,,prelim9>y ,,specifications --- ,,programm$ ,,data ,,processor ,,model ,,?ree 7,,pdp-#c7 --- ,octob]1 #aifj ,digital ,equipm5t ,corporation ,mayn>d1 ,massa*usetts ,,table ,,( ,,cont5ts ,,introduction #a ,g5]al ,description #a ,sy/em ,block ,diagram #a ,electrical ,description #d ,me*anical ,description #d ,environm5tal ,requirem5ts #e ,,c5tral ,,processor #f ,op]at+ ,spe$s #f ,in/ruction ,=mat #f ,numb] ,sy/em #g ,index+ #h ,indirect ,address+ #h ,in/ruction ,li/ #i ,manual ,controls #bj ,,/orage #bb ,,/&>d ,,input-,,output #bc ,pap] ,tape ,read] #bc ,pap] ,tape ,pun* #bd ,typewrit] #bd ,,optional ,,input-,,output #bf ,sequ5ce ,break ,sy/em #bf ,high ,spe$ ,9-,out ,*annel #bf ,magnetic ,tape #bg ,,crt ,display #cc ,real ,"t ,clock #cc ,l9e ,pr9t] #cd ,,utility ,,programs #ce ,,frap ,sy/em #ce ,,decal ,sy/em #ce ,float+ ,po9t ,subr\t9es #cf ,ma9t5ance ,r\t9es #cg ,miscellane\s ,r\t9es #cg ,,introduction ,,g5]al ,,description ,! ,,dec ,programm$ ,data ,processor ,model ,?ree 7,,pdp-#c7 is a high p]=mance1 l>ge scale digital comput] featur+ reliability 9 op]ation toge!r ) economy 9 initial co/1 ma9t5ance & use4 ,?is comb9ation is a*iev$ by ! use ( v fa/1 reliable1 solid /ate circuits c\pl$ ) sy/em design re/ra9t4 ,! simplicity ( ! sy/em design excludes _m m>g9al or sup]flu\s features & ?us _! att5dant co/ & ma9t5ance problems4 ,! av]age int]nal in/ruction execution rate is ab\t #ajj1jjj op]ations p] second ) a peak rate ( #bjj1jjj op]ations p] second4 ,?is spe$1 toge!r ) its economy & reliability1 recomm5ds ,,pdp-#c z an excell5t in/rum5t = complex real "t control applications & z ! c5t] ( a mod]n comput+ facility4 ,,pdp-#c is a /or$ program1 g5]al purpose digital comput]4 ,x is a s+le address1 s+le in/ruction ma*9e op]at+ 9 p>allel on #cf bit numb]s4 ,x features multiple /ep indirect address+ & index+ ( addresses4 ,! ma9 memory makes #eaa regi/]s available z index regi/]s4 ,! ma9 /orage is co9cid5t curr5t magnetic core modules ( #djif words ea*4 ,! comput] has a built-9 facility to address #h modules & c be exp&$ to drive #fd modules4 ,! memory has a cycle "t ( five microseconds4 ,,sy/em ,,block ,,diagram ,! fl[ ( in=mation betwe5 ! v>i\s regi/]s ( ,,pdp-#c is %[n 9 ! ,sy/em ,block ,diagram 7,fig4 #a74 ,!re are f\r regi/]s ( #cf bit l5g?4 ,_! functions are describ$ bel[4 ,memory ,buff] ,! ,memory ,buff] is ! c5tral swit*+ regi/]4 ,! ^w com+ f or go+ to memory is reta9$ 9 ?is regi/]4 ,9 ari?metic op]ations x holds ! add5d1 subtrah5d1 multiplic&1 or divisor4 ,! left #f bits ( ?is regi/] communicate ) ! ,in/ruction ,regi/]4 ,! address portion ( ! ,memory ,buff] ,regi/] communicates ) ! ,index ,add]1 ! ,memory ,address ,regi/]1 & ! ,program ,c\nt]4 ,9 c]ta9 in/ructions1 ! address portion ( ! control ^w does n ref] to memory b specifies v>iations ( an in/ruction1 ?us1 ! address portion ( ! ,memory ,buff] is connect$ to ! ,control ,elem5t4 ,accumulator ,! ,accumulator is ! ma9 regi/] ( ! ,ari?metic ,elem5t4 ,sums & diff]5ces are =m$ 9 ! ,accumulator4 ,at ! completion ( multiplication x holds ! high ord] digits ( ! product4 ,9 division x initially conta9s ! high ord] digits ( ! divid5d & is left ) ! rema9d]4 ,! logical functions ,,&1 inclusive ,,or1 & exclusive ,,or1 are =m$ 9 ! ,accumulator4 ,c>ry ,/orage ,regi/] ,! ,c>ry ,/orage ,regi/] facilitates high-spe$ multiply & is prop]ly "p ( ! ,accumulator4 ,9-,out ,regi/] ,! ,9-,out ,regi/] is ! ma9 pa? ( communication ) ext]nal equipm5t4 ,x is also "p ( ! ,ari?metic ,elem5t4 ,9 multiplication x ends ) ! l[ ord] digits ( ! product4 ,9 division x />ts ) ! l[ ord] p>ts ( ! divid5d & ends ) ! quoti5t4 ,! ,9-,out ,regi/] has a full set ( %ift+ prop]ties1 7ari?metic & logical74 99 99 99 99 99 ,!re are ?ree regi/]s ( #ae bit l5g? :i* deal exclusively ) addresses4 ,! design all[s = expansion to #ah bits4 ,^! regi/]s are3 ,memory ,address+ ,! ,memory ,address ,regi/] holds ! numb] ( ! memory location t is curr5tly be+ int]rogat$4 ,x receives ?is numb] f ! ,program ,c\nt]1 ! ,index ,add] or ! ,memory ,buff]4 ,program ,c\nt] ,! ,program ,c\nt] holds ! memory location ( ! next in/ruction to be execut$4 ,index ,add] ,! ,index ,add] is a #ae bit r+ accumulator4 ,! sum ( an in/ruction base address1 ,y1 & ! cont5ts ( an index regi/]1 ,c7x71 are =m$ 9 ?is regi/]4 ,?is regi/] holds ! previ\s cont5t ( ! ,program ,c\nt] 9 ! jump & save ,program ,c\nt]1 jps1 in/ruction4 ,! ,index ,add] also s]ves z ! /ep c\nt] 9 %ift1 multiply1 & divide4 99 99 99 99 99 ,! ,control ,elem5t conta9s two six bit regi/]s & sev]al miscellane\s flip-flops4 ,! latt] deal ) index+1 indirect address+1 memory control1 etc4 ,! six bit regi/]s are3 ,in/ruction ,regi/] ,! ,in/ruction ,regi/] receives ! fir/ six bits ( ! ,memory ,buff] ,regi/] dur+ ! cycle :i* obta9s ! in/ruction f memory 7cycle z]o74 ,?is in=mation is ! prim>y input to ! ,control ,elem5t4 ,program ,flags ,! six ,program ,flags act z conv5i5t program swit*es4 ,!y are us$ to indicate sep>ate /ates ( a program4 ,! program c set1 cle>1 or s5se ! individual flip-flops4 ,! program c also s5se or make ! /ate ,all ,flags ,,z]o4 ,!y c also be us$ to syn*ronize v>i\s input devices :i* occur at r&om times 7see ,input-,output1 ,typewrit] ,input74 99 99 99 99 99 ,?ree toggle swit* regi/]s are connect$ to ! ,c5tral ,processor 7see ,manual ,controls74 ,te/ ,address ,! fifte5 ,te/ ,address ,swit*es are us$ to indicate />t po9ts & to select memory regi/]s = manual exam9ation or *ange4 ,te/ ,^w ,! ?irty-six ,te/ ,^w ,swit*es indicate a new numb] = manual deposit into memory4 ,!y may also be us$ = ins]tion ( con/ants :ile a program is op]at+ by means ( ! op]ate in/ruction4 ,s5se ,swit*es ,! six ,s5se ,swit*es all[ ! op]ator to manually select program options or cause a jump to ano!r program 9 memory4 ,! program c s5se individual swit*es or ! /ate ,all ,swit*es ,,z]o4 ,,electrical ,,description ,! ,,pdp-#c circuitry is ! /atic type us+ saturat+ transi/or flip-flops &1 = ! mo/ "p1 transi/or swit* elem5ts4 ,! prim>y active elem5ts are ,micro-,alloy & ,micro-,alloy-,diffus$ transi/ors4 ,! flip-flops h built-9 delay s t a logic net may be sampl$ & *ang$ simultane\sly4 ,ma*9e tim+ is p]=m$ by a delay l9e *a94 ,auxili>y delay l9e *a9s "t ! /ep c\nt] in/ructions 7multiply1 divide1 etc474 ,! ma*9e is ?us int]nally syn*ron\s ) /ep c\nt] in/ructions be+ asyn*ron\s4 ,! ma*9e is asyn*ron\s = 9-out op]ations1 t is1 ! completion ( an 9-out op]ation initiates ! foll[+ in/ruction4 ,,me*anical ,,description ,! ,,pdp-#c consi/s ( two me*anical assemblies1 ! ,console & ! ,equipm5t ,frame4 ,fig4 #c is a photograph ( ,,pdp-#a :i* is an #ah bit v]sion ( ,,pdp-#c4 ,console ,! ,console is a desk approximately sev5 feet long4 ,x conta9s ! controls & indicators necess>y = op]ation & ma9t5ance ( ! ma*9e4 ,a cable connects ! ,console to ! ,equipm5t ,frame4 ,equipm5t ,frame ,! ,equipm5t ,frame is approximately six feet high & two feet deep4 ,! l5g? is a function ( ! am\nt ( optional features includ$4 ,! ,c5tral ,processor requires a l5g? ( five & "o half feet4 ,! p[] cab9et is