the life and work of konrad zuse

8/12/2019 The Life and Work of Konrad Zuse

1/59

The Life and Work of Konrad Zuse (by Horst Zuse)

Part 1: Konrad Zuse Prior to 1934

Konrad Zuse was born in in Berlin on June 22, 11!" #o ideas of $o%&uters orrelated &roble%s $an be found in his re$ords &rior to 1'" t is un*uestionable thathe was a $reati+e student at s$hool, he built $ranes and %ade a lot of &aintins" -nee.a%&le of his early &aintins is a $artoon of the Schtzenfest(rifle%en/s %eetin) inHoyerswerda fro% 120 (i")"

i"'" (Left) ost offi$e in Hoyerswerda34er%any (125)" Konrad Zuse li+ed with his &arents and hissister Lieselotte below the roof of this buildin" n the near future, this buildin will be the Konrad Zuse6o%&uter 7useu%" i"" (8iht) -ne of Konrad Zuse/s $artoons showin the rifle%en9s %eetin inHoyerswerda (120)"

Konrad Zuse %ade his s$hool lea+in e.a%ination in 125 in Hoyerswerda 3:a.onia" ;urin his study he $haned his dire$tions three ti%es" :o%eti%es he saidthat he did not know what to study"


2/59

i"=" ? &aintin Konrad Zuse $reated toraise %oney to &ay for his studies (120)"

7y father first started thinkin about$o%&uters as early as 1'" This was&ro%&ted by the %any $al$ulations hehad to &erfor% as a $i+il enineer,Today it is $lear to %e that he really

hated &erfor%in these $al$ulationsand he wanted to %ake thins easierfor enineers and s$ientists"This is a little si%ilar to 6harlesBabbae, who said in 1512@ I wish toGod these calculations had beenperformed by steam. Howe+er, %yfather did not be$o%e aware ofBabbae/s work until 1=30"


Part 2: Konrad Zuse's First Ideas on Computing

n 1', dri+en by his dislike of the ti%eA$onsu%in $al$ulations he had to &erfor%as a $i+il enineer, Konrad Zuse bean to for%ulate his first ideas on $o%&utin" Hisfeelin was that su$h stu&id $al$ulations should be &erfor%ed by %a$hines and notby hu%an beins" The first *uestion he &osed in 1' was:

What mathematical problems should a computing machine solve?

His answer was the followin definition of $o%&utin (1'0)@

o build new specifications from given specifications by a prescription.

n the year 1' he e.tended the definition to:

!omputing is the deviation of result specifications to any specificationsby a prescription"

ro% these definitions, Konrad Zuse defined the loi$al ar$hite$ture of his Z1, Z2,Z', and Z $o%&uters ro% the beinnin it was $lear for hi% that his $o%&utersshould be freely &rora%%able, whi$h %eans that they should be able to read anarbitrary %eaninful se*uen$e of instru$tions fro% a &un$h ta&e" t was also $lear tohi% that the %a$hines should work in the binary nu%ber syste%, be$ause hewanted to $onstru$t his $o%&uters usin binary swit$hin ele%ents" #ot only shouldthe nu%bers be re&resented in a binary for%, but the whole loi$ of the %a$hineshould work usin a binary swit$hin %e$hanis% (!A1A&rin$i&le)"
http://www.epemag.com/zuse/Images/fig5b.jpg


3/59

He &lanned a hih &erfor%an$e binary floatin &ointunit in the se%iAloarith%i$ re&resentation, whi$hwould allow hi% to $al$ulate +ery s%all and +ery binu%bers with suffi$ient &re$ision"

He i%&le%ented a hih &erfor%an$e adder with aoneAste& $arryAahead and &re$ise arith%eti$e.$e&tions handlin"He de+elo&ed a %e%ory in whi$h ea$h $ell $ould beaddressed by the &un$h ta&e and $ould storearbitrary data"inally, he $onstru$ted a $ontrol unit that $ontrolledthe whole %a$hine, and i%&le%ented in&ut andout&ut de+i$es fro% the binary to the de$i%alnu%ber syste% and +i$e +ersa" n art ' we/ll start totake a $loser look at these %a$hines"

i"0" Konrad Zuse workinon a Z 6o%&uter (12)"


Part 3: Konrad Zuse's First Computer -- The Z1

n 1'0, %y father finished the loi$al &lan for his first $o%&uter, the


4/59

The Z1 did not use relays, but instead $onsisted $o%&letely of thin %etal sheets,whi$h he and his friends &rodu$ed usin a Cisaw" The only one ele$tri$al unit was anele$tri$al enine, whi$h was used to &ro+ide a $lo$k fre*uen$y of one Hert>"The Z1 was &rora%%ed +ia a &un$h ta&e and a &un$h ta&e reader" There was a$lear se&aration between the &un$h ta&e reader, the $ontrol unit (whi$h su&er+isedthe whole %a$hine and the e.e$ution of the instru$tions), the arith%eti$ unit (withreisters 81 and 82), the %e%ory, and the in&ut3out&ut de+i$es"

n 150, Konrad Zuse de$ided to rebuild the Z1 (i" 1'), be$ause the ar$hite$ture ofthe Z1 was al%ost identi$al to that of his Z' $o%&uter (dis$ussed below), whi$h wasunfortunately destroyed in the :e$ond World War" Thus, the sayin DWar is thefather of everything,D is not true in the $ase of the in+ention of the $o%&uter"

i"" The rebuilt Z1 seenfro% a DbirdsAeyeD +iew"(:our$e@ ;euts$hes Te$hnik7useu% Berlin)

#ote how it rese%bles a%odern sili$on $hi&"

i"1!" HihAle+el blo$kdiara% of the Z1"

#ote how this blo$k diara%%a&s onto the &hysi$al Z1shown in i" (abo+e)"
http://var/www/apps/conversion/tmp/scratch_5/Images/fig9b.jpg


5/59

7ost of the $o%&onents are selfAe.&lanatory" The %e%ory, whi$h $onsisted of 0words, ea$h $ontainin 22 bits, was for%ed fro% three blo$ks" The first blo$k$ontained 0 words for the e.&onents and sins (5 bits for ea$h word)" The othertwo blo$ks ea$h $ontained '2 words for the %antissa (1 bits for ea$h word)" Thesele$tion unit inter&reted the address for the %e%ory by the $ontrol unit" The

arith%eti$ unit was an adder, and all of the o&erations were redu$ed to additions orsubtra$tions (addin and subtra$tin are +ery si%ilar o&erations)"

The reisters 81 and 82 were two words, ea$h $ontainin 22 bits" The two $ir$leson the leftAhand side (on the $lo$k enerator blo$k) are $ranks for e.e$utin a $lo$k$y$le %anually, where the u&&er one is for the %e%ory and the lower one for the$ontrol and arith%eti$ unit"


Part 3 (ontinued!: The Z1

Konrad Zuse rebuilt the Z1 in his atelier in HEnfeld between 15 and 15" Theoriinal Z1 was &ri+ately finan$ed by Konrad Zuse, his &arents, his sister Lieselotte(1!5A1='), and friends" 8ebuildin the Z1 was a diffi$ult task for %y fatherbe$ause he was years old" t was also +ery e.&ensi+e (finan$ially) to re$onstru$tall the &ie$es of the %a$hine" n fa$t the $ost of rebuildin the Z1 was around 5!!!!! ;7" The :ie%ens ?4 $oordinated a $onsortiu% of about fi+e $o%&anies and&aid the %aCor &art of the $osts"Workin in his atelier, Konrad re$reated thousands of enineerin drawins of e+ery&ie$e of the %a$hine, be$ause the oriinal &lans were destroyed durin the war" ?tthe end of 15 the re$onstru$tion of the Z1 was interru&ted when %y fathersuffered a heart atta$k" Howe+er, after 0A%onths, the $onstru$tion of the %a$hine&ro$eeded"

i"11" -n the brownA$olored drawin boardKonrad Zuse desined the Z1 a se$ond ti%e"

i"12" ?nother +iew in the atelier ofKonrad Zuse (150)"

?&&ro.i%ately '!,!!! $o%&onents for this %a$hine AA drawn by Konrad Zuse AAwere then $onstru$ted by :ie%ens ?4 in Bad Hersfeld usin %odern nu%eri$al

%a$hines" These $o%&onents were then asse%bled by Konrad Zuse, an e%&loyeeof :ie%ens ?4, and two students :$hweier and :au&eF:6HW5Gfro% Kln"
http://www.epemag.com/zuse/Bgraphy.htm#SCHW89http://www.epemag.com/zuse/Images/fig12b.jpghttp://www.epemag.com/zuse/Images/fig11b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#SCHW89


6/59

i"1'" The rebuilt Z1 in the atelier of Konrad Zuse"(This &i$ture was taken on ;e$e%ber 2=, 155 by Horst Zuse)

The re$reated Z1, whi$h was $o%&leted in 15, was %o+ed fro% HEnfeld to Berlin"8ebuildin the Z1 was a tre%endous a$hie+e%ent, whi$h allowed %y father to showthe world the first freely &rora%%able $o%&uter based on binary floatin &ointnu%bers and a binary swit$hin syste%"

?s we &re+iously dis$ussed, the Z1 had a 0Aword%e%ory, where ea$h word $ontained 22 bits" I+eryword was dire$tly addressable by the &un$h ta&e andthe &un$h ta&e reader toether with the $ontrol unit,and data $ould be read fro% and written to ea$h word"t is worth notin that this %e$hani$al %e%ory was noslower than a %e%ory $onstru$ted usin relays, butthe %e$hani$al %e%ory re*uired %u$h less s&a$e" i"1" -ne bit of Zuse/s

%e$hani$al %e%ory"

t is undis&uted that this ty&e of %e%ory is uni*ue, and Konrad Zuse obtained a&atent for this %e%ory in 1'0 FZ:I'0G" The %etal sheet shown in i"1 stores onebit" n this illustration, a binary 1 (left &osition) is stored (the riht &osition e*uates toa binary !)" The %etal sheets aand bare %o+eable, and are dire$ted by the $ontrolunit to store a bit (at the $lo$k fre*uen$y enerated by the ele$tri$al enine)"
http://www.epemag.com/zuse/Bgraphy.htm#ZUSE36http://www.epemag.com/zuse/Images/fig13b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#ZUSE36


7/59


Part 3 (ontinued!: The Z1

?s was noted earlier, the Z19s &rora%s (8e$hen&lans) were stored on &un$h ta&esusin an 5Abit $ode" :torin the &rora%s on ta&e rather than DhardAwirinD the%into the %e$hanis% was what %ade the Z1 a freely &rora%%able %a$hine" Theinstru$tion set of the Z1 was as follows@

r >8ead the $ontents of the %e%ory $ell > into 8eisters 81 or 82"

s > Write the $ontents of 8eister 81 to the %e%ory $ell >"

Ls1 ?dd the two floatinA&oint nu%bers in the 8eisters 81 and 82"

Ls2 :ubtra$t the two floatinA&oint nu%bers in the 8eisters 81 and 82"

L% 7ulti&ly the two floatinA&oint nu%bers in the 8eisters 81 and 82"

Li ;i+ide the two floatin &oint nu%bers in the 8eisters 81 and 82"

Lu To $all the in&ut de+i$e for de$i%al nu%bers"

Ld To $all the out&ut de+i$e for de$i%al nu%bers"

i"1=" The &un$h ta&e (usin '=%% standard%o+ie fil%) and the &un$h ta&e reader of the Z1"

i"10" The full Z1"n the foreround is the %anual$rank for dri+in the $lo$k fre*uen$y by hand"

The full Z1 is shown in i"10" n addition to the $rank (in the foreround) for%anually $y$lin the %a$hine, there was also an ele$tri$ %otor, whi$h was used toenerate a $lo$k fre*uen$y of one Hert> (one $y$le &er se$ond)" To the rear of this

