MITRAC runs on Windows 3? :)

[Telcontar]

I don't think anyone was seriously suggesting that Windows 7 would make a good embedded OS. I'm not in the embedded OS market – the only modern, lightweight OS I'm even halfway familiar with is EPOC32 (which was British!) EPOC32 gave you protected memory, pre-emptive multitasking, task priorities, microkernel modularity including a separate, distinct and swappable UI layer, top-to-bottom object orientated, and it was famously rock solid stable. Memory consumption for all this? 1 MB. Ran pretty well on an 18 MHz ARM CPU, but I'd estimate you'd want 72 MHz at least to be comfy given the high overheads of microkernel architectures.

It was also only single-user, which means that it would not be suitable for a desktop system now, but whether that would concern anyone in the rail industry I don't know – probably not if they're running Windows 95, which was also single-user, and Windows 98 was still a joke operating system. I don't know whether EPOC32 become secure multi-user since it became Symbian, though – I only know that Symbian phones took advantage of the fact that the UI could be replaced wholesale with something else. (The same was true of Linux on the Psion Revo – you'd get the PicoGUI embedded window system instead of X11 as X11 is too larget to into 16 MB RAM.)

It's a sad state of affairs if people's only view of embedded computing is considering it legitimate to place the least-engineered, tackiest and most gruesome consumer operating systems ever made into high speed passenger transport. At least with Mac OS 7–9 you knew that your Mac loved you even if it did crash all the time. To this day, we still live with the legacy of the phenomenal FAIL of all of Microsoft's consumer systems.
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I should also note: EPOC32 was designed (like its predecessor, EPOC16 AKA SIBO) from the ground up by a little British company, Psion PLC, for their range of palmtop computers. The ARM CPU, originally the Acorn RISC Machine, was also designed from the ground up by a little British company, Acorn, for their then-forthcoming 32-bit desktop computer (the Archimedes). You don't always have to settle for second best.

 

[dosxuk]

I don't think anyone was seriously suggesting that Windows 7 would make a good embedded OS.

You mean like Windows Embedded 7?

The embedded versions of Windows have a different modular architecture to desktop Windows, and a different support lifestyle. Only the original NT Embedded has now stopped being supported - even XP Embedded is still fully supported. You could deploy a version of Windows which only has a command line and networking support - completely unsuitable for general use, but a valid set up for an embedded device.

The choice of OS for an embedded device is much more complicated than chosing a multi-purpose general OS. The most recent release is not always suitable for the hardware you're targetting, or may be overkill for what you need to do. You also need to consider what happens over the lifetime of the product you are building. After 30 years, will there still be sufficient knowledge of the OS around to repair / bug fix any issues - with this type of life span it tends towards using OSs which are "mature" when the product is designed as opposed to using something which is brand new, but may disappear the day after you ship.

 

[Telcontar]

Neither did I say that it didn't exist. The very thought of wanting to marry the mess that is Windows, with embedded, should send shivers down your spine.

 

[dosxuk]

Neither did I say that it didn't exist. The very thought of wanting to marry the mess that is Windows, with embedded, should send shivers down your spine.

Why?

Surely it entirely depends on what product your building?

 

[Telcontar]

Why?

Surely it entirely depends on what product your building?

If you're asking this as someone with experience of even just the latest version Windows, I envy your brand of turd polish. I also suspect that you have a lot of repressed memories waiting alongside the skeletons in the cupboard. I'm not sure how much longer I can keep using Windows before I completely lose the will to live.

 

[Oswyntail]

Windows in all its incarnations has suffered a lot from anti-Microsoft bias. In my experience, most of the problems encountered in 3.1 and 3.11 arose from the software writers incorrectly implementing the documented interface, or when installations were trying to push it beyond its designed limitations. And all OS suffer from that. Windows 3.1 does what it says it does, and, if you use it properly, it will continue to do what it say it does.
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... I'm not sure how much longer I can keep using Windows before I completely lose the will to live.

And yet you are still around See post above!

 

[Telcontar]

Objectively, 16-bit Windows:

– lacks pre-emptive multitasking – the simplest bug can hang the computer ("System has either become busy or has become unstable. Press ctrl-alt-del to throw away your work, and cry into another beer while I take an age to reboot, via DOS.")

– lacks memory protection – the simplest bug can crash the computer – I have a MIDI file somewhere, that will hang Windows 3.11 – I had the player on random so I never did work out which, just had to keep rebooting (I was probably using the PC just as a music player at that point.)

I doubt that the kernel API has 100% sanity check coverage or anything close, so an incorrect instruction can cause the kernel to commit suicide (certainly true of classic Mac OS). These alone would make anyone run away.

Windows 95 and 98 (and Me?) as I understand it didn't protect the upper 2 GB of address space where DLLs live, so a DLL that goes wrong will take out the system too.

Subjectively, you don't have threading, you don't have usable filenames (this legacy has never faded), you don't have usable message passing (still true to this day – see Apple Events and D-Bus), it's not multi-user, you don't have symlinks (let alone aliases), the resource system stinks (still true to this day) and the 16-colour palette was designed by a colour-blind man. The list of mistakes goes on forever, and many of which have discoloured Windows to this day, from the kernel right up to user level.

Windows 7 contains all sorts of gems as a result. Aero lets you see inactive windows via alt-tab previews, win+tab, and taskbar previews. If a window is minimised, Aero will show a cached preview, placing yet another cognitive load onto the user, where they have to guess/remember whether they minimised the window and thus deteremine whether they're seeing a live image or a preview (for example if they're waiting for a program to do something, though the new animated progress bars help here). This may or may not be related to minimise shrinking a window to 0×0 pixels and moving it to something like (−3200,−3200).

Too many people haven't experienced the alternatives past and present, and just don't know any different. Time spent with RISC OS, AmigaOS, BeOS, Linux flavours, Mac OS 7, 8, 9 and X (all different), EPOC16, EPOC32, Acorn MOS and so many other systems will provide a fascinating insight into how many ideas have fallen by the wayside and died over the years – alternate takes on file systems, message passing, HCI and more. Windows is mostly bogged down by the multitude of mistakes set in stone by the 16-bit and early 32-bit versions, with no way out.

 

[barrykas]

Having seen the MITRAC startup on a 168/2, those definitely run embedded Linux and an X Server.

And the 357/0s started out on Win95...with no DOS mouse driver (for the touchscreen)...so if ScanDisk started, you were stuffed and had to open up a "cupboard" to plug in a keyboard. And not forgetting the infamous bug of it deciding the train had no motors after 75 minutes and promptly shutting down.

Cheers,

Barry

 

[Telcontar]

screwyoucharacterlimit

 

[D365]

Having seen the MITRAC startup on a 168/2, those definitely run embedded Linux and an X Server.

I guess that means 170s run Linux too; is it a custom build? I wish Linux or similiar OSs could be used everywhere!

 

[rf_ioliver]

I guess that means 170s run Linux too; is it a custom build? I wish Linux or similiar OSs could be used everywhere!

You're in luck, probably most of what is running today is in someway descended from a Unix variant...

I used to teach at university courses on operating system design* and for the first lecture we listed all the features that made modern operating systems cool, eg: virtualisation, virtual memory etc and then plotted back to when those features were first introduced - typically (almost invariably) this mean 1960's and 1970's mainframes.

But back to this discusson, trains don't run Windows or Linux per se - there are some computers on board that do, but that's usually because there's UI code for these available. These computers then communicate with various microcontrollers and other wierd bits of hardware that do the real work. Certainly for any (hard) real-time or safety-critical work then the better known desktop operating systems aren't used or are used in a very limited set of circumstances.

t.

Ian

*the standard course material practically everywhere is Tanenbaum's Modern Operating Systems - an excellent book for anyone interested in O/S workings and design. Prof. Tanonbaum is also famous for Minix and an "argument" with a certain Linus Torvalds...

 

[WelshBluebird]

Too many people haven't experienced the alternatives past and present, and just don't know any different. Time spent with RISC OS, AmigaOS, BeOS, Linux flavours, Mac OS 7, 8, 9 and X (all different), EPOC16, EPOC32, Acorn MOS and so many other systems will provide a fascinating insight into how many ideas have fallen by the wayside and died over the years – alternate takes on file systems, message passing, HCI and more. Windows is mostly bogged down by the multitude of mistakes set in stone by the 16-bit and early 32-bit versions, with no way out.

One thing that is also interesting is how many ideas fall and die over the years, only to be reinvented several years later as something fantastically new!

 

[Telcontar]

One thing that is also interesting is how many ideas fall and die over the years, only to be reinvented several years later as something fantastically new!

Maybe … for the most part I'm still waiting.

 

[danielnez1]

Given the train wreck (forgive the pun) that GNOME 3 and Unity are (and what Windows 8 is likely to be), people in the computer world currently seem to have forgotten all of the well established usability principles to try to pander to tablets and be “hip” at the same time.

 

[LE Greys]

Rather worryingly, I was in the radar room on HMS Daring a few years ago, and half the computers were displaying a Windows XP login screen.

Are you sure you want to launch at the incoming missile?
OK / Cancel

 

[sprite]

Rather worryingly, I was in the radar room on HMS Daring a few years ago, and half the computers were displaying a Windows XP login screen.

As would I be, surely they should have Windows for Warships installed.

 

[LE Greys]

As would I be, surely they should have Windows for Warships installed.

As this was a public event, it could be that they didn't want us to know about that.

 

[Telcontar]

You mean, maybe the Windows XP logon screens were all disinformation?

 

[TDK]

Sorry guys and gals but they flew to the moon without windows so I am sure the software currently used be it windows 7 or windows NT is sufficiant to assist in the running of a train.