nz juh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9;...

45

Upload: others

Post on 31-Oct-2020

2 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

������������ � ��� ���������������� � ������ �!���#"�$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

F G H I.JLKNM0O�O�M0O PRQTS H I+JLKUM0O�O V JWQYXZI+JW[

\ ]�^�_ ` a b cd] e ^

f gihkjmlonZpqprn�p sNtvu gihkjmlonZpqp wxj�t4yqhqj{z| } n�~Rt���y:��j�t�p�jU��� g�hqjml�n�pkp� ����pEyknZ� p�pEy�s�y:n ��p���g�hqjml�n�pkp ��y�s�y:n� � � ��y�s�ykn gihkjmlonZpqp�� jmu�n�z� gihkjmlonZpqp w�hqn+s�yk��j�t���� �vs�y u�j�n�p���y � n+sNt��  gihkjmlonZpqp�¡¢ndh:� �£tvs�y:��j�t�¤¥p � n+sNt��£t§¦

f�¨ � ©ª����n ��y«s�ykn � jmu�n�z¬j{�Tgihqj0lon�pkp wxj�t�ykhqjUzfUf ­ ®�n�®�n��£t�¦ � jmu�ndz>p�jU�¯����pEyknZ� p°�vs��m�£t�¦ ±r²{³fZ� ����s%´�´��>t�¦ µ-�m®vp2´YnZt�u��>t�¦�¶·g�hqjml�n�pkp2nZpf�¸ wxg�¹ � ��yº� ±2²�³ sNt�u �m®�pr´Yn�tvu�n�u ��y«s�yknf | ³ ´Yn�h�s�yk��j�t�p°j�t gihkjmlonZpqprn�pfZ� ³ ²{� pk®�´�´WjNh2y ��jNh gihkjmlonZpqprn�pf�� ³ ²{� » z�jU¼�s%z½gihqj0lon�pkp ��ykh:®�l¾yº®0hkn�p

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 2: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

������������ � ��� ���������������� � ������ �!���#"�$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

f � � nZ� jUh2� ¡Ës%¼�z�n�pf�  ±2²{³ ¡Ës%¼�z�n�pf�  ©Ì��z�n ¡Ës%¼vz�n�pf�  gihkjmlonZpqp�¡Ës%¼vz�n�pf�Í gihkjmlonZpqp�±�� s%¦{n�N¨ gihkjmlonZpqp wxj�t�ykhqjUz½ÎÆz�j0lºÏmp�mf gihkjmlonZpqp�� n�� jNh2� � sNtvs%¦{n�� n�t�y�U� ³ ²{� ¹ prn jU�TgÐwxÎ�p�N¸ ³ ²{� Ñ ndh:t�n�zT��n�hr�m�£l�n�p� | gihkjmlonZpqp ��� ��yºl«�§�£t�¦�U� Ò ®�tvt��£t�¦ yº�§n ³ ²{��N� gihkjmlonZpqprn�p sNtvu ¡°�0hqn+sNu�p� � ¡°�0hqn+sNu � sNtvs;¦Un�� n�t�y �>t Ó �£t�u§jZ� p°Ô ¡�N  Õ�Ö�sU� ´�z�n�px× � Ø ��NÍ � Ø � ÙL�>p�y ��yqh:®vlÚyº®�hqn�p¸U¨ Õ�Ö�sU� ´�z�n�px× ¹ t���Ö¸{� | � | Î � } ¹ t§�@Ö �ml«�§n�u�®�z��£t�¦

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 3: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

������������ � ��� ���������������� � ������ �!���#"�$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

¸U¸ | � | Î � } gihqj0lon�pkp ��ykh:®�l¾yº®0hkn¸ | | � | Î � } gihqj0lon�pkp�ÕÛt4yqh2�¸{� | � | Î � } gihqj0lon�pkp » hqj4®�´¸U� | � | Î � } gihqj0lon�pkp » hqj4®�´¸ � | � | Î � } gihqj0lon�pkp ��y«s�yknZp¸U  Õ�Ö�sU� ´�z�n�px× Ó �£t�u§jZ� p°Ô ¡¸UÍ Ü s�h:um��s�hkn �m®�´v´YjNh2y���jNh } nd¼�®�¦U¦U�>t�¦| ¨ ¹ t��@Ö �m®�´v´YjNh2y ��jNh } nd¼�®�¦U¦U�>t�¦| � g¯ykhºsNl�n × ¹ t���Ö �m®�´�´YjUh2y���jNh } nd¼Ý®�¦{¦U�£t�¦| ¸ g¯ykhºsNl�n ©Y®�t�l¾yk��j�tvs%z���y��|U| ¹ t��@Ö gihkjmlo�'p�~vz�n p���pEyknZ�

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 4: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

Þ���$%��,¥5À��56�>5ß���( ��-,ZB �������� � $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

à G á M�âªQTã�X+ã�JWQTO JYä å H I.JLKNM�O�O} n���ykn�zxæ@f¾ç½jNèYn�hºp�yº�§n ��jUz�z�jZ� �£t�¦ u�n�~�t§��yk��j�t�pdéfU� � ´§hkjU¦Nh�sN� �>t noÖ0n�l�®myk��j�t�m� � t sUp���tvl«�0hkj�t�j�®�p�sNl¾yk���m��y(�¸0��yº�§n êrsUt��£� s�yknZu p2´���hq��yºë jU�ªs ´§hkjmlonZu�®0hqn| ��yº�§n ê�z�jmld®vp°jU��loj4t�yqhkjUz£ë jU�Ìs ´§hkjU¦NhºsU� �£t

n¾Ö�n�ld®0yk��j4t�m��yº�Ýs�y°� �§�£l«� �>p � sUt�����n�pEy ¼�� y���n n¾Ö0�>p�y:n�t�l�n j{�Ìs

´§hkjmlonZpqp°loj4t�yqhkjUz�¼�z�j0lºÏ �£t yº�§n ³ ²{��0��yº�Ýs�y n�t�y:��y�� � ���>l«� �£p sNpkpr��¦�t�nZu ykj ´§hqjml�n�pkp2jUh:p� ��yº�§n ê2u§�£pr´�s�yºlÈ�vs%¼�z�n�ë ®�t���y

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 5: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì§��3#?( ����7/� { ��>�A�£�í< �)��d������� � �3#�>�A���î$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ï G ðòñLOoX�M0ó O OoX�P§X�M ôLONõ H I.JLKNM�O�O ðòX�P§X�MfU� ��j�� n ´§hqj0lon�pkprn�p�s�hqn hkn�pr�£u�nZt�y �£t � nZ� jUh2�4��m� ¡°��n ÏUn�hºt�ndz��>p s%z���sd�§p°hqnZp2�>u�n�t4y��¸0� ³ t�n ´§hqjml�n�pkp�h:®�tvp s�y s y:�£� n{�

©ª��¦�®�hqn fUéx���§p�y:n�� � n�� jNh2� ÙTs���j�®my

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 6: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ö ��B ÞÉ3#�>�A���§��������� � �Ç�����*" $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

÷ G å à ðòX�P�X�M H I.JLKNM�O�O ø JLSLM0[wxg�¹ �£p�y���n j�t�z�� hkn�prj�®0h:l�n ��jNh � sNt�� ù�j{¼Ýp��fU�°ÕÛt4ykn�hÐ× g�hqjml�n�pkp wÛhknZs�y:��j�t�m� } �>p2´�s�yºl«� × �mlÈ��n�u�®§z��£t§¦�²{­ ®�n�®§nd�£t§¦ } �>pql���´�z��£t�n¸0�°g�sU®�p2n × » ����n j;yº��ndh�ù�j{¼Ýp�s lÈ�vsNt�l�n| �°Õ�Ö���y�× gihkjmlonZpqp�¡¢ndh:� �£tvs�yk��j4t