&i$ture are the three blo$ks of %e%ory, while the binary floatin &oint arith%eti$ unitis on the riht"
http://www.epemag.com/zuse/Images/fig16b.jpghttp://www.epemag.com/zuse/Images/fig15b.jpg


8/59

i"1" The Z1/s binary floatin &oint arith%eti$unit" Thousands of thin %etal &lates were

re*uired to i%&le%ent this unit"

i"15" The interfa$e between the arith%eti$ unit(left) and the %e%ory (riht)" n today/s ter%sthere was a &arallel bus between the units"

f you write two floatinA&oint nu%bers on a &ie$e of &a&er usin the binary nu%ber

syste%, and you try to de+elo& the alorith%s to &erfor% the basi$ arith%eti$o&erations on these nu%bers, then you will understand Cust how %u$h effort wasne$essary to build the Z19s arith%eti$ unit" 7y father9s desin for the Z19s arith%eti$binary floatin &oint unit was inenious" Howe+er, the te$hni$al reali>ation usin thethin %etal sheets was too $o%&le." The arith%eti$ unit in the oriinal Z1 was not +eryreliable (si%ilarly with the rebuilt Z1)"

i"1" The Z1/s in&ut (botto% riht) and out&utde+i$es (%iddle of &i$ture)"

i"2!" Konrad Zuse enters a de$i%al nu%ber intothe in&ut de+i$e (abo+e the keys the e.&onent

$ould be set fro% 5 to A5"

The Z1 had de$i%al in&utA and out&ut de+i$es" The nu%bers were &resented to the%a$hine in a de$i%al for% with an e.&onent" The Z1 then $on+erted the de$i%alnu%bers to a binary nor%ali>ed floatin &oint re&resentation" :i%ilarly, the out&utde+i$e $on+erted the binary floatin &oint nu%ber in 8eister 81 into a de$i%alnu%ber with an e.&onent"
http://www.epemag.com/zuse/Images/fig20b.jpghttp://www.epemag.com/zuse/Images/fig19b.jpghttp://www.epemag.com/zuse/Images/fig18b.jpghttp://www.epemag.com/zuse/Images/fig17b.jpg


9/59

i"21" The out&ut de+i$e was reali>edas an annun$iator" The e.&onent is %arked

red at the botto%"

i"22" ?dCustin the %etalsheets and the &ins"

Thus, as early as 1'0A1'5, the Z1 e.hibited al%ost all of the fa$ilities of the soA$alled +on #eu%ann %a$hine F#I7=G, FB8K0G" n fa$t the only feature that wasnot i%&le%ented was loadin the &rora% into the Z19s %e%ory" This was be$ausebuildin a lare %e%ory was a +ery e.&ensi+e task at that ti%e" The $al$ulation of adeter%inant (third rade) re*uires about =! instru$tions and 1= words of %e%ory forthe +ariables and the inter%ediate results" This si%&le e.a%&le shows that storinthe &rora% in %e%ory would blo$k the idea of a freely &rora%%able %a$hine"

i"2'" Konrad Zuse with the rebuilt Z1 in the $eutsche echni% &useumin Berlin in :e&te%ber15"
http://www.epemag.com/zuse/Bgraphy.htm#NEUM45http://www.epemag.com/zuse/Bgraphy.htm#BURK46http://www.epemag.com/zuse/Images/fig23b.jpghttp://www.epemag.com/zuse/Images/fig22b.jpghttp://www.epemag.com/zuse/Images/fig21b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#NEUM45http://www.epemag.com/zuse/Bgraphy.htm#BURK46


10/59


Part 4: Konrad Zuse's Z1 and Z3 Computers

The Z2 Computernsatisfied with the reliability of the binary swit$hin %etal sheets used in the Z1,Konrad Zuse ne.t $onstru$ted the Z2 $o%&uter" The Z2 used the sa%e ty&e of%e$hani$al %e%ory as the Z1, but he used 5!! old relays fro% &hone $o%&anies to$onstru$t the arith%eti$ and $ontrol units" The Z29s arith%eti$ unit $onsisted of a 10Abit fi.edA&oint enine, be$ause he wanted to test the reliability of relays forarith%eti$ $al$ulations" nfortunately, &hotos and &lans of the Z2 were destroyed byallied air raids durin the war" Howe+er, the Z2 ser+ed its &ur&ose, be$ause it$on+in$ed %y father that relays were indeed reliable, and he subse*uently built hisZ' $o%&uter $o%&letely out of relays (0!! for the arith%eti$ unit and 1,5!! for the

%e%ory and $ontrol units)"The Z3 Computer (1939-1941!Hel&ed by friends and with so%e s%all su&&ort fro% the o+ern%ent, Konrad Zuse$onstru$ted his Z' %a$hine fro% 1' to 11 in the 7ethfesselstrae in BerlinAKreu>ber" He wanted to use the Z' to de%onstrate that it was &ossible to build areliable, freely &rora%%able $o%&uter based on a binary floatin &oint nu%ber andswit$hin syste%, whi$h $ould be used for +ery $o%&li$ated arith%eti$ $al$ulations"or reliability reasons he used relays for the entire %a$hine"

i"2" The oriinal desin of the Z'drawn by Konrad Zuse in 1'"

i"2=" The Z' that was rebuilt byKonrad Zuse in 10!301"

The oriinal desin of the Z' is illustrated in i"2"nfortunately no &hotos of the oriinal Z' e.ist,be$ause all do$u%ents and &hotora&hs weredestroyed by allied air raids durin the :e$ond WorldWar"

Konrad Zuse rebuilt the Z' at his Zuse K4(')$o%&anybetween 10! and 101 (i"2=) in order tode%onstrate the &erfor%an$e of this %a$hine to Custifyhis &atents and to show the world his $reation (and

(')The Zuse K4 (where DK4D%eans a s&e$ial ty&e of$o%&any in the for% of ali%ited &artnershi&) wasfounded in 1 in#eukir$hen (Kreis HEnfeld)"This is about 12!k% north ofrankfurt"

n 1=, the Zuse K4 was


11/59

also to de%onstrate the %a$hine for ad+ertisin&ur&oses)" Like the oriinal %a$hine, the rebuilt Z' is$o%&letely $onstru$ted fro% relays" The Z'/s %e%ory(0 words, ea$h $o%&risin 22 bits) is seen on the leftA

hand side of i"2=" The $onsole is at the front, whilethe binary floatin &oint arith%eti$ unit a&&ears on therihtAhand side" The Z' is about fi+e %eters lon, two%eters hih, and 5!$% wide"

%o+ed to Bad Hersfeld,whi$h lies 1=k% north of#eukir$hen" This %o+e was&ro%&ted by the la$k of

s&a$e for roo%s and the$ra%&ed &rodu$tionfa$ilities"

i"20" Konrad Zuse with the rebuilt Z' in 101" The %e%ory ison the left (note the DZD loo Z of the Zuse K4 $o%&any)" The

arith%eti$ unit with the ste&wise relays are on the riht, andthe $onsole with &un$h ta&e reader is on the front left"

i"2" ? &ae fro% KonradZuse9s diary fro% 7ay 12, 11,

when he &resented the workinZ' to s$ientists in Berlin"

t is now undis&uted that the Z' was the first reliable, freely &rora%%able, workin$o%&uter in the world based on a binary floatinA&oint nu%ber and swit$hin syste%"n 11, the Z' $ontained al%ost all of the features of a %odern $o%&uter as definedby John +on #eu%ann and his $olleaues in 10 FB8K0G" The only e.$e&tion wasthe ability to store the &rora% in the %e%ory toether with the data" Konrad Zusedid not i%&le%ent this feature in the Z', be$ause his 0Aword %e%ory was too s%allto su&&ort this %ode of o&eration" ;ue to the fa$t that he wanted to $al$ulatethousands of instru$tions in a %eaninful order, he only used the %e%ory to store

+alues or nu%bers"
http://www.epemag.com/zuse/Bgraphy.htm#BURK46http://www.epemag.com/zuse/Images/fig27b.jpghttp://www.epemag.com/zuse/Images/fig26b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#BURK46


12/59

i"25" ? blo$k diara% of the Z'" i"2" The rebuilt Z' (101)"

The blo$k stru$ture of the Z' is +ery si%ilar to a %odern $o%&uter" The Z' $onsistedof se&arate units, su$h as a &un$h ta&e reader, $ontrol unit, floatinA&oint arith%eti$unit, and in&ut3out&ut de+i$es" With res&e$t to this the%e, Burks et al" FB8K0Gwrote as late as 10, DIn as much as the completed device will be a general'purpose computing machine it should contain main organs relating to arithmetic"memory'storage" control and connection with the human operator. It is intended thatthe machine be fully automatic in character" i.e. independent of the human operatorafter the computation starts.(

t is i%&ortant to note that the Z' fully %et Burks9 re*uire%ents" ?lso, the Z'su&&orted a s&e$ial o&eratin %ode, be$ause the )uinstru$tion sto&&ed the&rora% and a$ti+ated the in&ut de+i$e" The hu%an o&erator $ould $he$k, a%onother thins, the $ontents of the 8eisters 81 and 82 in the arith%eti$ unit, he orshe $ould &erfor% inter%ediate $al$ulations usin the 8eisters 81 and 82, then theo&erator $ould $ontinue runnin the &rora%"


Part 4 (ontinued!: The Z2 and Z3

#ow let us $onsider the dis$ussion of floatinA&oint nu%bers in Burks9 &a&er FB8K0G,whi$h states DIt would therefore seem to us not at all clear whether the modestadvantages of a floating binary point offset the loss of memory capacity and theincreased comple*ity of the arithmetic and control circuits.( (?lso note that the use ofthe binary syste% for $o%&uters was &ro&osed in John +on #eu%ann9s (+irst $raft ofa report on the ,$-!(F#I7=G)

t is +ery i%&ortant to note that floatinA&oint nu%bers were dis$ussed as late as 10by Burks et al", at whi$h ti%e they were still not $on+in$ed that this was a ood

$on$e&t" By $o%&arison, Konrad Zuse des$ribed the $on$e&t of a floatin &ro$essorin 1' and i%&le%ented su$h a unit in 1'0, fully ten years before Burks9 &a&er
http://www.epemag.com/zuse/Bgraphy.htm#BURK46http://www.epemag.com/zuse/Bgraphy.htm#BURK46http://www.epemag.com/zuse/Bgraphy.htm#NEUM45http://www.epemag.com/zuse/Images/fig29b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#BURK46http://www.epemag.com/zuse/Bgraphy.htm#BURK46http://www.epemag.com/zuse/Bgraphy.htm#NEUM45


13/59

&ostulated it as a conceptfor %odern $o%&uters and not as a built %a$hine"

#ow let us $onsider the loi$al $on$e&ts of the Z' in detail@

Para""e" #ahine: The Z' was a &arallel workin %a$hine" ? 22Abit word of data$ould be %o+ed fro% the %e%ory to the 8eister 81 and +i$e +ersa in one ste&($lo$k $y$le)" The sa%e holds true for the arith%eti$ unit, where, a%onst otherthins, &arallel adders were used"

#emor$: The %e%ory of the Z' $onsisted of 0 words, ea$h $ontainin 22 bits" Ia$hword was dire$tly addressable by the instru$tions r > or s >, where > is the addressin the rane@ 0 MN > MN 1" ? relay was needed for ea$h bit"

F"oating Point %um&ers: Konrad Zuse e%&loyed a se%iAloarith% re&resentation ofnu%bers" Let us take the nu%ber 1!!" n the binary syste% this nu%ber $an be

written as@

1!! N 1.20 1.2= !.2 !.2' 1.22 !.21 !.2!N 0 '2

The nu%ber 1!! $an be $reated by the &ower of 2 related to the nu%bers@ 20, 2=and22N 0 '2 " n the binary re&resentation we use the 1 or ! in order to re&resentthe nu%ber" (These are e.a$tly the fa$tors 1 and ! before the %ulti&li$ation sin" nthe binary diit syste% the nu%ber 1!! $an be written as@ 11!!1!!" This is a binarynu%ber without a de$i%al &oint" The nu%ber 1!!"= $an be re&resented as@

1!!"= N 1.2

0

1.2

=

!.2

!.2

'

1.2

2

!.2

1

!.2

!

