Testers Needed for New RTAI Packages

BeagleBrainz wrote:

Not the 7i76 but the 7i76e

so as far as i could tell without cracking open the manual and just reading the descriptions, aside from the price and the number of i/o, it seems that the 7i76 and 76e pretty much similar, right? the 7i76 sounds like it should suffice for my machines and still give a little padding for expansion. you are right tho, the 76e looks like its overkill that can be expanded to serious overkill

The 7i76e is kind of a combo card. It is pretty much a 7i80 Ethernet FPGA card with a 7i76 built in, and would be all you would need.

But I'm not sure I'd go so far as to say it's simple. You have to use the right kernel with the right version of Linuxcnc, and correctly configure the Ethernet to work with it. (There seems to be a lot of traffic here on the forum from people asking questions after stumbling on those 3 things.)

Plus if you want to have ordinary network connectivity you have to arrange for that separate from the Ethernet port you are using to connect to the Mesa card. Which means having some other additional form of Ethernet or wifi dongle.

Well if a dumb*** labourer who left highschool after 3 years, such as moi, can do a basic setup, it falls into the realm of simple.

From what I've seen there's the "Linux is hard" attitude, not fully reading the instructions and not taking time to search the forums, most of the troubles that people have, usually, have been sorted in other threads. Occasionally there's there's the oddball hardware that can throw a spanner in the works, that is somewhat harder to sort out. Of yeah sometimes you just plain old eff up.
And debian can be a bit of pain with hardware, especially those that need a "non-free" driver or blob to work.

Oh, using bootlace ferrules makes wiring a lot easier, especially for moving wires from one connector to another.

The initial outlay for Mesa hardware looks pricey, but in the long run I think it's a wise choice.

Todd wrote:

The 7i76e is kind of a combo card. It is pretty much a 7i80 Ethernet FPGA card with a 7i76 built in, and would be all you would need.

thats the best news i've heard all day

Todd wrote:

But I'm not sure I'd go so far as to say it's simple. You have to use the right kernel with the right version of Linuxcnc, and correctly configure the Ethernet to work with it. (There seems to be a lot of traffic here on the forum from people asking questions after stumbling on those 3 things.

that sounds like pretty much the definition of linuxcnc really. from what little i have read this afternoon, it looks like the default stretch image with rt_preempt, and 2.8 should work, right? and networking, well now we have crossed into the borderlands of my territory... as long as it doesnt conflict with wifi, i am all good, and even if, there is always sneakernet.

BeagleBrainz wrote:

Well if a dumb*** labourer who left highschool after 3 years, such as moi, can do a basic setup, it falls into the realm of simple.

who just happens to neglect that they release linux respins in their spare time...

BeagleBrainz wrote:

Oh, using bootlace ferrules makes wiring a lot easier, especially for moving wires from one connector to another.

i always tin my tips because for some reason i can never seem to keep them on

BeagleBrainz wrote:

The initial outlay for Mesa hardware looks pricey, but in the long run I think it's a wise choice.

considering that i have easily spent DOUBLE than that on parallel cards and intermediate hardware not to mention the hours of headbanging (frustration, not slayer) and the many facepalms. one of my machines didnt move for a solid month trying to figure this out. had i only known about this. from the posts i have seen, as todd said, lots of people show up after trying mesa hardware. just the mention of it made me tremble in fear as if somebody said "we are the knights who say: MESA!"

the sweet thing is that now i can use those intel boxes. they are DH61DL i3 and come in this micro aluminum case with mounting flanges that i can screw under my table! hell i've had sandwiches bigger than this computer... yea free space! soon as i come up with the cheddar JT is getting a new customer!

A mention of Slayer & Monty Python in the one post, you're alright

Even the Mint RT_PREEMPT will work as well.

Actually a proper crimp is better than soldering, I know it sounds wrong, but when wires are crimped properly Good Things happen. It's similar to a wire wrap connection done properly an airtight seal is formed and a "cold weld" is formed. With soldering, solder can wick up the wire and case the wire to become stiff where you don't want that stiffness, creating a point of fatigue. I always thought soldering was better than crimping until I started to look into it. Probably not a big issue on a homebrew setup, but interesting.
Geesh the The Apollo Guidance Computer was wire wrapped, I know things have moved on, but if it was good enough for that.......unless of course you're a flat earther and deny space exists and the whole moon thing never happened. But I have it on good authority the Kubrick was such a perfectionist he demanded the whole fake moon landings were filmed on the moon.

The dumb ass bit was being talked out pursuing an IT career in the late 80's when I was at high school. A family friend who worked in the industry pronounced "there is no future in computers". Tho on looking back I don't play well with others in confined spaces, specially if those confined spaces are the same ones day after day year after year.

BeagleBrainz wrote:

A mention of Slayer & Monty Python in the one post, you're alright

this is so getting framed and hung over my wife's side of the bed as a constant reminder that no matter what she says, there are people who appreciate the finer things in life...

BeagleBrainz wrote:

With soldering, solder can wick up the wire and case the wire to become stiff where you don't want that stiffness, creating a point of fatigue.

that is exactly what what used to happen to me, they would always break right at the edge of the soldier joint and insulation, so that is why i have taken to just tinning about the first 1-2mm of any screw terminal wiring, just to keep the unruly bebes in line. otherwise you have about as much luck getting all the wires in the same hole as getting a shopping cart at walmart who's wheels all go the same direction.

trust me, IT was not all it was cracked up to be. i stepped out of industry about 12 years ago because i got tired of competing with 20 something manbuns because i too dont play well with others. i am much happier now (outside of my job because it sucks) working on these things on my off time. i just wish that i would have done a traditional minor such as EE or ME. at heart i truly am an engineer.

you had mentioned earlier that you might need to separate the cores in pairs on a 4 core processor. how do i know which ones to isolate? for some reason, on a 4 core i5, i am getting terrible numbers with rtai kernel and my histogram looks more like a SETI signal than a real histogram and im running around 12k latency when i was doing about 6k with rt.

tommylight wrote:

Dang, to late to the party, i was busy waiting for 20.03.2020 with $60 on the card! What the flying circussss ????

story of my life!! i think having to pay extra on amazon for britbox to watch decent tv is the brits revenge for that whole revolution thing. that silly walk will now cost you an extra 10 a month, take that yanks!

tommylight wrote:

Not sure but, cores 0 and 1 should be in the same /substrate/chiplet/die/whatever_they_are_callining_it_these_days/ and 1 and 2 on the other, or share the same L1 cache, or something something.

so far it seems that isolcpus=2,3 and isolcpus=0,1,2 seem to be getting the best results, tho im not exactly sure why.

It’s the way the cores are arranged on the die, what cores share what resources. A bit of googling will reveal what pairs best with best. I think sometimes it not quite intuitive.
And something about a sparrow and a coconut.