tw5ty-two in*es long4 ,a memory cab9et is ?irty-two in*es long & w hold ?ree memory modules 7#ab1bhh words p] cab9et74 ,memory cab9ets may be add$ at any "t4 ,magnetic tape units require tw5ty-two in*es p] transport4 ,a tape unit cab9et may be connect$ z an ext5sion ( ! ,equipm5t ,frame or may be a free-/&+ frame4 ,,environm5tal ,,requirem5ts ,! ,,pdp-#c requires no special room prep>ation4 ,! comput] w op]ate prop]ly ov] ! normal range ( room temp]ature4 ,! ,c5tral ,processor & memory toge!r require ?irty amp]es ( #aaj volts s+le phase #fj cycle ac4 ,ea* inactive tape transport requires two amp]es & ! "o active transport requires #aj amp]es4 ,,c5tral ,,processor ,! ,c5tral ,processor ( ,,pdp-#c conta9s ! ,control ,elem5t1 ! ,memory ,buff] ,regi/]1 ! ,ari?metic ,elem5t1 & ! ,memory ,address+ ,elem5t4 ,! ,control ,elem5t gov]ns ! complete op]ation ( ! comput] includ+ memory tim+1 in/ruction p]=mance1 & ! initiation ( input-output comm&s4 ,! ,ari?metic ,elem5t1 :i* includes ! ,accumulator1 ! ,9-,out ,regi/]1 & ! ,c>ry ,/orage ,regi/]1 p]=ms ! ari?metic op]ations4 ,! ,memory ,address+ ,elem5t :i* includes ! ,index ,add]1 ! ,program ,c\nt]1 & ! ,memory ,address ,regi/]1 p]=ms address bookkeep+ & modification4 ,,op]at+ ,,spe$s ,op]at+ times ( ,,pdp-#c in/ructions are normally multiples ( ! memory cycle ( #e microseconds4 ,two cycle in/ructions ref] twice to memory & ?us require #aj microseconds = completion4 ,examples ( ?is are add1 subtract1 deposit1 load1 etc4 ,"o cycle in/ructions d n ref] to memory & require #e microseconds4 ,examples ( ! latt] are ! jump in/ructions1 ! skip in/ructions1 & ! op]ate gr\p4 ,! op]at+ times ( v>iable cycle in/ructions dep5d ^u ! in/ruction4 ,= example1 ! op]at+ "t = a %ift or rotate in/ruction is #e #j4b,n microseconds1 :]e ,n is ! numb] ( %ifts p]=m$4 ,! op]at+ times = multiply & divide are functions ( ! numb] ( ones 9 ! multipli] & 9 ! quoti5t1 respectively4 ,maximum "t = multiply is #be microseconds4 ,?is includes ! "t necess>y to get ! multiply in/ruction f memory4 ,divide takes #ij microseconds maximum4 ,9-,out ,transf] in/ructions t d n include ! optional wait function require #e microseconds4 ,if ! 9-out device requires a wait "t = completion1 ! op]at+ "t dep5ds ^u ! device be+ us$4 ,if an in/ruction includes ref]5ce to an index regi/]1 an additional #e microseconds is requir$4 ,ea* /ep ( indirect address+ also requires an additional #e microseconds4 ,,in/ruction ,,=mat ,! in/ructions = ,,pdp-#c may be divid$ into ?ree classes3 #a4 ,indexable memory in/ructions #b4 ,non-indexable memory in/ructions #c4 ,non-memory in/ructions4 ,! lay\t ( ! in/ruction ^w is %[n 9 ,fig4 #b4 ,! octal digits #j & #a def9e ! in/ruction code1 ?us1 !re are #fd possible in/ruction codes1 n all ( :i* are us$4 ,! fir/ bit ( octal digit #b is ! indirect address bit4 ,if ?is bit is a ,,"o1 indirect address+ occurs4 ,! index address1 ,x1 is 9 octal digits #c1 #d1 & #e4 ,^! digits address an index regi/] = memory-type in/ructions4 ,if ^! digits are all ,,z]o1 index+ w n take place4 ,9 ma9 memory1 #eaa ( ! regi/]s c be us$ z automatic index regi/]s4 ,! in/ruction base address1 ,y1 is 9 octal digits #g ?r\gh #aa4 ,^! digits are suffici5t to address #cb1gfh words ( memory4 ,octal digit #f is res]v$ = fur!r memory expansion4 ,space is available 9 ! equipm5t frame = ?is expansion1 %\ld x prove desirable4 ,9 ^? in/ructions :i* d n ref] to memory1 ! memory address digits1 ,y1 & 9 "s cases ! index address digits also1 are us$ to specify ! v>iations 9 any gr\p ( in/ructions4 ,an example ( ?is is 9 ! %ift & rotate in/ructions 9 :i* ! memory address digits det]m9e ! numb] ( %ifts4 ,,numb] ,,sy/em ,! ,,pdp-#c is a fix$ po9t ma*9e us+ b9>y ari?metic4 ,negative numb]s are repres5t$ z ! #a's complem5t ( ! positive numb]s4 ,bit #j is ! sign bit :i* is ,,z]o = positive numb]s4 ,bits #a to #ce are magnitude bits ) bit #a be+ ! mo/ significant & bit #ce be+ ! lea/ significant4 ,! actual position ( ! b9>y po9t may be arbitr>ily assign$ to be/ suit ! problem 9 h&4 ,two common conv5tions 9 ! placem5t ( ! b9>y po9t are3 #a4 ,! b9>y po9t is to ! "r ( ! lea/ significant digit1 ?us1 numb]s repres5t integ]s4 #b4 ,! b9>y po9t is to ! "r ( ! sign digit1 ?us ! numb]s repres5t a fraction :i* lies betwe5 #a4 ,! conv]sion ( decimal numb]s into ! b9>y sy/em = use by ! ma*9e may be p]=m$ automatically by subr\t9es4 ,simil>ly ! output conv]sion ( b9>y numb]s into decimals is done by subr\t9e4 ,op]ations = float+ po9t numb]s are h&l$ by programm+4 ,! utility program sy/em provides = automatic ins]tion ( ! r\t9es requir$ to p]=m float+ po9t op]ations & numb] base conv]sion 7see ,utility ,programs74 ,,index+ ,9 ,,pdp-#c1 #eaa regi/]s ( ! ma9 magnetic core memory are available = use z automatic index regi/]s4 ,_! addresses are specifi$ by octal digits #c to #e ( ! in/ruction ^w4 ,^! regi/]s are memory locations #jja-ggg 7octal74 ,address #jjj specifies t no index regi/] is to be us$ ) ! in/ructions4 ,! cont5ts ( octal digits #g ?r\gh #aa ( ! select$ index regi/] are add$ to ! unmodifi$ address 7octal digits #g ?r\gh #aa ( ! in/ruction74 ,?is sum is us$ to locate ! op]&4 ,! addition is done 9 ! ,index ,add] :i* is a #ae bit #a's complem5t add]4 ,! cont5ts ( ! ,accumulator & ! ,9-,out ,regi/] are unaffect$ by ! index+ process4 ,an in/ruction :i* has us$ index+ is reta9$ 9 memory ) its orig9al address unmodifi$4 ,memory regi/]s #a-ggg 7octal7 are available = use z normal memory regi/]s if !y are n be+ us$ z index regi/]s4 ,! left half ( ^! regi/]s is available = ! /orage ( con/ants1 tables1 etc41 :5 octal digits #g ?r\gh #aa act z index regi/]s4 ,?ree special in/ructions snx1 spx & lir1 are available to facilitate resett+1 advanc+1 & sampl+ ( ! index regi/]s4 ,s9ce ! index regi/]s are normal memory regi/]s1 _! cont5ts c also be manipulat$ by ! /&>d comput] in/ructions4 ,,indirect ,,address+ ,an in/ruction :i* is to use an indirect address w h a ,,"o 9 bit six ( ! in/ruction ^w4 ,! orig9al address1 ,y1 ( ! in/ruction w n be us$ to locate ! op]& ( ! in/ruction1 z is ! normal case4 ,in/ead1 x is us$ to locate a memory regi/] ^: cont5ts 9 octal digits #g ?r\gh #aa w be us$ z ! address ( ! orig9al in/ruction4 ,?is new address is kn[n z ! indirect address = ! in/ruction & w be us$ to locate ! op]&4 ,if ! memory regi/] conta9+ ! indirect address also has a #a 9 bit six1 ! indirect address+ proc$ure is repeat$ aga9 & a ?ird address is locat$4 ,!re is no limit to ! numb] ( times ?is process c be repeat$4 ,index regi/]s may be us$ 9 conjunction ) indirect address+4 ,9 ?is case1 ! address aft] be+ modifi$ by ! select$ index regi/] is us$ to locate ! indirect address4 ,! indirect address c be act$ on by an index regi/] & def]r$ aga9 if desir$4 ,ea* use ( an index regi/] or an indirect address ext5ds ! op]at+ "t ( ! orig9al in/ruction by #e microseconds4 ,,in/ruction ,,li/ ,?is li/ includes ! title ( ! in/ruction1 ! normal execution "t ( ! in/ruction1 i4e41 ! "t ) no index+ & no def]r+1 ! mnemonic code ( ! in/ruction1 & ! op]ation code