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Alan Cox
Works at Intel Corporation
Attended school a long time ago
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Alan Cox

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"Unsupported models will rely on Linux operating system vendors releasing new kernel and drivers to support features such as RAID on SSD"

Good to see that the tech press fact check comments from companies as well as the political press fact check politicians. I'm reading this on a box with RAID1 SSD. It's had RAID1 SSD for some years.

Linux has supported RAID on SSD for years, in fact it supported it from the moment you could plug an SSD into a Linux PC.

Linux RAID is different from much of the Windows experience, for a mix of sound technical reasons and historical ones.

Back in the DOS days, CPU's were relatively slow, memory bandwidth and especially I/O bandwidth were limited and you only had one core.

A range of products grew up in that space which put something like an i960 and several RLL, SCSI, and later IDE controllers on a board along with a bit of RAM and did RAID and other cool things. In that environment they worked and were way faster than software RAID could have been. Every vendor did it differently, everyone had their own firmware and naturally enough moving those disks to another controller broke it all.

These boards got rapidly less effective as PCI bus solved the bandwidth problem and processors got faster and grew MMX and similar instructions. By the time we reached the Pentium II they were basically a joke except for some of the very high end boards, and even those were dubious compared to just going more SMP. Moore's law won again.

The RAID vendors responded in two ways - some of them went upmarket to do fancy high end controllers for big enterprise, but pursued by faster processors, faster busses and ever more cores they all merged into one or two companies and mostly went away.

The others started doing software RAID, adding BIOS support to their cards for 'RAID' boot up and moving their firmware into software drivers you installed on the PC. This was often portrayed as a cheap hack ('fakeraid'), but the benchmarks usually showed otherwise.

In order to keep their revenue stream even though they were often using the same chip or even boards as their bottom end dirt cheap IDE controllers they locked the firmware to particular PCI identifiers. In some cases people even used to solder jumper wires on the IDE cards to use a Windows RAID driver with them rather than buy the expensive card with the jumper set.

Today it's much the same except that most of the PC vendors bundle their software RAID products as free value add but still tied to their product.

The Linux RAID history is different because unlike Microsoft the decision was made to integrate software RAID properly with the OS.

The Linux RAID (md) drivers don't care what you are RAIDing providing it looks like a disk. It may not make sense but you can RAID floppies,  even ramdisks. Actually RAID floppies were useful in the early days - it was the one cheap hot-pluggable media everyone had for testing 8)

Because RAID is simply part of the OS core you can build RAID volumes that are spanning two vendors controllers, or on low end controllers despite the vendors best effort to lock you out. It's also bus agnostic as anyone who has ever rescued  RAID volumes removed from a server and stuffed in a USB caddy will appreciate.

When volume management got added to Linux (the dm driver) it was also added in an abstracted way and knows how to divide disks up and present slices of them in all sorts of orders. This allowed the Linux raid drivers to be used to manage the same interfaces vendors used in their proprietary windows products. Some vendors contributed to that support, others got reverse engineered - and it turned out easier than expected because a lot of them seem to use the same layout with just a few numbers changed - maybe they all licensed the same firmware. This is what the dmraid tool does.

Over time the RAID layers in the kernel also grew a wide range of other features  such as being able to use a small fast device (eg a battery backed RAM or a fast SSD) to front a slower device, to stack with encryption, even to emulate failing devices for debugging.

There is a whole load of magic to find volumes, assemble them and also to make installation work. That's a big piece of work the distributions did that while invisible shouldn't be forgotten.

Today lots of PC hardware still has this legacy of strange rival drivers and the fact Windows didn't integrate RAID support at the time. The standard AHCI controllers can often be given multiple PCI identifiers so the right 'vendor' driver can be loaded in Windows. This is why there is a big list of identifiers in the AHCI driver beyond the class driver and why we keep having to add them as we find new ones. I suspect NVMe will go the same way.

Some Windows oriented vendors don't like the fact we do things the right way and still push their own stuff

but from a technical perspective, and an architectural one what Linux does (and what in fact most non PC systems do) is the right thing for the user.

If you write a driver for a disk or a new kind of transport appears the chances are you've already got RAID support in Linux, because it's designed right.

If you need to move a disk between machines or controllers it just works, because it's designed right.

I never found out why Microsoft didn't integrate RAID in Windows when it would have made sense to do so. Possibly not wanting to tread on their partners toes, perhaps worries about anti-trust given the time period this was happening.
Yuhong Bao's profile photoPaul Farquhar's profile photoDarren Johnston's profile photoHans Franke's profile photo
+Darren Johnston mind reading all the way thru before posting? It's about demonstration to the public, not softwaretesting. What lesson do you want to tell with a bunch of USB sticks?
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Alan Cox

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Wonder how many US senators use third party ink in their offices....
HP detonates its timebomb: printers stop accepting third party ink en masse
HP detonates its timebomb: printers stop accepting third party ink en masse
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Darren Hart's profile photoJeroen Wiert Pluimers's profile photoAndrej Kvasnica's profile photoMikko Rantalainen's profile photo
Epson has had similar stuff in their cartridges for a long time. Fortunately, third parties are creating new empty refillable cartridges that appear to automatically fill every time the power is cycled as far as the firmware can see it.
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Alan Cox

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Cool. "In September of 2016, a talented programmer released his own cooked update to a major company’s legacy operating system, purely because it needed to be done. A raft of new features, wrap-in programs, and bugfixes were included in this release, which I stress was done as a hobby project.

The project is understatement itself, simply called Prodos 2.4. It updates ProDOS, the last version of which, 2.0.3, was released in 1993.

You can download it, or boot it in an emulator on the webpage, here.

As an update unto itself, this item is a wonder – compatibility has been repaired for the entire Apple II line, from the first Apple II through to the Apple IIgs, as well as cases of various versions of 6502 CPUs (like the 65C02) or cases where newer cards have been installed in the Apple IIs for USB-connected/emulated drives. Important utilities related to disk transfer, disk inspection, and program selection have joined the image. The footprint is smaller, and it runs faster than its predecessor (a wonder in any case of OS upgrades).

The entire list of improvements, additions and fixes is on the Internet Archive page I put up [ ]."
In September of 2016, a talented programmer released his own cooked update to a major company’s legacy operating system, purely because it needed to be done. A raft of new features, wrap-in p…
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Paolo Borsa's profile photoColin King's profile photo
I managed to write a tiny micro scheduler that had the same primitives as pSOS for a Philips TriMedia VLIW media processor that could fit inside the instruction cache. Mostly C and assembler. All good fun.
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Alan Cox

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The second hand machines I acquired had Nvidia video. I was expecting trouble but not quite the way it turned out.

Windows took two days to upgrade itself to  a current state and the Nvidia graphics drivers cause the display to strobe black/desktop when it goes full screen for games.

Fedora installed in 2 minutes, and the graphics just work with the open source driver.
Max Eliaser's profile photoAlan Olsen's profile photoThorfinn Hrolfsson's profile photoJeffrey Haskovec's profile photo
If you are coming from a pure gaming perspective on Windows NVidia seems to have much better drivers than AMD. I have had 1 and card and got so many buggy driver releases with it I was done with those cards. From a Windows direct X standpoint NVidia is where it is at.
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Alan Cox

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Theo Debrouwere's profile photoGraham Whaley's profile photo
Why yes, it does doesn't it :-)
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Alan Cox

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Silvan Jegen's profile photoMathieu Schroeter's profile photoEd S's profile photo
Ed S
There's Lilith though...
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Alan Cox

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"Some people have told me they don't think a fat penguin really embodies the grace of Linux," -- Linus

Of course I can't help feeling nowdays a fat squat bird with a bit of a waddle is the perfect logo 8)
Mark van Walraven's profile photoMatthias Welwarsky's profile photoCathy Raymond's profile photoCymru Llewes's profile photo
+Cathy Raymond come up to Boston for the New England Aquarium. The penguins have a HUGE space right when you walk in. There is a light that you can shine in to their pool that puts the shape of a fish on the bottom of the pool. Penguins are as playful as kittens following after that light fish.
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Alan Cox

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+Andrej Kvasnica pointed me at the immediate results of the HP printer fiasco - people downloading old firmware.

More alarming there seems to be exactly zero mention of needing a password in the video (not that I speak Portugese!). Sure the firmware is signed but if you can upload downgraded (insecure) firmware to a printer without a password you can downgrade it then attack it properly.