©Ì��¦�®0hkn �mé���y�s�y:n } �>s%¦UhºsN� jU��wxg�¹ ³ t§z�� ����pEyknZ�

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 7: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

Ã����������� � ��+���*�A�!56���:8rúNû��A������� �56��/í�'�-�2ü$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ý G H I+JLKUM0O�O V I+M�P§X.ã�JYQ�þÌÿ �LP�X SLJ�M0O ã�X ó M�P�Q����j�� n hqn+sNp2j4t�p���jUh ´§hqjml�n�pkp°l¾hqn+s�yk��j�t �£t�l�z£®�u§n{éfU� � t�n�� ¼�s�y�l«� ù�j{¼�m�°±t4ykn�h�sNlÚy:����n ³ ²{� z�jU¦{�£t¸0� ³ ²{� l¾hqn+s�yknZu| � ��´�s�� t§n�u ¼�� sNt n¾Ö��£pEyk�£t§¦ ´§hqjml�n�pkp

¡°��n ��hkn���®§n�t�l¾� jU�T´§hkjmlonZpqp°l¾hknZs�y:��j�t hkn��vnZlÚyºpÐy���nn¾Ö�´Yn�t�prn j{��l¾hqn+s�yk��j�t��

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 8: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

�§���������� � �«�*�£/m5À���A�>5ß���� �/í�'����5Ê�(Á+$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

� G H I+JLKUM0O�O �MmI�ó ã*QLP§X.ã�JWQ��£O ó MíP�QTã*Q����j�� n hqn+sNp2j4t�p���jUh ´§hqjml�n�pkpÐykn�hº� �>tvs�y:��j�t �>t�loz>®�u�n{éfU�°Ô jNh:� s%zTwxj�� ´�z�noyk��j�t�m�°Õ�Ö�lon�pkpr����n Ò nZp2j4®0h:l�n ¹ prn

µAs4¶ wxg�¹ ¡��£� n ³ ®myµ*¼Y¶ ±�t�pq®�� l���n�t4y�� n�� jNhr�µ7l+¶ ©ª��z�n p���pEyknZ� �*®§z�z�n�hqhqjNh

¸0� ��nZld®0hk��y�� Ø ��jUz!s�yk��j�t�p�²�gihkjU¦Nh�sN� � n�h Õ�hrhqjUh:pµAs4¶ ±(z�z�n�¦4s%z � uvu0hqnZpqpµ*¼Y¶ ±(z�z�n�¦4s%zL±t�pEyqhº®�lÚy:��j�tµ7l+¶ g�hq���0��z�n�¦Un�u ±�t�pEyqh:®vlÚyk��j�tµ7uR¶ } s�y�s � �>pq®vp2n µ�y(�m´Yn n�hqhqjNhȲ��£t§��yk�!s%z����Zs�y:��j�t

ndhrhqjUhǦ

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 9: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

�§���������� � �«�*�£/m5À���A�>5ß���� �/í�'����5Ê�(Á+$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

| � ����pEyknZ� p wxj�t4yqhqj{zµAs4¶ g¯s�hqnZt�y �Uj{¼ ¡¢ndh:� �£tvs�y:n�uµ*¼Y¶ ¡¢ndh:� �£tvs�y:n�u ¼�� g�s�hkn�t�yµ7l+¶ ³ ´Yndhºs�y:jNh�jNh ³ ²{� �>t�ykndh2��nZt�yk��j�t

¡°��n ��hkn���®§n�t�l¾� jU�T´§hkjmlonZpqp°l¾hknZs�y:��j�t hkn��vnZlÚyºpÐy���nn¾Ö�´Yn�t�prn j{��l¾hqn+s�yk��j�t��

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 10: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

� ��B �Ú5=<��Ý3#�>�A�£��Ç�����*"Ú�-,.��������� � ������ �!���#"$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

� G å � ã�ô�M ðòX�P§X�M ø JLSLM0[·JYä H I.JLKNM0O�O V JWQYXZI.JY[ÎÆz�jmlºÏí�£t�¦ × Ó �§n�t s ´§hkjmlonZpqpÐ��s%��yºp�j4t s t�j�t���lo´Ý®prn�h2�0�£lon µ�y��m´��>l�s%z�z�� ±r²{³ ¶È�Ò n+s%z½pE��p�y:n�� p��vsd��n ±r²{³ �vp2j s � jNhkn hqn+s%z��>p�y:�£l � jmu�n�z�£pdé

©Ì��¦�®0hqn ¸�éx��y�s�y:n } �>s%¦UhºsN� jU�¯wxg�¹ sNt�u ±r²{³ pE��pEyknZ�

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 11: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

�§���{1(�71(�'5Ê�(ÁWÇ�����*"ß 4�-,+3#?( ����7/í �û���<E5Ê�(ÁYÂ! ¿$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

" G # $LM�$LM0ã*Q�� ø JLSLM0[*O JYä ðòñLOoX�M0ó O �LP�ôLã*Q�� %'&)(� t s%h:l«�§��yknZlÚy�®0hqn � ��y�� ±r²{³ sUt�u wxg·¹ �£pdé

©Ì��¦�®0hkn | é�­ ®§n�®�n��£t�¦ � jmu§ndz�jU��wxg�¹ sUt�u ±r²{³ pE��pEykn��

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 12: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

*§��3#ú�� &E&E5À�(Á�+ 3�1( >&2�7���E5À�(Á-,%�d������ � ��� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

. G ðòÿ P0/1/Ëã�Q�� 2:ð�$TO3/�M0QTSTã*Q���4 H I.JLKNM�O�O�M0O

�m®�pr´YnZt�u��£t§¦ s gihqj0lon�pkp�× Ó ��nZt y���n ³ ²�� p:sd��nZpÆyº��npEy�s�y:n j{�Ìs t�j4t0h:®�tvt��£t�¦ ´§hkjU¦NhºsU� ��hqj�� � s%�>t� n�� jNh2� ykj sN®mÖ0��z�z��>s%h2� � n�� jNhr�4�� lÚy:���Ns�y:��j�t × Ó ��n�t yº��n ³ ²{� hqndz�j4sNu�pkp spk®�p2´Wn�t�u�nZu ´§hqj0lon�pkp��£t4ykj � s;�£t � nZ� jUh2� ��hqj��sN®íÖ���z�z��>s�hr� � n�� jNh2�����j�� n hqn+sNp2j4t�p���jUh p���s%´�´v�£t�¦ j�®my ´§hkjmlonZpqprn�pÆ��hqj��� n�� jNh2�òéfU� ����pEyknZ� � s;z��'®�t�lÚy:��j�t × �0sd�4n pEy�s�ykn sNt�u hqnZpq®�� n

s%��ykndh�~§Ö�m�°¹ p2ndh pq®�pr´��>lo��j4®�p s%¼Yj4®my°´Rs�h2y:�>s%z½hqn�pk®�z�yºp�×

} n�¼Ý®�¦U¦U�>t�¦�²%lÈ��n�l�Ï�´YjU�>t�yk�>t�¦¸0� wxjNhrhkn�l¾y pq��jUh2y°ykndh:� z�j4sNu µ*jNh � n�� jNhr�

hqn5��®���hqn�� n�t4yȶ6��®�l¾yº®vs�y:��j�tvp| ��©Ws%��hºt�n�pkp µ'j�t�n ¼���¦ ´§hkjmlonZpqpд§hqn���n�t�y�p�j;y���n�hºpx��hqj��

h:®vt�t��£t§¦�¶

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 13: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

�*ħ�����d9�úN56�!û�Â! ¿ ������3�1( £&r�7����*��3#�>�A���$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

