* Posts by Richard Plinston

2608 publicly visible posts • joined 27 Apr 2009

When can real-world laws invade augmented reality fantasies? A trial in Milwaukee will decide

Richard Plinston

Re: a Mortal Threat...to augmented reality games

> with their pictures encouraging people to visit national parks

Actually, they are providing pictures so that you don't have to visit national parks.

Raspberry Pi sours thanks to mining malware

Richard Plinston

Re: Bah!

> Yes. The Pi is meant for playing around or research into future systems. It is a good and cheap platform for that, but don't expect too much of it.

The Pi is running exactly the same operating system as is run on anything from phones and embedded devices to supercomputers. It is no more riskier than any other computer, and a lot less than many.

> That is why well-designed systems come with built in checks to make sure you don't use them incorrectly.

Who is it that defines what is 'incorrect' ?

Richard Plinston

Re: Bah!

> Not sure what you mean here. Linux distributions test Linux and apps in the base release, but I don't think apps in general.

This was in response to someone saying the same about Apple in a message about MacOS that was saying it was more secure because Apple tested stuff (when it seems he was confusing it with iOS).

In fact with Linux there are _thousands_ of programs in the distro's repository so there is little need to look for alternate sources that may be insecure, and zero need for WareZ.

Richard Plinston

Re: Bah!

> End users just download whatever app they feel like. Of course Apple tests the apps for them - so really end users are doubly protected.

Linux distro makers test the 'apps' for them and puts these in the repository - so really, end users are doubly protected.

Richard Plinston

Re: Captain Bodge-tastic speaking

> within a few minutes there were failed login attempts showing up

That sounds like a job for fail2ban or denyhosts.

Elon to dump Trump over climate bump

Richard Plinston

Re: Coal stocks fell today

> Let's build some modern CLEAN coal-fired plants

There is no such thing, especially since Trump revoked the requirements to filter the smoke output and allowed plants to pollute the water.

Just because Trump said 'clean coal' a couple of times does not make it a thing.

Richard Plinston

> The sooner this appalling buffoon is impeached the better.

Pense will be worse because his God directs all his thoughts and actions.

Richard Plinston

Re: Whack-a do lobby

> Trump will probably be swayed by the crazy religious groups

Trump and the Republicans _are_ "the crazy religious groups".

Trump's religion is 'eliminate everything that Obama did'. Obama signed the Paris Agreement so Trump has to get rid of that. In announcing that he also said he will renegotiate to get back into it. This is just so it will be 'Trump Saving The World' rather than Obama's legacy.

The same with health care. He only cares that it is no longer Obama's but has the Trump name stamped on it. Cutting 800 billion to give to the rich is just a bonus.

The Republicans don't want the Paris Agreement and claim that "God will fix the problems":

https://www.youtube.com/watch?v=N1sEbUdl5r0

Microsoft Master File Table bug exploited to BSOD Windows 7, 8.1

Richard Plinston

Re: More like from the 1970s

> I suggest this may possibly give grounds for HP (the owners of DEC VMS IP) to demand to see Windows source code etc. as perhaps Dave Cutler took more with him than just what was in his head...

They already did that a couple of decades ago. They threatened to sue over NT and extracted a settlement from MS alleged to be $100million plus other items:

http://windowsitpro.com/windows-client/windows-nt-and-vms-rest-story

""""Why the Fastest Chip Didn't Win" (Business Week, April 28, 1997) states that when Digital engineers noticed the similarities between VMS and NT, they brought their observations to senior management. Rather than suing, Digital cut a deal with Microsoft. In the summer of 1995, Digital announced Affinity for OpenVMS, a program that required Microsoft to help train Digital NT technicians, help promote NT and Open-VMS as two pieces of a three-tiered client/server networking solution, and promise to maintain NT support for the Alpha processor. Microsoft also paid Digital between 65 million and 100 million dollars."""

Richard Plinston

Re: Applications are vulnerable?

> all of those black hats that are currently busy ignoring Linux (in desktop form) would find it an increasingly worthwhile target.

There are actually more Linux servers on the internet than Windows servers and yet it is the Windows servers that are being attacked more often.

There are more difficulties to attacking Linux than you imagine. First of all Windows is almost a monoculture with only a small number of variations. Linux has dozens of variations, each recompilation by the distro builders can move the potential attack surface.. This means that if a vulnerability exists there may have to be many variations of the exploit code, each only working with a subset of the systems.

