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by ejolson
Tue Oct 22, 2019 4:53 pm
Forum: Advanced users
Topic: RP4 Cluster Hardware?
Replies: 11
Views: 313

Re: RP4 Cluster Hardware?

Ya the network boot is quite intriguing and I would have to assess how to net boot for more than 255 items (subnet). Not too clear on that one. I've seen 3U or 4U banks of multiple Zeros that way. Are the purchase limits on the Zero still applicable? How has that restriction changed? I know their p...
by ejolson
Tue Oct 22, 2019 4:16 pm
Forum: General discussion
Topic: Raspberry Pi Cluster Computer?
Replies: 35
Views: 1053

Re: Raspberry Pi Cluster Computer?

What architecture could be designed so just buying another "module" and plugging it in increases the processing power? Composability of compute hardware to expand capability by plugging another module here or a different module there is what OpenCAPI is about. https://www.nextplatform.com/2019/08/0...
by ejolson
Tue Oct 22, 2019 5:12 am
Forum: Networking and servers
Topic: Suggested USB3 to SATA adaptors (without power!) - what works well for you?
Replies: 3
Views: 151

Re: Suggested USB3 to SATA adaptors (without power!) - what works well for you?

2.5" HDD enclosures aren't really a solution as they rely on the USB for power. I want to provide my own power to the drive, and have a separate SATA to USB link to the pi. Finding an adapter with a separate power supply is going to be the difficulty and unfortunately I have no recommendation. I su...
by ejolson
Mon Oct 21, 2019 4:51 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1207
Views: 59151

Re: Liberation through Computer Literacy

Presently I'm using spaghetti to measure the stochastic parameterisation of turbulence models What is the accuracy of a piece of spaghetti as a measuring tool? Not very good, though with many pieces the accuracy improves as does ones knowledge about the inaccuracy. I much prefer raspberry pie becau...
by ejolson
Mon Oct 21, 2019 4:39 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1207
Views: 59151

Re: Liberation through Computer Literacy

What happened to E ? - E for Experimental. The algorithm I ant to experiment with is really short and sweet. I was reserving grade E for the programs I write, but experimental works just as well. Presently I'm using spaghetti to measure the stochastic parameterisation of turbulence models. I'll thi...
by ejolson
Mon Oct 21, 2019 3:53 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1207
Views: 59151

Re: Liberation through Computer Literacy

The question then is how to compare such fuzzy results? How about F for a program that produces wrong answers D for one which fails to compile C for one that segfaults B for one that is slow A for one which is liberating Here liberating means the programming language allowed the programmer to expre...
by ejolson
Mon Oct 21, 2019 2:56 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1207
Views: 59151

Re: Liberation through Computer Literacy

What do you mean C++ is written in C? These days the Linux kernel is written in C and C is written in the C++ programming language. Maybe someday C++ will be written in Python or maybe Basic. The reason the previous challenges measured the wall time elapsed from the command used to start the progra...
by ejolson
Mon Oct 21, 2019 2:20 am
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1207
Views: 59151

Re: Liberation through Computer Literacy

John_Spikowski, I would like to see challenges that result in some useful code. Absurd is getting old. Well... there is one little problem I have been meaning to toy with for a long time. Which does have real world applicability. It's the problem of rapidly finding all the objects in a two dimensio...
by ejolson
Sun Oct 20, 2019 11:05 pm
Forum: General discussion
Topic: Raspi 4 file server disappointing transfer speed, degradation and segfaults
Replies: 51
Views: 1672

Re: Raspi 4 file server disappointing transfer speed, degradation and segfaults

Issues like this are commonly OS internal and shouldn't be blamed on hardware. Crashes are also common because of broken hardware. It is difficult to know what is going on unless someone tries and is either able or unable to reproduce the reported degradation and crashes. As far as commercial Linux...
by ejolson
Sun Oct 20, 2019 4:28 pm
Forum: General discussion
Topic: Raspi 4 file server disappointing transfer speed, degradation and segfaults
Replies: 51
Views: 1672

