DISKHOI KOMPYUTER

Tavre ki allakay medonem, dar kompyuterhoi IBM PC funksiyahoi khotirai berunaro diskho va digar barandagoni informatsiya mebozand. Onho asosan baroi sabt namudan, az yak kompyuter ba kompyuteri digar kuchonidan va duru daroz yo muvaqqatan nigoh doshtani informatsiyai lozimi, istifoda burda meshavand. Masalan, vinchester, diskhoi magnitii andozaashon khurd (disketho), diskhoi magnitooptiki, kompakt–diskho, lentahoi magniti va gayra barandagoni informatsiya ba hisob meravand.

Baroi ba vositai diskho sabt namudan yo khondani iformatsiya gunkunandahoi magniti khizmat merasonand, ki onhoro diskdonho ham meguyand. Odatan diskdonhoi disketho, kompakt–diskho va vinchester dar bloki sistemavii kompyuter joygir karda meshavand. Disketho va kompaktdiskho ba diskdonhoyashon ozodona guzoshta va girifta meshavand. Vale azbaski vinchester dar okhili bloki sistemavi vasl karda shudaast, in amaliyotro bo on ijro namudan gayriimkon ast. Disketho, vobasta az diametrashon, ba du namud judo meshavand: diskethoi 5,25 dyuymagi (133 mm) va diskethoi 3,5 dyuymagi (89 mm).

Hajmi diskethoro az rui miqdori informatsiyae, ki onho gunjonida metavonand, muayyan menamoyand. Hajmi disket az namud va zichii sabti on vobasta meboshad. Disketho az rui zichiashon ba du guruh judo meshavand: DD (Douile Density – zichiashon duchanda) va HD (Hight Density –zichiashon baland). Vobastagii bayni namud va gunjoishi disketho dar jadvali zerin nishon doda shudaand: 

Namudi disket gunjoishi disket

5,25 dyuym 3,5 dyuym

DD 360 Kbayt 720 Kbayt

HD 1,2 Mbayt 1,44 Mbayt

Qayd namudan zarur ast, ki dar kompyuterhoi peshina diskdonhoi diskethoi panjdyuymagi va ham sedyuymagi istifoda burda meshudand. Kompyuterhoi hozirazamon be

diskdonhoi diskhoi panjdyuymagi istehsol karda meshavand va chunin disketho holo qarib dar furush nestand. Ammo joi diskdonhoi in diskethoro holo diskdonhoi CD–ROM giriftaast.

Har yak disketi sedyuymagi dar qismi boloii khud ishorati tircharo dorad, ki on baroi bekhato ba diskdon guzoshtani disket khizmat merasonad. Dar qismi poyonii disket boshad, zabonchai kvadratii plastmassagie hast, ki on baroi az sabtkunihoi tasodufi emin nigoh doshtani disket khizmat merasonad. Hamin tariq, baroi informatsiyai muhimro az nestshavi himoya namudan, kifoya ast, ki zabonchai disketro kushoda monem.

Disketho bo qabati magniti pushonida shudaand, binobar in sabt va khondani informatsiya dar onho az rui prinsipi kori magnitafonho amali megardad.

 Agar dar lentai magniti ovoz dar payrohai makhsus sar to sari lenta sabt gardad, on goh dar disket payrohaho dar shakli davrahoi konsentriki tashkil karda shudaand. Har yak payroha ba sektorho taqsim karda shudaast. In imkoniyat medihad, ki informatsiya dar disk dar namudi porsiyaho (qism ba qism) nigoh doshta shavad. Har yak payroha va har yak sektori payroha raqami tartibii khudro dorad. Masalan, dar disketi sistemavi, ki baroi ba kor darovardani kompyuter peshbini karda shudaast, sektori nolumi rohravi raqami noldoshta programmai ogozkunandai kori sistemai operat- sioniro dar bar megirad.

Agar dar disket shumo informatsiyaro gashtayu bargashta yakchand marotiba sabt karda va khonda tavoned, on goh dar CD-ROM in korro karda nametavoned. SD-ROM (Sompact Disk-Read Only Memoqy) – tanho baroi khondani informat- siyai dar diski CD mahfuzbuda peshbini shudaast. Azbaski informatsiya az CD–ROM bo yorii lazer khonda meshavad,

onro diski optiki niz meguyand. Gunjoishi in diskho benihoyat kalon meboshad. Onho 640 Mbayt va az on ham ziyodtar informatsiyaro gunjonida metavonand. Istehsoli CD-ROM boshad, bisyor ham oson ast. Az in ru, narkhi onho ruz to ruz pasttar shuda istodaast. Holo aksariyat programmaho, makhsusan programmahoi kaloni kompleksi, bozihoi kompyuteri, ensiklopediyaho va gayraho bo yorii kompakt–diskho pahn karda meshavand. Agar dar kompyuter kartahoi ovozi va tasviri mavjud boshand, on goh bo yorii audiokompakt–diskho musiqiro shunidan va bo istifodai videokompakt–diskho videofilmhoro tamosho kardan mumkin ast.

