Lego 60116 Ambulance Plane .Lego 60116 rescue aircraft .Leather assembly aircraft.
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Why are Floppy Cables Twisted? [Byte Size] | Nostalgia Nerd - Duration: 5:46.
Hello, and welcome to Byte Size.
Today's question is; Why are floppy cables twisted?
It's the age old question.
A question that has been boggling mankind for decades.
Why do floppy ribbon cables contain a twist?
I've wondered this from the moment I first opened my PC to reveal it's glorious contents.
It looks like a hack.
Something wasn't quite right in the design, but was fixed by reversing a few wires.
And this is essentially, accurate.
Modern systems generally lack our beloved A: drive.
That magical slot which brought such a wide variety of sound and volatility to proceedings,
but go back a couple of decades and these devices were completely essential.
During the 1990s they were commonly connected directly to the motherboard, much like your
hard drive, and with a cable very much reminiscent to your hard drive's IDE connection, however
whereas an IDE cable has 40 wires, the floppy cable only has 34.
Much like an IDE cable, a floppy ribbon usually has multiple connectors.
For IDE these were used to connect up to 2 drives which could then be denoted as a slave
drive, or a master drive, allowing 2 hard drives or a hard drive and CD drives to be
linked to a single IDE channel.
Traditional floppy cables would have 5 connections.
One to attach to the motherboard, with 2 for the A: drive, depending on whether it's a
5 1/4" drive - which use card edge connections, or a 3.5" - which use pin header connections,
and 2 for the B: drive.
In later systems the 5 1/4" connectors were negated, as was sometimes the B: drive connection,
meaning a cable could just have the drive and motherboard connector.
So that's all good and dandy, but what about this little twist?
To answer this we have to go back to the birth of floppy drives - in an IBM PC sense at least,
and as usual we begin with the IBM 5150.
Back then floppy drives relied on a drive select jumper to determine which drive as
A: and which drive was B:.
These jumpers required setting, even if there was only 1 floppy unit in the system.
With 2 drives installed, this was essential so that the single floppy header could determine
which drive it was talking to on the single cable.
If you wanted to install a new drive in your single drive system, then you'd have to make
sure the jumpers were set correctly on each drive so the system could differentiate between
them.
Likewise, if you wanted to remove a floppy, you'd have to remove the one setup as the
B: drive, or swap the jumper settings over.
This doesn't sound like much of a chore, but IBM realised that it was a pain swapping jumpers
around when dealing with mainframes.
Their solution for this was to setup every floppy drive to be a B: drive as standard
and instead rely on the cable to determine which is which.
The twisted wire numbers 10 to 16.
Wires 11,13 and 15 are ground wires which carry no signals, however wire 10 and 16 are
the motor enable wires for drives A and B respectively, whilst 12 and 14 are drive select
B and A respectively.
Therefore, by inverting these wires, any drive after the twist automatically becomes the
A: drive and the drive before the twist remains as a B: drive.
So rather than messing around with jumpers, you simply plugged the last connector into
the floppy you wanted as A: and the other connector would plug into B:.
The other wires carrying the data and head select routines would then only apply to which
drive was selected by the floppy controller, as an unselected drive simply ignores the
input.
For a while some systems actually retained the jumper approach or even actually tried
to use their own hack, such as twisting the signals on the motherboard rather than the
cable, but this just caused confusion, especially when a twisted cable was used, and the IBM
standard was eventually adopted by everyone.
It's quite a simple hack, which although gives the ribbon cable an "after-thought" appearance,
works beautifully and saves us from losing all those plastic jumper connectors under
our desks for the rest of eternity.
So what about our IDE cables and hard drives?
Well, there was actually a cable select protocol which used the exact same idea.
To use it, both devices needed to be setup for "cable select", ironically through the
use of a jumper, and then through use of a specific cable, wire 28 is only connected
to the master drive.
This means that in this instance, the master drive needs to be the middle connector and
the slave the end connector, the opposite of our floppy setup.
This inconsistent implementation was one reason it never really caught on, unlike our simple,
but beloved floppy cable twist.
Strangely there was also a cable which did the twist before the first connector, and
then twisted again for the second drive, requiring drive A: to be placed in the middle connector.
This appears to be to meet a particular case design, because other than that, it's rather
bizarre to say the least.
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How To Ride And Look Like A Belgian Professional Cyclist - Duration: 3:18.
- Belgians, or to be more specific, Flandrians,
are legends of the sport of cycling.
Not only do they win copious amounts of races,
they also have a certain style and attitude
which means you can spot them a mile off.
- Yeah, now the good news is you don't have
to be from Flanders in order to be a Flandrian.
So here are our top tips.
- Now that is a bike.
- A true Flandrian bike.
What have you brought?
(upbeat guitar music)
- [Narrator] Before we even set out,
you need to make sure that you look right.
Always wear long white socks, and if you must wear tights,
your socks need to be over the top of them.
And if it's really cold, just stick another pair
of white socks over the top of your shoes.
And likewise gloves.
Expose your hands to cold weather enough,
and you won't ever need gloves.
Gloves are for soft people and Southern Europeans.
If your hands get cold, just stop thinking
about them and pedal harder.
(upbeat guitar music)
- This simply isn't an option for a Belgian pro.
Doggedness and blind determination would drive a Flandrian
on to the point his body will give up long before the mind,
and if there's a chance they could turn just one
more single pedal revolution,
then they will, regardless of the circumstance.
(upbeat guitar music)
- Shifting onto the small ring on a climb
is essentially admitting defeat,
which we know a Flandrian would never do.
In fact, the only acceptable climb
to put on the small ring for is the Koppenberg,
which we're on now.
- In our big rings.
Yes!
It's quite steep, this, isn't it mate?
- It's quite steep.
It's still on the big ring.
(upbeat guitar music)
- [Narrator] Belgian toothpaste.
Never heard of this?
Well, most Belgian pros eschew more conventional methods
of dental hygiene in favour of going natural,
the mud coated roads of Flanders providing
enough organic matter to keep the pearly whites
of the best riders in good condition.
- So, what do you think it takes to be a true Flandrian?
Have we missed anything out?
You know what to do.
Leave your comments down below.
- You know what a true Flandrian would do, Matt, as well?
- What?
- They'd subscribe to GCN.
To do that, just click on the globe, Flandrian or not.
- Now for some more, blimey, cobbled content,
how 'bout clicking just down here
where you got homies that'll teach you
how to ride cobbled climbs?
- The most Flandrian of all Flandrians,
or for the most Flandrian climb,
how about a bit of insight into the iconic Koppenberg?
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