1.2

A1

N 0 '2 !"=

n the binary syste% we write this as 11!!1!!"1, where the 1 to the riht of thede$i%al &oint re&resents 2A1N !"= (this for% of re&resentation is known as Dfi.edA&ointD)" 8e&resentin nu%bers usin a binary (! and 1) notation has bi ad+antaesfor $o%&uters" This has not $haned to the &resent day" :in$e only two states or twonu%bers are $onsidered, we $an use &air $ir$uits to store nu%bers and to o&eratewith the%" n 1', relays were su$h buildin blo$ks" Howe+er, the abo+ere&resentation of nu%bers has a disad+antae" Konrad Zuse used 22 bits for hisnu%bers, but with inteer re&resentations 22 bits $an only be used to re&resent s%allnu%bers in the rane MN 222A1" or this reason, Konrad Zuse used the binary floatinA

&oint (se%iAloarith%i$) re&resentation" Let us $onsider the nu%ber 1!! aain@

1!! N 1.20 1.2= !.2 !.2' 1.22 !.21 !.2!N 0 '2

Konrad Zuse di+ided the nu%ber into an e.&onent and a %antissa" n the $ase of oure.a%&le of 1!!, he would ha+e for%ed his e.&onent fro% the &ower of two of thehihest e.&onent in our nu%ber (0)" This nu%ber would then be $on+erted into binaryto i+e 11!" :i%ilarly, the %antissa asso$iated with our e.a%&le would ha+e been thebinary nu%ber 11!!1!!" This would ha+e resulted in a floatinA&oint re&resentationas follows@

!!!!!11! 11!!1!!!!!!!!!!


14/59

sin this s$he%e the first diit of the %antissa is always 1" or this reason, the first1 is inored, lea+in the %antissa as 1!!1!! instead of 11!!1!!" sin thiste$hni*ue, Konrad Zuse %anaed to ain an e.tra diit, whi$h he $ould use to&ro+ide hiher a$$ura$y" That is, instead of 1 bits, he effe$ti+ely had 1= bits for the

%antissa" The end result is that our nu%ber of 1!! would now be re&resented asfollows@

!!!!!11! 1!!1!!!!!!!!!!

:o the nu%ber 1!!"= in the binary syste% is re&resented as11!!1!!"1, while thefloatin &oint e*ui+alent is as follows@

!!!!!11! 11!!1!!1!!!!!!!

n the Z', this nu%ber would be re&resented as follows@

!!!!!11! 1!!1!!1!!!!!!!

sin this $on$e&t, Konrad Zuse was able to handle +ery bi and +ery s%all nu%bersin the rane of a&&ro.i%ately O 2A0'to O 20'"

i"'!"I.a%&les of floatin &oint nu%bers of the Z'"


15/59

Ls1 ?ddition@ 81 @N 81 82 '

Ls2 :ubtra$tion@ 81 @N 81 A 82 A=

L% 7ulti&li$ation@ 81 @N 81 P 82 10

Li ;i+ision@ 81 @N 81 3 82 2!

Lw :*uare root@ 81 @N :Q8(81) 2!

Lu To $all the in&ut de+i$e for de$i%al nu%bers A1

Ld To $all the out&ut de+i$e for de$i%al nu%bers A1

The two basi$ arith%eti$ o&erations of the Z' are the addition and substra$tion ofthe e.&onent and sins" ?ddition and subtra$tion re*uire %ore than one $y$lebe$ause, in the $ase of floatin &oint nu%bers, $are has to be taken to set the si>eof the e.&onent of both aru%ents to the sa%e +alue" This re*uires so%e e.tra$o%&arisons and shiftin" The nu%ber of $y$les needed for the )uand )dinstru$tions is +ariable, be$ause it de&ends on the e.&onent of the aru%ent" ?nu%ber $an be stored in %e%ory (s) in >ero $y$les when the result of the last

arith%eti$ o&eration $an be redire$ted to the desired %e%ory address" n this $ase,the $y$le needed for the store instru$tion o+erla&s the last $y$le of the arith%eti$alo&erations"

Rou %ay be a little sur&rised to note that the $onditional bran$h instru$tion is%issin" n his &a&ers between 1'0 and 1=, Konrad Zuse des$ribed %anys$ientifi$ and nu%eri$al &roble%s he wanted to sol+e with his %a$hines, but none ofthese &roble%s re*uired the use of the $onditional bran$h"

Howe+er, in 1, he did %ention the $onditional bran$h when he introdu$ed +ree4rograms 2+reie /echenpl5ne3FZ:I=, &10G" His definition was@ 6ei den freien

/echenpl5nen beeinflussen die eigentlichen -ariablen den blauf der /echnung.7un5chst %8nnen die bei den 9uasistarren /echenpl5nen besprochenen4lanvariablen wie variable perationszeichen" Stru%turzeichen usw. +un%tionen dereigentlichen -ariablen sein. ,s %ann z.6. die rt der peration in einer/echengleichung erst errechnet werden.

his translates as@With free programs the actual variables influence the e*ecutionof the calculation. +irst of all the variables" li%e operation signs and structure signs"as defined with the 9uasi rigid 29uasi starr3 programs" etc." can be functions of theactual variable. It is" for e*ample" possible to calculate the type of operation in acalculation e9uation.

rithmeti nit and Carr$ )oo*-head: The arith%eti$ unit of the Z' was KonradZuse/s %asterstroke" He redu$ed all the arith%eti$ o&erations to addition orsubstra$tion (subtra$tion is an addition of the $o%&le%ent of one nu%ber and thenu%ber)" or the reali>ation of the addition he i%&le%ented a s&e$ial swit$h,be$ause he wanted to a+oid usin too %any $y$les for the addition of two binaryfloatin &oint nu%bers" sin this swit$h, he $ould redu$e the addition of twofloatinA&oint nu%bers fro% a %ini%u% of 1 $y$les (with a serial addition) to onlythree $y$les (with a &arallel addition)" ?lthouh there were only fi+e instru$tions forarith%eti$ o&erations (Ls1, Ls2, L7, Li, and Lw), so%e additional o&erations werei%&le%ented that $ould be $alled fro% the in&ut de+i$e" He also si%&lified thee.e$ution of the arith%eti$ o&erations with %i$roAse*uen$es $ontrolled by ste&wiserelays"
http://www.epemag.com/zuse/Bgraphy.htm#ZUSE45http://www.epemag.com/zuse/Bgraphy.htm#ZUSE45


16/59

i"'1" Blo$k diara% of the Z'/s arith%eti$ unit" i"'2" ? relay fro% the Z'"

Konrad Zuse e%&loyed a selfAde+elo&ed carry loo%'ahead$ir$uit $onstru$ted fro%relays for the addition of floatinA&oint nu%bers" ?ssu%in the nu%bers to be addedwere still in the %e%ory, then fi+e $y$les were re*uired@ two for the r instru$tion andthree for the Ls1" The first $y$le was used to transfer the first o&erand to 8eister

81, while the se$ond $y$le was used to transfer the se$ond o&erand to 8eister 82"The e.&onent and %antissa were then added and the result was stored in 8eister81 (after this 8eister 82 is set e%&ty)" We write this as@ Ls1@ 81 @N 81 82" (#otethat Konrad Zuse used additional internal reisters whi$h are not shown on the&i$ture abo+e" These reisters were two bits loner than the %antissa in order to&ro+ide hiher a$$ura$y results")

The Z'/s %ulti&li$ation alorith% is like the one used for de$i%al %ulti&li$ation byhand" That is, it is based on re&eated additions of the %ulti&li$ator a$$ordin to theindi+idual diits of the %ulti&li$and" The di+ision alorith% is si%ilar to that for%ulti&li$ation, e.$e&t that re&eated substra$tion is used"

The instru$tion alorith% behind the instru$tion )wis one of the DCewelsD of the Z'"The %ain idea is to redu$e the s*uare root o&eration to a di+ision (:ee also thedis$ussions on the Z 6o%&uter)"


Part 4 (ontinued!: The Z2 and Z3

rithmeti +,eption and"ing: The Z' in$luded the ability to &erfor% arith%eti$e.$e&tion handlin" Konrad Zuse i%&le%ented this e.$e&tion handlin be$ause hewanted to be sure that the Z' would $al$ulate nu%bers $orre$tly, e+en when it wasworkin without a su&er+isor" Thus, the Z' was desined to re$oni>e the followino&erations@

nderflow of the rane of nu%bers is !

-+erflow of the rane of nu%bers is infinity

or $al$ulations in+ol+in !@

! . N .

! P . N !. 3 ! N infinity
http://www.epemag.com/zuse/part5a.htmhttp://www.epemag.com/zuse/part5a.htm


17/59

! 3 ! N S

or $al$ulation in+ol+in infinity@

infinity . N infinity

infinity P . N infinity

1 3 infinity N !

?ll o&erations with S ha+e the result S

! 3 ! N undefined

infinity A infinity N undefined

infinity 3 infinity N undefined

! . infinity N undefined

The undefined state was dis&layed on the leftAhand side of the out&ut de+i$e usins%all lihts" or the nu%bers ! and infinity, Konrad Zuse used s&e$ial bit $odes inthe e.&onent" ?n e.&onent of 0' was used to re&resent de$i%al !, while ane.&onent of 0 or 0' re&resented O infinity" The Z' always &erfor%ed $al$ulations

$orre$tly if one aru%ent was ! or infinity and the other aru%ent was in the allowedrane"

i"''"The Z'9s in&ut and out&ut de+i$e" #u%bers$ould be entered usin four buttons for the%antissa and 1 buttons for the e.&onent"

8esults were dis&layed usin la%&s"

i '"The Z'9s out&ut de+i$e showinthe la%&s for the de$i%al nu%bers (riht)

and the arith%eti$ e.$e&tion handlin (left)"

n order to dis&lay results, the binary floatinA&oint nu%bers used inside the Z' were$on+erted to de$i%al floatinA&oint nu%bers (ea$h $on+ersion re*uired between and 1 $lo$k $y$les, de&endin on the e.&onent)" The %antissa $onsisted of de$i%al diits (fi+e diits for the 1) and the e.&onent was between 5 and 5" Thebiest de$i%al nu%ber whi$h $ould be shown was 1I1!5"

C"o*ed #ahine: The s&eed of the Z' was o+erned by the fre*uen$y of a s&e$iali%&ulse enerator (or D$lo$kD) that was used to syn$hroni>e the %a$hine" n fa$t the$lo$k is a$tually an ele$tri$ %otor dri+in a shaft3dru%, u&on whi$h are atta$hed anu%ber of Dar%sD (or &rotrudin le+ers)" Ia$h ar% was used to $lose a swit$h, whi$hin turn a$ti+ated rou&s of relays" The anular se&aration between the ar%s $aused

different swit$hes to be $losed at different ti%es, thereby allowin the syste% to$ontrol the flow of data between the +arious units"


18/59

i"'= (left) and i"'0 (riht)" The Z'/s s&e$ial i%&ulse enerator ($lo$k)"The s&eed of the $a&stan $ould be $ontrolled in ste&s"

Konrad ob+iously wanted the $lo$k fre*uen$y to be as hih as &ossible so as to%ake the Z' &erfor% its $al$ulations as *ui$kly as &ossible" Howe+er, there was atradeoff to be %ade, be$ause hiher $lo$k s&eeds $aused s&arkin of the tele&honerelays" The $lo$k fre*uen$y that was e+entually used was around ="' Hert>de&endin on the *uality of the relays"n talks with 8oCas F8-J?5aGand %yself, %y father %entioned that a %ulti&li$ation oftwo floatin &oint nu%bers took about three se$onds (the Z' needed 10 $y$les for a%ulti&li$ation, so 10 $y$les 3 ="' Hert> N ' se$onds)" n order to a+oid s&arkin of therelay $onta$ts when swit$hin the%, he used the dru% to dro& off the ele$tri$ity atthe swit$hin ti%e" This &rin$i&le a+oided %aterial rust and uaranteed a lonfun$tionality of the relay $onta$ts"

