Computer Cache #4 Mystery Cache

Vyse uvedene souradnice Vas privedou pred dalsi budovu, ve ktere sidli jedna velka a znama pocitacova firma. POZOR: Cache na techto souradnicich nenajdete!!

Ve ctvrtem pokracovani nasi pocitacove serie se dostavame do sedmdesatych let, do obdobi nastupu micropocitacu. Byla to doba vpravde pionyrska, kdy byla rada nadsencu ochotna zaplatit neuveritelne sumy penez za ne zcela funkcni pristroje a programy ... Mala firma MITS v Novem Mexiku vytvorila v roce 1974 prvni "osobni pocitac" a nazvala ho Altair. V lednu 1975 o nem napsal docela dlouhy clanek casopis Popular Electronics. Tento clanek zcela zmenil zivot dvema studentum Harvardu - Billu Gatesovi a Paulovi Allenovi.

Oba citili zivotni sanci, a tak kontaktovali jeho vyrobce, a nabidli mu interpret jazyka Basic. Tento program vsak v te dobe samozrejme vubec nemeli, stejne jako zmineny mikropocitac. Paul vytvoril emulator procesoru Intel 8080 a celeho pocitace Altair na minipocitaci PDP a Bill pracoval dnem i noci na implementaci Basicu. Paul nakonec po nekolika mesicich letel do Albuquerque s pripravenou dernou paskou, aby demonstroval funkcni Basic, aniz predtim pocitac Altair vubec na vlastni oci spatril. Fungovalo to - a byl to docela husarsky kousek, ktery zahajil uspesnou karieru obou programatoru a take firmy Microsoft. Podobny tah se o par let podaril znovu s operacnim systemem MS-DOS a s firmou IBM, to uz je ale jina historie.

Jazyk Basic se tak stal zakladem uspechu firmy Microsoft, a tim i samozrejmym zadanim pro nasi ulohu. Nebojte se, programovaci jazyk je to opravdu velmi jednoduchy, jeho hlavnim kouzlem je prikaz GOTO, o kterem by dnesni ucitele strukturovaneho programovani nejradsi vubec neslyseli ! Jen v tomto jazyce tak muze vzniknout podobne neprehledny "spagetti" kod, jako je ten nasledujici - presto jsou v nem ukryty jednoznacne souradnice cache:

01 GOTO 50
02 B$="program "
03 C$=A$+B$
04 PRINT C$
05 RANDOMIZE TIMER
06 R%=1
08 R%=R%+INT(RND*10)
10 REM 
12 GOTO 860
14 A$="random "
16 B$="number "
18 C$=A$+B$
20 PRINT C$
22 GOTO 27
24 REM
26 REM
27 PRINT R%
28 GOTO 212
30 REM
50 A$="This "
60 GOTO 02
210 REM
212 A$="and terminates "
214 B$=":-) !"
216 C$=A$+B$
218 PRINT C$
220 END
850 REM
860 A$="only "
870 B$="prints "
880 C$=A$+B$
890 PRINT C$
900 GOTO 14

The above coordinates will bring you to another building in Prague used by the large and famous computer company. ATTENTION: There is no cache at those coordinates!!

In the fourth part of our Computer Caches Series we are in the seventies, when the microcomputers appeared on the scene. It was very interesting time, a lot of hobbyists were willing to pay unbelievable amount of money for not fully functional hardware and software. Small New Mexico company called MITS created the very first "personal computer" in 1974 and named it Altair. There was quite large presentation of this new device in the January 1975 issue of Popular Electronics magazine. This article has changed the life of two Harvard students completely. They were Bill Gates and Paul Allen.

Both have felt this is the biggest chance of their life, so they contacted the Altair producer and offered him the Basic interpreter. They did not have this program ready however, as well as they did not have the microcomputer. Therefore Paul created the emulator of the Intel 8080 processor and the Altair computer which worked at PDP computer. Bill worked hard day and night to implement the Basic interpreter. After several months Paul finaly flew to Albuquerque with the punch tape ready and demonstrated the Basic, although he never saw the Altair computer before. It worked without the glitch and it was really big triumph which started the Microsoft company. They have made the similar success with the operating system MS-DOS and IBM company several years later but this is already another story.

Basic became the first successful product of Microsoft and so it is the natural choice for our task. Do not be afraid, it is very simple programming language, its main magic is the GOTO command which today's programming lectures hate so much! This is the only language where such "spagetti" code like the above could be created. Still it contains the cache coordinates.

Good luck! Attention - the place is very busy! Please do not give any details about the cache position and hide. Thanks!!!