Page 336 - FUNDAMENTALS OF COMPUTER

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336 Fundamentals of Computers NPP

1. Primary Memory 1. àmB_ar _o_moar
2. Secondary Memory 2. goH§$S>ar _o_moar

Primary Memory àmB_ar _o_moar
The memory with which the CPU can di- dh _o_moar {Oggo CPU grYo-grYo OmZH$mar àmá
rectly communicate is called primary memory. H$aVm h¡, àmB_ar _o_moar H$hbmVr h¡Ÿ& `h H$åß`yQ>a H$m
This is an essential part of the computer. There-
fore it is also called as main memory. These are Amdí`H$ {hñgm h¡Ÿ& Bg{bE Bgo _¡Z _o_moar ^r H$hVo
available as semiconductor chips, therefore it is h¢Ÿ& My±{H$ `h AY©MmbH$m| go ~Zr hmoVr h¡, Bg{bE Bgo
also called semiconductor memory. The CPU AY©MmbH$ _o_moar ^r H$hVo h¢Ÿ& Bgr _o_moar go CPU
takes instruction from this memory and ex- B§ñQ´>ŠeZ H$mo boH$a EŠOrŠ`yQ> H$aVm h¡Ÿ& gmW hr `hr
ecutes it. At the same time “data” is also sup- _o_moar Amdí`H$ "S>mQ>m' àXmZ H$aZo H$m H$m`© ^r H$aVr
plied by this memory. Since, CPU is a semicon-
ductor device its speed matches with main h¡Ÿ& My±{H$ Bgr Ho$ g_mZ CPU ^r EH$ AY©MmbH$ `wpŠV
memory. Main memory and CPU both perform h¡, AV… XmoZm| H$s J{V _| {ZH$Q>Vm nmB© OmVr h¡& XmoZm|
parallel data transfer. There are two types of hr g_mZm§Va S>mQ>m Q´>m§g\$a H$aVo h¢Ÿ& Xmo àH$ma H$s àmB_ar
primary memory: _o_moar hmoVr h¡…
(a) RAM (Random Access Memory) (a) RAM (a|S>_ EŠgog _o_moar)
(b) ROM (Read Only Memory) (b) ROM (arS> AmoZbr _o_moar)
Secondary Memory (Auxillary memory) goH§$S>ar _o_moar (ghm`H$ _o_moar)
Secondary Memory are the storage devices. goH§$S>ar _o_moar g§J«hU H$aZo dmbr `wpŠV`m± hmoVr h¢Ÿ&
Large programs and huge amount of data are ~‹S>o-~‹S>o àmoJ«m_ Am¡a ~hþV A{YH$ _mÌm _| S>mQ>m BZ_| aIm
stored in this memory. These are permanent
memory. That means, when power goes off the ahVm h¡ & `o ñWm`r _o_moar hmoVr h¢Ÿ& Š`m|{H$ {dÚwV Ho$
information is not lost. The information is stored ~§X hmo OmZo na BZH$s OmZH$mar Zï> Zht hmoVr h¡Ÿ&
in the form of magnetic field. Thus, these are OmZH$mar H$mo Mw§~H$s` âbŠg Ho$ ê$n _| g§J«hrV {H$`m
also known as “Magnetic memory”. Informa-
tion not currently needed by processor is stored OmVm h¡ & Bg{bE BÝh| “Mw§~H$s` _o_moar” ^r H$hVo h¢Ÿ&
in secondary storage. The examples of these Bg _o_moar _| do OmZH$mar hmoVr h¡ {OgH$m CPU H$mo
memory are Hard disk, floppy disk and mag- VËH$mc H$m_ Zht n‹S>Vm h¡& BgHo$ CXmhaU h¡, hmS>© {S>ñH$,
netic tape. Their storage capacity is relatively
large. As per as block diagram of computer is âbm°nr {S>ñH$ Am¡a _o¾o{Q>H$ Q>on BZH$s j_Vm AË`{YH$
concerned this memory is shown as input out- hmoVr h¡Ÿ& H$åß`yQ>a _| `o BZnwQ>-AmCQ>nwQ> H$m H$m`© H$aVo
put device. These devices are slowest. h¢Ÿ& BZH$s J{V AË`§V H$_ hmoVr h¢&
Now, consider main memory in detail: A~ h_ _w»` _o_moar H$mo {dñV¥V ê$n go g_PVo h¢…

4.3 Main Memory 4.3 _oZ _o_moar
The main memory holds currently needed `o dmo _o_moar hmoVr h¢ {OZ_| AË`mdí`H$ àmoJ«m_ d
programs and data. These are relatively expen- S>mQ>m aIm OmVm h¡Ÿ& `o AY©MmbH$m| H$s {Mn (IC) Ho$ ê$n
sive and available in the form of semiconduc- _| hmoVr h¢ Am¡a _h±Jr hmoVr h¢Ÿ& H$åß`yQ>a _| Xmo àH$ma H$s
tor IC. There are two types of main memory
used in computer system: _oZ _o_moar Cn`moJ _| AmVr h¢…