Binary Computing

[kalvado]

Plain text files are a rarity outside of some configuration these days

This is almost certainly the wrongest post made on the forum this year—even .docx, which you mention in your post, is just a bunch of plain text files in a .zip wrapper!

Nope.
MS .docx is an .xml (and a few other things) in a zip wrapper, not a plain .txt. And .xml standard is system-agnostic and requires use of linux-style LF.

[Scott5114]

Plain text files are a rarity outside of some configuration these days

This is almost certainly the wrongest post made on the forum this year—even .docx, which you mention in your post, is just a bunch of plain text files in a .zip wrapper!

Nope.
MS .docx is an .xml (and a few other things) in a zip wrapper, not a plain .txt. And .xml standard is system-agnostic and requires use of linux-style LF.

XML and TXT are the same thing—you can convert one to the other just by changing the file name. The XML standard is just saying what W3C would like to see inside the TXT file.

What makes something not "plain" text is binary content.

[kalvado]

Plain text files are a rarity outside of some configuration these days

This is almost certainly the wrongest post made on the forum this year—even .docx, which you mention in your post, is just a bunch of plain text files in a .zip wrapper!

Nope.
MS .docx is an .xml (and a few other things) in a zip wrapper, not a plain .txt. And .xml standard is system-agnostic and requires use of linux-style LF.

XML and TXT are the same thing—you can convert one to the other just by changing the file name. The XML standard is just saying what W3C would like to see inside the TXT file.

What makes something not "plain" text is binary content.

Any file can be converted to anything by changing file extension. It may not work, though. /s ASCII symbols are also binary, after all.
I just opened a document.xml extracted from a .docx created by a winword running on windows  - in a simple hex editor.
MS being MS, they have exactly ONE CR-LF symbol in entire file, after the first line - and neither 0A nor 0D anywhere else.
two other .xml from the same document are created the same way, endless flow of tags without any regard to human readability after the first line .

(later addition) .docx created by Google docs has only 0D in the same position of XML, and  also no 0A or 0D elsewhere in XML

[Dirt Roads]

And connecting things to neutral is a big no-no. Most outlets these days carry a third ground wire for that.

I agree.  However, I am unconvinced that most of the modern computer world understands the difference between "neutral", "house ground", "frame ground" and "earth ground". 

Back in my day, many of the personal computers simply had a two-wire power supply cable and everything had to use the neutral.  When the era of the three-wire Japanese Standard power plugs became commonplace, most power supplies didn't reconnect the neutral to the ground (from the third-wire) at either the transformer or the ring-diode rectifier (whichever came first in the power supply).  As a result, the third-wire ground became a parallel neutral.  Also, oftentimes the low-voltage DC signal would be connected to "house ground" and "frame" at the same location, thereby creating a bypass of the transformer and causing the frame to still be connected to "neutral".

I'm still a bit confused on how this works today, but from what I can tell many suppliers of laptop power supplies still do the same things.  At least most desktops try to avoid connecting the "frame" to the "house ground", but still provide a path for draining off high-voltage noise between the two with a capacitor. 

It was always somewhat disconcerting that many computer technicians never seemed to know which side of the power supply to connect their wrist ground strap to.  At least the old way, any old ground stud would do fine.  (Which wasn't necessarily a good thing).

[kalvado]

And connecting things to neutral is a big no-no. Most outlets these days carry a third ground wire for that.

I agree.  However, I am unconvinced that most of the modern computer world understands the difference between "neutral", "house ground", "frame ground" and "earth ground". 

Back in my day, many of the personal computers simply had a two-wire power supply cable and everything had to use the neutral.  When the era of the three-wire Japanese Standard power plugs became commonplace, most power supplies didn't reconnect the neutral to the ground (from the third-wire) at either the transformer or the ring-diode rectifier (whichever came first in the power supply).  As a result, the third-wire ground became a parallel neutral.  Also, oftentimes the low-voltage DC signal would be connected to "house ground" and "frame" at the same location, thereby creating a bypass of the transformer and causing the frame to still be connected to "neutral".

I'm still a bit confused on how this works today, but from what I can tell many suppliers of laptop power supplies still do the same things.  At least most desktops try to avoid connecting the "frame" to the "house ground", but still provide a path for draining off high-voltage noise between the two with a capacitor. 

It was always somewhat disconcerting that many computer technicians never seemed to know which side of the power supply to connect their wrist ground strap to.  At least the old way, any old ground stud would do fine.  (Which wasn't necessarily a good thing).