Second there are much fewer 'convenience' features in Linux. Windows has designed in mechanisms intended to make it easier for users that make it _much_ easier for black hats. Many of these have been disabled or been notified with a dialog box, but not all of them. For example downloaded files can be executable with no further action; inserting USBs, CDs and DVDs could execute code automatically; clicking on an email, even if selecting it for deletion, could cause an application (such as Office) to open an attachment and execute macros or code inside; network ports used to be (and may still be) left open by default; on boot the network starts before the firewall has been loaded giving a small window of opportunity.

Linux doesn't do any of those.

Distro watch for Ubuntu lovers: What's ahead in Linux land

Richard Plinston

Re: Now if just 1 major PC maker installed Linux by default...

> So what, charge the retail price for Windows on top of the systems, you don't have to have cheap Windows licensing.

Yes, the OEMs and retailers do. The difference between OEM and retail pricing is > $100 and that would mean zero or negative profit or zero sales against nearly identical machines from other OEMs that were $100 or more cheaper. It is just as well that nobody employs you as anything to do with costs and finance.

> Apple seems to do just fine without Windows.

Apple produce a superior system at a premium price but can also run Windows.

> I suspect if an OEM emerged specialising in Linux and picked a universally usable Linux distro and configured it appropriately out of the box there would be a decent level of success.

> Chromebooks have found their place. Why not Linux?

ChromeOS _is_ a Linux distro, and has a decent level of success, which is why some OEMs have chosen to sell it. Android is a Linux distro too, just not a GNU/Xwindows one (for good technical reasons).

> Forcing windows by claiming something "isnt supported" is as bad as ...

OEMs and retailers make very small margins on selling computers, the market is too competitive with many manufacturers having nearly identical machines. They need to make their profit by including added-value (and added price) items or up selling with expensive addons. Windows makes this easy to do with games, security products, Office and so on. They also get a replacement sale every two or three years, or at least upgrades. This makes it a profitable business.

Apple have a much higher price and a good profit margin, so these are profitable even if there is much less add-on and upgrade market.

ChromeBooks have a free (or very cheap) OS and low end hardware and so do make a profit even though they are inexpensive. Windows 10S is likely to be free to OEMs to compete.

Selling a Linux based system would need to undercut the same hardware with Windows, would not have the profitable add-ons and would not have the repeat upgrade and replacement business because Linux machines are not replaced and upgraded like Windows machines are (my machines are all 5 to 14 years old, mostly discards from clients).

Why would an OEM or retailer want to add a non-profitable line to their business ?

Richard Plinston

Re: Printing

> with Linux or OSX/MacOS

The CUPS printing system was written by Apple for Unix like systems which includes their BSD based OSX. I have never had a problem getting specific drivers for the printers that I have used because [most] manufacturers need to support their use on Apple computers.

Your roadmap to the Google vs Oracle Java wars

Richard Plinston

Google had copied

> Google had copied 600 classes, 6000 methods and 11,000 lines of Java

No, Google did not copy classes and methods, it only copied names and parameters. The "and 11,000 lines" is misleading, it implies that they also copied and additional 11,000 lines when those lines are the ones containing the names and parameters required for interfacing - at less than 2 lines each.

In any case I am not sure why Google is not using as a defence:

"""Sun released the complete source code of the Java Class Library under the GPL on May 8, 2007, ..."""

Richard Plinston

Re: OTGH

> But what replaces Davik, or whatever is the execution engine for the Java like applications.

Dalvik has been replaced by ART for some time now, since 4.1.

> I'm confused as to what Google's plan B is?

They seem to be moving to Kotlin.

Windows 10: Triumphs and tragedies from Microsoft Build

Richard Plinston

Re: What Is Microsofts End Game ?

> It is not as if Microsoft will force developers to UWP etc., so they can take 30% of the developers revenue.

That is what Windows 10S is designed to do: force users* to only buy from the store so that developers have to follow or lose market share.

Note that with Windows 10S they will also be taking OEMs revenue and profit. MS Office, for example will no longer be pre-installed and added to the price of the machine (revenue and profit to OEM) but will be bought by the user from the store (all revenue and profit to MS) because it would be associated with their MS account.

* 'force' them by getting OEMs to sell cheaper machines with 10S that requires additional money to allow non-UWPs to be installed.