numb]4 ,! notation us$ requires ! foll[+ def9itions4 ,! cont5ts ( a regi/] ,q are indicat$ z ,c7,q74 ,! address portion ( ! in/ruction is indicat$ by ,y4 ,! index regi/] address ( an in/ruction is indicat$ by x4 ,! effective address ( an op]& is indicat$ by ,z4 ,z may be equal to ,y or x may be ,y z modifi$ by def]r+ or by index+4 ,indexable ,memory ,in/ructions ,ari?metic ,in/ructions ,add 7#aj usec47 add x ,y ,op]ation ,code #dj ,! new ,c7,,ac7 are ! sum ( ,c7,z7 & ! orig9al ,c7,,ac74 ,! ,c7,z7 are un*ang$4 ,! addition is p]=m$ ) #a's complem5t ari?metic4 ,if ! sum exce$s ! capacity ( ! ,accumulator ,regi/]1 ! ov]fl[ flip-flop w be set 7see ,skip ,gr\p in/ructions74 ,subtract 7#aj usec47 sub x ,y ,op]ation ,code #db ,! new ,c7,,ac7 are ! orig9al ,c7,,ac7 m9us ! ,c7,z74 ,! ,c7,z7 are un*ang$4 ,! subtraction is p]=m$ us+ #a's complem5t ari?metic4 ,if ! diff]5ce exce$s ! capacity ( ! ,accumulator1 ! ov]fl[ flip-flop w be set 7see ,skip ,gr\p in/ructions74 ,multiply 7approximately #be usec47 mul x ,y ,op]ation ,code #ed ,! ,c7,,ac7 are multipli$ by ! ,c7,z74 ,! mo/ significant digits ( ! product are left 9 ! ,accumulator & ! lea/ significant digits 9 ! ,9-,out ,regi/]4 ,! previ\s ,c7,,ac7 are lo/4 ,divide 7approximately #ij usec47 div x ,y ,op]ation ,code #ef ,! ,accumulator & ! ,9-,out ,regi/] toge!r =m a #gj bit divid5d4 ,! high ord] "p ( ! divid5d is 9 ! ,accumulator4 ,! l[ ord] "p ( ! divid5d is 9 ! ,9-,out ,regi/]4 ,! divisor is 7,z74 ,^u completion ( ! division1 ! quoti5t is 9 ! ,9-,out ,regi/]4 ,! rema9d] is 9 ! ,accumulator4 ,! sign ( ! rema9d] is ! same z ! sign ( ! divid5d4 ,if ! divid5d is l>g] ?an ,c7,z71 ! ov]fl[ flip-flop w be set & ! division w n take place4 ,logical ,in/ructions ,logical ,,& 7#aj usec47 & x ,y ,op]ation ,code #jb ,! bits ( ,c7,z7 op]ate on ! correspond+ bits ( ! ,accumulator to =m ! logical ,,&4 ,! result is left 9 ! ,accumulator4 ,! ,c7,z7 are unaffect$ by ?is in/ruction4 ,logical ,,& ,function ,table ,,ac ,bit ,c7,z7 ,bit ,result #j #j #j #j #a #j #a #j #j #a #a #a ,exclusive ,,or 7#aj usec47 xor x ,y ,op]ation ,code #jf ,! bits ( ,c7,z7 op]ate on ! correspond+ bits ( ! ,accumulator to =m ! exclusive ,,or4 ,! result is left 9 ! ,accumulator4 ,! ,c7,z7 are unaffect$ by ?is ord]4 ,exclusive ,,or ,table ,,ac ,bit ,c7,z7 ,bit ,result #j #j #j #j #a #a #a #j #a #a #a #j ,inclusive ,,or 7#aj usec47 ior x ,y ,op]ation ,code #jd ,! bits ( ,c7,z7 op]ate on ! correspond+ bits ( ! ,accumulator to =m ! inclusive ,,or4 ,! result is left 9 ! ,accumulator4 ,! ,c7,z7 are unaffect$ by ?is ord]4 ,inclusive ,,or ,table ,,ac ,bit ,c7,z7 ,bit ,result #j #j #j #j #a #a #a #j #a #a #a #a ,g5]al ,in/ructions ,load ,accumulator 7#aj usec47 lac x ,y ,op]ation ,code #bj ,! ,c7,z7 are plac$ 9 ! ,accumulator4 ,! ,c7,z7 are un*ang$4 ,! orig9al ,c7,z7 are lo/4 ,deposit ,accumulator 7#aj usec47 dac x ,y ,op]ation ,code #bd ,! ,c7,,ac7 replace ! ,c7,z7 9 ! memory4 ,! ,c7,,ac7 are left un*ang$ by ?is in/ruction4 ,! orig9al ,c7,z7 are lo/4 ,deposit ,address ,"p 7#aj usec47 dap x ,y ,op]ation ,code #bf ,octal digits #f ?r\gh #aa ( ! ,accumulator replace ! correspond+ digits ( memory regi/] ,z4 ,c7,,ac7 are un*ang$ z are ! cont5ts ( octal digits #j ?r\gh #e ( ,z4 ,! orig9al cont5ts ( octal digits #f ?r\gh #aa ( ,z are lo/4 ,deposit ,in/ruction ,"p 7#aj usec47 dip x ,y ,op]ation ,code #cj ,octal digits #j ?r\gh #e ( ! ,accumulator replace ! correspond+ digits ( memory regi/] ,z4 ,! ,accumulator is un*ang$ z are digits #f ?r\gh #aa ( ,z4 ,! orig9al cont5ts ( octal digits #j ?r\gh #e ( ,z are lo/4 ,load ,9-,out ,regi/] 7#aj usec47 lio x ,y ,op]ation ,code #bb ,! ,c7,z7 are plac$ 9 ! ,9-,out ,regi/]4 ,c7,z7 are un*ang$4 ,! orig9al ,c7,,io7 are lo/4 ,deposit ,9-,out ,regi/] 7#aj usec47 dio x ,y ,op]ation ,code #cb ,! ,c7,,io7 replace ! ,c7,z7 9 memory4 ,! ,c7,,io7 are unaffect$ by ?is in/ruction4 ,! orig9al ,c7,z7 are lo/4 ,jump 7#e usec47 jmp x ,y ,op]ation ,code #fj ,! ,program ,c\nt] is reset to address ,z4 ,! next in/ruction t w be execut$ w be tak5 f memory regi/] ,z4 ,! orig9al cont5ts ( ! ,program ,c\nt] are lo/4 ,jump & ,save ,program ,c\nt] 7#e usec47 jsp x ,y ,op]ation ,code #fb ,! cont5ts ( ! ,program ,c\nt] are transf]r$ to ! ,index ,add]4 ,:5 ! transf] takes place1 ! ,program ,c\nt] holds ! address ( ! in/ruction foll[+ ! jsp4 ,! ,program ,c\nt] is !n reset to address ,z4 ,! next in/ruction t w be execut$ w be tak5 f memory regi/] ,z4 ,skip if ,accumulator & ,z diff] 7#aj usec47 sad x ,y ,op]ation ,code #ej ,! ,c7,z7 are comp>$ ) ! ,c7,,ac74 ,if ! two numb]s are diff]5t1 ! ,program ,c\nt] is index$ "o extra position & ! next in/ruction 9 ! sequ5ce is skipp$4 ,! ,c7,,ac7 & ! ,c7,z7 are unaffect$ by ?is op]ation4 ,skip if ,accumulator & ,z are ! same 7#aj usec47 sas x ,y ,op]ation ,code #eb ,! ,c7,z7 are comp>$ ) ,c7,,ac74 ,if ! two numb]s are id5tical1 ! ,program ,c\nt] is index$ "o extra position & ! next in/ruction 9 ! sequ5ce is skipp$4 ,! ,c7,,ac7 & ,c7,z7 are unaffect$ by ?is op]ation4 ,non-,indexable ,memory ,in/ructions ,^! in/ructions h ! same ^w =mat z ! indexable in/ructions4 ,s9ce !y op]ate on ! index regi/] location1 x1 !y _c be index$4 ,skip on ,negative index 7#aj usec47 snx x ,y ,op]ation ,code #df ,! numb] 9 octal digits #g ?r\gh #aa ( ! in/ruction ^w is add$ to ! ,c7x74 ,?is addition is done 9 ! #ae bit ,index ,add] us+ #a's complem5t ari?metic4 ,if1 aft] ! addition1 ! sum is negative1 ! ,program ,c\nt] is advanc$ "o extra position & ! next in/ruction 9 ! sequ5ce is skipp$4 ,! cont5ts ( octal digits #j-e ( ! index regi/] location are unaffect$ by ?is in/ruction4 ,skip on ,positive index 7#aj usec47 spx x ,y ,op]ation ,code #dd ,! numb] 9 octal digits #g ?r\gh #aa ( ! in/ruction ^w is add$ to ! ,c7x74 ,?is addition is done 9 ! #ae bit ,index ,add] us+ #a's complem5t ari?metic4 ,if1 aft] ! addition1 ! sum is positive1 ! ,program ,c\nt] is advanc$ "o extra position & ! next in/ruction 9 ! sequ5ce is skipp$4 ,! cont5ts ( octal digits #j-e ( ! index regi/] location are unaffect$ by ?is in/ruction4 ,load ,index ,regi/] 7#aj usec47 lir x ,y ,op]ation ,code #ad ,! octal digits #g ?r\gh #aa 7,y7 ( ! in/ruction w replace ! correspond+ digits ( ! memory regi/] specifi$ by x4 ,octal digit #f ( ! memory regi/] w be left cle>4 ,digits #j-e ( ! memory regi/] are un*ang$4 ,deposit ,index ,add] 7#aj usec47 dia x ,y ,op]ation ,code #af ,! ,c7,,ia7 replace ! octal digits #g ?r\gh #aa ( memory location ,y4 ,octal digit #f ( ,y is cle>$4 ,digits #j ?r\gh #e ( ,y are left un*ang$4 ,! x portion ( ! in/ruction is ignor$4 ,non-,memory ,in/ructions ,rotate & ,%ift ,gr\p ,?is gr\p ( in/ructions w rotate or %ift ! ,accumulator &_/or ! ,9-,out ,regi/]4 ,:5 ! two regi/]s op]ate comb9$1 ! ,9-,out ,regi/] is consid]$ to be a #cf bit magnitude ext5sion ( ! "r end ( ! ,accumulator4 ,rotate is a non-ari?metic cyclic %ift4 ,t is1 ! two ends ( ! regi/] are logically ti$ toge!r & in=mation is rotat$ z ?