Class II appliances?

[Dirt Roads]

And connecting things to neutral is a big no-no. Most outlets these days carry a third ground wire for that.

I agree.  However, I am unconvinced that most of the modern computer world understands the difference between "neutral", "house ground", "frame ground" and "earth ground". 

Back in my day, many of the personal computers simply had a two-wire power supply cable and everything had to use the neutral.  When the era of the three-wire Japanese Standard power plugs became commonplace, most power supplies didn't reconnect the neutral to the ground (from the third-wire) at either the transformer or the ring-diode rectifier (whichever came first in the power supply).  As a result, the third-wire ground became a parallel neutral.  Also, oftentimes the low-voltage DC signal would be connected to "house ground" and "frame" at the same location, thereby creating a bypass of the transformer and causing the frame to still be connected to "neutral".

I'm still a bit confused on how this works today, but from what I can tell many suppliers of laptop power supplies still do the same things.  At least most desktops try to avoid connecting the "frame" to the "house ground", but still provide a path for draining off high-voltage noise between the two with a capacitor. 

It was always somewhat disconcerting that many computer technicians never seemed to know which side of the power supply to connect their wrist ground strap to.  At least the old way, any old ground stud would do fine.  (Which wasn't necessarily a good thing).

Class II appliances?

I'm assuming that you are asking about the use of wrist ground straps.  I retired before that section of the IEC was established, but many of the devices that we required use of wrist ground straps involved open racks, open-face circuit boards and open face wiring, and thus would have not have been designed for any form of electrical shock protection.

Also, most of the power supplies were 120VAC ungrounded and either 12VDC ungrounded or 2VDC (or similar) ungrounded.  I had a section of railroad in Western Pennsylvania where even our 6600VAC transmission power line system was ungrounded.  But we did have a lot of microprocessor-based control equipment; telephonics equipment (some of which was electronic); power frequency/audio frequency/radio frequency communications either in analog or digital; voice radio interfaces; and data radio interfaces.  Many circuits were required by regulation to have ground fault detection. 

In the office setting, I also worked with mainframe computers and a variety of rack-mounted mini-computers (the newest of which still utilized tape drives and spin-pack drives (multiple hard platters), even though they also had newer hard drives.  I have previously told the story about the technician from Intergraph who blew out one of our hard drive controllers on a brand-spanking new VAX 11/785 system after I reminded him that he was not wearing his strap (it purported cost them over $500K to replace).

I was no longer in the hands-on world, but the driverless train industry had evolved to where the central control systems look more like a standard IT network server room, with whatever telecommunications equipment that goes along with the system mounted in separate racks.  I assume that today's world still resembles that model.

Anywhoosit, all of this stuff has separate grounding buss bars for each type of electronic function and those ground wires were direct wired to whichever device needed certain protection.  Much of the equipment was exposed to the elements and required lightning protection on circuits other than power feeds (and surprisingly, underground equipment in tunnels is sometimes more prone to lightning surges).

So, back to your original question.  Even if we had equipment that qualifies as Class II appliances under IEC 61140, we would still need to assume that there are electrical safety issues related to the way things are interfaced to the harsh elements that still require a bunch of "grounding" protocols when working in and around an electronic interface boards.

[kalvado]

And connecting things to neutral is a big no-no. Most outlets these days carry a third ground wire for that.

I agree.  However, I am unconvinced that most of the modern computer world understands the difference between "neutral", "house ground", "frame ground" and "earth ground". 

Back in my day, many of the personal computers simply had a two-wire power supply cable and everything had to use the neutral.  When the era of the three-wire Japanese Standard power plugs became commonplace, most power supplies didn't reconnect the neutral to the ground (from the third-wire) at either the transformer or the ring-diode rectifier (whichever came first in the power supply).  As a result, the third-wire ground became a parallel neutral.  Also, oftentimes the low-voltage DC signal would be connected to "house ground" and "frame" at the same location, thereby creating a bypass of the transformer and causing the frame to still be connected to "neutral".

I'm still a bit confused on how this works today, but from what I can tell many suppliers of laptop power supplies still do the same things.  At least most desktops try to avoid connecting the "frame" to the "house ground", but still provide a path for draining off high-voltage noise between the two with a capacitor. 

It was always somewhat disconcerting that many computer technicians never seemed to know which side of the power supply to connect their wrist ground strap to.  At least the old way, any old ground stud would do fine.  (Which wasn't necessarily a good thing).