#iro-.e/uener and Pipe"ining: The heart of the Z'9s $ontrol unit $onsisted of

%i$roAse*uen$ers" I+ery $y$le in the Z' was di+ided into fi+e ste&s ( to in e.e$ution ti%e to be +ery i%&ortant, so he e.e$utedinstru$tions usin an o+erla&&in te$hni*ue (see i"')"

This o+erla&&in of instru$tions is a ty&e of &i&elinin" ?lthouh it is not well known,

Konrad Zuse was awarded a &atent for a &i&elined $o%&uter on June '! th, 1"
http://www.epemag.com/zuse/Bgraphy.htm#ROJA98ahttp://www.epemag.com/zuse/Images/fig36b.jpghttp://www.epemag.com/zuse/Images/fig35b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#ROJA98a


19/59

i"'5" The first &i&elined $o%&uter in the world" i"'" Konrad Zuse/s &atent"

The title of this &atent is@ D/echenmaschine zur $urchfhrung arithmetischer/echenoperationen 2z.6. &ultipli%ationen3(whi$h translates as(!alculator for thee*ecution of arithmetic operations 2for e*ample multiplication3.This was a %a$hine$onsistin of eiht inde&endent arith%eti$ units, ea$h of whi$h $ould e.e$ute &artial

arith%eti$ o&erations on $ertain data, whi$h %ade it &ossible to e.e$ute theseo&erations on lare data sets"

We now return to the Z'9s %i$roAse*uen$ers, whi$h Konrad Zuse i%&le%ented usinste&wise relays" These se*uen$ers, whi$h were &art of the $ontrol unit, were used toenable a se*uen$e of re&eated %i$roAinstru$tions" or e.a%&le, the instru$tion L% isreali>ed by a se*uen$e of additions" n the Z' we find %i$roAse*uen$es for theinstru$tions Lw, L%, Li, Lu and Ld" #ote that this is not the sa%e as the %odern$on$e&t of %i$roA&rora%%in, but is instead an e.a%&le of hardAwired %i$roAse*uen$in"

i"!" The Z'9s %i$roAse*uen$ers reali>ed usin ste&wise relays" i"1" ? ste&wise relay"

?n I.a%&le Z' rora% (olyno%ial)@ Let us now$onsider an e.a%&le &rora% for

the Z'" Let us assu%e that we wish to $al$ulate the &olyno%ial@
http://www.epemag.com/zuse/Images/fig41b.jpghttp://www.epemag.com/zuse/Images/fig40b.jpghttp://www.epemag.com/zuse/Images/fig39b.gifhttp://www.epemag.com/zuse/Images/fig38b.gif


20/59

((a. a'). a2). a1

Let us further assu%e that the +alues for a, a', a2, and a1 would first be loaded intothe %e%ory $ells , ', 2, and 1 usin the in&ut de+i$e"

Lu To $all the in&ut de+i$e for the +ariable .

s = To store +ariable . in %e%ory word =

r Load a1 in 8eister 81

r = Load . in 8eister 82

L% 7ulti&ly@ 81 @N 81 . 82

r ' Load a' in 8eister 82

Ls1 ?dd@ 81 @N 81 82

r = Load . in 82

L% 7ulti&ly@ 81 @N 81 . 82

r 2 Load a2 in 8eister 82Ls1 ?dd@ 81 @N 81 82

r = Load . in 8eister 82

L% 7ulti&ly@ 81 @N 81 . 82

&r 1 Load a1 in 8eister 82

Ls1 ?dd@ 81 @N 81 82

Ld :hows the result as a de$i%al nu%ber

The Lu instru$tion at the beinnin of the &rora% instru$ts the in&ut de+i$e to reada +alue for ." The Ld instru$tion at the end of the &rora% dire$ts the Z' to dis&lay

the result as a de$i%al nu%ber"#inima" 0esign Prinip"e and the niersa" Computer (Turing!Konrad Zuse followed a %ini%al desin &rin$i&le in the $onstru$tion of his$o%&uters, be$ause his oal was to build a &owerful $o%&utin %a$hine with%ini%al effort and $ost" He really didn/t ha+e any other $hoi$e, be$ause his &arentswere not ri$h and he didn9t ha+e %u$h %oney" ?s far as he was $on$erned, the Z'was the last in a series of trial %a$hines (Z1AZ') that were intended to &a+e the wayto a %a$hine that would be able to sol+e the %athe%ati$al &roble%s of enineersand s$ientists"

Konrad Zuse was $on+in$ed that his $o%&uter $ould $al$ulate all %athe%ati$al&roble%s (in 11 he told his friends that his %a$hine was $a&able of &layin$hess), but he $ould not &ro+e that this was he $ase" n fa$t it wasn9t until 15(three year9s after Konrad9s death) that 8aul 8oCas F8-J?5aGfor%ulated the &roofthat the Z' was a truly uni+ersal $o%&uter in the sense of a Turin %a$hine"The .1 and .2 ComputersThe :1 and :2 $o%&uters were %andated by the Hens$hel air$raft $o%&any in123'" These were s&e$ial de+elo&%ents for %easurin the wins of air&lanes"The :1 e%&loyed a&&ro.i%ately 0!! relays and had hardwareAwired &rora%s" The

:2 was the su$$essor of the :1, and $onsisted of a&&ro.i%ately 5!! relays andabout 1!! dial aes in order to %easure the surfa$e of the wins" t was used by
http://www.epemag.com/zuse/Bgraphy.htm#ROJA98ahttp://www.epemag.com/zuse/Bgraphy.htm#ROJA98a


21/59

the Hens$hel ?ir$raft 6o%&any sin$e 12" The :2 $an be rearded as the first&ro$ess $o%&uter in the world"


Part : Konrad Zuse's P"an*a*" Programming)anguage (1942-1945!

ro% 12A1=30 (at the sa%e ti%e as he was de+elo&in the Z $o%&uter, asdis$ussed in art 0of this arti$le), Konrad Zuse was also de+elo&in ideas as tohow his %a$hines $ould be &rora%%ed in a +ery &owerful way (that is, %ore&owerful than arith%eti$ $al$ulations only)"He $onsidered %any of the &roble%s that enineers and s$ientists needed to sol+e,analy>ed and des$ribed these &roble%s, and $reated do>ens of e.a%&les" Basedon these e+aluations, it be$a%e $lear to %y father that he re*uired a so&histi$atedte$hni*ue for for%ulatin tasks that the $o%&uter should sol+e" or e.a%&le, one ofhis ideas was related to &erfor%in the $al$ulations used to build brides" n this$ase he belie+ed that the in&ut data for a brideAbuildin &rora% should be the ty&eof bride re*uired and the $onditions of the bride related to the %aterial and theen+iron%ent" Based on this, the $o%&uter should then &ro&ose a reliable bride"

Zuse denoted su$h %a$hines as )ogistische

&aschinen(loisti$ %a$hines), as o&&osed toalebrai$ %a$hines su$h as the Z1, Z2, Z'(and the Z as des$ribed in art 0), whi$hwere only a&&ro&riate for nu%eri$al$al$ulations" n order to &ro+ide this ability to$a&ture the diffi$ult &roble%s of enineers in$o%&uter &rora%s, Konrad Zuse for%ulatedthe re%arkably so&histi$ated &rora%%inlanuae lankalkEl"()n addition to &urestate%ents for nu%ber $al$ulations, Zuse alsoused rules of %athe%ati$al loi$"

()The na%e lankalkEl is deri+edas a $o%bination of two words@DlanD and DKalkElD" Konrad Zusereferred to his &rora%s as a/echenplans(6o%&utin lans)"

The ter% KalkEl ($al$ulus) is wellknown in %athe%ati$s, so he &utDlanD and DKalkElD toether tofor% 4lan%a%l, %eanin D$al$ulusfor a $o%&utin &lanD"

-n the one hand he used the &owerful &redi$ate loi$ Boolean alebra as lanuae$onstru$ts" -n the other hand he de+elo&ed a %e$hanis% to define &owerful datastru$tures, $o%%en$in with the si%&le bit (binary diit) and workin u& to$o%&li$ated hierar$hi$al stru$tures" n order to de%onstrate that the lankalkEllanuae $ould be used to sol+e s$ientifi$ and enineerin &roble%s, Konrad Zusewrote do>ens of e.a%&le &rora%s" n his notes one $an find the sortin of lists,sear$h strateies, relations between &airs of lists, et$"

Konrad Zuse fo$ussed on the ty&es of loi$al &roble%s that ha+e to be sol+ed withthe $o%&uter" ro% %y &oint of +iew there is no other work a+ailable (at or before this

ti%e) where so %any written &rora%s a&&lied to enineerin &roble%s $an be found"The final +ersion of lankalkEl was finished in Hinterstein (?llVu) in 1030, but it
http://www.epemag.com/zuse/part6a.htmhttp://www.epemag.com/zuse/part6a.htmhttp://www.epemag.com/zuse/part6a.htmhttp://www.epemag.com/zuse/part6a.htmhttp://www.epemag.com/zuse/part6a.htm


22/59


23/59

6onditional state%ents (but no IL:I state%ent)"

8e&etition of state%ents (loo&s)"

-&erations of &redi$ate loi$ and Boolean alebra"

owerful o&erations on lists and &airs of lists"

#o re$ursion"

;ata ty&es like@ floatin &oint, fi.ed &oint, $o%&le. nu%bers"

?rrays, re$ords, hierar$hi$al data stru$tures, list of &airs"

?rith%eti$ e.$e&tion handlin"

?&&li$ations to &lay $hess are des$ribed on %ore than 0! &aes"

?ssertion(0)as was subse*uently used in the IIL and 7-;L?A2lanuaes"

6o%&li$ated e.&ressions with &arentheses and nestin"

(=)Hein> 8utishauser was (toether with ?%bros :&eiser) one of the s$ientistsworkin with the Z at the ITHAZEri$h, as dis$ussed in art 0"(0)?ssertion is a &ro&erty of so%e of the +alues of &rora% entities" or e.a%&le, anassertion %ay e.&ress that a $ertain inteer has a &ositi+e +alue or that a $ertainreferen$e is +oid"

? ood introdu$tion to lankalkEl $an be found in F:IBI0G" Howe+er, after 1Konrad Zuse had no %ore ti%e to $onsider a&&li$ations for lankalkEl and other&rora%%in lanuaes, be$ause at this ti%e he founded the Zuse K4 $o%&any"We will return to $onsider the Zuse K4 in art , but first we %ust return to 1! X""


Part 5: The Z4 Computer and the Zuse pparate&auin 6er"in (1947-194!

n 1!, Konrad Zuse for%ulated a +ision, whi$h was to use$o%&uters to release the s&irits of hu%ans fro% the stu&id task of$al$ulations" n order to build his $o%&uters, Konrad Zuse foundeda $o%&any $alled the Zuse ?&&aratebau in Berlin on ?&ril 1, 1!"

The Zuse ?&&aratebau was a s%all $o%&any lo$ated in the 7ethfesselstrae and
http://www.epemag.com/zuse/part6a.htmhttp://www.epemag.com/zuse/Bgraphy.htm#SEBE96http://www.epemag.com/zuse/part7a.htmhttp://www.epemag.com/zuse/part6a.htmhttp://www.epemag.com/zuse/Bgraphy.htm#SEBE96http://www.epemag.com/zuse/part7a.htm


24/59

1! in BerlinAKreu>ber" By 11, Konrad Zuse was sure that the eneral &roble%sof buildin &owerful $o%&uters were sol+ed" He &lanned the Z to be a &rototy&e of$o%&uters for enineerin bureaus and s$ientifi$ institutes" Based on hise.&erien$es with the Z1 to Z' %a$hines, and knowin the &roble%s he wanted tosol+e for the enineers, he reali>ed that the Z needed %u$h %ore %e%ory than in

the &re+ious %a$hines"

or this reason, he $o%&ared the ad+antaes and disad+antaes of a %e%ory builtusin relays to a %e%ory $onstru$ted fro% thin %etal sheets (like the Z1 and Z2)"His $on$lusion was that $onstru$tin the %e%ory fro% %etal sheets was %u$h lesse.&ensi+e than buildin a relay %e%ory" t was $lear to hi% that a %e%ory of onethousand '2Abit words $onsistin of relays would be too bi, be$ause he would need%ore than 1!!! . '2 N '2,!!! relays" His &atented %e$hani$al %e%ory (1'0)worked +ery reliably, and for 1!!! words he would not need %ore than one $ubi$%eter of s&a$e" Konrad Zuse also esti%ated the $osts of one '2Abit word of his%e$hani$al %e%ory as bein = 87 (8ei$h%arks), whi$h e*uated to a&&ro.i%ately

Y2"=! : in 12"

By 1= the Zuse ?&&aratebau had about 2! e%&loyees" nfortunately, at this ti%ethe buildin and the $o%&any were $o%&letely destroyed by air raids," To this day,the &lot of land in the 7ethfesselstrae is a bo%bed site" iure 'b shows the7ethfesselstrae and 1!, where Konrad Zuse built the Z' and started the$onstru$tion of the Z"

i"'b (Left)" The 7ethfesselstrae in Berlin (1)" The Z' and Z were $onstru$ted in a house onthis &lot of land (Cust to the riht of the red $ar)" i" (8iht)" Konrad Zuse (15) at the entran$e ofthe 7ethfesselstrae "

The Z4 ComputerThe oal of the Z, whi$h was de+elo&ed between 12 and 1=, was to build the&rototy&e for a %a$hine that was intended to be &rodu$ed in the thousands"nfortunately, the war destroyed %y father9s ho&e, whi$h was that his %a$hinesshould su&&ort the work of enineers of the ti%e"
http://www.epemag.com/zuse/Images/fig44b.jpghttp://www.epemag.com/zuse/Images/fig43bb.jpg


25/59


26/59

Part 5 (ontinued!: The Z4 a8ter the ar

7ost &eo&le today $annot i%aine how bad the situation in 4er%any in 1= was"Berlin was atta$ked e+ery day and niht by %ore than 5!! bo%bers" Konrad Zuse

e+entually fled fro% Berlin with his &renant wife 4isela and the Z in 7ar$h 1="The Z itself was trans&orted on a %ilitary tru$k" This was %ade &ossible by so%e$onfusion between the Z $o%&uter and the


27/59

i"=! (Left)" The Hotel :teinadler in Hinterstein (?llVu)" i"=1 (8iht)" The barn where the Z washidden fro% 1=A10" t is interestin to note that the Z was the only $o%&uter in 4er%any (and&robably in Iuro&e) until 1=1[

The situation around Hinterstein was $o%&li$ated" or e.a%&le, there were %ore

than 12!! refuees, 2!! soldiers, and so forth" Konrad Zuse and his wife found aroo% in the House Tannhei%er" ro% 1= till 1 it was al%ost i%&ossible torestore the da%aed Z, whi$h was, at this ti%e, the only $o%&uter in 4er%any(and &robably in Iuro&e)[Konrad Zuse des&erately wanted to resu%e work on the Z, but his first &roble%was to sur+i+e the years after the war" n order to et so%e food, he %ade wood$utsand sold the% to the far%ers and the ?%eri$an troo&s" iure =' shows a wood$utby Konrad Zuse, whi$h de&i$ts Hinterstein" The Z $o%&uter was hidden $lose tothe $hur$h"

i"=2 The s%all +illae of Hinterstein (15=)"i"=' (8iht)" ? wood$ut of Hinterstein by Konrad Zuse (10)"
http://var/www/apps/conversion/tmp/scratch_5/Images/fig53b.jpghttp://var/www/apps/conversion/tmp/scratch_5/Images/fig52b.jpghttp://www.epemag.com/zuse/Images/fig51b.jpghttp://www.epemag.com/zuse/Images/fig50b.jpg


28/59

i"= (Left)" The House Tannhei%er in Hinterstein, where Konrad Zuse and his fa%ily found roo% onthe first floor (the four windows at the front ede of the house)" i"== (8iht)" ? wood$ut of the HouseTannhei%er by Konrad Zuse (1=)"

i"=0 (Left) ? three $olor wood$ut (0!$% . 5!$%) of the waterfall Zi&felsfVlle in Hinterstein byKonrad Zuse" He used three se&arate wood &lates, one for yellow, one for blue, and one for red (thereen $olor was $reated fro% the $olors yellow and blue)" Ia$h wood &late was &ressed onto thesa%e &ie$e of &a&er in turn to $reate the final i%ae" i"= (7iddle)" ? wood$ut by Konrad Zuse,

whi$h shows the hut 8ohEtte and the Ir>ber %ountain $lose to Hinterstein in the winter of1=30" i"=5 (8iht)" ? wood$ut of the $hur$h in Hinterstein in 10"


Part 5 (ontinued!: The Z4 a8ter the ar

;urin the &eriod fro% 1= to1 itwas al%ost i%&ossible to fully restore the

da%aed Z" Howe+er Konrad Zuseused tin $ans he obtained fro% the allies

n FZ:IGKonrad Zuse wrote thefollowin state%ent related to $o%&uters

in the future@ $ie in diesem7usammenhang auftretenden 4robleme
http://www.epemag.com/zuse/Bgraphy.htm#ZUSE47http://www.epemag.com/zuse/Images/fig58b.jpghttp://www.epemag.com/zuse/Images/fig57b.jpghttp://www.epemag.com/zuse/Images/fig56b.jpghttp://www.epemag.com/zuse/Images/fig55b.jpghttp://www.epemag.com/zuse/Images/fig54b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#ZUSE47


29/59

to re&air &arts of the Z9s %e$hani$al%e%ory"nfortunately there was nowhere inHinterstein that was suitable for Konrad

Zuse to set u& the Z" Thus, in 1,Konrad Zuse, his wife 4isela, and theirson (%yself Horst) %o+ed to Ho&ferau(Ba+aria), whi$h is about '! k% north ofHinterstein" By 15, the Z wasreasse%bled in a for%er flour store inHo&ferau" :o%e $al$ulations $ould be&erfor%ed, but the ele$tri$al &ower wasonly a+ailable for a few hours ea$h day,and it was enerally not suffi$ient toa$$o%odate the Z9s &ower

$onsu%&tion"

n 15 Iduard :tiefel fro% the ITHAZEri$h wanted to set u& a new nstitutefor ?&&lied 7athe%ati$s" :tiefel9sde$lared oal was to ad+an$e nu%eri$alanalysis" ?$$ordinly he was lookin fora way to ain a$$ess to $o%&utin&ower beyond the le+el that $ould be&erfor%ed by si%&le deskto& $al$ulators"

sind so umfangreich" da; eineGeneration von Wissenschaftlern"echni%ern und Wirtschaftlernerforderlich sein wird" um sieersch8pfend zu bearbeiten.

Translation@ he problems in this conte*tare so e*tensive" that a generation ofscientists" engineers and economists willbe necessary" to process themsufficiently.

By D&roble%sD %y father %eant theintrodu$tion of $o%&uters in s$ien$e and$o%&anies" His &lan was to build loisti$$o%&uters" These $o%&uters were

e.tended alebrai$ $o%&uters, like theZ, in order to sol+e &roble%s of theenineers" These &roble%s should befor%ulated in the lankalkEl, whi$h todayis a$$e&ted as the first &rora%%inlanuae of the world" ?lready in 1'he wrote, that the &roble%s of alebrai$$o%&uters are sol+ed"

:tiefel *ui$kly reali>ed that $o%%er$ial &un$hed $ard %a$hines were not suited for%athe%ati$al work, and that the ele$troni$ $o%&uter &roCe$ts under way, %ainly inthe :, but also in Britain, would not fill the a& for se+eral years to $o%e" He thusde$ided that ITH should build his own ele$troni$ $o%&uter" or this &ur&ose, hedeleated two of his assistants, Hein> 8utishauser and ?%bros :&eiser, to +isit :"Their assin%ent was to study the stateAofAtheAart in : $o%&utin and then to starta suitable &roCe$t at the ITH"8utishauser and :&eiser s&ent %ost of 1 at Ha+ard with Howard ?iken and atrin$eton with John +on #eu%ann, but they also +isited a nu%ber of other $o%&uter

installations, in$ludin the I#?6 at ?berdeen and the 7?8K at ;ahlren" n1, :tiefel was infor%ed about the e.isten$e of the Z and he was told that the%a$hine %ay &ossibly be for sale" To this day it is not $lear fro% who% he hadheard about the Z in Ho&ferau"


30/59

i"= (Left)" Konrad Zuse9s worksho& in Ho&ferau (?llVu) in 1, where he installed the Z" TheZ stood at the rihtAhand side of the worksho&" i"0! (7iddle)" The Z9s in&ut and out&ut de+i$esand the lanfertiunsteil (&rora% $onstru$tion unit) in Ho&ferau" i"01 (8iht)" rof" Iduard :tiefel

fro% the ITHAZEri$h, who &ur$hased the Z for =!,!!! ;7 and trans&orted it fro% Ho&ferau toZEri$h in 1"

rof" :tiefel ins&e$ted the Z $o%&uter in Ho&ferau in 1" Konrad Zuse e.&lainedthe s&e$ifi$ations of the Z, whi$h were +ery $on+in$in" :tiefel then a+e KonradZuse a differential e*uation to sol+e" 7y father for%ulated the &rora% for the Z,$reated a &un$h ta&e, and the Z bean to work" The result was $orre$t" Thus,des&ite the fa$t that the Z was only barely in o&erational $ondition, :tiefel de$idedthat the idea of transferrin it to the ITH ZEri$h should by all %eans be studied"

:tiefel wrote a letter to 8utishauser and :&eiser who were in Ha+ard at this ti%e"

?lthouh ?iken dissuaded :&eiser and 8utishauser fro% a relay %a$hine (he&ro&osed to build and use ele$troni$ %a$hines) 8utishauser and :&eiser wrote to:tiefel that the idea of takin the Z should not be flatly reCe$ted" :tiefel also&ersuaded the ITH resident, Hans all%ann, to %ake the ne$essary fundsa+ailable for rentin the Z" :tiefel %ust therefore re$ei+e $redit for a wise de$isionF:I5G, be$ause there were enouh reser+ations that ha+e $ould %ade hi% shyaway fro% this ste&" ?%on these reser+ations were@

8elays were a te$hnoloy of the &ast, ele$troni$s $ould do the Cob 1!! ore+en 1!!! ti%es faster, as ?iken stated"

The $ondition of the Z and its de%onstration to :tiefel were not fully$on+in$in" t was un$ertain whether the s%all rou& around Zuse would beable to brin the %a$hine u& to a reliable o&eratin le+el"

The %e$hani$al %e%ory was %ost unusual and nobody had e+er seenanythin si%ilar" ?n infor%ed &redi$tion of the Z9s o&eratin &erfor%an$esee%ed to be i%&ossible" ? failure of the %e%ory would ha+e rendered theentire %a$hine useless"

nstallation and o&eration of the Z would absorb all the efforts of :tiefel9ss%all rou&"

?%bros :&eiser, who was a s$ientist workin with the Z in ZEri$h in 1=!, said in
http://www.epemag.com/zuse/Bgraphy.htm#SPEI98http://www.epemag.com/zuse/Images/fig61b.jpghttp://www.epemag.com/zuse/Images/fig60b.jpghttp://www.epemag.com/zuse/Images/fig59b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#SPEI98