Why Microsoft's Windows game plan makes us WannaCry

Richard Plinston

> you really want her to have to faffle with many [operating] systems just to get the results of the tests?

Users don't run operating systems, they run applications designed for their needs. 'Test result' programs should look and work identically whether they are installed on Windows, Linux or Android. If they are browser based they should be identical whether on IE6, Chrome or Firefox.

> You can train the nurse to use Windows XP (which she has used for 10 years now), then you suddenly expect her to jump to Linux, OSX and Windows 10?

I would expect that someone familiar with Windows XP would find it easier to 'jump to' Linux than to Windows 8 or 10.

Richard Plinston

> Just try explaining mount to someone that isn't a developer.

You are obviously decades away from recent reality*. I plug in a DVD, USB or MicroSD and a dialog box pops up asking me what I want to do, or it simply gives me a file manager with the directories. It, however, does _not_ automatically execute any code on that device.

Other distros options or configurations may just add other partitions or devices as icons on the desktop ready to double click to mount them, or provide a GUI program to list these and/or available shares.

* the last 10 years or so.

Richard Plinston

Re: Bovine Excrement! @ AC

> Or are all the updates and patches for Linux just because the programs love to add bulk?

Many, or most, updates are adding new features to the programs. 'Updates' for a Linux distro are not just for the operating system but also for several thousand system and application programs, not just bug fixes but new versions.

DeX Station: Samsung's Windows-killer is ready for prime time

Richard Plinston

> Let's face it, desktop GPU's and CPU's are great, but expensive. They cannot fit into a phone - it just can't happen. But stick them in a dock, ...

... and the dock will be just as expensive as a complete PC.

Richard Plinston

Re: Linux

> It's running Android which isn't GPL Linux.

Yes, it is "GPL Linux".

"""Prominent free software programs licensed under the GPL include the Linux kernel."""

You probably meant "GNU/Linux" which includes both the Linux kernel and GNU software. No, Android does not come standard with a complete set of GNU software, but it is readily installable if required. For example there are several terminal apps in the Play Store that give GNU command line programs as well as Midnight Commander, GCC and other development software. Or you can go full X GUI with:

https://www.fossmint.com/install-run-linux-on-android-device/

Microsoft to spooks: WannaCrypt was inevitable, quit hoarding

Richard Plinston

> I do like how all the haters keep suggesting everyone ditch Windows and move to Linux. If that were to happen then all the bad guys would do the same and Linux would become the infection riddled beast while Windows was left alone to be clean and care-free.

No. The real problem is that Windows caters for malware _by_design_, and as 'convenience' features.

For example when a USB drive was inserted* then Windows would automatically execute code on the drive which could well be malware infecting the machine. When an email was opened, or merely clicked on in order to delete it, then attachments were opened and, potentially, code was executed, such as excel macros. When a file is downloaded then it may be executable without any further action. File types are deliberately hidden which disguises the actions that may be taken if the name is clicked on.

These, and many others, were all stupid decisions made by Microsoft which were avoided by other systems such as Linux and BSD.

The other issue is that Windows is a virtual monoculture with only a handful of variations. This allows malware like Wannacry to spread easily to large numbers of machines. Linux distros have a large variety of differences so that malware designed to infect one brand using, say, a buffer overflow, probably won't work in other distros.

> Windows is only as dirty as it is because of it's popularity!

No. It is as dirty as it is because Microsoft prefer it to be 'convenient' (including for malware) instead of secure.

* several of these issues have been fixed or avoided over the years.

Richard Plinston

Re: Let's mention Microsoft's Policy of hoarding patches unless you pay up.

> Is this in any way dissimilar to e.g. our paid RHEL support? Or any other paid software support? If the $vendor needs to code a patch for a paying client, should the $vendor then release it for free for the non-paying customers as well,

I run CentOS* and get RHEL patches, thank you.

* my clients do run RHEL and pay for support (which pays for CentOS too).

Richard Plinston

Re: If you cannot patch it quarantine it

> I thought Window XP only worked with SMB1, as does Server 2003.

Yes. From the Samba docs:

SMB2: Re-implementation of the SMB protocol. Used by Windows Vista and later versions of Windows. SMB2 has sub protocols available.

SMB2_02: The earliest SMB2 version.

SMB2_10: Windows 7 SMB2 version.

SMB2_22: Early Windows 8 SMB2 version.

SMB2_24: Windows 8 beta SMB2 version.

