Discovered: The User Manual for the Oldest Surviving Computer in the World

Image by Clemens Pfeif­fer via Wiki­me­dia Com­mons

The first com­put­er I ever sat before, the 1983 Apple IIe, had a man­u­al the size of a text­book, which includ­ed a primer on pro­gram­ming lan­guages and a chap­ter enti­tled “Get­ting Down to Busi­ness and Plea­sure.” By “plea­sure,” Apple most­ly meant “elec­tron­ic work­sheets,” “word proces­sors,” and “data­base man­age­ment.” (They hadn’t ful­ly estab­lished them­selves as the fun one yet.) Get­ting these pro­grams run­ning took real effort and patience, espe­cial­ly com­pared to the Mac­Book Air on which I’m typ­ing now.

All those old tedious process­es are auto­mat­ed, and no more do we need manuals—we’ve got the inter­net, which also hap­pens to be the only way I could oper­ate an Apple IIe, whether that means track­ing down a man­u­al on eBay or find­ing a scanned copy some­where online. Luck­i­ly, for vin­tage Apple enthu­si­asts, this isn’t dif­fi­cult, and some­one with rudi­men­ta­ry knowl­edge of Apple DOS could mud­dle through with­out one.

When we go fur­ther back into com­put­er his­to­ry, we find machines that became incom­pre­hen­si­ble over time with­out their oper­at­ing instruc­tions. Such was the case with the Zuse Z4, “con­sid­ered the old­est pre­served dig­i­tal com­put­er in the world,” notes Vice. “The Z4 is one of those machines that takes up a whole room, runs on mag­net­ic tapes, and needs mul­ti­ple peo­ple to oper­ate. Today it sits in the Deutsches Muse­um in Munich, unused. Until now, his­to­ri­ans and cura­tors only had a lim­it­ed knowl­edge of its secrets because the man­u­al was lost long ago.”

The computer’s inven­tor, Kon­rad Zuse, first began build­ing it for the Nazis in 1942, then refused its use in the VI and V2 rock­et pro­gram. Instead, he fled to a small town in Bavaria and stowed the com­put­er in a barn until the end of the war. It wouldn’t see oper­a­tion until 1950. The Z4 proved to be “a very reli­able and impres­sive com­put­er for its time,” Sarah Felice writes. “With its large instruc­tion set it was able to cal­cu­late com­pli­cat­ed sci­en­tif­ic pro­grams and was able to work dur­ing the night with­out super­vi­sion, which was unheard of for this time.”

These qual­i­ties made the Zuse Z4 par­tic­u­lar­ly use­ful to the Insti­tute of Applied Math­e­mat­ics at the Swiss Fed­er­al Insti­tute of Tech­nol­o­gy (ETH), where the com­put­er per­formed advanced cal­cu­la­tions for Swiss engi­neers in the ear­ly 50s. “Around 100 jobs were car­ried out with the Z4 between 1950 and 1955,” writes Her­bert Brud­er­er, retired ETH lec­tur­er. “These includ­ed cal­cu­la­tions on the tra­jec­to­ry of rock­ets… on air­craft wings…” and “on flut­ter vibra­tions,” an oper­a­tion requir­ing “800 hours machine time.”

René Boesch, one of the air­plane researchers work­ing on the Z4 in the 50s kept a copy of the man­u­al among his papers, and it was there that his daugh­ter, Eve­lyn Boesch, also an ETH researcher, dis­cov­ered it. (View it online here.) Brud­er­er tells the full sto­ry of the computer’s devel­op­ment, oper­a­tion, and the redis­cov­ery of its only known copy of oper­at­ing instruc­tions here.

Relat­ed Con­tent:

Hear the First Record­ing of Com­put­er Gen­er­at­ed Music: Researchers Restore Music Pro­grammed on Alan Turing’s Com­put­er (1951)

Meet Grace Hop­per, the Pio­neer­ing Com­put­er Sci­en­tist Who Helped Invent COBOL and Build the His­toric Mark I Com­put­er (1906–1992)

The First Piz­za Ordered by Com­put­er, 1974

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness