Recent Posts

1

Programming / Re: Are data type compiler-dependent or target dependent

« Last post by DiTBho on Today at 10:58:16 am »

I know C well enough to see that it is impossible to make it "safe" like MISRA and the various aeronautical etc. rules try to; it is futile.

My point is that MISRA does it make it safer as consequence of making it easier to be automatically debugged.

Easier to be debugged => safer

DO178 is about life cycle, life cycle is also about debugging sessions and test cases, and debugging sessions are about AI-assisted debuggers; what I usually call "ICEs" are smart devices with a super fast optic link (48Mbps) and a strong MMA processors able to understand C at the language level, but you have to help them, that is the purpose of MISRA

myC is more AI-ICE friendly than common C

So, what do you want to achieve, how to verify it, help the ICE AI to help you

Does not sound so terrible ... It is not "dark side", but rather simply collaboration between humans and AI

2

Test Equipment / Re: Test Equipment Anonymous (TEA) group therapy thread

« Last post by Zenith on Today at 10:58:08 am »

I was an "Oxy-moron" for some years after buying my first oxy-acetylene set, finding uses for it everywhere.
Unfortunately, someone stole it some years later, & I was oxy-less for a couple of years, till I bought another.

I, again, found a lot of uses for it for a while, then the jobs dried up, almost coincident with available money for BO's exorbitant bottle rental!
I took the last bottles back & cancelled the agreement, packed the torch, regulators, & hoses up & put them in the shed.

Several times It would have come in handy after that, but my eyesight had deteriorated, so I left it there.
Since I had my cataract operation, I would be more certain of not pointing the torch at my hand instead of the work, & Bunnings will sell you bottles & refill them as required, so I'm getting those "Oxy-moron" urges again.

I keep seeing jobs which would be easy with the oxy set, but difficult without it, like making up brackets of various kinds which can be very handy, if a little unsightly, in my Lab, or making ham radio VHF antennas with copper water pipe.

I suppose the hoses are buggered by now, though---and I will have to buy Flashback Arrestors, which aren't cheap.
Back in the day, when men were men & sheep were frightened, we "didn't need no steenkin Flashback Arrestors"!

It was possible for a blowback to get into the acetylene bottle and the gas would start to decompose and eventually there'd be an explosion. I don't believe it happened often. Acetylene, with its triple bond, is only just on the edge of being stable under normal conditions.

OA is versatile but is a PITA unless you have a regular use for it. This is especially so with major company bottle rental charges. I think that just how casual the scene is regarding acetylene use depends where you are in the world. There are modern alternatives such as propylene which are supposed to be pretty good. I'm sure you can use oxy-propane for brazing, cutting, and silver soldering.

I'm strictly MIG and stick. With MIG you can get away with pub (food grade) CO2 bottles for steel.

To keep the post on topic, I acquired both my stick inverters not working. One had a burned out thermistor in the precharge circuit. The other had a dry joint to a small transformer used to give feedback to the control circuitry. A circuit diagram for these inverters was hard to find, but a Russian had reverse engineered them and published the cct diagrams on the WWW.

3

Computers / Re: Windows VMs under Linux with Native Performance

« Last post by JohanH on Today at 10:57:45 am »

In my own experience very special cases need constant kernel compiling. E.g. I had a dual Athlon workstation a long time ago. This was a buggy platform and needed some special treatment. At least I remember at that time patching and compiling kernels.

Then when digital TV became popular. Constant recompiling of the DVB loopback interface that was never accepted into the kernel (even if it by itself wasn't illegal, was clearly used for dubious purposes in user space such as TV decryption). But nowadays when there are streaming services, who bothers with this any more.

4

Manufacturing & Assembly / Re: Component distributors taking ESD precautions?