Class II appliances?

I'm assuming that you are asking about the use of wrist ground straps.  I retired before that section of the IEC was established, but many of the devices that we required use of wrist ground straps involved open racks, open-face circuit boards and open face wiring, and thus would have not have been designed for any form of electrical shock protection.

Also, most of the power supplies were 120VAC ungrounded and either 12VDC ungrounded or 2VDC (or similar) ungrounded.  I had a section of railroad in Western Pennsylvania where even our 6600VAC transmission power line system was ungrounded.  But we did have a lot of microprocessor-based control equipment; telephonics equipment (some of which was electronic); power frequency/audio frequency/radio frequency communications either in analog or digital; voice radio interfaces; and data radio interfaces.  Many circuits were required by regulation to have ground fault detection. 

In the office setting, I also worked with mainframe computers and a variety of rack-mounted mini-computers (the newest of which still utilized tape drives and spin-pack drives (multiple hard platters), even though they also had newer hard drives.  I have previously told the story about the technician from Intergraph who blew out one of our hard drive controllers on a brand-spanking new VAX 11/785 system after I reminded him that he was not wearing his strap (it purported cost them over $500K to replace).

I was no longer in the hands-on world, but the driverless train industry had evolved to where the central control systems look more like a standard IT network server room, with whatever telecommunications equipment that goes along with the system mounted in separate racks.  I assume that today's world still resembles that model.

Anywhoosit, all of this stuff has separate grounding buss bars for each type of electronic function and those ground wires were direct wired to whichever device needed certain protection.  Much of the equipment was exposed to the elements and required lightning protection on circuits other than power feeds (and surprisingly, underground equipment in tunnels is sometimes more prone to lightning surges).

So, back to your original question.  Even if we had equipment that qualifies as Class II appliances under IEC 61140, we would still need to assume that there are electrical safety issues related to the way things are interfaced to the harsh elements that still require a bunch of "grounding" protocols when working in and around an electronic interface boards.

Wrist strap is a static protection, not power voltage protection.
In my world, galvanically isolated low voltage side doesn't need to be grounded, until it's a noise issue. IEC/UL is implemented in US  primarily as a money grab, safety being  very distant second.
 Safety ground is a joke in terms of noise anyway.

[Dirt Roads]

Wrist strap is a static protection, not power voltage protection.

I've told the story before, but a technician from Intergraph came to work on problems with one of our first generation 500mB hard drives for a Vax 11/785 (a new system that still had tape drives and spin packs).  I was subbing for the SysAdmin and reminded him that he didn't have his wrist strap on.  He blew me off, then proceeded to zap the hard drive controller.  I was told that the replacement controller cost Intergraph slightly over $500K.

In my world, galvanically isolated low voltage side doesn't need to be grounded, until it's a noise issue.

We are on the same page here, except that I've been rambling instead of complaining/ranting as I should.  But over the years, I kept finding that the suppliers of power supplies (in some cases, manufacturers) still tied the low voltage negative to both "house ground" and "frame ground", usually at different points.  This both introduced noise and eliminated one particular aspect of static protection.

We also had some locations where some outdoors controller racks that were supposed to be fully shielded (Faraday cage) were subject to complete electronic failure when the rack doors were open whenever our 600MHz radios were transmitting nearby.  There were also some "good" locations with the same equipment that maintained shielding with the rack doors open.  I might have been totally wrong, but I was convinced that the problem was with grounding on the electronics side of the power supply.  Since we could solve the problem by closing the doors (or remembering not to transmit when they were open), nobody was going to spend money fixing that.

IEC/UL is implemented in US  primarily as a money grab, safety being  very distant second.

We had a bunch of transit systems and airports that wanted UL certification (and we always accepted IEC equivalents).  But only in rare cases, did any supplier ever have to modify their devices in order to obtain certifications.  However, this requirement did give us a chance to identify "product modifications" that had not been divulged in the Design Review process.  There was very little design scrutiny for devices that had been used on another system that had more than a certain lifespan of safe and reliable operation.  But many component suppliers that were trying to upgrade their devices on large, well-funded projects with lengthy schedules would try not to get caught.

[kalvado]

IEC/UL is implemented in US  primarily as a money grab, safety being  very distant second.

Illegal under the code of federal regulations
We had a bunch of transit systems and airports that wanted UL certification (and we always accepted IEC equivalents).