F87 G V H 9 ÿ ã�X:� %'&)( P�QTS ð�$TO3/�M0QTSLM0S ðòX�P§X�MÓ n l�sNt n���y���n�h°ykhqnZs�y s pk®�p2´Wn�t�pr��j�t sNp°�>t�u�nd´Wn�t�u�nZt�y��hqj�� ¼vz�jml�Ï��£t�¦v��jNh sNp�� ®myº®Ýs%z�z�� n¾Ö§l�z£®�pr����n��

©Ì��¦�®0hknÆ�0é�³ ²{� pk®�´�´WjNh2y:�£t�¦ ÎÆz�j0lºÏ��>t�¦ sUt�u �m®vp2´YnZt�pr��j�t

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 14: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

�-��� ¿ &r�*���7�!5ß�#�( {�#���d������� � ��� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

FRF G ( /�MmI+P�X+ã�JWQTO JWQ H I.JLKNM�O�O�M0O} n���ykn�zxæ@f¾ç½z��>p�y�p prj�� n jU´Wn�hºs�yk��j4t�p�j�t ´§hqj0lon�pkprn�pdéfU� w�hqn+s�ykn s ´§hqj0lon�pkp�m� } nZp�ykhqjZ� µ�y:n�hº� �>tvs�ykn�¶�s ´�hqjml�n�pkp¸0�°ÎÆz�jmlºÏ s ´§hqj0lon�pkp| � �m®�pr´YnZt�u s ´§hqjml�n�pkp�m�°Ò nZpq®v� n µAsNl¾yk���Ns�ykn�¶�s ´�hqjml�n�pkp�0� wÆ�vsNt�¦{n s ´§hkjmlonZpqpd¤¥p�´§hk��jNhk��y(�� ��Ó s%ÏUn ®�´ s ´§hkjmlonZpqp 0��Ó s%ÏUn ®�´ s ´§hkjmlonZpqp µ'´Ý®my ��y �>t�ykj yº�§n hknZsNu0�

pEy�s�y:n.¶Í0�°ÕÛtÝs%¼�z�n s ´§hkjmlonZpqpÐykj loj4� � ®�t��>l�s�y:n ����yº�

sNt�jNyº��ndh°´�hqjml�n�pkp µ'�£t�y:n�hk´§hqjml�n�pkp�loj�� � ®�t��£l�s�yk��j�t�¶

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 15: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

�'Þ�� ¿ -3W >1�&E&r�#�@�{, �#�{�������� � ��� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

F§à G ( &Rð O�$;/1/�JYIZX ä JYI H I+JLKUM0O�OoM�O

¡°��n ³ ²{� �>t ��yºp°hqjUz�n sNp�hqnZp2j4®0h:l�n � sNtvs%¦{n�h sNt�u sNph:®vt y:�£� n �£t�y:n�hq�7sNl�n l�j�t�ykhqjUz>p�hqnZp2j�®�h:lon sNl�lonZpqp�¼��� s%´�´��>t�¦ ´§hqjml�n�pkp2nZpÐykj hqn�prj�®0hºlonZp��

©ª��¦�®�hqn �0é¯g�hqjml�n�pkp2nZp°sUt�u Ò n�prj�®0hºlon�p

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 16: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

�*ì§� ¿ -3=<�"6�#CE�-"��������� � �3#�!��1���!1����� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

Fmï G ( &Rð > [�J@?¢P�[ÐH I.JLKNM�O�O ðòXZIA$TK;X:$ I+M0O¡°��n ¼���¦ ´��>lÚy�®0hqn ��jNh�´§hqjml�n�pkp�� sUtvs%¦UnZ� nZt�y z�j�jUÏ0pz���ÏUn{é

©ª��¦�®�hqn � é¯g�hqjml�n�pkp2nZp°sUt�u Ò n�prj�®0hºlon�p

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 17: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

� ö � ¿ -3=<�"6�#CE�-"��������� � �3#�!��1���!1����� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

F�÷ G ø M0ó JYIZñ ÛPB?Ë[�M0O� n�� jNh2� y�s;¼�z�nZp�hqn�l�jNh:u yº�§n ��jUz�z�jZ� �£t§¦ �£t���jNhº� s�y:��j�t�éfU� ¡°��n s%z�z�jml�s�y:��j�t jU�Ë� s%�£t sNt�u sN®íÖ0��z�z��!s�h2� � n�� jNhr�

ykj ´§hkjmlonZpqprn�p�m�°� n�� jNh2� ´§hkj;yknZlÚyk��j�t µ-³ ²{� ��p��i®�prn�hºp��v®vp2ndh:p

��hqj�� n+sNl«� j;yº�§n�h���hknZsNu j�t�z�� ��p��Ì��hq��y�s%¼vz�n{��£tvp�ykh:®�l¾yk��j4t�p���pd�iuvs�y�s4¶

¸0� wxj�t�ykhqjUz��>t���jNh:� s�yk��j�t ��jNh°yº��n �m��h2yº®Ýs%zL� n�� jNh2�� sNtvs%¦Undh

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 18: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

� � � ¿ -3=<�"6�#CE�-"��������� � �3#�!��1���!1����� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

F§ý G %'&0( �PB?Ë[�M0O

� sNtvs%¦Un �vs%h:um��s�hkn loj�t�ykhqjUz·µ sNt�u ´Yn�hº�vs%´Ýp°����¦���ndhz�n���ndz½l�j�t�ykhqjUz�¶ÐjU��l«�vsUt�t�ndz>p sNt�u ´Yn�hk��´Ý�§n�hºs;z£p°�>t y���npE��p�y:n�� �

FC� G � ã*[�M ÛPB?Ë[�M0OgihkjZ�m�>u�n p2nZld®0hk��y(�4�ÝsNl�lon�pkp°loj�t4yqhqj{zA��sNtvu tvsU� �>t�¦pk®�´�´YjNhry ��jNh�´Yndh:pr�£pEyknZt�y jU¼�ùEn�lÚy�p��

F � G H I.JLKNM0O�O ÛPB?Ë[�M0O� sNtvs%¦UnZp�nZsNlÈ� �>t�u����0�£u�®vs;z�´§hqj0lon�pkpd¤¥p°uvs�y«spEyqh:®vlÚyº®�hqn�pd��p�y:jNhqnZp�p2nZld®0hk��y(� ´Wn�h:� �£pkpr��j�t�pd��sNtvu´§hkjmlonZpqp°pEy�s�y:n �>t���j��

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 19: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

�D�§�¬�d������� � � /0� Á-� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

F8" G H I+JLKUM0O�O %�ó PE�RMgihkjmlonZpqp�±�� s;¦Un × ¡��§n pEy�s�ykn �£t���jNhº� s�y:��j�tµAs�yryqhk��¼Ý®0ykn�p�¶xjU�¢yº�§n ´�hqjml�n�pkpµ7uÝs�y�s�²;p�y«sNlºÏ§²��£t�pEyqhº®myk��j�t�pd��±2²{³ p�y«s�ykn�¶È��gihkjmlonZpqp�£� s%¦UnZp�y��0´��£l�s%z�z�� loj�t�y«s%�£t�éfU�°¹ p2ndh } s�y�s�m�°¹ p2ndh�gihqj{¦NhºsN� µ*±�t�pEyqh:®vlÚyk��j�t�p�¶¸0� ����pEyknZ� ��y�sUlºÏ| �°gihkjmlonZpqp wxj�t4yqhqj{z�ÎÆz�jmlºÏ

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 20: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

�D*§�¬�d������� � ������ �!���#"�F�"6��HG� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

FC. G H I.JLKNM�O�O V JWQYXZI.JW[JI [�JLK:K�OgihkjmlonZpqp wxj�t4yqhqj{z�ÎÆz�jmlºÏmp µ'gÐwxÎ�p�¶ × ¡°��n uvs�y�spEyqh:®vlÚyº®�hqn�pÐy���n ³ ²�� s%z�z�jml�s�yknZp°��jNh � sUtvs%¦U�>t�¦ nZsNlÈ�´§hkjmlonZpqpd��loj�t�y«s%�£t§�£t�¦�éfU�°gihkjmlonZpqp��>u�n�t4yk��~Ýn�h:p�× ´�hqjml�n�pkpÆ�>u���´�s%hqn�t4y��>u��

®�prn�h��£u���m�°gihkjmlonZpqp ��y�s�y:n ±�t���j × ¹ p2ndh�Ø �>p2��¼�z�n Ò nd¦{�£pEykn�hºp��

wxj�t�ykhqjUz�Ò nd¦U�>p�y:n�hºp µAsNt�u gÐw°¶Ú��sNt�u p�y«sNlºÏ´YjU�>t�ykndh��

¸0�°gihkjmlonZpqp wxj�t4yqhqj{z�±t���j × �0l«��nZu�®�z��>t�¦ sNt�u ��y�s�y:n�£t§��j��É����p�y:n�� } s�y�s ��yqhº®�lÚy�®0hqnZp���±�t�ykndhq´§hkjmlonZpqpwxj�� � ®�t§�£l�s�yk��j4t�p��ÝgihkjmlonZpqp�´§hk���m��z�n�¦Un�pd�v� n�� jNh2�� sNtvs%¦UnZ� nZt�y���Ò n�prj�®0h:l�n ³ � t�ndh:pk����´ sNt�u¹ yk��z��L�+s�yk��j�t��

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 21: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

Þ Ä§�¬�d������� � �Ç��7/��#��?�ÇÉ����� Á-�'/í�7� ��$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

àB7 G H I.JLKNM0O�O ø M0ó JYI+ñ ø P�QLPM��M�ó M0QYXÕ�sUl«� ´§hqjml�n�pkp��£� s%¦Un �>p s%z�z�jml�s�ykn�u ��yºp°jZ� t �m��h2yº®Ýs%z� n�� jNh2���

©Ì��¦�®0hkn  0é�gihqj0lon�pkp�� n�� jNh2� � sNtvs%¦�� n�t4y

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 22: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

Þ��� ¿ -3�9� ����-,+���NFd $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

à¬F G ( &Rð 9 O�M JYä H V I O¡°��n p��§p�y:n�� sNl�lon�pkprn�pÆ´§hqjml�n�pkp2nZpÐ�m�>s yº�§nd��h gÆwxÎ�p°��jNhpEy�s�y:n ykhºsNtvp2��yk��j4t�p sNtvu pkl«��nZu�®�z��>t�¦ sNp°´Yndh pEy�s�yknu��!s%¦NhºsU� sNt�u ��®�nZ®�nd�>t�¦ � jmu�n�z£pd�gihkjmlonZpqpÐÙL�>p�y�pi× w�jUhrhqnZp2´Wj�t�u ykj �í®�n�®�nZpÆsNt�u prn�hr�m�£l�npEyqh:®vlÚyº®�hqn�p��>t �í®�n�®�n��£t�¦ � jmu�ndz �

©Ì��¦�®0hkn Í0éx³ ²{� ®vp2n jU�TgÐwxΰp°�£t gihkjmlonZpqp�Ù¢�£pEyºp

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 23: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

Þ-Þ�� ¿ -3PO;�'���(�'"d3��*��<�5Ê��� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

à�à G ( &Rð Q MmI%QLM0[°ð¬MmI+ô½ã*KUM0O

� t ³ ²{� ÏUndh:t�n�z�´§hqjZ�0�£u�nZp�´§hq���m��z�nd¦UnZu sNldl�n�pkpxy:jpE��p�y:n�� hkn�prj�®0h:l�n�pd�0h:®�t�t§�£t�¦ �£t pE��pEykn�� p�� jmu�n{�loj4t�yqhkjUz½� j0u�n{�§jNh Ï{n�h:t§ndz�� j0u�n{�¡i�m´��>l�s%z�Ñ ndh:t�n�z�prn�hr�m�£l�n�p��>t�loz>®�u�n{éfU�°gihkjmlonZpqp�� sNtvs;¦Un�� n�t�yÐ× gihkjmlonZpqp w�hknZs�y:��j�t��

gihkjmlonZpqp�¡¢ndh:� �£tvs�yk��j4t��vg�hqjml�n�pkp ������yºlÈ���£t�¦gihkjmlonZpqp ����t�l«��hqj�t����Zs�y:��j�t��§±t�y:n�hq´�hqjml�n�pkpwxj�� � ®�t§�£l�s�yk��j4t��

�m�°� n�� jNh2� � sNtvs%¦UnZ� nZt�yÐ× � z�z�jml�s�yk��j�t jU�sNu�u�hqn�pkp�pr´�sNlon ykj ´§hkjmlonZpqprn�pd�R����s%´�´��>t�¦��0�m��h2yº®Ýs%z� n�� jNh2� � sNtvs%¦UnZ� nZt�y��

¸0�°±2²�³ � sNtvs%¦UnZ� nZt�yÐ× Î�®0èYndh � sNtvs;¦Un�� n�t�yZ�u�n��m�£l�n sNtvu lÈ�vsNt�t�n�z½s%z�z�jml�s�y:��j�t y:j ´�hqjml�n�pkp2nZp

| � ����pEyknZ� p �0®�´�´YjNhryx× ±�t�ykndhrhº®�´�y �vsNt�u§z��£t§¦��� ldl�j�®�t�y:�£t�¦��§� j�t���ykjNhk�£t�¦v�

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 24: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

Þ ì§�¬�d������� � �3#ú;56�>�û�5À�(Á $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

àÝï G H I.JLKNM0O�O ðòÿ ã�X.KN�Tã*Q��gihkjmlonZpqp�pE� ��y�l«���>t�¦ �£p�y���n ³ ²�� ykhºsNt�pr��n�hrhk�£t�¦ l�j�t�yqhkjUz��hqj�� j4t�n ´§hqjml�n�pkpÐykj sNt�j;y���n�h��±pkpk®�n�p��>t�loz>®�u�n{éfU��Ó �§n�t y:j p�� ��y�l«��� gihkndnZ� ´�y:��j�t ��pd��Ô j�t

gihkndnZ� ´�y:��j�t�m� wxj�t�y:n¾Öíy ��� ��y�l«���>t�¦ × u�j�t�n sNp°��jUz�z�jZ� pdé

µAs4¶ g�hqn�prn�hr��n yº��n hº®�t�t��>t�¦ ´�hqjml�n�pkp�¤ p°p�y«s�ykn �£t y���ngÆw�Î �����ªp���s%´�´v�£t�¦ pks���n �£� s%¦Un��

µ*¼Y¶ Ù¢j4sNu ´§hqj0lon�pkp��£� s%¦Un�¤¥p°gÆwxÎ �£t�y:j pE��pEyknZ�hknd¦U�>p�y:n�h:p sNt�u � nZ� jNhr� hqn�pEykjUhqn yº��n ´§hkjU¦Nh�sN�l�j�®�t�y:n�h��

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 25: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

Þ ö �SR%1E�E��5À�(Á��!û(� ¿ -3 $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

à�÷ G T $TQTQTã*Q�� X:�LM ( &Rð

¡°��n ��jUz�z�jZ� �>t�¦ s�hqn y��m´v�£l�s;z¬j{�ª³ ²{� h:®�t yk�>� n pk®�´�´YjNhrypEyqh:®vlÚyº®�hqn�pdéfU�°Ô j�t�´§hkjmlonZpqp ³ ²{� × � � jNhqn ´§hk�£� ��y:����n

pEyqh:®vlÚyº®�hqn µ*� �� } ³ �Y�Yw�gƲ�� ¶�m� ���>t�¦Uz�n prnd´Rs�hºs�y:n Ñ ndh:t�n�z�gihqj0lon�pkp�× � � jNhqn