« Last post by SMTech on Today at 10:57:32 am »

It's not uncommon to see ESD areas equipped with a turnstile linked to an ESD test station, no footstrap that functions, no entry. I would suspect Farnell etc operate at this level, in addition to having all other sensible precautions and treatments. The number of faulty semiconductors we see is really really tiny, almost every fault we encounter is a manufacturing defect or ham fisted use of a test probe etc. In fact the only notable instances of dodgy semi's we've ever seen have come during periods of shortage like this from parts sourced outside of distribution. In those cases we've  had regulators that don't all function (looked like they had been very well "reconditioned"), MCU's that are missing their ICP bootloader and really really old stock that needed a serious baking to avoid popcorning. I don't think we've seen any indication of poor ESD handling practices, however RS and Farnell are both terrible for grabbing QFPs with tweezers despite then packing them with labels telling you to only handle with a pickup tool, this has resulted in £60 FPGAs that are unusable, a different failing but one you can at least see before soldering.

Never seen a factory quite so scruffy as to have actual rubbish shoved under benches

5

Microcontrollers / Re: Any micros with ETH and hardware incoming packet filtering by IP?

« Last post by 2N3055 on Today at 10:54:14 am »

So much wrong information here..

IP layer is layer 3. It lives in application processor, and Ethernet controller is completely oblivious of it by design...
TCP/IP stack is software stack. Period. OSI layers and such nonsense..

TCP/IP was conceived to run on UNIX workstation... IOT was not it's design target, and it shows..

Broadcasts are nominal part of how network works,  ARP broadcasts for instance..
As said, good switch's job is to pass only packets for your MAC, which include all broadcasts.

Any cleanup of traffic needs to happen inside network equipment.

DOS will kill all equipment. Network equipment can (should) have built in tools to fight that..

Once network is complicated (or screwed up) enough you need to hire network expert to sort it out for you.. Networking is complicated and hard enough, and it is a full time job, on anything more than dozen of hosts on a home router....

6

General Technical Chat / Reliability of accelerometers.

« Last post by Psi on Today at 10:53:43 am »

I've been using an old NXP/Freescale MMA7660 accelerometer in a product for many many years and never had any problems with it.  But the chip has been out of production for a while now and I've been running through my old stock which is now gone.

It has come time to replace the accelerometer in the product with something new and I'm unsure how reliable the modern brands are.  For this application I do need one that isn't going to lock-up randomly.
Some drift/error is ok, but not a lockup.

Anyone have any recommendations for good brands, or brands to stay away from?

I see there are lots of MEMSIC accelerometers available, but I've never heard of that brand until now.
And some ST ones are available too, but stock is limited.

7

General Technical Chat / Re: Proof that software as service/cloud based, will never work for long term ...

« Last post by Karel on Today at 10:52:58 am »

On October 13, 2022 we're removing the option to transfer playlists to your Fitbit watch through your computer. ...

https://help.fitbit.com/articles/en_US/Help_article/2251.htm

8

Dodgy Technology / Re: Spinlaunch... Can it succeed?

« Last post by wraper on Today at 10:52:49 am »

Can be just youtube doing their usual - placing normal comments into spam.

9

Metrology / Re: 3458A / SN18 in a non-temperature controlled environment

« Last post by srb1954 on Today at 10:51:47 am »

I have just been evaluating my 3458A (2005 build) after having a new A3 board fitted.

The drift appears to be dominated by temperature effects. After compensating for the effects of temperature I get:

CAL72 drift:   -0.006ppm/day
                    +0.45ppm/K

This is after after only 3 days monitoring with the new A3 board so it may still be too early to determine the true time-related drift. With the old A3 board it was very easy to pick out the time-related drift as it drifted a total of 50ppm over a 31 day test period! 
At times the drift was up to 0.55ppm/hour!                                 

10

Dodgy Technology / Re: Spinlaunch... Can it succeed?

« Last post by EEVblog on Today at 10:50:10 am »

I don't think my comment is showing up. Does he have comment approvals turned on?
I listed by newest comments first and my comment was 6 hours ago, and it didn't show up in all the comment from the last 10 hours.