Re: Raspi 4 file server disappointing transfer speed, degradation and segfaults

The original post used XFS. Subsequently the problem was reproduced using EXT4. Those in the know, not me, claim BTRFS is a joke and full of problems. They go for ZFS. Those who claim they are in the know are likely interested in building petabyte storage appliances using RAIDz and a terabyte of EC...
by ejolson
Sun Oct 20, 2019 2:49 pm
Forum: General discussion
Topic: Raspi 4 file server disappointing transfer speed, degradation and segfaults
Replies: 51
Views: 1672

Re: Raspi 4 file server disappointing transfer speed, degradation and segfaults

It does look like there is a bug somewhere, but I don't think its in Raspberry Pi specific code, my suspicion is a code path in the crypto stuff that is only exercised on 32 bit systems, perhaps in a Raspberry Pi specific usecase. As for the performance issues, I think that's likely to be the lack ...
by ejolson
Sun Oct 20, 2019 12:01 am
Forum: Off topic discussion
Topic: Auto locking threads
Replies: 26
Views: 689

Re: Auto locking threads

Is that the same as: https://www.phpbb.com/customise/db/extension/auto_lock_topics/ which Google found with a simple search? Similar - the mod is a very good tool and will certainly handle the lock basics - no idea if it runs on this version of the code. One of the attractions for me of this partic...
by ejolson
Sat Oct 19, 2019 5:03 pm
Forum: Beginners
Topic: Why buy 32GB or less MicroSD card when 64GB is a few dollars more?
Replies: 18
Views: 510

Re: Why buy 32GB or less MicroSD card when 64GB is a few dollars more?

There are still many devices in use that will not work with cards larger than 32 Gbyte so saying that a 64 Gbyte or larger card that were no longer wanted for a RPI could be repurposed is not the whole story. My understanding is that all models of Pi will read and write 32GB cards. I've certainly n...
by ejolson
Sat Oct 19, 2019 4:47 pm
Forum: Networking and servers
Topic: Pi-hole & OMV - Enclosure options for HDDs and the feasibility using two USB hubs to connect 4-8 HDDS
Replies: 21
Views: 1151

Re: Pi-hole & OMV - Enclosure options for HDDs and the feasibility using two USB hubs to connect 4-8 HDDS

I do suggest you cover the unused GPIO pins, like in the pic below to prevent those accidental shorts to the GPIO pins... fan power is always taken directly from power-in port (not from GPIO header) Where did you get the GPIO pin cover? Can I punch a hole for the fan power? How do you power fan via...
by ejolson
Sat Oct 19, 2019 3:27 pm
Forum: General discussion
Topic: Raspi 4 file server disappointing transfer speed, degradation and segfaults
Replies: 51
Views: 1672

Re: Raspi 4 file server disappointing transfer speed, degradation and segfaults

Well without any crypto just on basic EXT4 filesystem I get: rx: 381.76 Mbit/s 36883 p/s tx: 16.73 Mbit/s 12450 p/s^C According to IOTOP a stable 30MB/s+ write on the disk which is blazingly fast without any crashes in the dmesg. Although I would note for this speed I have to use FTP, even SSH/rsyn...
by ejolson
Sat Oct 19, 2019 12:28 pm
Forum: General discussion
Topic: Raspi 4 file server disappointing transfer speed, degradation and segfaults
Replies: 51
Views: 1672

Re: Raspi 4 file server disappointing transfer speed, degradation and segfaults

It's not clear to me what that Adiantum thing actually is. Adiantum seems to be a type of fern that does the cha cha cha with your hard disk. Note the same dance-themed cypher is behind WireGuard as well. It is good to have ruled out XFS. That filesystem is currently on my list to try in a new serv...
by ejolson
Sat Oct 19, 2019 2:55 am
Forum: General discussion
Topic: Raspberry Pi Cluster Computer?
Replies: 35
Views: 1053

Re: Raspberry Pi Cluster Computer?

