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<br />Sunr�m�r� of �uffer �lperat�on tween 1604's or between one 1604 and peripheral `
<br />equipment having cc�mparable speed.
<br />•The Mod�1 1604 buffer control continually inter-
<br />rogates all communication channels to determine �► 4nly one instruction is required `for a block of
<br />if; a peripheral equipment is ready to send or input or output data. A 48-bit word is transferred '
<br />receive information. in or oi�� in 4.8 microseconds.
<br />` o If a peripheral equipment has data ready for o All transfer operatinns are carried out via chan=
<br />transfer, znterrogation waits momentarily while a nel 7.
<br />word is bPing buf�'ered. Tlle buffer control then re- �u�nmary of Pr��ra�n Interru t
<br />sumes interrogating thc communica+:ion channels. �
<br />e The Model 1604 recognizes an interrupt signal
<br />�- c� Buffering initiates communication between com- �,�,hich may be either a signal indicating th�t a;
<br />,: p u t e r m e m o r y, t h e t r i r e e b u ff e r i n p u t c h a n n e l s,
<br />���pheral equip�..ent has compleied sending or
<br />�.nd the' three buH'er output channels. Thes�. buf- receiving information or it may be a iault condi ..
<br />fer information in :and aut asynchronousl�� with
<br />Lion, e.g., an overflow. �
<br />the main computer program.
<br />� ` s A subroutine determines what has caused the in, �. '
<br />' The'three buf-i'ered.: input 'channels and the three ,:
<br />, , , , terrupt, e.g., what specific periphexal equipment -' ;;
<br />` bt�ff�red output channels the interrupt line,- and
<br />' is causing the interrupt ar�d'an avhzch channe� the :
<br />t� �� the r�a� time clock are rapidly scai�ned by a scanner
<br />interrupt is taking place.
<br />which Ia�ks fdr action requests fram all channels. ;;
<br />' ` s The subroutine takes action with the origtn�.ting ;
<br />These a�ction rPyuests are initiated by the peripheral '
<br />#}' equipmen� r�y rndicator; "flags." `A complete scan is peripheral equipment by first removing`�he inter '` � 4
<br />� made in 3:2 micr��eGonds, which`carres}�onds to the ` ` r u p t si g na l to preven t re-recogni tian ',
<br />++ p�i�.s"e rat�;: nf �rria�;netic core memary. • The appropriate condition is set up in compl�ance `
<br />; ' ` : with the interrupt. If it has come fro'm a per� '
<br />,'When .a xequesti..is dete:cted, by the scanner, the ,
<br />'> ma�n computer;;prcigram is halted inomentarily to pheral equi}�menC, the actipn is c�mpleted 'after ;:
<br />r` ` mave th� data ;between niemory and the requesting Which there is a return td the ma�n computer ; �<
<br />� �. , program. ' " 4
<br />�, , ` channel The main program pr` oceeds immediately „
<br />� `,�,fter' this :action unless the scanner detects that ' � ''
<br />Su�nmary a� .Ex�ernal F���t�an .
<br />r�, a�other c�iannel has requested servicing. Ia'or exam- ,.` r>
<br />` n T his instruction rovi des con�ro l,� and � eommuni �� ��;
<br />� `ple, if` the'sysfien� includes six 1L�0? magn�txe tape P _:
<br />, ,. ,
<br />'_:sys�ems, a11 �tlircf buffered input cha�nels and alI cation between the IViodel 1�i�4 and p�ripl�er�l
<br />�'� `three bu#�erec� -out�auf channel� of the 1G04 can o:p- equipment. . It cuntains eight sub instrucfiio�s �
<br />, ;
<br />�,
<br />�� exax'e,in the l�uffer mode, simultaneousl�y servicing at which select and,sense peripheral`equipments, or `',�
<br />` 4;`��a�l tape "ra,te ttixe� 1607 rriagnetic tape un7ts oper- activate buf�'er. channels. " ,;;
<br />� r . . ; '
<br />ati�g�in f�he r�ad mode arid three 1607 magrietic �The select sub�in$�ructi�n Z4Q 1s znterpr�ted as,,; ,' ���;
<br />�<< ta�e �anits opexating, in the;write mode. follo�vs (see.illustratiori next;page)` the leftmost 6 .�;
<br />, , � , , : ;;
<br />�` �` bits are the oper�,tion code;�'the n�xt 3 b�ts des�g '. � F:
<br />, , , ..
<br />� � �.' ���i�f�� Q� ,�i� � � S �eed � nate `that,this is'a: sel'ect sub-instruction, the n�Yt;3 `;t , ' c `
<br />� � � ,_ ,
<br />`� ?' �r'�n�fer 0 " ��t'��IO�i �, ' bits are the;channel dr�internal �oriditian selectian ' ? � �;
<br /># F F ; � cod�, the next 3 bits ar.e the equipment selec#xon � r°�:
<br />�, _
<br />'���` �, rr The main coniputer progr,am per�ornls the high- code, and :t�ie ,last 9 bits spec�fy the apexafi�on�for `�' `, �
<br />�,7
<br />���f'�j 1A : speed �ngut output; t� ansfer of information be- • tlie selected equ�ipment. � � �``",;
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