� j�t�jUz���yº�§�£l s%´v´§hqj4sUl«���v�vsUpÆyº��n n�� lo��n�t�l¾�sNum�UsNt�y�s;¦Un jU�T��n��Ðn�h loj�t4ykn¾Ömy pE� ��yºlÈ��n�pd��¼Ý®0y°z�n�pkp�vnoÖ0��¼�z�n µ7� sNl¾hkjUÏUn�hºt�ndz��.¶È� µ*¹ t��@Ö�²�ÙL�>t�®íÖ¬�§� sNl³ �Y�0Ø � �§� Ø �§¶È�

¸0� ����pEyknZ� prn�hr�m�£l�n�pÛ�0�>s Ñ ndh:t�n�z�sNt�u ¹ prn�h�´§hqjml�n�pkp2nZp× � � jNhqn �Ýn¾Ö0��¼�z�n s%´�´�hqj4sNlÈ� µA� �>l¾hkjUÏUn�hºt�ndz��.¶È�µ�Ó �£t�u§jZ� p°Ô ¡ �W³ ��²N�m�§� � wxÜ �Y» Ô ¹ Ü ¹ Ò } �� � ��¦4s } ³ �§¶Ú�

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 26: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

Þ-Ã��¬�d������� � ��� ��-���P�%û����'� � $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

àRý G H I+JLKUM0O�OoM0O P�QTS � I.M�P�STO��j�� n ´Yndj{´�z�n loj4t�p2�>u�n�h�y��0hqn+sNu�p�sNp s p2´Wn�lo�!s%z���jNh:� j{�´§hkjmlonZpqpd�fU�°gihkjmlonZpqprn�p°l�j�t�yqhkjUzLs ®�t���y�j{� hqn�prj�®0hºlon

jZ� t�ndh:pk����´���m� � ´§hkjmlonZpqp��>p�y��0´��£l�s%z�z�� yº��n ®�t���y jU��u��£pr´�s�y�l«���>t�¦��¸0� ¡°�0hqn+sNu�p�pk�vs�hkn ´�hqjml�n�pkp�l�j�t�y:n¾ÖíyZ�| � ¡°�0hqn+sNu�p s�hkn sNp��§t�l«�0hkj�t�j�®vp���m� ¡°�0hqn+sNu�p��vs���n z�n�pkp l�j�t�yknoÖíy�yº�vsNt ´§hkjmlonZpqprn�pd��0� ¡°�0hqn+sNu�p�l�sNt ¼Yn lohqnZs�ykn�uR²+ykndh:� �£tvs�y:n�u s�y s z�jZ�Ðn�h

loj4p�yZ�� � ¡°�0hqn+sNu�p�l�j�jU´Yndhºs�y:n y:j u�j s ´§hqj0lon�pkp��£t ´�s�h�s%z�z�ndz

� ��y�� µ*hqndz!s�yk����ndz��v¶i~�t§n ¦Nh�sNt�®�z!s�hq��y�� jU��´�s�h�s%z�z�ndz��£pk�¡°�0hqn+sNu�p s�hkn pq®§��yknZu y:j pk�vs�hkn�u � nZ� jUh2� ��� g� sNl«���>t�n�pd�

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 27: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ÞU�§�V�%û����'�-��ÇY�����AÁ-�7/í�'�-�45À�WÅi5À����'ú% �WX�$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

àM� G � I+MíP�S ø PRQLPE�RM0ó M0QYX ã�Q Y ã*QTSLJíÿ O Z ¡°�0hqn+sNu�pÆy(�m´��£l�s%z�z�� loj�j{´Yn�h�s�ykn ykj u�j yº��n p:sN� n �ÐjNhkÏsNp°s yqh�sNu���yk��j4tvs%z�´§hqj0lon�pkpd��³ ��y:n�t y���n pE��p�y:n�� p2ndh2�m�>lon�ps�hkn u�j4t�n �>t ®vp2ndh�pr´�sNl�n �£t s � �£lohqjUÏ{n�h:t§ndz½pE��p�y:n�� µ�y:j� s%ÏUn yº�§n�� h:®vt y:�£� n loj�t0~ݦ�®0hºs;¼�z�n�²:�vn¾Ö���¼�z�n � ��yº� sNtn�� lo��n�t�l¾� ´YnZtvs%z�y��v¶Ú�

©Ì��¦�®0hkn fZ¨0é wxj�j{´Yn�h�s�yk��j�t �>t s ¡i�m´��>l�s%z�¡°�0hknZsNu ����p[�yknZ� µ*Ô ¡ ¶

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 28: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

Þ � �S\^]���/0&E"ß�� `_ Ç0a43 $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

à � G b c�P�ó /Ë[�M0O d ø e ð� Ø � �vsNp ¸ y«sNp2Ï µ*´�hqjml�n�pkpº¶Ðp�y«s�yknZp�é�Ò nZsNum����� l¾yk����n{�Ó s%��y:�£t�¦��¯Õ�t�yk��hqn y«sNprÏ � sd� ¼Yn p���s%´�´Wn�u ykjsN®íÖ���z�z��>s�hr� pEykjNh�s%¦Un��wxj�t�pr�£u�ndh s y«sNprÏ l�j�� ´Yj�prn�u j{�(éfU� s � s%�>t ´§hqj{¦NhºsN� ��m� s ld®�pEykj�� n�h��>tE��®���h2� � jmu�®�z�n{�¸0� sNt jNh:u§n�h n�t4yqh2� � jmu�®�z�n sUt�u| � s ´§hqjmuv®�lÚy:��j�t yqh�sNlºÏ��>t�¦ � j0u�®�z�n

©Ì��¦4®0hqn f{fUé�� Ø � � uvu0hqnZpqp ��´RsNlon Õ�Ö�sU� ´�z�n

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 29: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ÞU�§��Ç0a43=fº5ß ��03#�>�£1�!��1����� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

àM" G ø e ð gxã*O¾X ðòX+IX$TKNX'$ I+M�O� Ø � yqh�sNlºÏ0p�p���pEyknZ� hqnZp2j4®0h:l�n�p°®�prn�u sUt�u y«sNprÏmp®�pr�£t�¦ z��£pEy p�ykh:®�l¾yº®0hkn�pd�

©Ì��¦�®0hkn fZ�mé�� Ø � Ù¢�£pEy ��yqhº®�lÚy�®0hqnZpÆÕ¯Ö�sN� ´�z�n

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 30: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ÞU*§�S\^]���/0&E"ß�� `_ 9;��5h] $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

àM. G b c�P�ó /Ë[�M0O d 9 QTãic¹ t��@Ö �vsUp s � sNl¾hkjUÏUndh:t�n�zA��sNtvu ´§hkjmlonZpqprn�p µAp2j�� n��ndh:pr��j�t�p t�jZ� �Ýsd��n yº�0hknZsNu pq®§´�´YjNhryȶÈ�

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 31: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ÞU*§�S\^]���/0&E"ß�� `_ 9;��5h] $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

©Ì��¦�®0hqn fZ¸0é�¹ t§�@Ö gihkjmlonZpqp ��y«s�yknZp

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 32: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì-ħ� ö ) ö F+3�$ 9;��5h]L3�û(�*�21�"Ê5À�(Á $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ï)7 G ÷¢õ�÷ I ð�á 9 QTãic ð�KN�LM�S1$T[�ã*Q��| � | Î � } �£� ´�z�nZ� nZt�yºp s ´�hq��jUhq��y(� pkl«��nZu�®�z�ndhÆ� ���>l«�fU�°�7sd��jNhºp°�£t�y:n�h�sNlÚy:����n ´§hkjmlonZpqprn�p�jZ�4n�h�¼�s�y�l«� ù�jU¼�p���m�°�£p�yk�£� n prz��£l�n�u µ7l�j�� ´�z�n�yk�£t§¦ s y:�£� n p2z��£lon z�jZ�Ðn�hºp

