The only "standards" for the most part are set by the specific manufacturer, for a specific product line. There literally thousands of product lines in current use, and tens of thousands more historic lines that are no longer made. As you can see here at a popular parts supplier in the US: https://www.digikey.com/en/products/category/connectors-interconnects/20 there are over 5 million separate results searching for "connector". That is FAR from a comprehensive list. There are hard metric, hard English pin size/spacing's and a few that are "both" meaning close to an even mm dimension and an English dimension that is an even fraction of an inch. Sizes range from so tiny you cant see the individual pins to huge (for high power AC distribution for example), depending on application. By convention the headers on mother boards are .1" spacing (both ways if multiple rows). The shroud (with or without key slot) is optional and often omitted as a cost saving measure. these are a significant improvement over edge card connections, but still not exactly "safe". The pins are always square and "tinned (coated or plated with metals similar in appearance and possibly composition to solder)" or gold plated, which effects reliability, cost, and capability (voltage and current specs). The mating female connectors come in a variety of sizes, and internal construction in turn effecting cost and performance. MOST of an EE's job in the modern world is about selecting parts for availability, spec, cost, etc. EVERYTHING is tradeoffs: cost vs performance vs thermal management vs ease of use/manufacture etc. etc. Every manufacturer thinks their products are superior - and maybe they are in some applications. Nothing works well everywhere. Some (like 0.1" pitch headers) are more common than others. Even in specialized applications like RF there are dozens of kinds in common use, all have their pluses and minuses. And a hundred more that are very uncommon and found only in certain applications or in certain countries products.

Using the latest technology to create tomorrows problems today.

I have multiple degrees in abstract math (functional analysis mainly) and I have never seen that symbol used in English, German or Russian texts. Must be something new.....

Using the latest technology to create tomorrows problems today.

I agree - Eclipse was hard to get used to after years of VS, but once I learned it, its very nice and works extremely well for Java, on the plus side I can move projects freely between Linux, MAC and PC with few or no changes. I also use it for php based web app development and it works very well (the Aptana variant).

Using the latest technology to create tomorrows problems today.

ELF-II like this but without all the "fancy" expansion boards Elf Photo 256 Bytes of memory programmed in machine language (anyone remeber assembler forms?) then a ZX-1000 with 16K expansion memory then a PDP-11/20 (and a room full of peripherals including a card reader) ... PC-XT - dual floppies

Using the latest technology to create tomorrows problems today.

WD-40 cleans the goo very handily - hence the need for wd-40

Using the latest technology to create tomorrows problems today.

I actually have a degree in theoretical physics so I can answer this. The laws of physics are the same everywhere comes from applications Noether's theorem (technical stuff to do with symmetry and conserved currents) - for example if conservation of mementum is true anywhere then it must be true under any translation (i.e. everywhere). If conservation of angualr momentum is true anywhere the it must be true under any rotation (i.e. in any direction). From (formally nasty complex mathematical) statements like these we conclude that the laws of physics are the same everywhere. The laws of physics don't change - much trickier. If you mean conservation of memntum is always true and always was then yes, BUT if you mean the speed of light is was and ever shall be ~3.0e8 m/s then thats an open question. There is a whole group of theories that require various constants to have changed or still be changing. There is another aspect too - you might think conservation of energy would give you constancy of the laws of physics over time, but we know that conservation of what we normally call energy is only approximate, it is absolutely not true on either the largest or the smallest scales.

Using the latest technology to create tomorrows problems today.