[SSOWorld]

there are 10 types of people in this world


those that understand binary, those that don't

[kalvado]

there are 10 types of people in this world


those that understand binary, those that don't

Those who understand binary, those who don't, and those who prefer base 3

[Dirt Roads]

IEC/UL is implemented in US  primarily as a money grab, safety being  very distant second.

We had a bunch of transit systems and airports that wanted UL certification (and we always accepted IEC equivalents).

Illegal under the code of federal regulations

Explain, please. 

For context, my pat response would be related to Federal Transit Administration regulations (and other similar Federal regs) not applying to transit agencies that are not using Federal funding; same thing applies to most on-airport transit systems.  To be honest, I don't know why certain contracts had such requirements.  Since safety certification ended up being my area of expertise, I'm quite curious about how/when Federal Law banned agencies from making such requirements.

By the way, in most cases Underwriters Laboratories was unwilling to perform the certification testing needed for many of the devices that we were working with, probably because of liability issues related to [the fact that lots of people ride these trains].  There were plenty of other testing labs being used on these projects (including a fair number of European labs), albeit way more expensive than UL.  For the record, the safety certification process was more involved with testing of the software/hardware safety functionality and equipment certification was more of a check-box effort to make sure someone took responsibility for the minutiae inside those boxes.

[kalvado]

IEC/UL is implemented in US  primarily as a money grab, safety being  very distant second.

We had a bunch of transit systems and airports that wanted UL certification (and we always accepted IEC equivalents).

Illegal under the code of federal regulations

Explain, please. 

The following is my understanding of regulations. jackhammered into my head by the safety department. Not a legal advice or common sense issue.  Wording of those regulations have changed since last time i read it, but essence seem to be the same
Regulations cited are 29CFR1910.302 and 29CFR1910.303 (and a whole tree mentioned in .302).

§ 1910.303 General.

(a) Approval.  The conductors and equipment required or permitted by this subpart shall be acceptable only if approved, as defined in § 1910.399.

Interpretation: if it touches power grid and used within OSHA domain (workplace), it must be "acceptable" and "approved"

§ 1910.399 Definitions applicable to this subpart.
Acceptable.   An installation or equipment is acceptable to the Assistant Secretary of Labor, and approved within the meaning of this subpart S:

(1) If it is accepted, or certified, or listed, or labeled, or otherwise determined to be safe by a nationally recognized testing laboratory recognized pursuant to § 1910.7; or...

Interpretation: ...which means it must be listed in the database of a Nationally Recognized Testing Laboratory, NRTL.

While UL and IEC regulations are in process of harmonization, with many being the same letter by letter, CE mark (manufacturer's statement that the product is compliant to applicable standard) has no legal meaning in US. Compliance must be tested by NRTL for a modest fee.
It is not about safety, it is about legal compliance.

To make things worse... UL standards (and IEC standards, and some other - like CGA) are proprietary. They can be purchased, and not cheap. Catch is, purchased use is to a single person - if they leave the organization, things must be purchased again. Moreover, those with access are not allowed to share derived work. I.e. NRTL worker doing setup certification may not share the checklist they use in verifying equipment compliance.

Many people consider it essentially a private law imposed - with government help.

[Dirt Roads]

We had a bunch of transit systems and airports that wanted UL certification (and we always accepted IEC equivalents).

Interpretation: ...which means it must be listed in the database of a Nationally Recognized Testing Laboratory, NRTL.

While UL and IEC regulations are in process of harmonization, with many being the same letter by letter, CE mark (manufacturer's statement that the product is compliant to applicable standard) has no legal meaning in US. Compliance must be tested by NRTL for a modest fee.

Understood.  And I realize that I was using mixed metaphors in my original response (quoted above).  In reality, almost every electrical, electronic and electro-mechanical device that was installed fell under multiple U.S. standards, all of which included NFPA 70 (National Electric Code).  Because the IEC has an area of rail transit specialty, most of the devices fell under a single IEC standard (which referred to all of the other requirements inferred therein).  And we had a group of folks that specialized in discerning the differences between say an IEEE standard and its so-called equivalent IEC standard, so that we could hammer the testing laboratory if they missed the [proper] certification regulation.

I can't help but overemphasize, it was a tricky environment.  Railroading and rail transit, in general, was way behind the times with respect to technology.  It was hard for the suppliers to catch up on their own nickel, and we had tough rules about trying to catch up the technology on large, well-funded projects.  There were a lot of devices going through the testing laboratory for the first time.