toy BIOS. Apo ton pyrhna 2.2.2 ola ayta dior8w8hkan (xrhsimopoiwntas ta H kai S toy BIOS kai ypologizontas to C = xwrhtikothta/(H*S)). Synh8ws to problhma lunetai me to na ry8mistei o diskos ws Normal sto BIOS (h akomh kalutero ws None, xwris na anafer8ei ka8oloy sto BIOS). An ayto den einai dynato epeidh prepei na ekkinhsete apo ayton h xrhsimopoieite DOS/Windows kai h anaba8mish se 2.2.2 h megaluterh ekdosh de ginetai, xrhsimopoihste parametroys ekkinhshs ston pyrhna.

11.2 Braxykyklwthres

Polloi IBM diskoi exoyn braxykyklwthres (jumpers) poy epitrepoyn na epilejete metaju gewmetria 15 h 16 kefalwn. Oi synh8eis ry8miseis 8a sas dwsoyn 16 kefales. Merikes fores kai oi dyo gewmetries dinoyn ton idio ari8mo tomewn, merikes fores me 15 kefales dinontai ligoteroi tomeis. Yparxei enas kalos logos gia ayth thn epilogh: o Petri Kaukasoina grafei: `Enas 10.1 Gig IBM Deskstar 16 GP (IBM-DTTA-351010) htan ry8mismenos gia 16 kefales alla sto palio PC (me AMI BIOS) den ekkinouse kai eprepe na to ry8misw se 15 kefales. To hdparm -i leei oti RawCHS=16383/15/63 kai LBAsects=19807200. Xrhsimopoiw 20960/15/63 gia na exw th megisth xwrhtikothta.' H gewmetria 16383/15/63 den anagnwrizetai apo ton pyrhna, opote xreiazontai parametroi ekkinhshs. Gia tis ry8miseis deite http://www.storage.ibm.com/techsup/hddtech/hddtech.htm.

11.3 Braxykyklwthres poy meiwnoyn th synolikh xwrhtikothta

Polloi diskoi exoyn braxykyklwthres poy kanoyn ton disko na fainetai mikroteros. Arketa anohto, kai mallon kanenas xrhsths toy Linux de 8a 8elei na to xrhsimopoihsei, alla merika BIOS kollane me megaloys diskoys. H synh8hs lush einai na krathsete ton disko ejw apo to BIOS. Alla ayto ginetai mono an den einai o diskos ekkinhshs.

To prwto sobaro orio htan twn 4096 kylindrwn (dhladh, 16 kefales kai 63tomeis/ixnos, 2.11GB). Gia paradeigma, enas Fujitsu MPB3032ATU 3.24 GB diskos exei gewmetria 6704/15/63, alla mporei na emfanistei ws 4092/16/63, kai meta anaferei LBA xwrhtikothta 4124736 tomeis, wste to leitoyrgiko susthma na mporei na mantecei oti sthn pragmatikothta einai megaluteros. Se ayth thn periptwsh (me ena BIOS poy kollaei otan dei poso megalos einai o diskos sthn pragmatikothta wste na xreiazetai o periorismos) xreiazontai parametroi ekkinhshs gia na peite sto Linux to mege8os toy diskoy.

Oi perissoteroi diskoi mporoun na emfanistoun ws diskoi 2GB kai meta na anaferoyn thn kommenh gewmetria ws 4092/16/63 h 4096/16/63, alla akoma anaferoyn thn plhrh LBA xwrhtikothta. Tetoioi diskoi doyleuoyn swsta kai anaferoyn thn plhrh xwrhtikothta sto Linux, asxeta me tis 8eseis twn braxykyklwthrwn.

Ena pio prosfato orio einai to orio twn 33.8 GB. Pyrhnes palaioteroi apo ton 2.3.21 xreiazontai patch gia na mporesoyn na xrhsimopoihsoyn megaluteroys IDE diskoys apo 33.8GB. Merikoi megaluteroi diskoi mporoun na ry8mistoun me braxykyklwthres wste na emfanizontai ws 33.8 GB. Gia paradeigma, o IBM Deskstar 37.5 GB (DPTA-353750) mporei na ry8mistei wste na emfanizetai ws 33.8 GB, kai meta anaferei gewmetria 16383/16/63 opws oloi oi megaloi diskoi, alla LBA xwrhtikothta 66055248 (antistoixa me 65531/16/63 h 4111/255/63)). Aytoi, otan ry8mistoun ws 33.8GB, xreiazontai parametroys gia plhrh xwrhtikothta sto Linux. Deite to the BIOS 33.8 GB limit.