´§hk��jNhk��y��ݶÈ�¸0� u�n�ykn�l¾yºpÆ�£t�pk®8� lo��n�t�y � n�� jNh2� l�j�t�u���yk��j4t�p sNt�u

pE��s;´Ýp�j�®my�y���n z�nZsNpEy hqnZlonZt�ykz�� hº®�t ´�hqjml�n�pkp��

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 33: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì���� ö ) ö F+3�$ �d������� � �3#�>��1���!1���� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ï�F G ÷¢õ�÷ I ð�á H I+JLKUM0O�O ðòXZIA$TK;X:$ I+M| � | Î � } µ�y���n ¼RsNp2�>p°��jNh�©Ýhkndn�Î � } ¶Æ�vsUp�pq®�´v´YjNh2y ��jNh�Ns�hk�>s%¼vz�n �Ðnd��¦���y�y��0hqn+sNu�pd�0� �§n�hqn y���n Ï{n�h:t§ndz�ÏUn�nd´Ýpyqh�sNlºÏ jU�Tn+sNl«� yº�0hknZsNu���m��j+� ©Ì��¦�®0hqn � l�Ñ ®vp2�>lºÏ ©ª��¦�®�hqn | �£f Ü ndhqn

©ª��¦�®�hqn f | é | � | Î � } ¹ t��@Ö g�hqjml�n�pkp ��y�s�y:n�p

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 34: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì�Þ�� ö ) ö F+3�$ �d������� � �3#�>��1���!1���� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ïYà G ÷¢õ�÷ I ð�á H I.JLKNM�O�O b QYXZIZñÕ�sUl«� ´§hqjml�n�pkp�n�t�ykh2� loj�t�y«s%�£tvp�éfU�°gihkjmlonZpqp��>u�n�t4yk��~Rl�s�y:��j�t × ´��£u sNtvu ´�s%hqn�t4y�´v�£u�m� �mlÈ��n�u�®§z��£t§¦ × ´§hk��jNhk��y�����®�prn�hj�#� jmu�n pkl«��nZu�®�z��>t�¦��

wxg�¹ ®myk��z��L�+s�yk��j�t sNtvu y:�£� n p2´YnZt�y p2z�ndnd´v�£t�¦¸0�°gihkjmlonZpqp ��y�s�y:n × k l�mMmVnoqpsrut�v)psrwryx0z{m�|At}v)~���xxEr��

sNt�u yº�§n �6nAzD~��^�8nXmBmVrqp½u�nZpqlohq��¼v�£t�¦ yº�§n n���n�t4yx��yÆ�£p��s%��y:�£t�¦ j4t��ÝsNt�u s p�ykhq�£t§¦ u§n�pkl¾hq��¼��£t§¦ y���n no��nZt�y��

| � ����¦�tvs%zLpEy�s�ykn × ´Yn�t�u§�£t�¦ p2��¦�tvs%z>p��Rp2��¦�tvs%zL� sNprÏmpsNt�u sNl¾yk��j4t�p��

�m� ¡LhºsUlo�£t§¦ µ'��jUh u§nd¼Ý®�¦{¦U�£t�¦�¶�0�°� sNl«���>t�n ��y�s�ykn� � ¡��£� n�hºpÐ× Ò n+s%z¬yk�>� n sNtvu wxg�¹ �

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 35: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì-ì§� ö ) ö F+3�$ �d������� � �3#�>��1���!1���� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ïRï G ÷¢õ�÷ I ð�á H I+JLKUM0O�O > I.J@$;/¡°��n ´§hqj0lon�pkp�¦Nhqj4®�´ pq®�¼�p�ykh:®�l¾yº®0hkn�p�loj�t�y«s%�£t�éfU�°gihkjmlonZpqp » hkj�®�´ ±u�nZt�yk��~�l�s�yk��j4t�m�°¹ p2ndh wÛhkn�u�nZt�yk�!s%z£p¸0�°� n�� jNh2� � sNtvs%¦UnZ� nZt�y| ��©Ì��z�n } n�pkl¾hq��´�ykjUh�m�°Ò nZp2j4®0h:l�n sNl�loj�®vt�yk�>t�¦ µ sNt�u z��£� ��y�pº¶�0� ��y«s�yk�>p�y:�£ldp µ*n{� ¦���´§hkjN~vz��>t�¦ �£t���j�¶� � ����¦�tvs%z¢sUlÚyk��j�t�p 0�°¹ p2ndh ��yqhº®�lÚy�®0hqn

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 36: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì ö � ö ) ö F+3�$ �d������� � �3#�>��1���!1���� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ï�÷ G ÷¢õ�÷ I ð�á H I+JLKUM0O�O > I.J@$;/¡°��n ´§hqj0lon�pkp�¦Nhqj4®�´ pq®�¼�p�ykh:®�l¾yº®0hkn�p�loj�t�y«s%�£t�éfU�°gihkjmlonZpqp » hkj�®�´ ±u�nZt�yk��~�l�s�yk��j4t�m�°¹ p2ndh wÛhkn�u�nZt�yk�!s%z£p¸0�°� n�� jNh2� � sNtvs%¦UnZ� nZt�y| ��©Ì��z�n } n�pkl¾hq��´�ykjUh�m�°Ò nZp2j4®0h:l�n sNl�loj�®vt�yk�>t�¦ µ sNt�u z��£� ��y�pº¶�0� ��y«s�yk�>p�y:�£ldp µ*n{� ¦���´§hkjN~vz��>t�¦ �£t���j�¶� � ����¦�tvs%z¢sUlÚyk��j�t�p 0�°¹ p2ndh ��yqhº®�lÚy�®0hqn

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 37: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì�Ã�� ö ) ö F+3�$ �d������� � �3#�>�A���� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

��������� ���������� ���� ��

�� ���� ¡¢¢¡¢£¥¤ ¦¡§£ ¡¨ �©©� ª«�¬­ ¢§ ¤§ ¡¢ ®

proc

ess

acqu

ires

reso

urce

ssi

dl

ssle

ep

ssto

p

srun

fork

()

pare

nt tr

ace

orsi

gnal

cont

rol

retu

rned

wai

tfo

r ev

ent

com

plet

eev

ent

szom

bte

rmin

ated

pare

ntno

tifie

dR

esou

rces

Rec

laim

ed

¯ � ¬¡°¡  ±§« ¬­ ��� ¡¢¢¡¢« ¬§£ ¡¢ �±¬� �¢¢© ¡¡�¢§ ¤§ ¡¤ �¡²±¡ ±¡³µ´

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 38: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì¶�§�S\^]���/0&E"ß�� `_ Å�5À����'ú% ·WA� $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ï0� G b c�P�ó /Ë[�M0O d Y ã*QTSLJmÿ O Z Ó �>t�u�jZ� p°Ô ¡ �£p � ®�z�y:��y��0hqn+sNu�n�u���sNt�u s%z�z�jml�s�ykn�p�vsNtvu�z�nZp���jNh � sNtvs%¦{�£t�¦ ´§hkjmlonZpqprn�p°sNt�u hqnZp2j4®0h:l�n�pd�¡°��n sNldl�n�pkpÐykjUÏUnZt �>u�n�t4yk��~Ýn�pÆyº�§n ®�prn�h��ÝsNt�u yº��n���hprn�ld®�hq��y(� ´Wn�h:� �£pkpr��j�t�pd�

©ª��¦�®�hqn fZ�0é¯� t Ô ¡ gihkjmlonZpqp sUt�u ±#yºp�Ò n�prj�®0h:l�n�p

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 39: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì � �S¸%�-���(ú��-����3�1�&E&2�#���U, �#��$;�*C21(Á-Á#5À�(Á$%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ï � G ¹ PÝI%S½ÿ PÝI.M ð�$;/1/�JYIZX ä JYI á MC?º$��)�Yã*Q��} n�¼Ý®�¦U¦U�>t�¦ hqn5��®���hkn�p�¼Yn��£t�¦ s%¼�z�n ykj p�y:jU´ sNt�u p�y«s�h2y s´§hkjmlonZpqpd�ÌÜ s�hr��s�hqn pk®�´�´WjNh2y �£tvloz£®vu�n�pdé

