2-Mavzu. Kompyuterlarni tashkil qilishning raqamli mantiqiy asoslari

PCM phase memory . Information carrier as chalcogenide of the bottle microscopic particles service they do _ two case in one to be possible . These states ( phases ) are optical and electric properties on difference does . Heat The material under the influence of a case to the other change possible . Optics memory devices such heating laser rays using instead is increased . In PCM mode through the heating material electric tokini transfer with heated _ _ section incoming situation current size , voltage and heating duration depending on . In the normal ( cold ) state, the material is high electric resistance has amorphous shihsasimon structure has _ High temperature under the influence of ( Celsius ) up to 600 degrees ) the material crystallizes and very low resistance has will be . Amorphous in phase high resistance binary "0 " , crystal low resistance in phase "1" expression for used . Potential as phase transition less than 5 ns time in happen to be possible , but in experiments this up to 16 ns level value achieve possible was . In general PCM cells _ The contents are 10 times the flash memory faster turn off possible and again write speed flash memory seven equal faster .
PCM data _ fast required to write use convenient because _ technology all a without removing the cells separately of bits change the values _ opportunity gives _ From this in addition to PCM memory elements fast . From the PCM 's flash memory more a advantage that is , the chip to decline encountered without again write cycles number 100 million reaches _
PCM fazali xotira. Ma’lumotlar tashuvchisi sifatida xalkogenid shishasining mikroskopik zarralari xizmat qiladi, ular ikki holatdan birida bo’lishi mumkin. Bu holatlar (fazalar) optik va elektr xususiyatlari bo’yicha farq qiladi. Issiqlik ta’sirida material bir holatdan ikkinchisiga o’zgarishi mumkin. Optik xotira qurilmalarida bunday isitish lazer nurlari yordamida amalga oshiriladi. PCM holatida usitish material orqali elektr tokini o’tkazish bilan isitilad, qizigan qism kiradigan holat tokning kattaligiga, kuchlanishga va isitish davomiyligiga bog’liq. Odatiy (sovuq) holatda material yuqori elektr qarshiligiga ega amorf shihsasimon tuzilishga ega. Yuqori harorat ta’sirida (Selsiy bo’yicha 600 darajagacha) material kristallanadi va juda past qarshilikka ega bo’ladi. Amorf fazadagi yuqori qarshilik ikkilik “0” ni, kristall fazasidagi past qarshilik “1” ni ifodalash uchun ishlatiladi. Potentsial ravishda fazali o’tish 5 ns dan kam vaqt ichida sodir bo’lishi mumkin, ammo tajribalarda shu paytgacha 16 ns darajadagi qiymatga erishish mumkin edi. Umuman olganda, PCM yaycheykalar tarkibini flesh xotiradan 10 baravar tezroq o’chirishi mumkin va qayta yozish tezligi flesh xotiradan etti baravar tezroq.
PCM ma’lumotlarni tez yozish talab etiladigan foydalanish qulay, chunki texnologiya butun bir yaycheykalarni o’chirmasdan alohida bitlarning qiymatlarini o’zgartirshga imkon beradi. Bundan tashqari, PCM xotira elementlari tezkor. PCM-ning flesh xotiradan yana bir afzalligi shundaki, mikrosxemaning tanazzulga uchragan holda qayta yozish tsikllari soni 100 millionga etadi.