31/59

an inter+iew to Horst Zuse in 15 FZ:I5G@

4rof. Stiefel did not want to build computers" he wanted to use them inan easy way for comple* numerical calculations.

or this reason the s&eed of the $o%&uter was not the %ost i%&ortant thin"?%onst other as&e$ts, the si%&li$ity of &rora%%in was +ery i%&ortant to :tiefel"The Z9s atta$hed lanfertiunsteil (&rora% $onstru$tion unit) $on+in$ed hi% totake the Z, be$ause it allowed s$ientists how to enter &rora%s in less than threehours" ?lso the &owerful arith%eti$ unit with its e.$e&tion handlin $a&ability was anideal &rere*uisite for the $al$ulations :tiefel wanted to %ake"n 15, re&resentati+es fro% B7 +isited Konrad Zuse in Ho&ferau" Howe+er, theywere %ore interested in %y father9s &atents than in his future ideas" B7 did notwant to uarantee Konrad Zuse that he $ould work on $o%&utin in the future" orthis reason only a short o&tion $ontra$t was $on$luded between Konrad Zuse andB7"


Part : The Zuse K;

n 1 Konrad Zuse founded the Zuse K4 with fi+e e%&loyees in a s%all +illae ofabout 5!! inhabitants $alled #eukir$hen (Kreis HEnfeld, 12! k% north of rankfurt)"(#ote that DK4D %eans a s&e$ial ty&e of $o%&any in the for% of a li%ited &artnershi&"ro% 1 to 1 the &artners were@ ?lfred I$kardt, Harro :tu$ken, and KonradZuse" ro% 1= the &artners were Konrad Zuse and his wife, and fro% 10

onwards the Zuse K4 had a nu%ber of owners as des$ribed later in this se$tion")The Zuse K4 was the first $o%&uter $o%&any in 4er%any" The buildin used by theZuse K4 in #eukir$hen was for%erly a &ost relay station"

i"0' (Left)" ? drawin of the Zuse K4 in #eukir$hen by Konrad Zuse in 1=!" i"0 (8iht)" ?&hotora&h of the a$tual buildin"The Z $o%&uter was restored on the first floor $lose to the stairs"

The first task of the Zuse K4 in 1 was to restore the Z for deli+ery to the ITHAZEri$h" The Z was %o+ed fro% Ho&ferau to #eukir$hen (a Courney of about =!! k%)and was enhan$ed with the followin features@
http://www.epemag.com/zuse/Bgraphy.htm#ZUSE98http://www.epemag.com/zuse/Images/fig64b.jpghttp://www.epemag.com/zuse/Images/fig63b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#ZUSE98


32/59

%&le%entin a $onditional bran$h $a&ability"

?ddin instru$tions for &rintin the results on a 7er$edes ty&ewriter or a&un$h ta&e"

:torin nu%bers on the &un$h ta&e in order to transfer the% into the Z9s%e%ory"

Writin results on a &un$h ta&e"

%&ro+in the fa$in of the %a$hine, for e.a%&le@ addin sheathin for therelay $u&boards"

:e&aratin the ser+i$e unit and the relay $u&boards"

The result of restorin the Z are shown in i"0= and i"00"

i"0= (Left)" The restored Z in #eukir$hen in 1=!" i"00 (8iht)"The Z9s $onsole" -n the left arethe in&ut and out&ut de+i$es for de$i%al floatin &oint nu%bers, in the %iddle the &un$h ta&e readersand &un$h ta&e writer, and to the riht is seen the lanfertiunsteil (&rora% $onstru$tion unit)"

The Z was deli+ered to the ITH ZEri$h on July 11, 1=!" This was a reat day forthe ITH and :wit>erland as was noted by :&eiser" -nly half a year after theinauuration of the Z at the ITH, 8utishauser $ould re&ort about the su$$ess ofusin the %a$hine"The restored Z $onsisted of about ten relay $u&boards $ontainin 2,2!! standardrelays, &lus 21 ste&wise relays for the %i$roAse*uen$er" The Z9s %e%ory was a%e$hani$al one with 0 words, ea$h $ontainin '2 bits" The stru$ture of the%e$hani$al %e%ory was si%ilar to the %e%ory of the Z1" Howe+er, while the Z1 hada word lenth of 22 bits, the word lenth of the Z was e.tended to '2 bits" Ia$hword was dire$tly addressable by the instru$tions on the &un$h ta&e" This%e$hani$al %e%ory was a uni*ue feature" n fa$t when the s$ientists fro% the ITHAZEri$h saw this %e%ory for the first ti%e in 15 in Ho&ferau, they re&orted torofessor :tiefel that they had ne+er seen su$h an e.traordinary $onstru$tionbefore" They also re&orted to rof" :tiefel, that they had doubts that this %e%ory

would e+er work reliably"


33/59

i"0 (Left) and i"05 (8iht)"The Z9s %e%ory $onsistin of thin %etal sheets" This ty&e of%e%ory worked +ery reliably in the Z1 (1'5) and Z2 (1') %a$hines" The $a&a$ity of the Z9s%e%ory was 0 words, ea$h $ontainin '2 bits"

?s :&eiser F:I5Gwrote about the o&eration of the Z@he machine was moved to ,< in September 0=>" and" after arelatively short period" assumed operation. he 7@ proved to bereliable" and the fre9uency of brea%downs was well within the limits ofwhat was compatible with satisfactory operation. Auite soon" themachine could be left running unattended overnight" which was 9uiteunusual at this time. 7use himself was understandable proud of thisachievement.


34/59

hardware and in the programs.

n fa$t the %e%ory, $onsistin of thousands of %etal sheets, s$rews and &ins, wasthe %ost reliable feature of the Z" The Z worked +ery reliably and also worked

durin the niht without su&er+ision" :&eiser, who was res&onsible for the%aintenan$e of the Z also wrote F:I5G@

lthough" as stated" reliability was 9uite good" I neverthelessremember many hours of searching for mista%es" which often had theirroots in the malfunction of relay contacts due to dust. We alsodiscovered several cold soldering Eoints that gradually failed to conductDfinding them was particularly bothersome" because they causedmista%es that were often intermittent. n two occasions I had todisassemble parts of the memory. his meant removing about 0pins and placing them bac% again. here were two %inds of pins" their

lengths were 1.> and 1.C mm. If due to a mista%e I mi*ed up one singlepin" the entire memory was bloc%ed" a very frustrating e*perience"

i"0 (Left)" Konrad Zuse workin at the Z in #eukir$hen (1=!)" i"! (8iht)" Konrad Zuse$onsiders one of the Z9s &un$h ta&es" These &un$h ta&es were what %ade Konrad Zuse9s $o%&utersfreely &rora%%able %a$hines"


Part (ontinued!: The Zuse K;

Konrad Zuse referred to &rora%s as/echenplans ($al$ulatin &lans)" TheZ %ade use of a unit $alled a4lanfertigungsteil (&rora%$onstru$tion unit),(5)whi$h was used to&rodu$e &un$h ta&es $ontainin

instru$tions for the Z in a +ery easyway" or this reason, it was &ossible

(5)Konrad Zuse also &lanned alanfertiunserVt (&rora% translationunit), whi$h was to be an e.tended +ersionof the Z9s lanfertiunsteil (&rora%$onstru$tion unit)" Konrad Zuse9s idea wasto write &rora%s in a sy%boli$ way, like

the notation in %athe%ati$s, and to then$o%&ile these hihAle+el &rora%s into the
http://www.epemag.com/zuse/Bgraphy.htm#SPEI98http://www.epemag.com/zuse/Bgraphy.htm#SPEI98


35/59

to learn the &rora%%in of the Z inas little as three hours"

Z9s %a$hine lanuae"

The lanfertiunsteil was already a &art of the Z in 1=" We $an see, thatKonrad Zuse tried to %ake it as easy as &ossible to write &rora%s for his %a$hine"

-n the one hand the lanfertiunsteil allowed the &rora%%er to use sy%boli$%e%ory $ells, instru$tions, and sy%boli$ arith%eti$ o&erations for the $reation of a&rora%, and it also was &ossible to $o&y &rora%s and to %ake $orre$tions" -n theother hand the instru$tions and data on a &un$h ta&e $ould easily be shown byla%&s"

i"1 (Left)" The Z9s 4lanfertigungsteil(&rora% $onstru$tion unit), whi$h was used to $reate &un$hta&es for the Z in an easy way" i 2 (8iht)" -ne of the Z9s &un$h ta&es with instru$tions on howto %ake it" t was also &ossible to store inter%ediate results on a &un$h ta&e and to then use this ta&e

as in&ut data"

The Z4


36/59

7onadi$ o&erations are@ .2, :Q8(.), 13., ] . ] , sin(.), .P132, .P2, .P(A1),.P1!, .P', .P13', .P13=, .P13, .Pi, .P13i"

nstru$tions for $o%&arison (. N !, . N !, ] . ] N infinity ) test the +alue in8eister 81 and set 8eister 81 to 1 if the $ondition is fulfilled, if not, then

the $ontents of 8eister 81 are set to 1" This instru$tion was already&lanned in 12, but la$k of %aterial %ade the reali>ation i%&ossible at thatti%e"

The $onditional bran$h :8 was a s&e$ial re*uire%ent by the ITH" Theinstru$tion :8 ski&s the &un$h ta&e to the instru$tion :T, if 8eister 81$ontains 1 (if 8eister 81 $ontains 1 then there is no i%&a$t)"

nstru$tion @ The Z had two &un$h ta&e readers" n the oriinal +ersionu& to si. su$h readers were &lanned (this was referred to as the sub&rora%te$hni*ue)" The instru$tion swit$hes fro% the %ain &un$h ta&e reader

(?!, see i"' below) to the sub &un$h ta&e reader (?t1)" The instru$tion# $auses a swit$h ba$k to ?!"

nstru$tions for -ut&ut@ A, ;, L, et$"@ These instru$tions $ause binarynu%bers to be $on+erted into their de$i%al e*ui+alents and the results to bedis&layed with la%&s, on the 7I86I;I: ty&ewriter as floatin or fi.ed &ointnu%bers, or on the &un$h ta&e"

nstru$tions for n&ut@ MA, ?t1, et$"@ These allow nu%bers to be read fro% the&un$h ta&e"

rithmeti +,eption and"ingLike the Z', the Z su&&orted &owerful arith%eti$e.$e&tion handlin" f there are nu%bers outside therane of a&&ro.i%ately 1!A2!M . M 1!2!then the%a$hine returns the rane where the result is, fore.a%&le@

-ery big F very big very big

-ery big H very big undefined

undefined

f a sin of undefined is $o%bined with another sin ofundefined, then the result is undefined" This %ethod$ould be used to &re+ent the Z fro% $al$ulatinin$orre$t nu%bers when it was workin withoutsu&er+ision (this was %ostly the $ase at the ITH)"

i"'" The Z9s two&un$h ta&e readers"

8estorin the Z $ost the Zuse K4 about 0!,!!! ;7" The ITH ZEri$h &aid ana%ount of !,!!! :wiss ran$s (around 1!!,!!! ;7 at that ti%e) in ad+an$e for the

Z" With this %oney it was &ossible to found the Zuse K4 and restore the Z" (t isworth %entionin that the a+erae in$o%e at this ti%e was about 15! ;7 &er


37/59

%onth") The Z was a reat su$$ess for both the ITH and the Zuse K4"

The Z40" weoffered to students a course in computer programming with practicale*ercises on the machine. We believe we were the first on the

,uropean continent to do so. his should be ta%en in consideration bythose who often criticize that Swiss Jniversities were late in
http://www.epemag.com/zuse/Bgraphy.htm#SPEI98http://www.epemag.com/zuse/Bgraphy.htm#SPEI98http://www.epemag.com/zuse/Bgraphy.htm#SPEI98http://www.epemag.com/zuse/Bgraphy.htm#SPEI98


38/59

recognizing the importance of informatics.

he situation in Germany in the early >Bs is worth being commented.While the 7@ was installed and operated in 7rich" there were three

computer proEects under way in West Germany: $armstadt" &nchen"and G8ttingen. heir interest in the 7@ was only moderate" to put itmildy. o understand this attitude one must ta%e in account thefundamental difference in priorities: Stiefel had the desire to havecomputing power at his disposal as fast as possible" even if it wasmodest. he three German groups on the other hand had the ambitionto build electronic computers with advanced technologyD they wereunder less pressure from the side of a computer'hungrymathematician. 6ut when the scientific results started to flow out of7rich in 0=>0 and 0=>1" there was some criticism voiced in Germanysaying the 7@ should have been %ept at home rather than let it go

abroad.

o me" and now in the light of retrospect" the e*planation of whathappened is 9uite clear: Jniversities in 0=> were still suffering fromthe effects of the war. 6uildings were badly damaged" e9uipment wasalmost non'e*istent" and" accordingly" the limited funds had to bespent for the urgent needs of the day in order to %eep university life onan acceptable level. he sum of >" $& we paid for the 7@ wasclearly outside the reach of any universities. +unds in this amountcould only have come from the federal ministry" possibly a stateministry" and from the &arshall 4lan whose influence was highlybeneficial. 6ut in these circles the opinion was crystal'clear: he futurebelonged to electronics" it would be a big mista%e to divert the limitedfunds to a relay machine.