» � pr´Yn�l��>s%z6o½¼wr�nX¾ x¿�Xz{m0~Ð�>t�ykndhrhº®�´�y�ykj pk®�p2´Wn�u y���nu�n�¼Ý®�¦U¦UnZu ´§hkjmlonZpqp�sNt�u pr��¦�tvs;z�yº��n u�n�¼Ý®�¦U¦{n�h��

» Ü s�h:u0��s%hqn ¼§hknZs%Ï ´YjU�>t�yºp�� ���>l«� l�sNt u�n�ykn�l¾y�éG } s�y�s Ò n+sNu�pG } s�y�s Ó hk��y:n�pG ±�t�p�ykh:®�l¾yk��j�t Ò nZsNuvpº²�Õ¯Ö0n�l�®mykn� sNt�� n¾Ö0�>p�y:�£t�¦ u�n�¼Ý®�¦U¦Undh:p°u�j t�j;y n¾Ö�´�z�jU��y�vs�hºum��s�hqn ¼�hqnZs;Ï ´Yj{�£t�y�p

¿ &2�'���A�>5À�(ÁW3#?( ����7/� �B���3ÂNà Ä-Ä ÅÆ)ºB�)ÈÇÉ����5Ê�A���@?

Page 40: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì¶�§�¬9;��5h]L3�1�&E&2�#�@�U, �#�{$%�'C21(Á-Á�5À�(Á $%�'&(�*)+�-,.����/0&21����'�43�56�7����-8:9;��5=<��'�� >5=�@?��A�4B;"DCE���-?

ï)" G 9 QTãic ð�$;/1/¯JÉI+X ä JYI á MC?º$��)�Wã*Q��¡LhºsUu���y:��j�tvs;z�z�� yº��n x@~À¼�n`�Ár pE��pEyknZ� l�s%z�z��£p ®vp2nZu ��jNhu�n�¼Ý®�¦U¦U�>t�¦��i¡°��n p��§p�y:n�� l�s;z�z·µ*�>t ©ÝhkndndÎ � } ¶xz�jíjUÏmpz���ÏUn{éÂ5Ã�ÄÅ ÄÇÆ�È8É`Ê;Ë^Â5Ã�Ä Æ¿Ê`ÌÎÍBÊ8Ï:ÄÑÐ ÒCÓ ÔÇÊ·Õ·ÊCÉNÄ)Ï ÖMÊX×·ÍCØ·Ø0Â5ÃCØ ÙBÉNÄ)ÂÛÚXÃ

Å ÂAÜ8ÝÞÄ Å ÂAÜ}Ð ÒCÓ ß·à@ÂáÉ'à Å Æ¿ÚCÉ`Ê8Ï·Ï ÄEÚ Ü8ÊX×·ÍCØ Ó`ÒÉÛÈ`Ü·ÜÆ¿ÝÞÄ È`Ü·ÜÆ�Ð ÒCÓ ß·àMÈÎÄ È`Ü·ÜÆ¿Ê8Ï·Ï ÄEÚ È8É·É`Ê8Ï·Ï Ó`ÒÂ5Ã�Ä ÜCÈÎÄ¿ÈEâ ÒCÓ ß·àMÈÎÄ ÜCÈÎÄ¿È ÄEÚ ÄÇÆ�ÈAÃ@ÏAã8ÊÎÆ Ó`Ò

Ó �§�£l«� ´Yndh:� ��yºpdé» �Ðyry«sNl«���>t�¦ ykj s ´§hqjml�n�pkp µ*�A� n{�iu�n�¼Ý®�¦ s hº®�t�t��>t�¦

´§hkjmlonZpqp�¶» } n�y�sNlÈ���£t�¦ s ´§hqj0lon�pkp µ*� � n���p�y:jU´ u§nd¼Ý®�¦{¦U�£t�¦ s

h:®vt�t��£t§¦ ´§hkjmlonZpqp�¶» � ldl�n�pkp�� n�� jNhr� sUpqprjmlo�!s�yknZu � ��yº� s ´§hqjml�n�pkp�é

ä Ò nZsNu } s�y�sä Ó hq��ykn } s�y«sä ÎÆhqnZs;Ï j�t ±tvp�ykh:®�l¾yk��j4t Ò nZsNuR²�Õ�Ö0nZld®my:nä » n�yȲ{��n�y°Ò nd¦U�>p�y:n�h°Ø�s%z>®�n�p

¿ÛåjæÀçLèêéìëîí Áµï�ðyñ é�æóò ñáôXõNïÂNà Ä-Ä Å÷öwôáöÈÇ èøí[ëùèêéLé ð

Page 41: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

ì¶�¿úSû í[ë ]�ï[ü åýåjþ�çÿé�� þ�ç��Aæ�� ü(Á-Á ëîí Á �AæÀåyé ö þ�� õ þ-ò8å ü é�æÀç ï�� ëhæóí � æ� û í[ë�øæÀç ñ ë é ð èêé ô � �ýèøí ð

» ����¦������Ûµ������������:®�´��Ú¶��º��� ����¼Ý®�¦U¦���� ´ �"!$#%��&�&('» Ô ! �"�*),+ �.-�� !{´/���.�0�"�1��2 &3+�&4�"��5 �6-��7�8�.-���&:9 ��!$#��;&"&��&:</�(�1��2 � �(<>=�2�2��;�?':@A=B&C��� 2 �.-�� DFEFG Ù$H�IEÝ�JKI �L��2B'

M �1�B#%� &C!�5 � #;���N�1& #O��� �����6=P�6� �6Q�RS� 2��*!�<S���?T��7���U��<B�N�@V�(�C�6��!FWX���(���B&Y�"! </� #Z-���#6[���� �"! �����"��#\�8�(�C�"!]�#%!^�B���_���N!���&�'

`ÛåjæÀçLèêéìëîíba ï�ðyñ é�æóò ñáôXõNï�c]dfe�e g÷öwôáöih èøí[ëùèêéLé ð

Page 42: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

j¶*¿úlk éìç�è � æ _ û í[ë ] ï[ü åýå þ�çÿé�� þøç��AæV� ü a�a�ëîíba�AæÀåyé ö þ�� õ þ-ò8å ü é�æÀç ï�� ëhæóí � æ� û í[ë�øæÀç ñ ë é ð èêé ô � �ýèøí ð

�m�� �����noqprts�vuww� ��x � ���y uzzr pz

{}|~� � �����~���������������� ��� � ��~�� �� ����� � |� �� ���� ����{���

� ��� � ��~��� � ��v|���� �  � ��¡ �� �¡ � ¢

£�¤¥ ¦¥¨§©ª«¬ £�¤¥ §«­ ®«¯¥i°±³²´ «µ «ª¥ ¯¶ «· ®¸¸£�¤¸¹ ª¥£³º ¤²±

¦£ »½¼¥¦£ » °±³²¾¿£ ª¿¦§ºª«¯¯¥ º» «· ®¸²±

ª©»»§ ¼¥ ©»» § °±³²¾¿ ©¥©»» §«¯¯¥ º©ªª«¯¯²±

£�¤¥» ©¥ ©À±³²¾¿ ©¥» ©¥ ©¥ º¥¨§© ¤¯Á « §²±

`�ÂÄÃ�ÅNÆÈÇ1ÉËÊbaÍÌÏÎbÐNÇ*ÃAÑKÐÓÒ7Ô0Ì c]dfe�e gXÕ Ò Õih Æ�Ê3ÉÖÆÈÇNÇtÎ

Page 43: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

× e Ølk Ç1Å*ÆfÙÚÃ�Û4Ü4Ê3Ù,Ç1ÉÞÝßÊ3Æ�àÖÉ�ÇtÎ á�Ã�ÂbÇ Õ Ý�âãÔ;ÝßÑPÂÄÜßÇ*Ã�Å^Ì�ÙäÉ�ÃAÊ3ÙÚÃ�å�æ Ê3É�ç�Ã�Å_Ð1É�ÇtÎèÆÈÇ^Ò àêé4Æ�Ê�Îëíì î ï ðòñòóSô�õ öø÷úùúô ðãûÚü/ùýóLþäû,ð.ÿ

