Thursday, August 16, 2012

Fixing Stuff 1 : Breaking Stuff ... 1

Had something highly expected happen last night when I was testing the laptop with its new hard disc.

When you make a hardware switch on a PC, you always expect a problem. If there's no problems, that's the time to worry. Anyway. This time, laptop boots up just fine with its new hard disc and it feels a little smoother too thanks to that special hybrid hard disc.

Ok. So no problems with the laptop. What I definitely didn't expect was that in the middle of watching a Yogscast video on the desktop, that the desktop would decide to pop its clogs ... Like : full machine crash type oopsie. And when you try a reboot of that Windows 7 machine, a "Starting Windows XP" screen would come up, quickly followed by a Blue Screen Of Death "Windows has stopped to protect the machine" ...

What ... The ... Hell ...

Cue a little bit of panic.

Thinking it through a bit more, I go check the BIOS (the bit that first appears when you hit the On switch and figures out what hardware is in the machine). The BIOS aka Basic Input Output System can't see the boot disc. That's either extremely bad news or a suggestion of something very easy to fix.

Aside - my desktop has 3 hard discs inside it :
60GB SSD - Windows 7 boots off this but it's too small to have any data or applications on it
250GB Seagate - my last machine's game drive, put in there to give the new machine a bit of storage space while I waited until big hard discs came down in price
1.5TB Western Digital drive - where my games, applications and data goes.

What seems to have happened is that a cable went dodgy, so the desktop couldn't see its SSD boot drive. What happens then is that the Bios tries each drive in turn, looking for something it can hand over to. When it found the Seagate, it would see the Windows XP installation on the games drive. However ... that's an installation that was set up for a very different machine ... AMD vs Intel, ATI vs nVidia, wholly different motherboard etc etc ad nauseum. Suffice to say, nothing is shared between last machine and new machine.

Desktop seems fine now after a little poking around inside its innards. I've also had the chance to tone down a fan that was getting rather intrusive with the noise, so I'll be curious to see what temperatures the machine will be running (before, it maxed out at 56 degrees C under load with hot ambient).

Where's the problem come from ? Miniaturisation.

Cabling for disc drives used to be pretty bombproof. It was solid enough that you had to tug quite hard on the cables to get them out. They had a really good grip.

That's an old Quantum Fireball EL drive. It's 3.5 inches wide and I've popped a 10p on there as comparison. I think it's a 7.6GB drive and dates back to when I was running an AMD K6iii powered machine. That ran at 450MHz, which is precisely half the clock rate of my desktop's graphics card.

Anyway - the white connector is a 4 pin Molex, these had a deathgrip. The 2xlots connector to the right is actually a floppy drive cable but hard disc wires were fairly similar (more pins). Data used to be sent around with lots of wires in parallel, using ribbon cables like in the picture. The problem there is that when you get to really high data rates, the neighbouring wires like to say hello, say "wotcha doing", "this is what I got", "can we share ?". That sharing thing is called "crosstalk". It's a big problem and is why instead of doing things in Parallel, electronics has moved to passing around 1 bit at a time. I.e. Serial instead of Parallel.

Ok. That's Dark Age tech, what's the new stuff ?

That's the drive that just came out of my laptop. It's a Western Digital Scorpio Blue drive that holds 320GB. It's 2.5 inches wide and much thinner than the 3.5" drives. What's beside it is the insides of my 2.5" USB caddy.

The ribbon data cable and the Molex power connector have been replaced by the two sockets with an L shaped connector. You can pull these out quite easily and it's my huge suspicion that one of them worked its way loose on its own.

When a hard disc goes Bang, the electronics that control it usually still work. That Bios thing can usually still identify that there's a drive plugged in. Self protection measures keep the control electronics intact if the motors fail in such a way to cause power spikes. So if a Bios can't see the drive, it's usually either :

Very Toasty Drive
Loose connector

If the Bios can see the drive but no data can be got from it, that's when it's time to chuck the drive in the bin. Thankfully, after unhooking the cables and plugging them back in (plus a swap of a couple), my desktop's up and running again - but I have just done a backup of its SSD drive again. Just to be safe ...

Addon - meh. It's not a loose connector. It's a toasty drive. Another failure after about an hour's running this time ...

PS Yes. That is the bottom half of a penguin and definitely the whole of a Biscuit puppy. You are not seeing things.
PS2 I deny all knowledge of dust.

1 comment:

  1. Someone peeked here !!! I have additional information that needs to be added.

    The problem wasn't a toasty drive. The firmware (the software inside the drive) had a bug with the running hours counter. It would be fine on a power cycle, however when the running hours hit +1, it would crash until the next power cycle. The issue was fixed with an update of the firmware and the drive has been rock solid every since.


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