Caching in on caches
Back when dinosaurs like me roamed the IT world, we neatly labelled our 8" floppy disks and dreamed of winning the lottery and being able to buy a 10MB hard drive. You might notice I said MB there - MegaBytes - not GigaBytes or Terabytes. Yeah, it was that long ago.
Those 8" floppies were huge though. If you took one outside on a windy day they could double as a hang glider. You'd usually have a little plastic case with a clear plastic top to store your oversized floppies, and there'd even be a little silver key on the front of the case so you could lock your precious work away. Of course that didn't stop someone lifting the thing up, taking it outside and smashing the thing open with a hammer, and then running off with all your candy-making secrets.
And then The Event happened, the IBM was released and the world was never the same again.
You had 5 and 1/4" inch floppies for a start. And then hard disks started appearing. 10MB became the norm. When I bought my first PC, an Amstrad PC1640(for which I took out a bank loan) it had, along with 256 colour VGA graphics, a whopping 32MB hard drive. It also had 640K of RAM - which was, according to Bill Gates "More than enough for anyone".
There were two words on everyones lips back then. Well not "everyone" but everyone I talked to, which was a subset of humanity populated by 100% hardcore geeks. Those words were "disk cache". Oh, the long conversations we had over caching your drives and how to fine tune the whole shebang.
For DOS computers using disk caching software was a lot cheaper than buying a controller with built in hardware cache. You could improve disk performance by up to around 20 times depending how you set things up. You'd probably average 10 times the performance improvement. Oh how many hours I lost sweating over my config.sys and autoexec.bat setting up disk cache drivers correctly!
But there was yet more fun to be had!
With space and performance at such a premium there was disk de-fragmentation too. Disk defragmenters were A Thing back then. Over time as files got deleted from your hard disk, you'd get these "holes" on your drive and the poor old read head would be jumping around all over the place when it should be doing nice sequential reads and writes.
The other problem of course with fragmentation is that many of those holes are a lot smaller than you'd like, and no good for pretty much anything - in fact they were, quite literally, a waste of space!
Enter these wonderful disk de-fragmenters. They were actually fun to watch. You'd run the tool and you'd get this colourful display, almost ASCII art in motion. It was quite fascinating to watch the de-fragmenter shuffle blocks around on your hard drive. Then, after what seemed like an interminable time, it would proudly tell you how much extra (usable) disk space you had. And your disk would be faster too of course. Magic!
Those were the days. I wonder if anyone thinks about things like disk caching and disk de-fragmenters these days? Somehow I doubt it, but I'm not completely sure that's a good thing.