Metric vs Imperial – Practical or Traditional?

[WolfieParticipant @wolfie]

“There are only 10 types of people in the world — those who understand binary, and those who don’t”

 

Ah yes. I’m an IT man too. That makes 10 of us

[Mark DickinsonParticipant @markdickinson21936]

Posted by John Olsen on 25/10/2010 21:45:09:

Mark…A byte should always be 8 bits. 

 

Pedant mode.

An octet will always be 8 bits. A byte’s is the smallest amount of memory that a CPU can address individually and in the past computer systems could have used more or less than 8 bits per bytes.

Nowadays it is usually assumed that a byte is the same as an octet, but I was always taught never assume anything.

 

anyway its all geek to me 

[John OlsenParticipant @johnolsen79199]

If you Google for it you will find that the vast majority of sources define a byte as 8 bits.

 

eg

Eight bits; also called an octet.

http://www.w3.org/TR/PNG-Glossary.html

 

Your definition of a byte is what I would call a word…eg the first microprocessor had a word length of 4, later ones had 8 and I have worked with machines with word lengths of 10, 16, 18, and 32 bits.  Your definition would also render the quoted sizes of hard drives and files completely meaningless, since different computers can have different minimum word lengths.

 

 regards

John

[Mark DickinsonParticipant @markdickinson21936]

John,

I only mentioned bytes to highlight the ambiguities of measurement systems, I wish I hadn’t bothered.

However

From the Oxford English Dictionary

byte

Pronunciation:/bʌɪt/

noun

Computing

a group of binary digits or bits (usually eight) operated on as a unit

a byte considered as a unit of memory size

another definition 

http://www.wordiq.com/definition/Integer_(computer_science)#Bytes_and_octets

I didn’t say it wasn’t 8 bits.

Non 8 bit byte architectures include CDC 6000 mainframes, DEC PDP-10 mainframes(yes obsolete now)

Hard drive sizes, would that be using manufacturers stated sizes where 1GB is 1000^3 or Microsoft’s reported sizes where 1GB is 1024^3

[Sam StonesParticipant @samstones42903]

This thread about standards, looks like it will go on forever.

So here’s another six penn’orth of stuff to add to the mix.

This time, it’s about thread standards, Metric and/or Imperial. Not the normal run-of-the-mill types though. Around the early 60’s, while working from a technical service laboratory, I noticed that there was a regular stream of requests from designers and manufacturers addressing the following problem.

 

Caps and closures, moulded in recently formulated polyolefins were working loose in service. The problem was fairly clear, but while trying to get the message across, I acquired a booklet which described thread profiles especially suitable for glass `finishes’, and their counterpart – (rolled) metal closures. And here’s my point:- 

There were about 125 different thread profiles!

These profiles had little to do with pitch or diameter, so you can guess how many permutations there could be. Fortunately, I’m happy to report, after spreading the word over a considerable period, buttress threads are now almost the standard.

If you want more on this latter topic, please – start another thread. Pun intended.

Sam

Edited By Sam Stones on 26/10/2010 04:14:32

[Anonymous]

The only axiomatic truth about standards is that they are non-standard.

 

Regards,

 

Andrew

[Sub MandrelParticipant @submandrel]

But John, are your words big or little endian? (that’s 11 of us Wolfie)

 

Neil

[John OlsenParticipant @johnolsen79199]

I thought the big endian thing only applied to numbers? I leave the programming to my sons these days. I liked programming in assembler on the old 68000 series, I don’t want to get into x86 in any shape or form. One thing about the byte though. I doubt if the meaning is legally defined anywhere, unlike say the metre or the foot. In English, that means that the only authority for the meaning of the word is usage.

 

The same probably applies to the “kilo = 1024” convention, which would mean that the hard drive manufacturers are strictly in the right when they quote in thousands  and millions…however, why a marketing person would want to leave so many customers feeling they have been short changed is a mystery to me.

 

The other thing about standards is the the old ones never really go away. So although here in NZ we metricated many years ago, you can still buy Imperial sizes, and indeed industry would grind to a halt if you could not. Actually lately it seems to be doing so anyway.

 

regards

John

 

 

[Anonymous]

Ah, but words here means numbers. Now is that English or binary?

 

For those unencumbered by the minutiae of microprocessor design I’ll explain the in-joke. When microprocessors came out that used 16 or 32 bits internally instead of 8, the problem arose of how to transfer those bits to a peripheral, say a UART, that only accepted data in blocks of 8 bits. The data can be transferred most significant bits first, known as big endian, or least significant bits first, known as little endian, in a salute to Swift.