\gh ! regi/] 7 a r+4 ,%ift is an ari?metic op]ation & is 9 effect multiplication ( ! numb] 9 ! regi/] by #b,n1 :]e ,n is ! numb] ( %ifts4 ,%ift or rotate in/ructions involv+ m ?an #cc /eps c be us$ = simulat+ "t delays4 #cf rotate /eps ( ! ,accumulator w return all in=mation to its orig9al position4 ,rotate ,accumulator ,"r 7#ac usec4 maximum = #cf %ifts7 r> ,n ,op]ation ,code #fga ,?is in/ruction w rotate ! bits ( ! ,accumulator "r ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ructions ^w4 ,rotate ,accumulator ,left 7#ac usec4 maximum = #cf %ifts7 ral ,n ,op]ation ,code #ffa ,?is in/ruction w rotate ! bits ( ! ,accumulator left ,n ,positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,%ift ,accumulator ,"r 7#ac usec4 maximum = #cf %ifts7 s> ,n ,op]ation ,code #fge ,?is in/ruction w %ift ! cont5ts ( ! ,accumulator "r ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,%ift ,accumulator ,left 7#ac usec4 maximum = #cf %ifts7 sal ,n ,op]ation ,code #ffe ,?is in/ruction w %ift ! cont5ts ( ! ,accumulator left ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,rotate ,9-,out ,regi/] ,"r 7#ac usec4 maximum = #cf %ifts7 rir ,n ,op]ation ,code #fgb ,?is in/ruction w rotate ! bits ( ! ,9-,out ,regi/] "r ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,rotate ,9-,out ,regi/] ,left 7#ac usec4 maximum = #cf %ifts7 ril ,n ,op]ation ,code #ffb ,?is in/ruction w rotate ! bits ( ! ,9-,out ,regi/] left ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,%ift ,9-,out ,regi/] ,"r 7#ac usec4 maximum = #cf %ifts7 sir ,n ,op]ation ,code #fgf ,?is in/ruction w %ift ! cont5ts ( ! ,9-,out ,regi/] "r ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,%ift ,9-,out ,regi/] ,left 7#ac usec4 maximum = #cf %ifts7 sil ,n ,op]ation ,code #fff ,?is in/ruction w %ift ! cont5ts ( ! ,9-,out ,regi/] left ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,rotate ,,ac & ,,io ,"r 7#ac usec4 maximum = #cf %ifts7 rcr ,n ,op]ation ,code #fgc ,?is in/ruction w rotate ! bits ( ! comb9$ regi/] "r 9 a s+le r+ ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,rotate ,,ac & ,,io ,left 7#ac usec4 maximum = #cf %ifts7 rcl ,n ,op]ation ,code #ffc ,?is in/ruction w rotate ! bits ( ! comb9$ regi/] left 9 a s+le r+ ,n position1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,%ift ,,ac & ,,io ,"r 7#ac usec4 maximum = #cf %ifts7 scr ,n ,op]ation ,code #fgg ,?is in/ruction w %ift ! cont5ts ( ! comb9$ regi/] "r ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 ,%ift ,,ac & ,,io ,left 7#ac usec4 maximum = #cf %ifts7 scl ,n ,op]ation ,code #ffg ,?is in/ruction w %ift ! cont5ts ( ! comb9$ regi/]s left ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w4 99 99 99 99 99 ,skip ,gr\p 7#e usec47 skp ,y ,op]ation ,code #fd ,?is gr\p ( in/ructions s5ses ! /ate ( v>i\s flip-flops & swit*es 9 ! ma*9e4 ,x does n require any ref]5ce to memory4 ,! address portion ( ! in/ruction selects ! p>ticul> function to be s5s$4 ,all memb]s ( ?is gr\p h ! same op]ation code4 ,skip on ,,z]o ,accumulator 7#e usec47 sza ,address #ajj ,if ! ,accumulator is equal to plus ,,z]o 7all bits are ,,z]o7 ! ,program ,c\nt] is advanc$ "o extra position & ! next in/ruction 9 ! sequ5ce is skipp$4 ,skip on ,plus ,accumulator 7#e usec47 spa ,address #bjj ,if ! sign bit ( ! ,accumulator is ,,z]o1 ! ,program ,c\nt] is advanc$ "o extra position & ! next in/ruction 9 ! sequ5ce is skipp$4 ,skip on ,m9us ,accumulator 7#e usec47 sma ,address #djj ,if ! sign bit ( ! ,accumulator is ,,"o1 ! ,program ,c\nt] is advanc$ "o extra position & ! next in/ruction 9 ! sequ5ce is skipp$4 ,skip on ,,z]o ,ov]fl[ 7#e usec47 szo ,address #ajjj ,if ! ov]fl[ flip-flop is a ,,z]o ! ,program ,c\nt] is advanc$ "o extra position & ! next in/ruction 9 ! sequ5ce w be skipp$4 ,! ov]fl[ flip-flop is cle>$ by ?is in/ruction4 ,?is flip-flop is set by addition1 subtraction1 or division t exce$s ! capacity ( ! ,accumulator4 ,! ov]fl[ flip-flop is n cle>$ by ari?metic op]ations :i* d n cause an ov]fl[4 ,?us1 a :ole s]ies ( ari?metic op]ations may be *eck$ = correctness by a s+le szo4 ,! ov]fl[ flip-flop is cle>$ by ! ,/>t ,swit*4 ,skip on ,plus ,9-,out ,regi/] 7#e usec47 spi ,address #bjjj ,if ! sign digit ( ! ,9-,out ,regi/] is ,,z]o ! ,program ,c\nt] is index$ "o extra position & ! next in/ruction 9 ! sequ5ce is skipp$4 ,skip on ,,z]o ,swit* 7#e usec47 szs ,addresses #aj1 #bj1 444 #gj ,if ! select$ ,s5se ,swit* is ,,z]o1 ! ,program ,c\nt] is advanc$ "o extra position & ! next in/ruction 9 ! sequ5ce w be skipp$4 ,address #aj s5ses ! position ( ,s5se ,swit* #a1 ,address #bj ,swit* #b1 etc4 ,address #gj s5ses all ! swit*es4 ,if #gj is select$ all #f swit*es mu/ be ,,z]o to cause ! skip to occur4 ,skip on ,,z]o ,program ,flag 7#e usec47 szf ,addresses #j to #g inclusive ,if ! select$ program flag is a ,,z]o1 ! ,program ,c\nt] is advanc$ "o extra position & ! next in/ruction 9 ! sequ5ce w be skipp$4 ,address #j is no selection4 ,address #a selects program flag "o1 etc4 ,address #g selects all programs flags4 ,all flags mu/ be ,,z]o to cause ! skip4 ,! in/ructions 9 ! ,"o ,cycle ,skip gr\p may be comb9$ to =m ! inclusive ,,or ( ! sep>ate skips4 ,?us1 if address #cjjj is select$1 ! skip w\ld occur if ! ov]fl[ flip-flop equals ,,z]o or if ! ,9-,out ,regi/] is positive4 ,! comb9$ in/ruction w\ld /ill take #e microseconds4 99 99 99 99 99 ,op]ate ,gr\p 7#e usec47 opr ,y ,op]ation ,code #gf ,?is in/ruction gr\p p]=ms miscellane\s op]ations on v>i\s ,c5tral ,processor ,regi/]s4 ,! address portion ( ! in/ruction specifies ! action to be p]=m$4 ,cle> ,9-,out ,regi/] 7#e usec47 cli ,address equal #djjj ,?is in/ruction cle>s ! ,9-,out ,regi/]4 ,load ,accumulator f ,te/ ,^w 7#e usec47 lat ,address #bjjj ,?is in/ruction =ms ! inclusive ,,or ( ! ,c7,,ac7 & ! cont5ts ( ! ,te/ ,^w4 ,?is in/ruction is usually comb9$ ) address #bjj 7cle> ,accumulator71 s t ,c7,,ac7 w equal ! cont5ts ( ! ,te/ ,^w ,swit*es4 ,complem5t ,accumulator 7#e usec47 cma ,address #ajjj ,?is in/ruction complem5ts 7makes negative7 ! cont5ts ( ! ,accumulator4 ,halt hlt ,address #djj ,?is in/ruction /ops ! comput]4 ,cle> ,accumulator 7#e usec47 cla ,address #bjj ,?is in/ruction cle>s 7sets equal to plus #j7 ! cont5ts ( ! ,accumulator4 ,cle> ,select$ ,program ,flag 7#e usec47 clf ,address #ja to #jg inclusive ,! select$ program flag w be cle>$4 ,address #jj selects no program flag1 #ja cle>s program flag #a1 #jb cle>s program flag #b1 etc4 ,address #jg cle>s all program flags4 ,set ,select$ ,program ,flag 7#e usec47 /f ,address #aa to #ag inclusive 99 99 99 99 99 ,9-,out ,transf] ,gr\p 7#e usec4 )\t 9-out wait7 iot x ,y ,op]ation ,code #gb ,! v>iations )9 ?is gr\p ( in/ructions p]=m all ! 9-out control & in=mation transf] functions4 ,if bit six 7normally ! ,indirect ,address bit7 is a ,,"o1 ! comput] w halt & wait = ! completion pulse f ! device activat$4 ,:5 ?is device deliv]s its completion1 ! comput] w resume op]ation ( ! in/ruction sequ5ce4 ,an incid5tal fact :i* may be ( importance 9 c]ta9 sci5tific or real "t control applications is t ! "t orig9 ( op]ations foll[+ an 9-out completion pulse is id5tical ) ! "t ( t pulse4 ,mo/ 9-out op]ations require a kn[n m9imum "t be=e completion4 ,?is "t may be utiliz$ = programm+4 ,! appropriate ,9-,out ,transf] is giv5 ) no 9-out wait 7bit six a ,,z]o74 ,! in/ruction sequ5ce !n cont9ues4 ,?is sequ5ce mu/ include an iot in/ruction :i* p]=ms no?