The Z Computern 1=!, the Leit> 6o%&any in Wet>lar ordered a bi relay $o%&uter, the Z=" i"

and i"= show the Z= and the e%&loyees of the Zuse K4 in 1=2, who built theZ=" Like the Z, the Z=, whi$h was sold for '!!,!!! ;7, was also a reat su$$essfor the Zuse K4"


39/59

i" (Left)" The Z= was an e.tended +ersion of the Z and was deli+ered to the Leit> 6o%&any in1=2" The %a$hine had about ',!!! standard relays and %ore than '! ste&wise relays" i"=(8iht)" The Zuse K4 built the Z= fro% 1=!A1=2 with about '! e%&loyees"

or the Z=, Konrad Zuse used 2,5!! unifor% %odern tele&hone relays in order too+er$o%e the bad reliability of +a$uu% tubes" The %a$hine itself o$$u&ied an areaof 1! %eters by "= %eters, while the in&ut and out&ut de+i$es re*uired 2"= %etersby "= %eters" The Z= was the first $o%%er$ial $o%&uter e+er built in 4er%any(&robably in Iuro&e) and deli+ered to a $o%&any in 4er%any" ?lso, the Z= was thereatest relay $o%&uter e+er $onstru$ted and deli+ered in WestA4er%any (in 1==the -8I7?, whi$h used 1,!!! relays, was $onstru$ted in IastA4er%any)"

The Z= was si. ti%es faster than the Z, had a twel+e word %e%ory (ea$h$ontainin '= bits, so floatin &oint nu%bers were re&resented usin 1 bit for thesin, bits for the e.&onent, and 2 bits for the %antissa), and a s&e$ial %e%ory tostore eiht $onstants (su$h as@ !, 1, 1!, i, 13', 13=, 13, 22!)" The Z= was

a three address %a$hine and had a $lo$k fre*uen$y of about ! Hert>"

t is i%&ortant to note that the Z= was not a stored &rora% %a$hine, be$ause the&rora% was not stored in the %e%ory alon with the data" nstead, the Z=e%&loyed a subA&rora% te$hni*ue reali>ed usin three &un$h ta&e readers (basedon '= %% standard %o+ie fil%), whi$h were a$ti+ated by ea$h other" The &un$h ta&ereaders read twel+e 2!Abit $o%binations &er se$ond (instru$tions and3or floatin&oint nu%bers)"

?lthouh the %e%ory was +ery s%all, it was &ossible to &erfor% the $o%&li$ated$al$ulations of the nu%eri$al %ethods re*uired for o&ti$al lens syste%s" The

e.e$ution ti%es were !"1 se$onds for an addition, !" se$onds for a %ulti&li$ation,!"= se$onds to &erfor% a di+ision or a s*uare s*uare root, !"!= se$onds to %ulti&lya floatin &oint nu%ber with a $onstant, and !" to 1" se$onds to $on+ert a floatin&oint nu%ber into its de$i%al e*ui+alent, or +i$e +ersa" The $al$ulation of the root ofan alebrai$ e*uation of the 5th deree took around '5 se$onds, and the $al$ulationof a deter%inate of the th deree took around 1= se$onds"

Howe+er, the Z= was the only bi %andate that the Zuse K4 ot between 1 and1==" ?t this ti%e, '!!,!!! ;7 was a lare a%ount of %oney" The %onthly in$o%eof a ty&i$al fa%ily was less than 2!! ;7" ?fter the :e$ond World War, the situationin 4er%any and Iuro&e was +ery diffi$ult" & to 0!^ of 4er%any was destroyed

and the $a&a$ity of the 4er%an e$ono%y was less than 2!A'!^ $o%&ared to 1'"Thus, $o%&anies si%&ly didn9t ha+e enouh %oney to buy $o%&uters" or this


40/59

reason, Konrad Zuse tried to %ake so%e business with : $o%&anies" Hesu$$essfully $on$luded a $ontra$t with the 8e%inton 8and 6or&oration, whi$h%eant he $ould sell about =! s%all relay %a$hines (ZAZ)" With the e.$e&tion ofthe 41 resear$h $o%&uter in 4ttinen by the tea% of Billin, and the institutes in

;ar%stadt and 7En$hen, the 4er%an o+ern%ent did not su&&ort institutions forbuyin $o%&uters until around 1=="

The Z11 Computer

?lthouh the situation in 4er%any was +erydiffi$ult, in 1= the Zuse K4 $onstru$ted theZ11 as a su$$essor of the %a$hine :71(1=2A1=), whi$h was de+elo&ed by:eifers in 7En$hen for $onsolidation offar%in &ur&oses" The Z11, whi$h had a$lo$k fre*uen$y of ! Hert>, was +ery&o&ular be$ause of the easy handlin by thehardware wired()&rora%s" These &rora%ssol+ed $al$ulations in the area of$onsolidation of far%in by &ressin si%&lebuttons"

()Hardware wired &rora%s arei%&le%ented usin relays andste&wise relays" The ste&wise relayssele$t %i$roAse*uen$es ofalorith%s i%&le%ented with relays"reely &rora%%able %a$hineswhose &rora%s are stored on a&un$h ta&e or a &un$h $ard are%u$h %ore &owerful than hardwarewired &rora%%ed %a$hines"

ro% 1==, the Z11 was ordered by sur+eyor9s offi$es for the $onsolidation offar%in" n 1=0, it was e.tended with &un$h ta&e readers and was %ade freely&rora%%able by a &un$h ta&e" The Z119s word lenth of '5 bits (hih a$$ura$y) andits floatin &oint arith%eti$ %ade this %a$hine +ery &o&ular in the o&ti$al industryand in uni+ersities" n 1=0 the Zuse K4 only sold fi+e Z11 $o%&uters, but by 1=the situation had $haned and the Zuse K4 $ould sell '= Z11s (the &ri$e of the Z11was 1!!,!!! ;7 in 1=)" ?t this ti%e the 4er%an o&ti$al industry was the leader inthe world, and al%ost e+ery $o%&any &rodu$in o&ti$al e*ui&%ent in 4er%any hadordered a Z11" ro% 1==, the ;4 (;euts$he ors$hunse%eins$haft) a+e%oney to install $o%&uters in uni+ersities"

i"0 (Left)" The Z11 $o%&uter was initially used for the $onsolidation of far%in" Later it wase.tended to a freely &rora%%able %a$hine and was used by the o&ti$al industry" i" (8iht)" TheZ11/s %e%ory with about 2! words of '5 bits and the wirin &attern"

The ;raphomat Z54


41/59

n 1==, Konrad Zuse bean de+elo&%ent on the 4ra&ho%at Z0, whi$h was adrawin %a$hine with an a$$ura$y of 132! %%"

i"5 (Left)" The Zuse 4ra&ho%at Z0 was used for a$$urate drawins in s$ien$e and $o%%er$iala&&li$ations (10)" i" (8iht)" The two earbo.es, whi$h $ould transfor% diital i%&ulses into 1=different s&eeds for drawin lines and $ur+es (these earbo.es were later re&la$ed by ste&&er%otors)"

With the Z0, Konrad Zuse tried to reali>e another +ision" He wanted to builddrawin %a$hines in order to %ake the results of $o%&le. $al$ulations %oreunderstandable and %ore +isible" The Z0 was $ontrolled by a &un$h ta&e, whi$hwas $reated by the $o%&uters Z22, Z2', Z2=, or Z'1 (these %a$hines areintrodu$ed below)" The %o+e%ent of the drawin &en$ils was $ontrolled by twoearbo.es, whi$h $ould transfor% diital i%&ulses into analo drawins" The

earbo.es were in+ented and $onstru$ted by Konrad Zuse in 1==A1=" The4ra&ho%at Z0 was a +ery reliable and wellAa$$e&ted %a$hine in industry andresear$h institutes" The hih a$$ura$y of drawins, the reliability, the low%aintenan$e $osts, and the enor%ous +ariety of a&&li$ations were hihlya&&re$iated"



The Z22 Computern 1=, the Zuse K4 started to build ele$troni$ $o%&uters (based on +a$uu%tubes), $o%%en$in with the Z22" The Cu%& in %a$hine nu%bers fro% the Z11 to theZ22 sinified the $hane of te$hnoloy, and the Zuse K4 needed a lon ti%e to$onstru$t its first ele$troni$ $o%&uter"


42/59


43/59

was $onstru$ted and i+en the na%e &inima" The Z22 was a +ery fle.ible %a$hine,and its &ri$e of 15!,!!! ;7 was %u$h lower than for %a$hines built in forein$ountries" The Zuse K4 re$ei+ed an ad+an$e &ay%ent by the Te$hnis$heHo$hs$hule Berlin and ?a$hen in order to &rodu$e the Z22" or the %aneti$ dru% a

li$ense aree%ent was %ade with 4erhard ;irks, who was another $o%&uter&ioneer in 4er%any and also in the :" By 1=5 the Z22 worked &ro&erly and in thesa%e year 15 %a$hines were sold"

The Zuse K4 underwent another lare $hane in 1=" The roo%s a+ailable in#eukir$hen had be$o%e too s%all, so the $o%&any %o+ed to Bad Hersfeld, whi$h isabout 1= k% north of #eukir$hen" ?t this ti%e, Bad Hersfeld had around 2= !!!inhabitants"

By 101302, %ore than fifty Z22s had been sold" Today, two fully workin Z22%a$hines $an be +isited in the a$hho$hs$hule Karlsruhe and in the

Bundes%inisteriu% fEr Bildun und Wissens$haft"

The Z23 ComputerThe de+elo&%ent of $o%&uters rew faster and faster" The transistor was now wellknown, and in 1= the Zuse K4 de+elo&ed the Z2', whi$h was a &owerfultransistor $o%&uter with al%ost the sa%e loi$ as the Z22" The Z2' re&la$ed theZ22 in 101302"

i"52" The Z2' had a si%ilar stru$ture as the Z22, and was the first $o%&uter with transistors"

The &erfor%an$e of the Z2' was %u$h better than that of the Z22" The first Z2'%a$hine was deli+ered in 101" This %a$hine had a ferrite $ore %e%ory of 2!

words (ea$h $ontainin ! bits), a %aneti$ dru% that $ould store 5,12 words (ea$h$ontainin ! bits)" The Z2' was three ti%es faster than the Z22, and &rora%swritten for the Z22 $ould run on the Z2' without any $on+ersions"