Microsoft's Windows 10 ARM-twist comes closer with first demonstration

Richard Plinston

Re: Performance @Updraft102

> (1) how compatible is the emulation? Are there some programs that won't run properly on it? How many?

As I understand it, the emulation is x86 and _not_ x86-64.

Richard Plinston

> python allows that for modern embedded systems too, as long as there is an entire OS present first.

MicroPython does not require "an entire OS", see Micro:bit or PyBoard.

Richard Plinston

> there's even a distribution for Pi's like yours

There was a thing called Windows 10 IoT which ran on a Pi3 (not on Pi1, 2 or Zero) which was not like Windows at all - no OS GUI or command line. It was merely a boot loader for a single UWP which had to be written on a desktop PC.

Windows 10 S forces Bing, Edge on your kids. If you don't like it, get Win10 Pro – Microsoft

Richard Plinston

> Google aren't allowing their apps on

Has it never occurred to you that is is Microsoft restricting what is in their store ?

https://betanews.com/2016/08/20/microsoft-family-block-chrome-firefox/

Richard Plinston

> The true antitrust story is that while Microsoft makes it's most popular applications available on every platform under the sun

Exactly where do I find MS Office for Ubuntu, or RedHat or BSD ?

Richard Plinston

Re: Hmm ChromeOS

> Given Mozilla's and Google's reluctance so far to use the store to distribute their browsers,

Does it not occur to you that their absence from the store is because Microsoft won't allow them* to be there ?

* Unlike Google and Apple where Microsoft software is in their stores.

S is for Sandbox: The logic behind Microsoft's new lockdown Windows gambit

Richard Plinston

Re: "but MS will control which apps are allowed"

> DigiKam for the "great danger" (LOL!) they pose

Apparently if you use the Windows 10 photo gallery it slups all the photos up to OneDrive. If you want to only have them locally held then a different program is required: Digikam (which is a photo organizer with a great editor) will not push them to any cloud.

Richard Plinston

Re: "but MS will control which apps are allowed"

> Google store? Do they allow any application?

Obviously they filter for malware, but they don't ban competitors like Microsoft does. You can get MS Office in the play store - for free.

> How MS could forbid different browsers in Windows, after that? While LibreOffice could be somewhat a competitor of Office (but again, would it risk an antitrust issue?),

MS don't 'forbid' other browsers from Windows - buy the $49 pro and get whatever browsers you want - but there aren't other browsers available for 10S.

LibreOffice is free. Pay MS $49 to be able to get it, or buy MS Office even if you only want to do simple tasks. It is about the money.

> GIMP is a competitor of what, from MS? Do you believe Adobe would ask MS to block GIMP or DigiKam

Does MS not have a paint program or a photo library with editor ?

> Just like there is a lot of Google software running on Windows?

Yes there is, but it seems that there won't be _any_ running on 10S, which is exactly the point of this OS version.

Richard Plinston

Re: "to be taxed by microsoft at rate of 30%"

> Just like any other store - and like the others, unless the app is free.

Maybe, but MS will control which apps are allowed in and which are not. Will there be Firefox or Chome, what about LibreOffice, GIMP, Digikam ?

> So, why this is a problem if it is a MS store, and not if it is an Apple or Google store?

This move is a revenue grab. Currently OEMs and retailers sell Office and much software from other vendors and collect the revenue and make a profit, and even collect subsidies for shovelware. MS want that revenue and profit. I would assume that apps loaded from the store is linked to the user's account so pre-loading the PC by the OEM would not be allowed, or perhaps the OEMs would not get a discount on the store prices.

Apple does not have OEMs so it is not stealing some other companies revenue, and it is not the only source of software for OS-X. Google does not restrict software sales to its own store, there are many other sources. Google also applies much less control over the software available - there are many Microsoft titles in the play store.

It is likely that even the $50 'tick the box' charge will be full revenue to MS only and not the OEMs. How soon will that option disappear ?

(You can't) buy one now! The flying car makes its perennial return

Richard Plinston

Re: Rotors "powered by the wind"

> The point is that air is a prerequisite for wind. A vacuum has no air. No air, no wind. No wind,

10 days and that is all you could come up with ?

Seeing as you are going completely absurd, I counter with:

https://en.wikipedia.org/wiki/Solar_wind

https://en.wikipedia.org/wiki/Solar_sail

Richard Plinston

> They are slow and require runways,

There are/have been autogyros that can do 300 knots.

Autogyros spin up their blades before take off and can jump start by over-speeding their blades at zero pitch and then adding pitch to jump off the ground with zero ground run.

https://www.youtube.com/watch?v=9ISIlgMcb-U

They can also land in a very small space.

https://www.youtube.com/watch?v=UJucumpKxUk

https://www.youtube.com/watch?v=N1_QLRy54Z8

Richard Plinston

Re: Rotors "powered by the wind"

> to overcome the lack of wind

So you agree that your 'cannot fly without wind' was incorrect.

> lack of wind. Try flying your kite in a vacuum

'Lack of wind' does not imply a vacuum. The air does not disappear because it is not moving.

> Wind means nothing when you have more energy than it.

Try flying a kite by running downwind!

Richard Plinston

Re: Rotors "powered by the wind"

> actually suggesting that the autogyro is in a constant state of falling

No. The rotor is tilted with the leading edge of the disk containing the blades higher than the trailing edge. Thus the air passes from the underside of the disk to the upperside interacting with the blades as it does so. This is so whether the vehicle is level, climbing, or descending.

This is in contrast to a helicopter where the air is pumped from above the rotor disk to below (unless the engine fails in which case it goes into auto-rotate mode which is as above, except in that case it _is_ in a state of falling).

Richard Plinston

3 wheeler

Did no one learn from watching Jeremy Clarkson driving a Reliant Robin ?

And then they put a load of gear on the roof to ensure a high CoG.

https://www.youtube.com/watch?v=QQh56geU0X8

Richard Plinston

Re: Rotors "powered by the wind"

> Kites are powered by the wind, and cannot fly without it.

Not true if you can run.

Scratch the Surface: Slabtop sales slump takes the shine off Microsoft's 2017 so far

Richard Plinston

Re: Organizations are turning to Microsoft as a partner they can trust.

> So most people don't care that Slurp/Microsoft/Facebook/Tinder/eBay/Linkedin/,,,* reads everything they do and sells it to advertisers...

FTFY

* plus, in USA thanks to Trump, all the ISPs.

Richard Plinston

Re: The whole point of the Surface Range...

> Some people might not like Windows 10, but the corporates are heading for it like flies to shit...

That is a really appropriate analogy.

Swamp-draining Trump pushes ex-AT&T lobbyist to oversee AT&T mega-merger

Richard Plinston

Re: Moving goalposts

> IIRC, Donald never threatened a tax on exports to Mexico

He did threaten to steal money being 'exported' by workers in the US to their families in Mexico.

It is several billion a year and Trump thought they would still keep sending it even though the families would not be getting it.

So few use Windows Phone, Microsoft can't be bothered: Security app is iOS, Android only

Richard Plinston

Re: Windows Phone is dead, long live Surface

> all development effort is now in Windows Mobile. For which universal apps can be written that run on both desktop and mobile....

Exactly, so all the developers who wrote for WM6.x and had to dump all their work to start again for WP7, and then had to rewrite for WP8, will now have to dump their work again and start afresh - of go to a more stable environment such as Android, or iOS if they haven't already.

Richard Plinston

Re: It still makes me giggle

> That a 5% market share for windows phone is a total failure

It probably wouldn't be a failure if it had ever been 5%. It is currently much less than 1%. It is a total failure because at one time Microsoft smartphones had 42% of the US market and have been going downwards since in spite of throwing billions at them and never making a profit. Microsoft also killed off several potential competitors: Symbian, Asha, Maemo/Meego (N9, N900), Meltemi, Nokia-X, WebOS; but it didn't help their marketshare.

> but a 2% desktop OS share for Linux is considered to be the impending year of linux on the desktop.

Desktop Linux doesn't lose billions of dollars and isn't decreasing. 'Personal' computers are no longer just desktops. The most personal are those that you carry in your pocket.

Richard Plinston

> - It's easier for an existing player in a market to re-invent itself

One of Microsoft's problem in mobile is because it _has_ continually re-invented itself and has dumped its previous products. Windows Mobile 6.x was completely dumped when MS re-invented itself as Windows Phone 7. This was dumped, including all the hardware and most of the software, when it re-invented itself as WP8. Most of the WP8 phones have now been dumped. But the real problem is that the complete development process has been re-invented at each stage so that developers have given up after having their development processes dumped several times

Crafty Fokker: Norfolk surgeon builds Red Baron triplane replica

Richard Plinston

Re: I wish him well

> Radials don't tend to have significant flywheels; the propeller and its boss fulfil this function.