����� � ���� �� ������� ������� ��� �������������� ����� �! " �#�$���$���%��& � ' � (�)'*����� � +,�.-/�0-21���354�& � ��46�6���%��&

(� '*�7�8�)� W! 9 ���:���;���<��& � (�)'=�7��� � +,�>-?�@-A�B�C'D 1(� 354�&0&D�<��& �

�C4E�6���<�(& (� '*�7�8�)� W! " � ����� �F� ��� '��#� �D�)�#'*�7�G�H� �81 I ����� � (�)'*����� ���

î J �8��1 9 �H�:� +LK,4E�6�M�C�N'@� �)��� 4���� Wî O �)��� � 9 �H�$�î P �)�8� [ '@� QR�E�B� �C46�S� �N'T� J �8��1VUHWX�=�8� 4*�C�î Y ���;U M ��� J � &D�%�B�C����Z[���%4����

! \ ��&@�E���]+L�<�@�C���)�C4��� W ����� 1���354�&D&D�81 (� '*�7�8�)� -! ^ '_� ��K`� �:��� '0����:�H� �%��& �B����� �8� ���E�a�F�:���<�b(�)'*����� �

�<�b3�� �%��& 1(� 354�&0&D��1c-b+d46�#�<�(& �:��� egfghji*k0l6m�njl oV��&6-\ �%�6�7� �#'@� � �����N�%� ���D� �)����4=��� p�qDrs� &D��'D3s���ctD�a�)�G��36�N�+,� �#����'guv��� �816�w� ' 3�� �$���8��xD�81 � ' 1���� �8�M�F� �#� '���7'T�61��y�C�N'@�E��-

z�ÂÄÃ�ÅNÆÈÇ1ÉËÊ|{ÍÌÏÎbÐNÇ*ÃAÑKÐÓÒ7Ô0ÌR}�~ e�e �XÕ Ò Õ;� Æ�Ê3ÉÖÆÈÇNÇtÎ

Page 44: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

×�� Ø æ Ê3É�����Å_Ý3Ù,â Ð�âqÉÖàÞÃPÐNÎbÐNÇ*ÃAÑ á�Ã�ÂbÇ Õ Ý�âãÔ;ÝßÑPÂÄÜßÇ*Ã�Å^Ì�ÙäÉ�ÃAÊ3ÙÚÃ�å�æ Ê3É�ç�Ã�Å_Ð1É�ÇtÎèÆÈÇ^Ò àêé4Æ�Ê�Î

ë�� î � ùúû`� ï ñãüýô0��� � þÚõ � ÿ��%ðOõ=�\ �%�6�7� �� ������� � ���j4��N�)�8��'@��� �����B�C��� �����N���� �b�<�@� 'DK1E�H�$�=r(� '*1������ � ���y� �5� t@� �s�C�8�.�C� I ���<�;� ����C� �y�:���! " �N��'8I � 1���354�&D&0����� ' &D�7� � '��)� �:�E��� ��� �%�@�

Iw'����:� 'DK�1E�H�$� �� � �B����� �8� �������]+�t(��-X�� ��������u;-! W[�D�$� � 4=�)�)���T�b6�)'*����� �F�5��� ��� ���@� ��� �<� �����

1��N�)���S� '��#����a *¡(¢*£3¤� (�)'=�7��� ���<1 +,E�<1suM-

! ��' ��� ����� �F15�H�:� �<� � (�)'=�7��� ��3�� �%��& 1�� 354(&D&D��1�r���(� 1���354�&D&0�����î ¥ ��8�6�w����� ��6(� 'D(� �%�H�C� (�)'*��K,��¦5�N�î \ ��� x � ' ����� ��66�)'D(� �%�H�C� �'@�#�y�C�N'@� �<�

� ��� '����î J �8��1 � �8� '��#� +,���NxD� � �8��1��%��& K§� '@� � ¦E���0¨©uî O �)��� � � ��� '���� +,���NxD� I�� �y�C�<��& �C' � ¦E����uî ª �N'T��� �:��� (�)'*��K,�v¦E���

z�ÂÄÃ�ÅNÆÈÇ1ÉËÊ|{ÍÌÏÎbÐNÇ*ÃAÑKÐÓÒ7Ô0ÌR}�~ e�e �XÕ Ò Õ;� Æ�Ê3ÉÖÆÈÇNÇtÎ

Page 45: nZ jUh2 ¡Ës%¼ z n pmaniatty/teaching/os/class02/lectfoils.pdf · /0&21 '43 56 7 -8:9; 5=< ' >5= @? A 4B;"DCE -? f nZ jUh2 ¡Ës%¼ z n p f ±2²{³ ¡Ës%¼ z n p f ©Ì

×�� Ø æ Ê3É�����Å_Ý3Ù,â Ð�âqÉÖàÞÃPÐNÎbÐNÇ*ÃAÑ á�Ã�ÂbÇ Õ Ý�âãÔ;ÝßÑPÂÄÜßÇ*Ã�Å^Ì�ÙäÉ�ÃAÊ3ÙÚÃ�å�æ Ê3É�ç�Ã�Å_Ð1É�ÇtÎèÆÈÇ^Ò àêé4Æ�Ê�Î

« ¬_« ­X« ® ¯�« °± qS² ³ - 9 � �y�C� �>-w´ µ ¶�µV·L�C�8¸a¹5��·Lº»�aµ ·¼� ½¾�6¿;�CÀ�·LºÁµÃÂ

Ä5Å �;·�¿MÆ �;- " 161��<�#'@� O �8�����7�¤r J �8��1(�<��&6r�� " r�q�ÇDÈDÇ=-±?É ² � -(Ê -(� �7Ê 46�#�<��x�r(Ê - P '@��� �<�Dr(� -EË Ê ���)� �%��rV���61

Ë6- \ -sÌ 4E����� � �C� ���c- Í�Î=¿ Ï ¿$�:º<Â_µ Àaµ�¸¶�Æ ��Ð�¿MÆ ¿MµV·¼À�·Lº»�aµ ��� ·dÎ=¿ ÑVÒÓÑ Ô Ä Ï ½Õ�6¿M� À�·LºÁµÃÂÄ5Å �;·�¿MÆ - " 161��%��'@� O ���#�N�7�¤r�q�ÇDÇDÖ�-

±Ø× ² O - \ �$���N���<��&@� - ½¾�(¿M�CÀ�·LºÁµÃ ÄsÅ �;·Ù¿MÆ � Úv¶�µV·�¿M�Mµ�À�ÐÛ�Àaµ�¸ Ï ¿;�:º<Â_µ Üv�;ºÁµ��Sº©�ÝÐ<¿;�;-XÞ2� ���@�C�<�7� ³ �����.rW]��&D���7Iw'j'*1 ª �N�Nß���r ^ Ë6r6à���� ��1���� �N'T�cr É�áDá qD-

z�ÂÄÃ�ÅNÆÈÇ1ÉËÊ|{ÍÌÏÎbÐNÇ*ÃAÑKÐÓÒ7Ô0ÌR}�~ e�e �XÕ Ò Õ;� Æ�Ê3ÉÖÆÈÇNÇtÎ