Metric Units

[Christos Ricudis]

  On 27 Oct 01, Giorgos Pallas wrote to All with subject "Re: I never thought
I'd come to this, what's this aaaaaaaaall about?":

 GP> emena i aporia mou egkeitai sto eksis : oi misoi kathigites sti
 GP> sxoli (pliroforiki thessalonikis) lene oti :
 GP> 1 Kbit = 1000 bits
 GP> kai oi alloi misoi :
 GP> 1 Kbit = 1024 bits

They both are right - dystyxws den yparxei symfwnhmeno protypo. 

 GP> mipws isxyei to deutero an prokeitai gia megales times twn bits?

Nai, otan ena bit einai mexri toso -> . tote to ena kilobyte metraei san 1024
bits. Otan ena bit omws einai pio megalo, as poyme toso -> O, tote xwrane
ligotera mesa sto kilobyte, kai einai 1000 bits. Polles fores pairnei kai
times metaksy aytwn twn dyo oriwn, mia poy ws gnwston to 1 einai pio lepto apo
to 0, kai ara xwrane perissotera 1 para 0 mesa sto kilobyte. 

Sthn arxh, den yphrxe kammia sygxish. Otan milousame gia bits, bytes, kai ta
loipa, ta metrika proshma (kilo, mega, ktl) orizan aneka8en dynameis toy 1024.
H sygxish arxise otan diaforoi eksypnoi kataskeyastes diskwn me prwth kai
kalyterh th seagate arxisan na kleboun sto zygi, orizontas to KByte ws 1000
bytes, to MByte ws 1000 KBytes, ktl - wste oi diskoi toys na fainontai
megalyteroi se MBytes.

To idio akribws kanoyn kai oi telecom equipment manufacturers gia na
megalwnoun ta transfer rates toys, ktl ktl ktl.

Kapoy akousa mia protash toy styl :

kByte = 1000 bytes
KByte = 1024 bytes

alla den to exw dei na xrhsimopoieitai h na anaferetai poy8ena, ara mallon
prokeitai gia arbitrary notation poy xrhsimopoiei mono aytos apo ton opoio to
akousa :>.

To problhma einai oti to dyadiko notation xalaei thn omorfia tou
pollaplasiasmou/diaireshs me metakinhsh toy plwtou shmeiou [1]. Oxi, mia
disketa twn 1440 KBytes DEN xwraei 1.44 MBytes.

[1] floating point. Allwste oloi kseroyn oti ypodiastolh = underdilatation.

--
Christos Ricudis

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