But they do have rather massive counter-weights on the crankshaft opposite to the throw. This is required because the crank and whole piston assembly will move in one direction while the counter-weight balances this by moving in the other direction. This acts as a flywheel by increasing the rotating mass (and the weight of the engine) but is required to stop the engine shaking itself apart.

> The only thing that rotates is the crankshaft.

Which includes the large counter-weight.

> Therefore the kinetic energy of rotation is very, very much less. But the vibration is exactly the same.

Rotaries don't have any significant vibration.

Rotaries also have much less mass in their cylinders than a radial does because the cooling is much more efficient and requires smaller cooling fins and less wall thickness. The crankcase is also lighter than a radial because it doesn't have to control the stresses that a radial produces. While the rotary does have greater angular momentum, it is not as different as you imply. The rotary is also much lighter than an equivalent radial of the same size, but it is much less efficient in fuel and oil usage.

Richard Plinston

Re: I wish him well

> It is the rotary that, in my example, is like the sun rotating around the Earth and not vice versa.

I made no comment about whether either of the engines were "like the sun rotating around the Earth [or] vice versa". I was merely pointing out, in the case of Earth-Sun, that your claim of '_mathematical_ equivalence' was incorrect. It may be that the relative motion can be contrived either way but any _mathematical_ calculations will show only one could possibly be correct.

> The rotary is like a large, heavy flywheel rotating at the same speed as a much smaller wheel. Attached to the much smaller wheel are the pistons, which travel around it in a kind of wave motion which accounts for the offset from the flywheel. The pistons thus rotate in a circle as well as going up and down.

No, you are quite wrong. The pistons do _not_ go "up and down". There is no 'wave motion'. There is a fixed centre of rotation of the crankcase (relative to the fuselage) and a fixed centre of rotation of the piston assembly. The latter is offset from the former by the crank and this is called the 'throw'. The pistons rotate at a fixed distance from the crank pin, controlled by the piston rods. The pistons make no motion (relative to the fuselage) other than around in a circle.

It happens that, because the two centres of rotation are offset, that the relative positions of the pistons within the cylinders changes as the two rotate. But neither the pistons nor the cylinders go 'up and down' nor 'left and right', nor 'wave', they only go in a circle at a fixed distance from their fixed centres of rotation.

> As a result the rotational energy is not only due to the big flywheel (the crank, cylinders etc.) but also the rotating masses of the pistons. As they go up and down, the variation in effective radius causes a variation in kinetic energy which manifests itself as a shaking of the whole system in a circumferential direction - exactly the same as with a radial or in-line engine on its crank.

No. Completely WRONG. They do not go 'up and down'. There is _no_ variation in effective radius. All parts are always at the same radius from their actual centre of rotation. There is _NO_ variation in kinetic energy during a rotation (except, of course, when the rpm changes). There is _NO_ "shaking of the whole system in a circumferential direction". That is one major reason why rotaries were used.

> You have been trying to suggest that both engine types have "wheels" of equivalent size and mass. They do not. The radial's single wheel is very much smaller than either of the "wheels" of the rotary.

I made no such suggestion about their size and mass, I was only indicating that the motion of the parts were completely different is response to your assertion that their motion might be "equivalent". It is not equivalent, especially mathematically.

The two wheels in my example that was illustrating the non-equivalence of motion in the radial, were the fixed circle of cylinders and the 'up and down, left and right' moving circle of pistons. I dispute that in two engines (of the same capacity) they would have 'wheels' of cylinders and pistons that were much different. You have obviously misunderstood a simple analogy by not noticing that I said in the case of the radial that the 'wheels' (of cylinders and pistons) were "two wheels that are not spinning", the 'up and down, left and right' are imparted by the crank.

Certainly in both engines the diameter of the circle defined by top of the piston heads is smaller that the diameter defined by the tdc of the cylinders - the difference being the stroke. I made no claims about what size the wheels in my example should be, it was merely to illustrate the actual motion, and the non-equivalence in opposition to what you claimed.

> Radials don't tend to have significant flywheels; the propeller and its boss fulfil this function.

Maybe, but many inline engines do.

> Remember that the energy of a small volume of a rotating component is proportional to radius squared, so the cylinder heads being well out from the hub have a much bigger effect than the relatively small rotating hub of the radial.

