Page 363 - FUNDAMENTALS OF COMPUTER

NPP

NPP Memory 363

Whatever page is needed, it is brought into O~-O~ {H$gr noO H$s Amdí`H$Vm hmoVr h¡ dh
main memory. In the above diagram page φ, _w»` _o_moar _| cm`m OmVm h¡Ÿ& Cnamoº$ {MÌ _| noO φ,8,62
page 8, page 62 and page 63 are brought in
different frames of main memory. There is a Am¡a 63 H$mo _w»` _o_moar _| cm`m J`m h¡Ÿ& EH$ Q>o~c hmoVr
table in the paging system which keeps record h¡ Omo noOm| H$m [aH$mS>© aIVr h¡& `h ~VmVr h¡ {H$ H$m¡Z gm
of pages; which page is in which frame. and noO _oZ _o_moar _| Zht h¡Ÿ& AJa h¡ Vmo {H$g \«o$_ _| h¡ & `h
which page is not in main memory. This table
is called Page Table. Q>o~c noO Q>o~c H$hcmVr h¡Ÿ&
Page Table has following entries: Bg Q>o~c _| {ZåZ à{d{ï>`m± hmoVr h¡:

Frame No. Secondary Presence
Address Bit
0 0 1
1 0
2 0
3 0
. .
. .
. .

8 3 1
. .
. .
. .
62 1 1
63 2 1

The table has one row for one page. Frame Q>o~c _| EH$ noO hoVw EH$ n§{º$ hmoVr h¡Ÿ& \«o$_ Z§.
No. tells that the corresponding page is in which ~VmVm h¡ {H$ AJa noO _w»` _o_moar _| h¡ Vmo {H$g \«o$_ _|
frame. As shown above, page 0 is in frame 0, h¡Ÿ& CXmhaUV: Cnamoº$ Vm{cH$m _| noO 0 \«o$_ 0 _| h¡ ;
page 8 is in frame 3 and so on. noO 8 \«o$_ 3 _| h¡ BË`m{XŸ&
Secondary Address field shows the sector goH§$S>ar ES´>og go nVm McVm h¡ {H$ hmS>©{S>ñH$ Ho$
and track numbers of the page in secondary {H$g Q´>oH$ d goŠQ>a Zå~a _| `h noO pñWV h¡Ÿ& àoO|g {~Q>
storage. Presence Bit tells whether the page is `h ~VmVr h¡ {H$ `h noO _w»` _o_moar _| CnpñWV h¡ `m
present in main memory or not. As shown in
the table, presence bits are "1" in case the bit is ZhtŸ& O¡gm Q>o~c _| Xem©`m J`m h¡ àoOoÝg {~Q²>g ''1'' h¡
present in main memory. O~ {~Q> _w»` _o_moar _| CnpñWV hmoVr h¡Ÿ&