H 26/9 inleiding, toledo, maple Z 27/9 internet en wwww H 3/10 systemen, gebruikers, web, virussen Z 10/10 tekstverwerking en rekenblad Z 17/10 samenwerkingH+Z 24/10 presentaties en rapportering, maple 3
week les zelfst oef 1 woe x 2 woe ma-vr 3 x ma-vr 4 x ma-vr 5 woe pten! 6 x 7 ma-vr 8 pten!
Componenten van computersysteem Besturings- systeem CPU Gebruiker RAM ApplicatiesHardware voorbeelden? 5
Moore’s law• ‘the number of transistors that can be placed inexpensively on an integrated circuit has doubled approximately every two years’ (1965)• ook • processing speed • memory capacity • sensors • network capacity • ... 8
what does “exponential” mean?if you fold a sheet of paper 50 times, then how thick is the result? about the distance to the sun... 9
wiring the ENIAC with a new programENIAC1946Mauchly and Eckertstats:3,000 cubic feet30 tons18,000 vacuum tubes70,000 resistors170 kilowatt power req.~1 kilobit memoryapproximate processing power of today’ssinging birthday cardbut not a stored-program device Great description here: www.computinghistorymuseum.org/teaching/lectures/pptlectures/7b-eniac.ppt
preparing punch cardsAn important by-product:confetti. All the chaff from allthose cards was just great tothrow around the dorm.
preparing punch cardsEach key press punches holes,so there’s no “erase.” Fixing amistake almost always requiredejecting the card and starting itover.In a pinch – say you reallyneeded to fix a card and thepunch was down – a cleveroperator might know enoughabout the card encoding toclose some holes with tape andopen others with a knife.So on the one hand, we wereadapting to the machines. Onthe other hand, the workings ofthe machines were exposed,right out where we could get tothem.