Izinhlelo zokugcina zanamuhla azikhuli nje kuphela ngama-terabits futhi zinezinga eliphezulu lokudluliswa kwedatha, kodwa futhi zidinga amandla amancane futhi zithatha indawo encane. Lezi zinhlelo zidinga nokuxhumeka okungcono ukuze zinikeze ukuguquguquka okwengeziwe. Abaklami badinga ukuxhumana okuncane ukuze banikeze amazinga edatha adingekayo namuhla noma esikhathini esizayo. Futhi inqubo evamile kusukela ekuzalweni kuya ekuthuthukisweni nasekuvuthweni kancane kancane ayisebenzi njengosuku. Ikakhulukazi embonini ye-IT, noma yiluphi ubuchwepheshe buhlala buthuthuka futhi buzishintsha, njengoba kunjalo ne-Serial Attached SCSI (SAS). Njengomlandeli we-SCSI efanayo, i-SAS specification ibilokhu ikhona isikhathi esithile.
Eminyakeni i-SAS edlulile kuyo, imininingwane yayo ithuthukisiwe, yize inqubo eyisisekelo igciniwe, empeleni azikho izinguquko eziningi kakhulu, kodwa imininingwane yesixhumi se-interface yangaphandle ishintshe kakhulu, okuwukulungiswa okwenziwe yi-SAS ukuze ivumelane nesimo semakethe, ngalezi "zinyathelo ezikhulayo kuya kumamayela ayinkulungwane" ukuthuthukiswa okuqhubekayo, imininingwane ye-SAS isivuthiwe kakhulu. Izixhumi ze-interface zemininingwane ehlukene zibizwa ngokuthi i-SAS, futhi ukuguquka kusuka ku-parallel kuya ku-serial, kusuka kubuchwepheshe be-SCSI obuhambisanayo kuya kubuchwepheshe be-SCSI (SAS) obuxhunywe nge-serial kushintshe kakhulu uhlelo lokuqondisa ikhebula. I-SCSI yangaphambili ehambisanayo ingasebenzisa iziteshi eziyi-16 eziphelele noma ezihlukile kuze kufike ku-320Mb/s. Njengamanje, i-interface ye-SAS3.0 evame kakhulu ensimini yokugcina yebhizinisi isasetshenziswa emakethe, kodwa i-bandwidth ishesha kabili kune-SAS3 engakathuthukiswa isikhathi eside, okungu-24Gbps, cishe u-75% we-bandwidth yedrayivu evamile ye-PCIe3.0×4 solid-state. Isixhumi sakamuva se-MiniSAS esichazwe ku-SAS-4 sicincane futhi sivumela ukuminyana okuphezulu. Isixhumi sakamuva se-Mini-SAS sinobukhulu obuyingxenye yesixhumi sokuqala se-SCSI kanye nobukhulu obungu-70% besixhumi se-SAS. Ngokungafani nekhebula lokuqala le-SCSI parallel, zombili i-SAS kanye ne-Mini SAS zineziteshi ezine. Kodwa-ke, ngaphezu kwesivinini esiphezulu, ukuminyana okuphezulu, kanye nokuguquguquka okwengeziwe, kukhona nokwanda kobunzima. Ngenxa yobukhulu obuncane besixhumi, umenzi wekhebula lokuqala, umhlanganisi wekhebula, kanye nomklami wesistimu kumele banake kakhulu amapharamitha obuqotho besignali kulo lonke ukuhlanganiswa kwekhebula.
Akuwona wonke ama-cable assembler akwazi ukunikeza amasignali esivinini esiphezulu asezingeni eliphezulu ukuze ahlangabezane nezidingo zobuqotho besignali zezinhlelo zokugcina. Ama-cable assembler adinga izixazululo ezisezingeni eliphezulu nezingabizi kakhulu zezinhlelo zokugcina zakamuva. Ukuze kukhiqizwe ama-cable assembler azinzile futhi ahlala isikhathi eside, kunezinto eziningana okudingeka zicatshangelwe. Ngaphezu kokugcina ikhwalithi yomshini wokusebenza nokucubungula, abaklami badinga ukunaka kakhulu amapharamitha obuqotho besignali enza ama-cable edivayisi yememori yesivinini esiphezulu yanamuhla abe nokwenzeka.
Ukucaciswa kobuqotho besiginali (Yisiphi isiginali esiphelele?)
Ezinye zezimiso eziyinhloko zobuqotho besignali zifaka phakathi ukulahlekelwa kokufakwa, ukukhuluma okuseduze nokuphela, ukulahlekelwa kokubuya, ukuphambuka kwe-skew kwe-difference pair ngaphakathi, kanye nokuphakama kwemodi yomehluko kwimodi evamile. Nakuba lezi zici zihlobene futhi zithintana, singacabangela isici esisodwa ngesikhathi ukuze sifunde umthelela waso oyinhloko.
Ukulahlekelwa kokufakwa (Amapharamitha emvamisa ephezulu Izisekelo 01- amapharamitha okunciphisa)
Ukulahleka kokufakwa ukulahleka kwe-amplitude yesignali kusukela ekugcineni kokudlulisa kwekhebula kuya ekugcineni kokwamukela, okulingana ngqo nemvamisa. Ukulahleka kokufakwa kuncike enombolweni yentambo, njengoba kuboniswe kumdwebo wokunciphisa ngezansi. Ezingxenyeni zangaphakathi zebanga elifushane zekhebula elingu-30 noma elingu-28-AWG, ikhebula lekhwalithi enhle kufanele libe nokunciphisa okungaphansi kuka-2dB/m ku-1.5GHz. Ku-6Gb/s SAS yangaphandle esebenzisa izintambo ezingu-10m, kunconywa ikhebula elinesilinganiso somugqa esingu-24, elinokunciphisa okungu-13dB kuphela ku-3GHz. Uma ufuna imajini yesignali eyengeziwe ngamanani aphezulu edatha, chaza ikhebula elinokunciphisa okuncane kumaza aphezulu ezintambo ezinde.
I-Crosstalk (Izisekelo Zezici Zezici Eziphezulu 03- Amapharamitha e-Crosstalk)
Inani lamandla adluliselwa kusuka kwesinye isignali noma umehluko webhangqa kuya kwesinye. Kumakhebula e-SAS, uma i-crosstalk eseduze (NEXT) incane ngokwanele, izobangela izinkinga eziningi zesixhumanisi. Ukulinganiswa kwe-NEXT kwenziwa ekugcineni kwekhebula elilodwa kuphela, futhi inani lamandla adluliselwa kusuka kumbhangqwana wesignali yokudlulisa okukhiphayo kuya kumbhangqwana otholayo wokufaka. I-crosstalk ekude (FEXT) ilinganiswa ngokufaka isignali yebhangqa lokudlulisa komunye umkhawulo wekhebula nokubheka ukuthi kusele amandla angakanani esignalini yokudlulisa komunye umkhawulo wekhebula.
I-NEXT ekuhlanganisweni kwekhebula kanye nesixhumi ivame ukubangelwa ukuhlukaniswa okungekuhle kwama-signal differential pairs, okungase kubangelwe yizindawo zokuxhuma kanye nama-plug, ukungafakwa kahle kwesisekelo, noma ukuphathwa kabi kwendawo yokuphela kwekhebula. Umklami wesistimu udinga ukuqinisekisa ukuthi i-cable assembler isixazululile lezi zinkinga ezintathu.
Amajika okulahlekelwa kwezintambo ezivamile ze-100Ω ezingama-24, 26, kanye nama-28
Ukuhlanganiswa kwekhebula lekhwalithi enhle ngokuhambisana ne-“SFF-8410-Specification for HSS Copper Testing and Performance Requirements” okulinganiswe ngokuthi i-NEXT kufanele ibe ngaphansi kuka-3%. Ngokuphathelene nepharamitha ye-s, i-NEXT kufanele ibe ngaphezu kuka-28dB.
Ukulahlekelwa Kokubuyiselwa (Izisekelo Zepharamitha Ezivamile Eziphezulu 06- Ukulahlekelwa Kokubuyiselwa)
Ukulahleka kokubuya kulinganisa inani lamandla abonakala ohlelweni noma ikhebula lapho kufakwa isignali. Lawa mandla abonakalayo angabangela ukwehla kwe-amplitude yesignali ekugcineni kokwamukela kwekhebula futhi angabangela izinkinga zobuqotho besignali ekugcineni kokudlulisa, okungabangela izinkinga zokuphazamiseka kwe-electromagnetic kuhlelo nabaklami besistimu.
Lokhu kulahlekelwa kokubuya kubangelwa ukungalingani kwe-impedance ekuhlanganisweni kwekhebula. Kuphela ngokuphatha le nkinga ngokucophelela okukhulu lapho i-impedance yesiginali ingashintshi khona lapho idlula kusokhethi, ipulaki kanye ne-wire terminal, ukuze ushintsho lwe-impedance luncishiswe. Izinga lamanje le-SAS-4 libuyekezwa libe yinani le-impedance elingu-±3Ω uma kuqhathaniswa ne-±10Ω ye-SAS-2, futhi izidingo zezintambo zekhwalithi enhle kufanele zigcinwe ngaphakathi kokubekezelelana okulinganiselwe okungu-85 noma 100±3Ω.
Ukuhlanekezela okugobile
Kumakhebula e-SAS, kunezindlela ezimbili zokushintshashintsha: phakathi kwama-pair okungafani kanye nangaphakathi kwama-pair okungafani (isignali yomehluko yethiyori yobuqotho besignali). Ngokombono, uma izimpawu eziningi zifakwa kolunye uhlangothi lwekhebula, kufanele zifike kolunye uhlangothi ngesikhathi esisodwa. Uma lezi zimpawu zingafiki ngesikhathi esifanayo, lesi simo sibizwa ngokuthi ukuguquguquka kwekhebula, noma ukuguquguquka kokulibaziseka. Kuma-pair okungafani, ukuguquguquka kwe-skew ngaphakathi kwe-pair yomehluko ukubambezeleka phakathi kwezintambo ezimbili ze-pair yomehluko, kanti ukuguquguquka kwe-skew phakathi kwama-pair okungafani ukubambezeleka phakathi kwamasethi amabili ama-pair omehluko. Ukuguquguquka okukhulu kwe-skew kwe-pair yomehluko kuzokwandisa ibhalansi yomehluko yesignali edlulisiwe, kunciphise ubukhulu besignali, kwandise i-jitter yesikhathi futhi kubangele izinkinga zokuphazamiseka kwe-electromagnetic. Umehluko wekhebula lekhwalithi enhle ekuguquguqukeni kwe-skew yangaphakathi kufanele ube ngaphansi kwama-10ps.
Isikhathi sokuthunyelwe: Novemba-30-2023