The Z2' was a +ery su$$essful %a$hine and, by January 1, 10, ninetyAse+en%a$hines had been installed in 4er%any"

The Z31 ComputerThe Z'1 was de+elo&ed in &arallel with the Z2'"This was the Zuse K49s first$o%&uter to $ontain a de$i%al arith%eti$ unit, and it was es&e$ially desined withbankin and $o%%er$ial a&&li$ations in %ind" i"5' shows a Z'1 fro% 102"


44/59

i"5'" The Z'1 %a$hine was the Zuse K49s first de$i%al $o%&uter"

The Z'1 $ost a reat deal to de+elo&, but only se+en %a$hines were sold" This wasa +ery e.&ensi+e %anae%ent %istake, and the Zuse K4 ot dee&er and dee&erinto finan$ial trouble"



The Z2 ComputerThe de+elo&%ent of the Z2= $o%&uter $o%%en$ed in 101" The oal was a s%all

and $hea& %a$hine that would be suitable for %any different a&&li$ations"

i"5" ? $o%&uter $enter $ontainin a nu%ber of Z2= %a$hines at the Thyssen ?4 (a steel$o%&any) in 10" The Z2= was used as a &ro$ess $o%&uter" n the Thyssen ?4, Z2= $o%&uters


45/59


46/59

#o other sour$es of in$o%e, be$ause $o%&uters were the only &rodu$tionsubCe$t of the Zuse K4"

8entin of $o%&uters instead of sellin the%" Banks did not i+e $redit forthis"

:tartin in 102, the Zuse K4 i%&le%ented %u$h effort to $ontrol &rodu$tion infa$tories usin &ro$ess $o%&uters" This was +ery interestin to a steel $o%&any$alled 8heinstahl, and the Zuse K4 was bouht by 8heinstahl in 10" n 10=,BB6 (Brown Bo+eri and 6ie), whi$h &rodu$ed &ower &lants, ele$tri$ e*ui&%ents,and so forth bouht the Zuse K4 fro% 8heinstahl" inally, in 10, the Zuse K4 wasbouht $o%&letely by the :ie%ens ?4" n 10, the Zuse K4 loo was deleted bythe :ie%ens ?4 and Konrad Zuse left the Zuse K4"

i"5 (Left)" ? %a& showin $o%&uters sold in 4er%any by the Zuse K4 fro% 1A10" The ZuseK4 sold about 2=! $o%&uters fro% 1 to 10 of a +alue of $a" 1!! 7illion ;7" i"55 (8iht)" ?Zuse K4 ad+ertis%ent fro% 101"

The followin table i+es an o+er+iew of the %ost i%&ortant $o%&uters &rodu$ed byKonrad Zuse and the Zuse K4 fro% 1'0A10 (note that the Die$esD $olu%n

refers to the nu%ber of units $reated)" We also %ention so%e %a$hines that werenot dis$ussed abo+e, but we do not list e+ery s&e$ial %a$hine that was &rodu$ed bythe Zuse K4" Howe+er, in FZ:I5Ge+ery %a$hine of the Zuse K4 is des$ribed andillustrated with a &i$ture, and a realAti%e si%ulation of the Z' is also &resented"

=ear(s!%ame Piees Comments

1'0A1'5

Z1 1 irst %a$hine in the world with@ a binary floatin &oint&ro$essor, binary loi$, &arallel workin de+i$es, freely&rora%%able, se&aration of %e%ory, $ontrol unit,

arith%eti$ unit, in&ut3out&ut de+i$es" Bistable%e$hani$al buildin blo$ks, 0 words (ea$h $ontainin
http://www.epemag.com/zuse/Bgraphy.htm#ZUSE98http://www.epemag.com/zuse/Images/fig88b.jpghttp://www.epemag.com/zuse/Images/fig87b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#ZUSE98


47/59


48/59

101 Z2' 5 irst transistor $o%&uter, sa%e loi$ as the Z22, threeti%es faster than Z22, ! bit words, +ery su$$essful":tored &rora% $o%&uter"

10' Z2= 1!= :%all and +ery fle.ible $o%&uter, 15 bit words, &ro$ess

$ontrol in $o%&anies, %any &eri&heral de+i$es, 5,!!!;7" :tored &rora% $o%&uter"

101 Z'1 arallel de+elo&%ent to the Z2', desined for$o%%er$ial a&&li$ations (su$h as banks), de$i%alarith%eti$ unit, too e.&ensi+e and too lare, flo& for theZuse K4" :tored &rora% $o%&uter"

1=5 Z0 5= ;rawin %a$hine with hih a$$ura$y (132! %%),$ontrolled by &un$h ta&es, used for ra&hi$alre&resentation and in the o&ti$al industry"

10= Z' 1!! 7odern transistor $o%&uter, TTL loi$" :tored &rora%$o%&uter"

Ta&"e 1:? list of the $o%&uters &rodu$ed by Konrad Zuse and the Zuse K4 fro% 1'0A10" Therebuilt Z1 stands in the ;euts$he Te$hnik 7useu% in BerlinAKreu>ber" The rebuilt Z' and the oriinalZ are on dis&lay in the $eutsche &useum &nchen" The Z11 $o%&uter $an be +isited in the


49/59

with about 12!! e%&loyees in 10" Konrad Zuse9s offi$e was on the to& of the buildin (red $olor)"

ro% %y &oint of +iew, Konrad Zuse was nota $olla&sed entre&reneur" Konrad Zuseand his $o%&any was years ahead of his ti%e in desinin $o%&uters, &rodu$in$o%&uters, drawin %a$hines $ontrolled by $o%&uters, and ideas related to

$o%&uters"


Part >: Konrad Zuse 8ter 1954

?fter 10, the Zuse K4 was no loner owned and $ontrolled by Konrad Zuse,althouh he did hold a $onsultant $ontra$t with the :ie%ens ?4 until 10" t was a

hea+y blow for %y father to loose his $o%&any, but there was no other way at thisti%e" ro% 1 to 10 he had %ade e+ery effort to kee& the $o%&any as his own,but in 10 he had to i+e u&, be$ause the a$ti+e debts were too hih"

He also had another &roble%, be$ause in 10 no de$ision had yet been %ade onthe &atents he had a&&lied for with his Z' $o%&uter" n 10 a de$ision was %ade bythe 4er%an &atent $ourt and Konrad Zuse lost his 20 year fiht about the in+entionof the Z' with all its new features F8-J?5G" Konrad Zuse/s early $o%&uters $onsistedof well known stru$tural $o%&onents, na%ely relays" sin these relays he$onstru$ted the Z' $o%&uter, but the (&atent) Custi$es $ould not follow the aru%entsthat well known $o%&onents $ould be $o%bined to for% a really new %a$hine" When

Konrad Zuse left the Zuse K4 in 10 he was = years old"

We will now dis$uss so%e of Konrad Zuse/s %aCor a$ti+ities followin 1030, whi$hwere his autobiora&hy, his (oil) &aintins, the $o%&utin uni+erse, there$onstru$tion of the Z1 (as dis$ussed earlier in this arti$le), and the Heli.ATower" Wewill not $onsider his works on selfAre&rodu$in syste%s and etriA#ets, be$ausefro% %y +iew his $ontributions to both of these fields were not &arti$ularly sinifi$ant"?lso, we will not dis$uss the &arallel $o%&uter, whi$h he desined (but didn/t build) in1=5, be$ause this would be beyond the s$o&e of this arti$le" 7y father re$ei+ed%any awards for his work on $o%&uters, so%e of whi$h we would like to %entionhere"

.ome o8 Konrad Zuse's ?ardsn 1=0, Konrad Zuse re$ei+ed the ;r"An" e"h" for his a$hie+e%ents in the area of$o%&utin fro% the Te$hni$al ni+ersity of Berlin" n 10=, he was i+en the Wernervon Siemens wardin 4er%any, whi$h is the %ost &restiious te$hni$al award in4er%any" n 10= Konrad Zuse re$ei+ed the Harry 4oode 7e%orial ?ward toetherwith :tibit> in Las was also a &ioneer of binary floatin &oint arith%eti$around 13=)"

?%onst %any other awards, Konrad Zuse was &resented with a do>en honorary

;o$torshi&s (in$ludin those fro% $eland, :wit>erland, and Iast 4er%any(;resden))" two honorary rofessorshi&s (fro% 4ttinen in 4er%any and :tettin in
http://www.epemag.com/zuse/Bgraphy.htm#ROJA98http://www.epemag.com/zuse/Bgraphy.htm#ROJA98


50/59

oland)" urther%ore, about twenty streets in different $ities are na%ed Monrad7use Stra;e, two s$hools (in HEnfeld and Hoyerswerda) $arry his na%e and he was%ade an honorary $iti>en in both HEnfeld and Hoyerswerda" There is also theMonrad 7use 7entrum fr Informationstechni%(6enter for :$ientifi$ 6o%&utin) in

Berlin, and in :e&te%ber 1 he will be %ade a fellow of the 6o%&uter History6enter in 7ountain en e.hibitions, and he also sold the &aintins"
http://www.epemag.com/zuse/Bgraphy.htm#ZUSE93http://www.epemag.com/zuse/Bgraphy.htm#ZUSE69http://www.epemag.com/zuse/Images/fig92b.jpghttp://www.epemag.com/zuse/Images/fig91b.jpghttp://www.epemag.com/zuse/Bgraphy.htm#ZUSE93http://www.epemag.com/zuse/Bgraphy.htm#ZUSE69


51/59

i"' (Left) and i" (8iht) Two of Konrad Zuse/s oil &aintins"


Part > (ontinued!: Konrad Zuse 8ter 1954

Konrad Zuse %ostly &ainted in oil, but so%eti%es he &ainted with $halks"


52/59

i"= (&&er Left), i"0 (&&er 7iddle), i" (&&er 8iht),i"5 (Lower Left), and i" (Lower 8iht)" :o%e of Konrad Zuse/s oil &aintins"

n fa$t i"5 and i abo+e, and i"1!! and i"1!1 below are four oil &aintins(!$% . 0!$%) fro% a series of se+en, whi$h $an be +iewed in the nternet athtt&@33ho%e"tAonline"de3ho%e3horst">useand are a+ailable in a li%ited edition foranyone who is interested"

i"1!! (Left) and i"1!1 (8iht)" Two &aintins (!$% . 0!$%) fro% a series of se+en, whi$h $an be+iewed on the internet and are a+ailable in a li%ited edition"

inally, we show three of Konrad Zuse/s self &ortraits, whi$h he $reated in 10 and1'31"
http://home.t-online.de/home/horst.zusehttp://www.epemag.com/zuse/Images/fig101b.jpghttp://www.epemag.com/zuse/Images/fig100b.jpghttp://www.epemag.com/zuse/Images/fig99b.jpghttp://www.epemag.com/zuse/Images/fig98b.jpghttp://home.t-online.de/home/horst.zuse


53/59

i"1!2 (Left)" :elf &ortrait of Konrad Zuse as a wood$ut (10)" i"1!' (7iddle)" :elf &ortrait in $halk(1')" i"1! (8iht)" :elf &ortrait in oil (1)"

The e"i,-To?erKonrad Zuse was still a %an of %any ideas" n 12 he started his last &roCe$t, atower for $at$hin wind in order to &rodu$e enery in an easier way" The idea of theHeli.ATower was a heihtA+ariable $onstru$tion in order to $at$h %ore or less wind to&rodu$e ele$tri$al enery" The &ro&eller and wind enerator had to be %ounted onthe to& of the tower" The %e$hanis% shown in i"1!0 is intended to raise or lowerhe tower" He used a +ery eleant %e$hani$al $onstru$tion and i%%ediately re$ei+ed

a &atent for this in 1'" The heiht of the tower $ould be %odified by addin orsubtra$tin buildin blo$ks fro% the sto$k as shown in i"1!0"

i"1!= (Left)" Konrad Zuse/s Heli.ATower, whi$h he desined and

the life and work of konrad zuse

Documents