Can a Portugese speaker confirm it's the case that you can downgrade HP printers remotely without any security ?
Petr Kočmíd's profile photoJames Henstridge's profile photoStefan G. Lesser (wharrgarbl)'s profile photoIsmael Luceno's profile photo
I can confirm most HP printers (tested quite a few) have security issues in up-to-date firmware versions, and worse, sometimes the exact same exploit can be reused in printers by different vendors!! (there's definitely no QA there)
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Alan Cox

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A day to restore my faith in the tech industry

After being disturbingly competent for a while +Virgin Media have successfully behaved like a telco. Nothing like being phoned up by part of a company and when phoning back discovering the rest of the company can't find out what is going on or the complaint that was made. Cue snotty letter and data protection request - if they can't work it out they can send me all their paperwork and phone call recordings so I can do it for them 8)

If they can't sort it out and insist on installing an extra line as part of my girlfriend moving in and getting rid of her old services then it'll be fun too - we will be having an install party for it - in the darkest most pointless corner of the basement so that they never ever get to re-use it or make it repay the costs of sending an engineer to install it. Then a few weeks later we are hopefully moving house so they can move it for free to an ever darker danker pointless corner of the new basement 8)

The new Google+ is gross if slightly better than the last one. We've gone from 'whitespace is cool' to 'Baby's first social media site' look and basic things people should check don't work - like resizing fonts clips the stuff on the left hand bar when in Firefox. Stuff any old school company would have failed in QA.

The bank updated their banking software and have replaced the use of the account/sort code (which you have to hand and not many people knew) plus password and other bits with a username/password which you don't, and which for most people will be the same username they use online everywhere else.

They've also apparently not read up on security codes because they ask for digits from a six digit code.

Why do you never use six digit codes - because everyone when asked for a six digit code uses a date, probably their mums birthday. This is #facepalm grade material.

They can't even get the tabbing between input boxes right, or font handling or fitting in a 1080 pixel wide window

On the bright side +Brett Gordon made Fuzix history by having his COCO3 serve its first web page.

Andrew Stephen's profile photoAlan Cox's profile photoJoe Philipps's profile photoChristoph Müllner's profile photo
I used "123456" as the digit part of that bank's pre-"password". It was not accepted. So I wrote them an email, asking why "123456" does not qualify for a non-secure prefix of a password. They just said they check for some sequences like "123456" or "111111" and the owner's data of birth. Further they said it is not a prefix but part of a minimum 10 character password...
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Alan Cox

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Every time you see a piece of old properly made furniture it reminds you why you hate Ikea

Every time you try and move a piece of old properly made furniture it reminds you why you love Ikea
Moving furniture with +Alan Cox.
I take serious issue with this cabinet label...
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Andreas Jellinghaus's profile photoDeborah Twist's profile photodigi owl's profile photoAndré Esteves's profile photo
+digi owl that's the guy next to you in the street... :(
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Alan Cox

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IoT failures.. just hope nobody using one was a long way away. Shades of Mabel the monkey

Pets left hungry as smart feeder breaks -
Owners of smart pet-feeding device Petnet are told to "feed their pets manually" after a server problem stopped the device from working.
Joe Philipps's profile photoMladen Mijatov's profile photoMichael Sheldon's profile photoMarcus Sundberg's profile photo
It's not IoT, it's PoT - Proprietarynet of Things... 
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Alan Cox

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Peter Toft's profile photoLinus Torvalds's profile photoLars Bjerregaard's profile photoDouglas Carnall's profile photo
Well merited. Congratulations!
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Alan's Collections
Hunting bugs
  • Intel Corporation
    Software Architect, 2014 - present
  • Etched Pixels Digital Design
    The Boss, 2008 - present
  • Intel Corporation
    Software Architect, 2010 - 2013
Basic Information
Hacker, model maker and very bad harpist
Bragging rights
Honorary Fellow, University of Wales: Trinity St David
  • school a long time ago
Railway station prices, walk outside cross the road and you can get sandwiches, drinks and chocolate from the shops adjacent to the station at normal prices.
Public - a month ago
reviewed a month ago
Cold and windy with overpriced poor quality food.
Public - a month ago
reviewed a month ago
Completely average, nothing to stand out but nothing bad either
Public - a month ago
reviewed a month ago
Service was fine
Public - a month ago
reviewed a month ago
85 reviews
Lovely place to sit and get a snack or a drink.
Public - a month ago
reviewed a month ago
Hideous building IMHO
Public - a month ago
reviewed a month ago
Not classy but good quality pub grub. Their spicy food seems to be very spicy so be warned on that. You won't leave hungry given the portion sizes.
Public - 2 months ago
reviewed 2 months ago