 

Motorola processors, eg. the 68000 and 68020, used big endian, while the Intel x86 processors were little endian. If IBM had gone with the 68000 for their PC the world might have been a very different place.

 

Regards,

 

Andrew

[Sam StonesParticipant @samstones42903]

There seems to be no endian in sight!

 

Or should that be insight?

 

Sam

Edited By Sam Stones on 27/10/2010 00:04:32

[Anonymous]

Some microprocessors felt the same; they were bi-endian.

 

Regards,

 

Andrew

[Bill PudneyParticipant @billpudney37759]

All the talk about measuring things in fractions of a horsehair made me think of when I had to work for a living….only a couple of years ago.  I was sort of responsible for buying machinery for a small machine shop.  One of the ongoing jobs had…and required very tight tolerances.  Generally tolerances were only tight where required, but there were lots of inter-related features with tight tolerances, in the order of +/- 0.01mm for instance. It could end up having a tolerance of “0” in fact if all the tolerance range was used up earlier in the process.  The various suppliers of co-ordinate measuring machines (CMM) were contacted with details of the spec required.  They were all really interested to start with but gradually said “…its too much for us”.

 We ended up having to make a laboratory standard enclosure, with its own air conditioning system controlled to +/- 1 degree Centigrade 24 hours a day, each CMM mounted on its own concrete base shock/vibration insulated from the machine shop floor.  The CMMs (we ended up with 3) were CNC and took about 3 hours to fully inspect about 90% of the features they also generated a report which we had to keep.  The items to be inspected were left in the CMM room for 24 hours to thermally adjust before inspecting, and were handled as little as possible….those hot handed inspectors!!

The first items that we made took about 50 hours to machine and another 70 or 80 to inspect….it was very very fiddly!!

When I retired the machining time was about 7 hours and inspection time was about 3.5 hours total.

Edited By Bill Pudney on 27/10/2010 04:40:00

[WolfieParticipant @wolfie]

“that’s 11 of us Wolfie”

 

Ahh 1 more and it’ll be 100

[DMBParticipant @dmb]

Hi all,

This is a response to Mark Dickinsons post of 25th; “In the 1960`s we took `acid` to make the world seem weird now the world is weird and we take Prozac to make it `normal`!”

[V8EngParticipant @v8eng]

I notice that UK based TV programmes seem to be trying to metricate us by giving distances in Kilometers. 

[Anonymous]

I would hope that they would at least have the decency to brainwash us with kilometres.

 

Regards,

 

Andrew

[John OlsenParticipant @johnolsen79199]

Ah, but they also say that if you can remember the sixties then you weren’t really there…

 

regards

John

[Steve GarnettParticipant @stevegarnett62550]

Posted by Andrew Johnston on 27/10/2010 22:44:42:

I would hope that they would at least have the decency to brainwash us with kilometres.

 

 Surely if they were doing any sort of washing, it would have to be litres?

[Nicholas FarrParticipant @nicholasfarr14254]

Hi. or millielitres.

 

Regards Nick

[V8EngParticipant @v8eng]

Oops!

 

Sorry folks, yes it should have been Kilometres.

Same as they use on the UK roadwork information website.

 

As somebody who went metric decades ago I would be quite happy with a single system, what we have at present is just a silly mix.

[chris stephensParticipant @chrisstephens63393]

Well it shows how stupid TV program makers are, the Mile is still the official unit of distance in this country. It was one of the exemptions to metrification, along with the pint! May it long be so.

chriStephens 

[Anonymous]

Ah, but how do we fathom which one, statute or nautical? 

 

Regards,

 

Andrew

[WolfieParticipant @wolfie]

If you’re on the nautical one you have wet feet…

[Anonymous]

Not necessarily; aviation uses nautical miles too! More like high and dry.

 

Regards,

 

Andrew

[Martin WParticipant @martinw]

Andrew

 

 

Is this a result of early long range flying being conducted in ‘Flying Boats’? Even now we have captains, first officers, etc on the ‘flight deck’ so is this another relic of bygone days?

 

Definitely a wet foot job if making a hard landing or should that be making a splash on your arrival  !!!

 

Just a couple of rumblings from an underused mind.

 

Cheers

 

Martin

 

PS.

 

Then there is of course the ‘pilot’ another nautical term, well in one meaning of the word .

Edited By Martin W on 29/10/2010 10:42:07

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