if you are not familiar with Intel Xeon computers here is a picture of a Intel Xeon 771 socket motherboard It looks like your motherboard got caught in a time warp from 2004. While it's amazing such hardware is available new for sale, current server hardware has undergone as much technical innovati...
by ejolson
Fri Oct 18, 2019 5:04 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1207
Views: 59151

Re: Liberation through Computer Literacy

Infinite, 4GB, meh close enough :) Who was it that once said no one would ever need more than 64K? My understanding is that computer programmers don't need memory any more than a drug addict needs drugs. Providing more in either case only makes the existing problems worse. For example, implementing...
by ejolson
Fri Oct 18, 2019 3:47 pm
Forum: General discussion
Topic: Raspberry Pi Cluster Computer?
Replies: 35
Views: 1053

Re: Raspberry Pi Cluster Computer?

Actually - I was considering having two Pis (due to memory constraints of one): one connected to monitor and keyboard running X windows and another on network using first as X terminal. Also, first (with SSD) would share disk over nfs (at least /home if not more!). That way I would be able to decid...
by ejolson
Fri Oct 18, 2019 9:26 am
Forum: General discussion
Topic: Raspberry Pi Cluster Computer?
Replies: 35
Views: 1053

Re: Raspberry Pi Cluster Computer?

The idea comes as naturally as the thought that welding two Mini vans together will make them faster. Which is equally naturally dismissed after one second. It's not clear to me how the idea ever makes it as far as this forum. It didn't take long to find https://cdn.comsol.com/wordpress/2014/04/Beo...
by ejolson
Fri Oct 18, 2019 2:57 am
Forum: General discussion
Topic: Raspberry Pi Cluster Computer?
Replies: 35
Views: 1053

Re: Raspberry Pi Cluster Computer?

Here is a picture of a computer using several video cards: https://www.rockpapershotgun.com/2015/02/26/sli-good-or-bad/ https://www.rockpapershotgun.com/images/15/feb/multigpu1.jpg It's odd that the picture depicts a GPU cryptocurrency mining rig and then the article is about video games. As you ha...
by ejolson
Thu Oct 17, 2019 6:53 pm
Forum: General discussion
Topic: Raspberry Pi Cluster Computer?
Replies: 35
Views: 1053

Re: Raspberry Pi Cluster Computer?

If you want to build a ARM powered cluster super computer this is how you do it: https://content.presspage.com/uploads/1369/1920_spinnaker1million-188542.jpeg I like how the air-conditioning ductwork is positioned at slightly different angles at the top of each cabinet and looks like giant springs....
by ejolson
Thu Oct 17, 2019 4:35 pm
Forum: General discussion
Topic: SD Card power failure resilience ideas
Replies: 31
Views: 1282

Re: SD Card power failure resilience ideas

ejolson, What?! You mean all this time I have brought up in discussions here over the years and there was actually a bug identified and fixed. Nobody ever mentioned it. Ah well, never mind, fixed and done now. The story, to my recollection, is that another group working on some sort of embedded dev...
by ejolson
Thu Oct 17, 2019 3:32 pm
Forum: General discussion
Topic: SD Card power failure resilience ideas
Replies: 31
Views: 1282

Re: SD Card power failure resilience ideas

Yes, I strongly suspect there were issues in software/hardware that caused a lot of failures in the early days. I don't think they were ever pinned down and when people came here with stories of failure the discussion always took off on the lines of bad power supplies, fake SD cards, file system co...
by ejolson
Thu Oct 17, 2019 3:24 pm
Forum: Networking and servers
Topic: Pi-hole & OMV - Enclosure options for HDDs and the feasibility using two USB hubs to connect 4-8 HDDS
Replies: 21
Views: 1151

Re: Pi-hole & OMV - Enclosure options for HDDs and the feasibility using two USB hubs to connect 4-8 HDDS

I'm thinking of using rsync instead of RAID now. Any reason why only once a week instead of daily? I think that's his preference you can do it daily or every 12hours, or every 4hours or whatever timing you think suits your requirements... you have full control over what you want do.... ....so you h...

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