Vinchester – diski magnitii hajman khele kalon buda, baroi nigoh doshtani informatsiya va khondani onho istifoda burda meshavad. Vinchesterro diski asosii (Haqd Disk) kompyuter ham meguyand. Dar vinchester odatan programmahoi sistemai operatsioni, paketi programmahoi zud–zud istifodashavanda, tahrirgarhoi matnho,

translyatorhoi zabonhoi programmasozi, tablitsahoi elektroni va gayraho nigoh doshta meshavand. Az hamai tajhizoti nigohdorandai informatsiya, ba gayr az khotirai favri, vinchester imkoniyati zudtari dastras namudani informatsiyaro tamin mekunad. Odatan in nishondihandai vinchester ba 7–20 millisoniya (ms) barobar ast. Surati sabt va khondani informatsiya niz dar vinchester bisyor baland ast (to 5 Mbayt/s).

Vinchester nom giriftani in disk ba nomi avvalai on 30/30 vobasta ast, ki on soli 1973 az tarafi firmai IBM sokhta shuda bud. In raqamho ba raqami kalibri miltiqi avtomatii mashhuri firmai Winchesteq muvofiq omada bud.

Az hamin sabab ham, nomi disk niz «Vinchester» shuda mond. Badtar hamai diskhoi digarro niz Vinchester nom meburdagi shudand. Dar yak kompyuter az yak vinchester ziyodtar diskhoro guzoshtan mumkin ast. In beshubha zudkorii kompyuterro yakchand marotiba ziyod megardonad. Vinchesterho az hamdigar az rui kharakteristikai zerinashon farq mekunand:

•  gunjoish – miqdori informatsiyae, ki gunjonida metavonand;
•  zudkori – vaqti dastras namudani informatsiya va surati khondanu sabti onho;
•  interfeys – namudi kontrollyore, ki disk ba on payvast karda shudaast (asosan IDE/EIDE va varianthoi gunoguni SCSI. Dar in jo IDE – Integqated Device Electqonics, EIDE – Extended IDE, SCSI -Smoll Computer System Interface).

Hamin tavr, kharakteristikai asosii vinchester gunjoishi on ba hisob meravad. Hajmi vinchesterhoi avvalin ba 5 Mbayt barobar bud. Qismi ziyodi vin–chesterhoi kompyuterhoi hozira boshand, az 800 Mbayt to 30 Gbayt gunjoish dorand. Imruzho vinchesterhoi to 500 Mbayt hajmdoshta kuhna hisob shuda, diskhoi 2–10 Gbayt ba jumlai molhoi seristemol dokhil shudaand. Hajmi maksimalii vinchesterho, ki interfeysi EIDE va SCSI imkoniyat medihand, ba 9,1 Gbayt rasonida shudaast. Vale istehsolkunandagoni vinchesterho modelhoi gunjoishashon 18 Gbayt va az on ham kalontarro tayyor karda istodaand.

Baroi durusttar tasavvur karda tavonistani hajmi diskho, farz mekunem, ki dar yak sahifai kitob ba hisobi miyona 2500 alomat megunjad. On goh diske, ki 1 Gbayt hajm dorad, metavonad kitobi 400 000 sahifadoshtaro gunjonad. Surati kori disk bo du nishondihanda – vaqti dastraskunii informatsiya va surati khondanu sabti

malumotho muayyan karda meshavad. Vinchesterhoi hozira metavonand dar zarfi 10–12 ms informatsiyaro dastras gardonand. Diskhoi boz ham zudkortar in vaqtro to ba 7–8 ms tabdil dodaand. Surati khondanu sabti informatsiya boshad, na tanho az khudi disk, balki boz az parametrhoi kontrollyor, namudi shina, zudkorii mikroprotsessor va gayraho vobasta ast. Surati miyonai sabtu khondani vinchesterhoi hozira ba 4–5 Mbayt/s barobar ast.

 Savolho:

1. Vazifahoi diskho az chi iborat ast?
2. Kadom namudhoi diskhoi kompyuteriro medoned?
3. Baroi chi diski asosii kompyuterro vinchester menomand?
4. Kadom gunjoishhoi diskethoro medoned?
5. CD-ROM az vinchester va disketho chi farq dorad?
6. Harakteristikahoi vinchesterho kadomhoyand?
7. Diskho az rui kadom nishondihandahoyashon az parametrhoi digar tajhizoti kompyuter vobastagi dorand?

 Suporish:

1. Matni mavzuro bodiqqat khoned va onro naql kuned.
2. Nomi diskhoi kompyuterro dar shakli tablitsa biyored va kharakteristikahoi onhoro nombar kuned.
3. On disku diskdonhoi kompyuterro, ki dida metavoned, muoina namoed va oidi funksiyayu kharakteristikahoyashon malumot dihed.