So I was walking by the old punchcard machine that the Faculty has on display in the Computer Science building, which brought back memories of an orientation week activity where students had to guess the number of feet on a tape reel, multiply it by the number of bits per inch, and find the total capactiy of the spool of tape. Really fascinating stuff! In my mind, I romanticize the days of computer science where programming involved soldering things together with now antiquated hardware.I laughed as I walked by the machine, and then did a double take. I was laughing at how data used to be literally stored as physical states, but now we can use solid state disks and today, the concentration of bits per square inch on a modern hard drive is so high as to be called magic. Gone are the days when we could think of data as something physical. I then I really stopped laughing, because I realized how wrong I was.
We've changed the ways in which we think of data, but the data are still just ones and zeroes. We organize it into classes, xml trees, and other "abstract" structures, but the actual data are still concrete. The only abstract thing about data is the way we organize it for our own convenience. When you're holding a flash drive, you're literally hanging onto millions and millions of ones and zeroes! When's the last time you held onto millions of anything which all have practical implications? Probably the last time you held a flash drive.
Just imagine those reels of tape which store bits of data. They have a special measurement: bits per inch. You had to be careful not to stretch the tape because if you did, the bits got bigger and the machine couldn't read them.
Image! A bit has a size!? But of course it does! This post you're reading now has a size: it's a bunch of bits, transmitted over a wired medium (say) - each bit was transferred sequentially*, took a certain time to get from sender to receiver, and therefore has a size! If that doesn't make you all tingly all over, you're doing it wrong.
It really made me think - computers are even more magic today than they were in my romantized past, but they're still just machines. Instead of moving switches, we have semiconductors, but the principles themselves haven't changed in a fundamental way since ... ever!
*(simplification for the sake of entertainment)
Posts
Of course modern hard drive platters have a finite density measured in bits per square inch as well. Your flash drive's flash chip also has a finite density of bits per square inch depending on the process used and the size of the die. True, that density is much higher, and it is a 2D density these days. But it's still the same principal as the tape.
ReplyDeleteThat's what I said - I'm trying to illustrate that how we think of data has changed while the principled behind it haven't.
ReplyDeleteThat's too deep for me. :-P
ReplyDelete