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動画の字幕をクリックしてすぐ単語の意味を調べられます！
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Have you ever looked at an older computer case and wondered about this thing?
This is what is known as a keylock, and these were a standard feature on tons of computer
cases from 1984 to around 1994.
Alongside the turbo button, the presence of a keylock is one of those things that instantly
dates a personal computer to that time period.
But what exactly did they do, where did they come from, and why aren’t they so commonplace
on the average home computer anymore?
To answer the first question, keylocks usually did exactly what you’d expect: they locked
the computer with a key.
How exactly it would do this depends on the type of lock and the wiring inside, but most
of the time it would prevent people from opening the case, prevent the keyboard from being
used, or a combination of the two.
For example, the LGR Woodgrain 486 has a keylock that only affects keyboard input.
When you turn the key, it shorts a jumper on the motherboard, which tells the computer
not to accept any signals from the keyboard.
It doesn’t stop anyone from just opening up the case and removing the connection between
the keylock and the motherboard of course, but it prevents the most casual of shenanigans
from taking place.
However, with certain other computers it’s another story, since the keylock physically
slides a piece of metal into place when activated, preventing the case from being opened at all.
Sometimes this also locks down the keyboard, sometimes it disables hard drive access, and
other times it might even prevent the computer from powering on in the first place.
But the method of disabling keystrokes and locking down the case seems to be the most
common. And the first mainstream appearance of this type of keylock was from IBM in 1984,
introduced with their 5170 model, the IBM PC AT.
To quote the November 13th, 1984 issue of PC Magazine, the AT provided “the first real
system for allowing executives to sleep at night: a hard-to-duplicate ‘tubular’ key
locks all but keyholders out of the system.”
This was a big deal because the original IBM PC and PC XT were utterly trivial to get inside of. All you needed to
do was loosen a few screws on the back of the case and you could mess around all day.
And there was nothing preventing anyone from using the computer at anytime since there
were no passwords or user profiles. And this was a problem for businesses.
So IBM contracted the Chicago Lock Company to address this, and they went with their
patented tubular lock, a compact type of cam lock that used a cylindrical key, the same
kind often used on vending machines, pinball tables, and alarm systems.
In reality it was a minimal security measure more for peace of mind than anything else, basically
just there to prevent casual stuff from happening that you don't want to,
but it served its purpose for the business market.
IBM also introduced the Personal Computer Keylock Option for IBM PC and XT users around
the same time, but this was a bit different.
Instead of disabling keyboard strokes, this thing locked the computer from being powered
on at all!
Connected to the key mechanism was this little arm inside that grabbed the power switch,
and when you turned the key it would control the power of the computer.
Not only that but it had a steel plate that clamped down on the case, preventing the thing
from being opened, and it even had a lock for the power cord itself so it couldn’t be unplugged.
And naturally, when IBM did something back then, everyone else had to follow, and the
age of the keylock was born.
Not all of these cloned keylocks were as robust or secure as they could’ve been though, and it was
quite often that one tubular key would unlock a variety of computer cases from all sorts
of manufacturers.
Sometimes they’d use a more traditional key instead because of this, and while this
could be easily copied at any hardware store, it was at least somewhat unique to the system.
Unfortunately, this also meant that if the keys were lost while the keylock was engaged,
using or opening your computer became a real pain in the nuts, and it’s not uncommon
at all to find a used vintage PC with a keylock and no keys.
There were a few other lock options for computers as well, like this one that locked down the
surge protector.
Instead of locking down
the power switch it’d lock down the box that all your components plugged into.
More exotic computers like this SGI Indigo2 used a metal bar with a hole in it, and the
idea here was that it prevented opening the case by sliding it through the middle of the
computer, and you’d place a padlock through the hole on the other side.
There were even options for locking down access to the floppy disk drive alone, with a rather
silly-looking disk-shaped lock device with a key awkwardly sticking out of it.
In the end, the thing that really ceased the need for a keylock was software, at least
when it comes to most everyday home consumer PCs and not counting exceptions like servers,
workstations, and enthusiast cases.
BIOS setups started including a password option on bootup to prevent unauthorized tampering
and operating systems began including password-protected user profiles.
Data encryption was also becoming more common all the time, so even if a user was able to
get past the flimsy Windows password check, sensitive files could still be protected by
a robust algorithm.
Plus, home users more often than not didn’t want or need a keylock at all, since it was
only themselves or their family using the computer anyway.
Of course, it’s a different story when it comes to laptop computers since those are
portable and easily stolen.
Many laptops still include a physical lock option, often from Kensington, but even then
it’s usually an extra purchase and not something that comes packed in with the system itself.
And that is the gist when it comes to computer keylocks.
They served their purpose for a time, and made their way into homes and businesses for
years, even though most people probably never even bothered with them.
Yet for some reason I still like using these things, even though I have absolutely
no logical reason to do so.
It feels nice and nostalgic, just like pressing in a turbo button or handling a floppy disk.
Sure it’s kinda pointless, but anytime I use a computer with a keylock, I can’t help
but mess around with it for a minute.
It’s a neat feature to look out for and mess with if you’re interested in classic
computer collecting, so keep an eye out for a machine with a keylock if you want the full
experience... just be sure it comes with the friggin' keys first.
And if you enjoyed this video on keylocks then perhaps you'd like to see my video on turbo buttons!
It's a somewhat related topic and I think this stuff is fascinating.
And as always thank you very much for watching LGR!
コツ：単語をクリックしてすぐ意味を調べられます！

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Why did old PCs have key locks? [LGR Retrospective]

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林宜悉 2020 年 3 月 20 日 に公開

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