+ b ! 9-out wait4 ,?is la/ in/ruction mu/ occur be=e ! safe m9imum "t4 ,a table ( m9imum times = all 9-out devices is deliv]$ ) ! comput]4 ,x li/s m9imum "t be=e completion pulse & m9imum ,9-,out ,regi/] free "t4 ,! details ( ! ,9-,out ,transf] v>iations are li/$ "u ,input-,output4 ,! mnemonic codes & addresses = ! /&>d equipm5t are3 ,read ,pap] ,tape ,alphanum]ic ,mode rpa ,address #a ,read ,pap] ,tape ,b9>y ,mode rpb ,address #b ,typewrit] ,output tyo ,address #c ,typewrit] ,input tyi ,address #d ,pun* ,pap] ,tape ,alphanum]ic ,mode ppa ,address #e ,pun* ,pap] ,tape ,b9>y ,mode ppb ,address #f ,,manual ,,controls ,! ,console ( ,,pdp-#c has controls & indicators = ! use ( ! op]ator4 ,fig4 #d is a close-up ( ! control panel ( ,,pdp-#a1 ! #ah bit v]sion ( ,,pdp-#c4 ,all comput] flip-flops h indicator lights on ! ,console4 ,^! indicators are prim>ily = use :5 ! ma*9e has /opp$ or :5 ! ma*9e is be+ op]at$ "o /ep at a "t4 ,:ile ! ma*9e is runn+1 ! brightness ( an indicator be>s "s relation%ip to ! relative duty factor ( t p>ticul> flip-flop4 ,?ree regi/]s ( toggle swit*es are available on ! ,console4 ,^! are ! ,te/ ,address 7#ae bits71 ! ,te/ ,^w 7#cf bits71 & ! ,s5se ,swit*es 7#f bits74 ,! fir/ two are us$ 9 conjunction ) ! op]at+ pu% buttons4 ,! ,s5se ,swit*es are pres5t = manual int]v5tion4 ,! use ( ^! swit*es is det]m9$ by ! program 7see ,sy/em ,block ,diagram & ,skip ,gr\p ,in/ructions74 ,op]at+ ,pu% ,buttons ,/>t - ,:5 ?is swit* is op]at$1 ! comput] w />t4 ,! fir/ in/ruction comes f ! memory location indicat$ 9 ! ,te/ ,address ,swit*es4 ,/op - ,! comput] w come to a halt at ! completion ( ! curr5t memory cycle4 ,cont9ue - ,! comput] w resume op]ation />t+ at ! /ate indicat$ by ! lights4 ,exam9e - ,! cont5ts ( ! memory regi/] indicat$ 9 ! ,te/ ,address w be display$ 9 ! ,accumulator & ! ,memory ,buff] lights4 ,deposit - ,! ^w select$ by ! ,te/ ,^w ,swit*es w be put 9 ! memory location indicat$ by ! ,te/ ,address ,swit*es4 ,read-,9 - ,:5 ?is swit* is op]at$1 ! photoelectric pap] tape read] w />t op]at+ 9 ! ,read-,9 mode4 7see ,input-,output74 ,9 addition to ! op]at+ pu% buttons1 !re are sev]al sep>ate toggle swit*es4 ,s+le ,cycle ,swit* - ,:5 ! ,s+le ,cycle ,swit* is on1 ! comput] w halt at ! completion ( ea* memory cycle4 ,?is swit* is p>ticul>ly useful 9 debugg+ programs4 ,repeat$ op]ation ( ! ,cont9ue ,swit* button w /ep ! program "o cycle at a "t4 ,! programm] is ?us able to exam9e ! ma*9e /ates at ea* /ep4 ,te/ ,swit* - ,:5 ! ,te/ ,swit* is on1 ! comput] w p]=m ! in/ruction indicat$ 9 ! ,te/ ,address location4 ,x w repeat ?is in/ruction ei!r at ! normal spe$ rate or at a s+le cycle rate if ! ,s+le ,cycle ,swit* is up4 ,?is swit* is prim>ily useful = ma9t5ance purposes4 ,s5se ,swit*es - ,!re are six swit*es on ! ,console :i* are pres5t = manual int]v5tion4 ,,/orage ,! int]nal ,memory ,sy/em = ,,pdp-#c consi/s ( modules ( #djif words ( co9cid5t curr5t magnetic core /orage4 ,ea* ^w has #cf bits4 ,! memory modules op]ate ) a read-rewrite cycle "t ( #e microseconds4 ,! driv+ curr5ts ( ! memory are automatically adju/$ to comp5sate = normal room temp]ature v>iations4 ,ea* core memory module consi/s ( ! memory /ack1 ! requir$ ,x & ,y swit*es1 ! ,x & ,y curr5t s\rces & s5se amplifi]s = t /ack4 ,! ,memory ,address ,regi/]1 ! ,memory ,buff] ,regi/]1 & ! ,memory ,tim+ ,controls are consid]$ to be "p ( ! ,c5tral ,processor4 ,! /&>d ,,pdp-#c ,memory ,address ,regi/] configuration is built to all[ up to #h modules ( core memory 7#cb1gfh words74 ,!re is a space 9 ! address+ section ( ! ma*9e to all[ expansion ( ! address+ by a factor ( eight = a total address+ capacity ( #bfb1add memory regi/]s4 ,! ,core ,memory may be supplem5t$ by ,magnetic ,tape ,/orage4 ,?is is describ$ "u ,input-,output4 ,,/&>d ,,input-,,output ,! ,,pdp-#c is design$ to accommodate a v>iety ( input-output equipm5t4 ,/&>d input-output units include a ,pap] ,tape ,read]1 ,pap] ,tape ,pun* & an ,electric ,typewrit]4 ,a s+le in/ruction1 ,9-,out ,transf] 7see ,c5tral ,processor71 p]=ms all 9-out op]ations ?r\gh ! #cf bit ,9-,out ,regi/]4 ,! address portion ( ?is in/ruction specifies ! 9-out function4 ,"o bit ( ! in/ruction selects an 9-out halt z requir$4 ,,pap] ,,tape ,,read] ,! ,pap] ,tape ,read] ( ! ,,pdp-#c is a photoelectric device capable ( read+ #cjj l9es p] second4 ,six l9es =m ! /&>d #cf bit ^w :5 read+ b9>y pun*$ eight hole tape4 ,five1 six & sev5 hole tape may also be read4 ,! read] w op]ate 9 "o ( two basic modes or 9 a ?ird special mode4 ,alphanum]ic ,mode rpa iot #a ,9 ?is mode1 "o l9e ( tape is read = ea* ,9-,out ,transf]4 ,all eight holes ( ! l9e are read4 ,! in=mation is left 9 ! "r eight bits ( ! ,9-,out ,regi/]1 ! rema9d] ( ! regi/] be+ left cle>4 ,! /&>d ,,pdp alphanum]ic pap] tape code includes an odd p>ity bit :i* may be *eck$ by ! program4 ,tape ( non-/&>d wid? w\ld be read 9 ?is mode4 ,b9>y ,mode rpb iot #b ,= ea* ,9-,out ,transf] in/ruction1 six l9es ( pap] tape are read & assembl$ 9 ! ,9-,out ,regi/] to =m a full comput] ^w4 ,= a l9e to be recogniz$ 9 ?is mode1 ! eigh? hole mu/ be pun*$2 i4e41 l9es ) no eigh? hole w be skipp$ ov]4 ,! sev5? hole is ignor$4 ,! patt]n ( holes 9 ! b9>y tape is arrang$ s z to be easily int]pret$ visually 9 t]ms ( ma*9e in/ruction4 ,read-,9 ,mode ,?is is a special mode activat$ by ! ,read-,9 ,swit* on ! ,console4 ,x provides a means ( ent]+ programs :i* nei!r rely on read-9 programs 9 memory nor require a plug bo>d4 ,pu%+ ! ,read-,9 ,swit* />ts ! read] 9 ! b9>y mode4 ,! fir/ gr\p ( six l9es & alt]nate succe$+ gr\ps ( six l9es are int]pret$ z ,read-,9 mode in/ructions4 ,ev5-numb]$ gr\ps ( #f l9es are data4 ,! ,read-,9 mode in/ructions mu/ be ei!r deposit 9-out 7dio ,y7 or jump 7jmp ,y74 ,if ! in/ruction is dio ,y1 ! next gr\p ( six b9>y l9es w be /or$ 9 memory location ,y & ! read] cont9ues mov+4 ,if ! in/ruction is jmp ,y1 ! ,read-,9 mode is t]m9at$ & ! comput] w comm5ce op]ation at ! address ( ! jump in/ruction4 ,,pap] ,,tape ,,pun* ,! /&>d ,,pdp-#c ,pap] ,tape ,pun* has a nom9al spe$ ( #bj l9es p] second4 ,x c op]ate 9 ei!r ! alphanum]ic mode or ! b9>y mode4 ,alphanum]ic ,mode ppa iot #e ,= ea* ,9-,out ,transf] in/ruction "o l9e ( tape is pun*$4 ,9-,out ,regi/] bit #ce conditions hole #a4 ,bit #cd conditions hole #b1 etc4 ,bit #bh conditions hole #h4 ,b9>y ,mode ppb iot #f ,= ea* ,9-,out ,transf] in/ruction "o l9e ( tape is pun*$4 ,9-,out ,regi/] bit five conditions hole #a4 ,bit f\r conditions hole #b1 etc4 ,bit z]o conditions hole #f4 ,hole #g is left blank4 ,! #h hole is always pun*$ 9 ?is mode4 ,,typewrit] ,! ,typewrit] w op]ate 9 ! input mode or ! output mode4 ,output ,mode tyo iot #c ,= ea* ,9-,out ,transf] in/ruction "o "* is typ$4 ,! "* is specifi$ by ! "r six bits ( ! ,9-,out ,regi/]4 ,input ,mode tyi iot #d ,?is op]ation