In the early 1990’s a very cleaver little formula become popular in computing and telecommunication fields. This little formula was called partial response, maximum likelihood (PRML), and it was able to identify the digital data stored in a very weak analog signal.
That might sound rather boring, but PRML was one of the turning points for stored and transmitted data. All of a sudden the amount of data that could be stored on a hard disk grew exponentially. Before PRML a big hard disk would have been 80MB, and it was limited because the space needed to store a bit of data was large due to the strength of the magnietic field needed to write a strong enough data bit. but as soon as PRML hit the streets a weaker magnetic field could be used and the space needed to store each bit was reduced dramatically. This allowed the capacity to jump up to 120MB, 250MB then 500MB and then 1GB, now drives are hundreds of gigabytes and often multiple terabytes per 3.5 inch disk (with multiple platters in each disk drive).
And as the capacity was growing, but the size of the disks stayed the same, data transfer rates also grew dramatically. This allowed Microsoft and others to create much larger bloatware. If it wasn’t for PRML maybe we would never have seen the paperclip in word, or be able to store just such an immense amount of porn and pirate movies on the internet.
And of course PRML was responsible for much more than just hard disks becoming massive. Another amazing PRML child was the digital cellphone. Before PRML cell phones were analog which meant that the quality of sound you heard in your ear was full of pops and whistles and people saying “hello can you hear me, this fu&*ing piece of Sh$t phone gaaaaaahhh”. And the phones themselves were much larger to deal with the much higher transmission powers.
But since PRML the sound you hear in your ear is crisp and clear, as it’s digital you either get a sound or you don’t. And with PRML checking every bit to work out if it’s a one or a zero amongst all that static and interference on the radio spectrum what you hear is clean. Of course cell phones still drop calls (yep, a lot less than decades ago, but still enough to drive us nuts). But when a call quality is so low that PRML can’t work out the signal, what you hear is silence, rather than the person at the other end screaming expletives into the mouthpiece.
As I’ve basically grown up with PRML, I’ve discovered another even more valuable use for the technology.
I use my own version of PRML on conversations people have with me. It’s so much easier than listening to every word. Now I just listen to the odd bit of a sentence and my PRMLing brain fills in the missing bits.
I find this process to be perfect, and I’ve convinced myself that I never miss anything important.
I suspect my wife does not totally agree…..