I left the discussion about the gyroscopic effects to others who had already dealt with that perfectly adequately.

Richard Plinston

Re: I wish him well

> Aren't they mathematically equivalent, it just depends on which you take as the fixed point about which things revolve? (Like Tycho Brahe's Earth-centred astronomy which was just the same as Copernicus's but using the Earth rather than somewhere inside the Sun as being the fixed point).

Not when you calculate the forces involved they aren't, in either case. For example: what would the gravitational attraction have to be to keep the Sun in orbit around the Earth on a daily basis ?

Get, say, a small bicycle wheel and spin it. A rotary runs like two of those with their axes offset. Now get two wheels that are not spinning, have one stationary and shake the other one sideways and up and down 2,000 times a minute. That is what a radial is like.

>I seem to recall that one alleged advantage of rotaries was that the force on the valves would tend to prevent a broken valve from dropping into the engine, a big problem in those days. Otherwise, the rotary was like the Wankel - nice in theory, a pig in practice.

Another advantage of the rotary is that it doesn't need a flywheel to keep it relatively smoothly running because the whole engine acts as a flywheel. This keeps the weight down compared to an inline or a radial.

Wankel's are fine, except the seals wear out too fast. I had one as an auxiliary in a sailboat: light, compact, simple, vibration free, reliable, quite cheap. It only ran about 2,000rpm so the seals were not a problem.

Richard Plinston

> One was that they were two stroke engines, with the oil being mixed in with the gasoline.

Most rotary engines used in WWI had a four stroke cycle, which is why they always had an odd number of cylinders. As they rotated past top dead centre (or so) each alternate cylinders was fired. Even with automatic inlet valves this worked because the expansion stroke kept the valve closed. They always had mechanical exhaust valves (which in some models were left open for part of the intake stroke to take in air).

The oil was mixed in with the petrol but this was required because the intake was done via the crank shaft and the crank case, this being the only link between the carburettor and the cylinders, and this oil was all that was available to the big and little ends and piston walls.

Two strokes usually rely on the piston downstroke reducing the crankcase volume and thus pushing the new charge into the cylinder. This only works where each cylinder's crankcase is separated (or on a single cylinder engine), or there is another mechanism such as a stepped piston or a supercharger. A rotary's crankcase had an almost constant volume.

Richard Plinston

Re: I wish him well

> original rotary (radial?

Rotaries and radials are different. They both have a single throw crank* surrounded by a circle of cylinders and pistons. The radial has the cylinders fixed with the crankshaft rotating while the rotary has a fixed crankshaft with the cylinders and pistons rotating.

While the radial has to push the pistons back and forth and up and down creating bad vibrations, the rotary moves its parts around in smooth circles, it is just that the pistons and cylinders have different centres of rotation.

Fokker used rotaries.

* some radials had two or more banks and thus more throws.

It's 30 years ago: IBM's final battle with reality

Richard Plinston

Re: "In the 1980s almost all software for CP/M and MS-DOS was developed on mini-computers"

> A lot of initial DOS software was often written directly in assembly (although C compiler became available quickly).

Perhaps I should have specified 'non-trivial software'.

Interesting that you start with: "A lot of initial DOS software", including MS-DOS itself, which obviously wouldn't have been written using DOS - because it wasn't available yet.

> IBM introduced its PC LAN quite early

It was initially released in 1984, 3 years after the IBM PC.

Certainly a team could use a network server, but then the PC is acting as a terminal.

> since often in the early days software was written by a single developer.

All the software you mentioned (except edlin) took more than a single developer.

> Disks weren't large, but applications were small as well.

The IBM PC initially catered for two 160Kb SSSD disks and only later went to DS and 10 sector to give 360Kb. It wasn't until MS-DOS 2.x and IBM PC-XT that hard drive were available.

On release the IBM PC catalogue listed PC-DOS, CP/M-86, UCSD, Wordstar, Visicalc, Peachtree, compilers for: BASIC, COBOL, Pascal, FORTRAN; Forth, a 'program generator', none of which were capable of being compiled using 160Kb disks, and the source code of each probably was too large for the 10Mbyte disk of the XT.

I was developing software on micros since the very late 70s, with way more resources than an IBM PC later had, using Wordstar and other, but it was only relatively small stuff, mainly in COBOL. The compiles would run all night