is completely asyn*ron\s & is !re=e h&l$ diff]5tly ?an any ( ! prec$+ 9-out op]ations4 ,:5 a ,typewrit] key is /ruck1 ,program ,flag ,numb] ,"o is set4 ,at ! same "t ! code = ! /ruck key is pres5t$ to gates connect$ to ! "r six bits ( ! ,9-,out ,regi/]4 ,?is in=mation w rema9 at ! gate = a relatively long "t by virtue ( ! sl[ me*anical action4 ,a program design$ to accept typ$-9 data w\ld p]iodically *eck ! /atus ( ,program ,flag ,"o4 ,if at any "t ,program ,flag ,"o is f\nd to be set1 an ,9-,out ,transf] in/ruction ) address f\r mu/ be execut$ = in=mation to be transf]r$4 ,?is ,9-,out ,transf] normally %\ld n use ! optional 9-out halt4 ,! in=mation conta9$ 9 ! ,typewrit]'s cod] is !n read into ! "r six bits ( ! ,9-,out ,regi/]4 ,,optional ,,input-,,output ,! ,,pdp-#c is design$ to accommodate a v>iety ( input-output equipm5t4 ,( p>ticul> int]e/ is ! ease ) :i* new1 & p]haps unusual1 ext]nal equipm5t c be add$ to ! ma*9e4 ,optional 9-out devices include ,ca?ode ,ray ,tube ,display1 ,magnetic ,tape1 ,real ,"t ,clock1 ,l9e ,pr9t] & ,analog to ,digital ,conv]t]s4 ,! me?od ( op]ation ( ,,pdp-#c ) ^! optional devices is simil> to ! /&>d input-output equipm5t4 ,,sequ5ce ,,break ,,sy/em ,an optional 9-out control is available = ,,pdp-#c4 ,?is control1 t]m$ ! ,sequ5ce ,break ,sy/em1 all[s concurr5t op]ation ( sev]al 9-out devices & ! ma9 sequ5ce4 ,! sy/em has1 nom9ally1 #af automatic int]rupt *annels arrang$ 9 a priority *a94 ,a break to a p>ticul> sequ5ce may be initiat$ by ! completion ( an 9-out device1 ! program1 or an ext]nal signal4 ,if ?is sequ5ce has priority1 ! ,c7,,ac71 ,c7,,io71 ,c7,,pc71 & ,c7,,ia7 are /or$ 9 ?ree fix$ memory locations unique to t sequ5ce4 ,s9ce ! ,c7,,pc7 & ,c7,,ia7 are eighte5 bits ea*1 ^! two regi/]s are /or$ 9 "o memory location4 ,! next in/ruction is tak5 f a f\r? location4 ,?is in/ruction is usually a jump to a suitable r\t9e4 ,! program is n[ op]at+ 9 ! new sequ5ce4 ,?is new sequ5ce may be brok5 by a high] priority sequ5ce4 ,a typical program loop = h&l+ an 9-out sequ5ce w\ld conta9 #c to #e in/ructions1 includ+ ! appropriate iot4 ,^! are foll[$ by load ,,ad & load ,,io f ! fix$ locations & a special indirect jump ?r\gh ! location ( ! previ\s ,c7,,pc74 ,?is special jump also loads ! ,,ia4 ,?is la/ in/ruction t]m9ates ! sequ5ce4 ,,high ,,spe$ ,,9-,,out ,,*annel ,! device connect$ to an 9-out *annel communicates directly ) memory ?r\gh ! ,memory ,buff] ,regi/]4 ,at ! completion ( ea* ma*9e in/ruction1 a *eck is made to see if ! 9-out *annel has a ^w =1 or ne$s a ^w f1 ! memory4 ,:5 necess>y1 a memory cycle is tak5 to s]ve ! *annel4 ,! op]ation is initiat$ by an 9-out comm&4 ,! 9-out transf] comm& indicates ! nature ( ! transf]4 ,! left half ( ! ,9-,out ,regi/] mu/ conta9 ! />t+ address ( ! transf]1 & ! "r half mu/ conta9 ! numb] ( words to be transf]r$4 ,if ! ,sequ5ce ,break ,sy/em is connect$1 ! completion ( ! transf] w signal ! prop] sequ5ce4 ,if no ,sequ5ce ,break ,sy/em is connect$1 ! completion ( ! 9-out *annel transf] sets a program flag4 ,,magnetic ,,tape ,! sy/em consi/s ( tape units connect$ to ! ,,pdp-#c ?r\gh a tape control 7,,tc74 ,?is tape is read or writt5 9 ,,ibm #gbi;,i =mat4 ,two hundr$ *>act]s1 ea* hav+ #f bits plus a p>ity bit1 are writt5 on ea* in* ( tape & ! tape moves at #ge in*es_/sec4 ,! tape control has ! job ( connect+ a specific unit to ! ,,pdp-#c & is a swit*4 ,x also has ! function ( controll+ ! =mat ( in=mation t is read or writt5 on tape4 ,9-out class comm&s in/ruct ,,tc to ! type ( in=mation transf] & select ! tape unit4 ,ano!r ,,iot comm& syn*ronizes ! transf] ( in=mation ?r\gh ! ,,tc to ! comput]4 ,! ,,iot ord] to select ! unit & function is decod$ z foll[s3 #a7 ,?ree bits specify ! function ( ,,tc4 #b7 ,! rema9+ #f bits select ! unit4 ,,iot ,motion ,comm&s = ,magnetic ,tape ,units ,,iot ,code ,abbreviation ,function #gc4444nn #fj mrb ,read a b9>y record4 #gc4444nn #fa mra ,read an alphanum]ic 7,,bcd7 record4 #gc4444nn #fb mbb ,backspace a b9>y record4 #gc4444nn #fc mba ,backspace an alphanum]ic record4 #gc4444nn #fd mwb ,write a b9>y record4 #gc4444nn #fe mwa ,write an alphanum]ic record4 #gc4444nn #ff mlp ,move tape to lead po9t 7rew9d74 ,:]e ! octal digits1 nn1 specify ! unit numb]4 ,! motion comm&s h ! def]r$ bit1 ?us1 ! program halts4 ,if ! ,,tc is free1 ! comm& w be transf]r$ to ! tape control = action & ! program re/>ts imm$iately4 ,if ! tape control is curr5tly busy ) an in/ruction1 i4e41 x hasn't f9i%$ a previ\s comm&1 ! motion comm& is held up until ,,tc is free to execute ! new comm&4 ,! transf] ( in=mation f ! comput] to ! ,,tc is accompli%$ ) ! pause & skip comm&1 ,,mps or ,,iot #gj4 ,?is comm& has ! def]r$ bit & halts a program until ! ,,tc c h&le ! transf]4 ,on completion1 ! transf] occurs & ! program re/>ts4 ,?is is us$ exclusively to syn*ronize ! fl[ ( in=mation betwe5 a tape unit & ! comput]4 ,?is comm& normally skips ! foll[+ in/ruction4 ,if a flag is set 9 ! ,,tc1 indicat+ incorrect in=mation fl[1 ! skip does n take place4 ,! ,,tc conta9s a #cf bit buff] :i* holds a complete ^w :ile in=mation is read or writt54 ,:5 an ,,mps ord] is giv5 & ! unit is read+1 ! ,,tc buff] is read into ! ,,io4 ,! ,,mps ord] giv5 dur+ writ+ causes ! ,,io to be transf]r$ to ! ,,tc buff]4 ,v>i\s conditions occurr+ 9 ! ,,tc cause ! no-skip condition1 :5 an ,,mps is giv54 ,tape control flags are exam9$ by ! comm&1 exam9e & cle> flags1 ,,mec or ,,iot #ga4 ,:5 ,,mec is giv51 ! flags are put into ! ,,io = program int]rogation1 & ! flags cle>$4 ,! flags are3 p>ity1 end ( tape1 an end ( record flag1 & read+-writ+ *eck4 ,! p>ity flag is set if ! p>ity condition is n met :ile ! tape is be+ read 7dur+ ,,mwa1 ,,mwb1 ,,mra1 or ,,mrb74 ,! end ( tape flag is set :5 ! tape comes to ! end ( tape1 mov+ 9 ei!r direction4 ,?ree conditions set ! read-write *eck flag3 #a7 ,if ,,tc is inactive1 i4e41 no unit or function select$1 & an ,,mps in/ruction is giv54 ,! ,,mps becomes a no-op]ation1 no-halt in/ruction4 #b7 ,:5 read+ in=mation & n empty+ ! ,,tc buff]1 by giv+ an ,,mps be=e m in=mation arrives f tape4 #c7 ,a unit becomes unavailable dur+ a normal sequ5ce4 ,! end ( record flag is set dur+ read+ or backspac+ :5 ! tape comes to an end ( record gap4 ,writ+ a ,record ( ,in=mation ,in=mation is writt5 on ! tape by giv+ a ,,mwb or ,,mwa comm&4 ,?is sets a write b9>y or a write alphanum]ic into ! ,,tc & selects ! unit4 ,a motion select comm& is execut$ imm$iately if ! ,,tc is free1 o!rwise1 ! comm& waits until x c be execut$4 ,normal programm+ c cont9ue aft] ! ,,mwa or ,,mwb is giv5 = approximately #e milliseconds4 ,at ?is "t1 an ,,mps ord] is giv5 & ! program pauses until in=mation c be writt54 ,:5 ! ,,mps is re/>t$1 in=mation is transf]r$ to ! ,,tc buff] f ! ,,io4 ,if no flags h be5 set1 ! foll[+ in/ruction is skipp$4 ,?ree-qu>t] in*es ( blank tape is writt5 by giv+ ei!r ! ,,mwa or ,,mwb ord]4 ,an end ( file is writt5 z foll[s3 #a7 ,f\r ,,mwa comm&s write ?ree in*es ( blank tape4 #b7 ,!n end ( file "* is writt5 by giv+ ! ,,mps ord]4 ,in=mation is read & *eck$ = correct p>ity :ile writ+4 ,if too _m program /eps are giv5 betwe5 ! motion select comm&1 ,,mwa or ,,mwb & ! fir/ ,,mps1 ! unit w deselect 7or disconnect74 ,! ,,mps is !n a no-op]ation comm&4 ,writ+ ,program ,z an example1 a program to write k words 9 b9>y =mat f /orage beg9n+ 9 regi/] ,a1 us+ tape unit numb] #jd1 is %[n4 ,! foll[+ program is writt5 9 /&>d ,,frap language4 ,! program beg9s 9 regi/] ent]write4 ent]write mec 1cle> flags initially mwb #djj 1#gcjjjjjjdfd lir x_/-k#a 1initialize index regi/] x b lio x_/ak-#a 1beg9 loop mps 1wait = ,,tc !n write ,c7,z7 jmp c 1error spx x_/#a 1add #a to index regi/] x jmp b 1return ( loop jmp done 1record writt5 c mec 1tape error ril #a spi jmp rwc/op 1read-write error or tape fault ril #a spi jmp b#c 1tape end hlt 1tape p>ity done 1resume programm+ ,read+ ,in=mation ,in=mation is read by giv+ ! ,,mra or ,,mrb ord]4 ,almo/ #aj ms4 is available aft] a read ord] is giv5 be=e in=mation actually ent]s ! ,,tc buff]4 ,to read a record ( unkn[n l5g?1 ! read ord] is fir/ giv54 ,! ,,mps ord] halts ! program until six *>act]s are assembl$ 9 ! ,,tc in=mation buff]4 ,! next in/ruction aft] ! ,,mps1 a jump in/ruction1 transf]s control f ! loop :5 any flag is set4 ,! next in/ruction deposits ! ,,io4 ,! record l5g? is det]m9$ by n skipp+ aft] ! ,,mps ord] on ! sett+ ( ! end ( record flag4 ,! read-write *eck flag or ! end ( record flag is !n int]rogat$ to see t ! tape is actually at ! end ( record4 ,if a tape is n at ! end ( record1 !n ! tape is ei!r at ! end ( ! reel1 or a p>ity *eck has occurr$4 ,read+ ,program ,program to read j b9>y words into /orage beg9n+ 9 regi/] d1 us+ tape unit #aj1 j is unkn[n4 ,! program beg9s 9 regi/] ent]ead4 ent]ead mec 1cle> flags initially mrb #ajjj 1#gcjjjjjjajfj dzm x 1put z]o 9 memory location x e mps jmp out*eck dio x_/d 1/ore 9 location modifi$ by x snx x_/#a 1add #a to ,c7x7 jmp e out*eck mec 1exam9e flags spi 1end ( record8 jmp record5d 1yes hlt 1error record5d snx x_/#a 1to f9d value ( j 1resume programm+ ,c7,,ia7 j ,=w>d ,spac+ ,=w>d spac+ is done by giv+ an ,,mrb or ,,mra ord]4 ,?is moves ! tape =w>d ) ! read-write head position$ at ! end ( ! foll[+ record4 ,if n read ord]s are giv51 ! tape is spac$ =w>d n records4 ,by giv+ ! ,,mec ord]1 p>ity flags are exam9$ to see t in=mation on tape has be5 read correctly4 ,backspac+ ,by giv+ an ,,mba or ,,mbb ord] ! tape is mov$ backw>ds a record ) ! read-write heads position$ 9 ! previ\s end ( record gap4 ,! end ( record flag is set :5 ! tape has mov$ backw>ds a record4 ,rew9d+ ,rew9d+ is accompli%$ by giv+ ! rew9d ord]1 move tape to load po9t1 ,,mlp4 ,! rew9d ord] />ts a unit rew9d+ & does n tie up ! ,,tc4 ,if a motion comm& is giv5 :i* calls = a unit t is rew9d+1 ! comm& is execut$1 b ! action w n take place until ! unit is available4 ,unit ,availability ,a unit is unavailable to ! program "u ! foll[+ conditions3 #a4 ,unit is rew9d+4 #b4 ,tape is improp]ly load$4 #c4 ,cov] door op54 #d4 ,unit ov]load$4 #e4 ,unit "u manual control4 #f4 ,p[] (f4 ,a select$ b unavailable unit holds up ! ,,tc if a motion ord] is giv5 = ! unit4 ,! ,,tc w be held up until ! unit is ready4 ,flag ,positions ,,io ,bit ,flag #j ,,eor - ,end ( record #a ,,rwf - ,read-,write #b ,,eot - ,end ( ,tape #c ,p>ity ,connection ) ,high ,spe$ ,*annel ,! high spe$ *annel directs ! tape control1 & ^w transf]1 j z a program w\ld4 ,a unit is fir/ />t$ read+ or writ+4 ,! high spe$ *annel is giv5 ! memory location ( ! in=mation1 & ! numb] ( regi/]s ! words read or writt5 w occupy4 ,! *annel effects ! in=mation transf]4 ,?us1 a high spe$ *annel connect$ to a tape control h&les ! programm+ = ! unit ^w transf]s4 ,completion ( ! block transf] is signifi$ by ei!r sett+ a program flag1 or ent]+ ! sequ5ce break4 ,connection ) ,sequ5ce ,break ,sy/em ,:5 ! ,,tc is connect$ to ! ,sequ5ce ,break ,sy/em1 ! program is automatically int]rupt$ ea* "t an ,,mps comm& ne$s to be giv54 ,programm+ is unaffect$ dur+ read+ & a record may be read ) no flags set4 ,! ,,tc initiates breaks s t an ,,mps may be giv5 9 "t4 ,simil>ly1 ! break is initiat$ dur+ writ+ ea* "t an ,,mps ne$s to be giv54 ,motion ,comm& ,summ>y ,"t be=e ,"t betwe5 ,"t aft] ,end ( ,flags t fir/ ,,mps ,,mps's ,record to deselect may be set ,,mwa #c ms4 #djj u4 #aj ms4 ,,rwf 7if unit ,,mwb 7long] "t is deselect$ causes deselection7 & ,,mps giv51 or unit becomes unavailable71 ,p>ity1 ,,eot4 ,,mra #g ms4 #djj u4 #e ms4 ,,rwf1 7if ,,mrb 7long] "t in=mation misses in=mation1 is miss$1 or & unit becomes rwc set7 unavailable71 ,,eot1 ,,eor1 ,p>ity4 ,,mba - - #aj ms4 ,,rwf 7if unit ,,mbb becomes unavailable71 ,,eor1 ,,eot4 ,,ca?ode-,,ray-,,tube ,,display ,! ,,pdp-#c ,ca?ode ,ray ,tube ,display is useful = pres5tation ( graphical or tabul> in=mation to ! op]ator4 ,x uses a #af in* r\nd tube ) magnetic deflection4 ,= ea* ,9-,out transf] ord]1 "o po9t is display$ at ! position indicat$ by ! ,9-,out ,regi/]4 ,bits #j-i ( ! ,,io indicate ! ,x coord9ate ( ! position1 & bits #ah-bg indicate ! ,y coord9ate4 ,! display takes #fj microseconds4 ,an additional display option is a ,light ,p54 ,by use ( ?is device ! comput] is signal$ t ! op]ator is int]e/$ 9 ! la/ po9t display$4 ,?us ! program c take appropriate action su* z *ang+ ! display or %ift+ op]ation to ano!r program4 ,a small] display is available4 ,?is display uses a five in*1 high resolution ca?ode ray tube4 ,! tube is equipp$ ) a m\nt+ bezel to accept a cam]a or photomultipli] device4 ,! op]ation ( ?is display is simil> to t ( ! #af in*1 except t #ab bits are decod$ = ea* axis4 ,,real ,,"t ,,clock ,a special input regi/] may be connect$ to op]ate z a ,real ,"t ,clock4 ,?is is a c\nt+ regi/] op]at$ by a cry/al controll$ oscillator4 ,! clock c be reset to z]o by manual op]ation4 ,a toggle swit* int]lock prev5ts an accid5tal reset4 ,! /ate ( ?is c\nt] may be read at any "t by ! appropriate ,9-,out ,transf] in/ruction4 ,,l9e ,,pr9t] ,a #gb column ,anelex pr9t] & control are available z an option = ,,pdp-#c4 ,! control conta9s a "o l9e buff]4 ,?is buff] is cle>$ by ! completion ( an ord] to space ! pap] "o position 7psp74 ,! buff] is fill$ f ! ,9-,out ,regi/] by a succession ( #ab load buff] ord]s 7plb74 ,! fir/ plb w put ! six *>act]s repres5t$ by ,c7,,io7 9 ! lead+ 7left-h&7 column positions ( ! buff]4 ,aft] ! buff] is load$1 ! ord]1 pr9t 7pnt71 is giv54 ,,utility ,,programs ,,frap-#c - ,! ,assembly ,program ,an assembl] or compil] prep>es a ma*9e language tape suitable = direct int]pretation by ! comput] f a program tape 9 op]ator language4 ,g5]ally speak+1 "o /atem5t accept$ by ,,frap produces "o in/ruction = ! ma*9e4 ,a s+le /atem5t writt5 = ! ,,pdp-#c compil]1 ,,decal-#c1 may cause sev]al in/ructions to be writt54 ,?us1 ,,frap causes a #a = #a mapp+ ( in/ructions = /atem5ts :ile ,,decal may produce _m in/ructions f "o /atem5t4 ,9 addition to all[+ program tapes to be prep>$ ) (f l9e equipm5t1 an assembly program has o!r functions4 ,normally1 ! ma*9e w\ld require #cf bits or #ab octal digits to be writt5 = ea* in/ruction us$ 9 ! ma*9e4 ,,frap all[s mnemonic symbols to be us$ = ! in/ructions4 ,^! mnemonic symbols aid ! programm] by repres5t+ ! in/ruction 9 an easily rememb]$ =m4 ,9 addition to all[+ mnemonic symbols to repres5t ! in/ructions1 v>iable l5g? sequ5ces ( alphanum]ic *>act]s may be us$ to repres5t memory addresses 9 symbolic =m4 ,! assembly program does ! address bookkeep+ = ! programm]4 ,a %ort example ( a ,,frap program is on ,page #bi4 ,s9ce few *>act]s limit or control ! =mat ( in/ructions writt5 9 ,,frap-#c language1 x is possible to write in/ructions 9 almo/ any =mat or /yle4 ,,frap-#c may also be us$ to prep>e tapes = int]pretive programm+1 s9ce arbitr>y def9itions = op]ation code symbols are p]mitt$4 ,a feature useful bo? = ease ( programm+ & = ma*9e simulation is ! ability to call = a s]ies ( in/ructions 7macro-in/ruction7 to be writt54 ,frequ5tly us$ in/ruction sequ5ces ?us ne$ only to be def9$ once4 ,,decal - ,! ,compil] ,program ,,decal-#c 7,digital ,equipm5t ,compil]1 ,assembl]1 & ,l9k+ load] = ,,pdp-#c7 is an integrat$ programm+ sy/em = ,,pdp-#c4 ,x incorporates 9 "o sy/em all ( ! ess5tial features ( advanc$ assembl]s1 compil]s1 & load]s4 ,,decal is bo? an assembl] & compil]4 ,x comb9es ! "o-to-"o translation facilities ( an assembl]1 & ! "o-to-_m translation facilities ( a =mula translation compil]4 ,problem ori5t$ language /atem5ts may be freely int]mix$ ) symbolic ma*9e language in/ructions4 ,a flexible load] is available to all[ ! specification ( program location at load "t4 ,! programm] may specify t c]ta9 v>iables & con/ants are sy/ems v>iables & con/ants4 ,! symbols s def9$ are univ]sally us$ 9 a sy/em ( _m r\t9es4 ,?us1 communications betwe5 p>ts ( a major program is facilitat$ ev5 ?\gh ^! p>ts may be compil$ sep>ately4 ,/orage requirem5ts = a l>ge program are less5$ by ?is te*nique4 ,,decal is an op5-end$ programm+ sy/em & c be modifi$ )\t a detail$ und]/&+ ( ! int]nal op]ation4 ,?is is a*iev$ by means ( a recursive def9ition facility bas$ on a skeleton compil] ) a small set ( logical capabilities4 ,! skeleton compil] acts z a boot/rap = introduc+ m sophi/icat$ facilities4 ,! compil] w be deliv]$ ) a fully def9$ subset ( =mula translation op]ators4 ,additional subsets may be def9$ by ! us] to be/ fit 8 s\rce language4 ,,float+ ,,po9t ,,subr\t9es ,a set ( subr\t9es are provid$ ) ! ,,pdp-#c to p]=m float+ po9t ari?metic4 ,9 ^!1 ! ,,pdp-#c #cf bit ^w is divid$ to =m a #bg bit mantissa1 a1 & #i bit expon5t1 b4 ,numb]s1 ?us1 appe> 9 ! =m3 k ax#b;b :]e1 a1 is consid]$ to be 9 fractional =m 9 ! range #a_/b a #a1 & b is an integ]1 #j b #bi4 ,?is gives numb]1 k1 ! range #aj-gf k #ajgf4 ,! subr\t9es are call$ ) "o op]& 9 ! accumulator4 ,aft] ! subr\t9e has be5 execut$1 ! accumulator conta9s ! answ]4 ,?us float+ po9t numb]s are ess5tially h&l$ z regul> logical works4 ,! =mat ( ! numb] all[s magnitude comp>isons to be made by conv5tional ari?metic z bit #j is ! sign ( ! numb]1 bits #a to #i ! expon5t1 & ! rema9+ #bf bits1 toge!r ) ! sign bit1 ! mantissa 9 ones complem5t ari?metic4 ,! ari?metic subr\t9es are3 add1 subtract1 multiply1 divide1 conv]t a float+ po9t numb] to b9>y1 conv]t a b9>y numb] to a float+ numb]4 ,additional r\t9es =m3 squ>e root ( x1 ex1 ln x1 s9e7pi_/#b7x1 cos7pi_/#b7x1 tan-#ax4 ,!re are also programs to conv]t betwe5 float+ decimal numb]s & ,,pdp-#c float+ numb]s4 ,r\t9es :i* require two op]&s1 e4g41 add1 subtract1 multiply & divide1 require an index regi/] to specify ! address ( ! second op]&4 ,an index regi/] also specifies p>amet]s 9 data conv]sions1 e4g41 ! position ( ! b9>y po9t :5 conv]t+ a b9>y numb] to a /&>d float+ numb]4 ,us+ ! float+ po9t subr\t9es1 additional r\t9es may be writt5 :i* h&le complex float+ numb]s & vector & matrix algebra4 ,,ma9t5ance ,,r\t9es ,ma9t5ance ,r\t9es are us$ exclusively to *eck ! op]ation ( ! ma*9e4 ,^! r\t9es are op]at$ :ile v>y+ ! bias supply voltages1 & ?us a *eck is made on possible degradation ( all compon5ts :i* w\ld affect ! op]ation ( ! ma*9e4 ,,miscellane\s ,,r\t9es ,a v>iety ( additional programs are provid$ ) ,,pdp-#c4 ,"o ( ! m important programs is ! ,typewrit] ,int]rogator ,program 7,,tip74 ,,tip all[s ! typewrit] to be us$ mo/ effectively z an input-output l9k by :i* programs & data are exam9$ & modifi$4 ,! features include reque/ = pr9t+ ( a s]ies ( regi/]s1 int]rogation & modification ( ! cont5ts ( regi/]s1 & ! ability to reque/ new tapes aft] programs h be5 suitably modifi$4 ,communication is done completely via ! typewrit] 9 ei!r octal numb]s1 decimal numb]s1 or alphanum]ic codes4 ,regi/] cont5ts are pres5t$ 9 simil> =m4 ,o!r miscellane\s r\t9es h&le ari?metic processes1 e4g41 numb] conv]sions1 & communication ) ! input or output devices4 ,^! r\t9es include v>i\s =mat pr9t outs1 pap] tape & magnetic tape read 9 programs1 & display subr\t9es4 99 99 99 99 99 ,illu/ration3 ,,sy/em ,,block ,,diagram ,,figure #a ,illu/ration3 ,,in/ruction ,,=mat ,,figure #b ,illu/ration3 ,,figure #c 99 99 99 99 99 ,transcrib]'s ,notes3 ,c 7,x7 & ,c7,x7 /&>diz$ to ,c7,x74 usec & usec4 /&>diz$ to usec4 ?r\gh\t text4 ,o!r *anges to ! orig9al text are li/$ bel[4 ,figure #d is ref]r$ to 9 ! text1 b a copy c\ld n be locat$4 ,und]l9$ ,text is enclos$ by und]scores4 ,sup]scripts are m>k$ ) c>ats x#b & y-#c4 ,greek symbols are surr\nd$ by tildes4 ,transcrib] ,*anges3 ,,table ,,( ,,cont5ts3 ,orig9ally ',op]ation' 7,op]at+ ,spe$s7 ,,table ,,( ,,cont5ts3 ,orig9ally ',frap' 7,,frap7 ,,table ,,( ,,cont5ts3 ,orig9ally ',r\t9es' 7,subr\t9es7 ,page #d3 ,orig9ally '!op]ate' 7:ile a program is op]at+ by means ( ! op]ate in/ruction47 ,page #g3 ,add$ comma 7,! in/ruction base address1 ,y1 is 9 octal digits #g ?r\gh #aa47 ,page #h3 ,/&>diz$ f 'sub-r\t9es' 7,! conv]sion ( decimal numb]s into ! b9>y sy/em = use by ! ma*9e may be p]=m$ automatically by subr\t9es47 ,page #h3 ,/&>diz$ f 'sub-r\t9e' 7! output conv]sion ( b9>y numb]s into decimals is done by subr\t9e47 ,page #af3 ,add$ comma 7,?is in/ruction w %ift ! cont5ts ( ! comb9$ regi/] "r ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w47 ,page #af3 ,mov$ comma4 ,0 'left1 ,n positions' 7,?is in/ruction w %ift ! cont5ts ( ! comb9$ regi/]s left ,n positions1 :]e ,n is octal digits #g-aa ( ! in/ruction ^w47 ,page #ai3 ,0 '"k' 7,mo/ 9-out op]ations require a kn[n m9imum "t be=e completion47 ,page #bj3 ,remov$ inconsi/5t comma 7,^! are ! ,te/ ,address 7#ae bits71 ! ,te/ ,^w 7#cf bits71 & ! ,s5se ,swit*es 7#f bits747 ,page #ba3 ,*ang$ comma to p]iod 7! comput] w halt at ! completion ( ea* memory cycle4 ,?is swit* is p>ticul>ly useful 9 debugg+ programs47 ,page #bh3 ,0 'tpae' 7dur+ read+ or backspac+ :5 ! tape comes to an end ( record gap47 ,page #bi3 ,/&>diz$ f 'de-select' 7! unit w deselect 7or disconnect747 ,page #ce3 ,0 'prop>es' 7,an assembl] or compil] prep>es a ma*9e language tape suitable = direct int]pretation7 ,page #ce3 ,remov$ comma 7,frequ5tly us$ in/ruction sequ5ces ?us ne$ only to be def9$ once47 ,page #cg3 ,0 ',r\ti9es' 7,r\t9es :i* require two op]&s1 e4g41 add1 subtract1 multiply & divide7