D2wn at 21:19, 10 October 2025

2025-10-10T21:19:12Z

D2wn: initial commit

2025-10-10T00:30:20Z

initial commit

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# We have two presentations today!
# First, a Computer Rescue Idea by [https://www.mtu.edu/humanities/department/faculty-staff/faculty/keirnan/ Professor Kiernan]!
## Who is Professor Kiernan?
### Worked at Ford
### Designed features for vehicles
### How users would interact with them
### Used Linux since 2007
#### Linux Mint really impressed him
#### But driver support was really bad
### Saw the potential
#### Kept checking in on the state of Linux back every year
#### Eventually things got really good
### Teaches some humanities courses at Tech
### Been speaking at MTU since 2002
## Hobby is giving friends' older computers a new life with Linux Mint/ZorinOS
### They don't know how to flash installer images onto a USB drive, but he can do that part
### Then, using the computer is simple enough and they can handle the rest
## Has an older MacBook Air with ZorinOS on it
## Prescient book from 1960
### Ahead of its time, predicted a lot
### coined "Planned Obsolescence"
## Apple devices getting worse and worse nowadays
### absurdly thin
### non-repairable
## Throw sand in their gears!
### 'Computer rescue' akin to a 'pet rescue'
### Save old machines from recycling and landfills
## B.A.S.I.C. group
### Run by Professors Steelman (Human Factors) and Wallace
### Seems to have been disrupted by the pandemic
## So many Windows 7/10 machines around that can't easily upgrade to Windows 11
## Plenty of Intel Mac's still around, can't run more recent versions of macOS
## Talk about how we might rescue Copper Country computers with Linux
## Help out a region he loves to keep computers out of the trash
# For our second presentation, Pipes by Ron!
## How water gets around your house
### and Super Mario
## But seriously, pipes are used to send the output of one program to the input of another program
### Allow two processes to communicate with each other
### <code>prog1 | prog2</code>
## Can pipe <code>cat</code> to <code>grep</code> (though you shouldn't do that), etc
## Subtleties
### Programs run in a pipe are run concurrently
### Demonstrated by running <code>yes | less</code>
### Can see that <code>less</code> receives input while <code>yes</code> is still running
### <code>ps</code> shows yes and less are still both running
## Programs are unaware of the pipe
### Means we can just use our normal I/O functions without any special considerations
### <code>grep</code> just takes from stdin
#### If you run <code>grep</code> without providing a filename, you can just type into it to have strings recognized
#### <code>grep</code> doesn't ''know'' we're typing its input, it just received it through stdin
#### The developers didn't have to do anything special to enable this to happen
## Pipe()
### Pipe just takes in an array of integers
### Populated the array with two file description
#### <code>fd[0]</code> (read)
#### <code>fd[1]</code> (write)
### This works because pipes are always unidirectional
### Ties into UNIX "everything is a file"
#### Pipes are just two file descriptors
#### Interact with them as normal files
## Using pipes between processes
### Fork the child process
### Will block reading from the pipe until it is ready
## Making this work with stdin/out
### <code>dup2()</code> allows duplicating file descriptors
### Have one file description (<code>oldfd</code>) pretend to be another file descriptor (<code>newfd</code>)
### Program that thinks it is writing to stdout is actually writing to the 'inside' of the pipe for another program to receive
## Adding in <code>exec()</code>
### Lets us wipe and replace the child's process in memory with a new process
### Forked copy gets copy of all file descriptors
## Example with a program that runs <code>ls -al</code> but modifies the output before printing to stdout
### <code>exec()</code> needs an array with each element being an argument of the command you want to run
### last element needs to be <code>NULL</code>
### <code>execvp()</code> = uses path, that's what the 'p' is for
## <code>pipe()</code>-<code>form()</code>-<code>dup()</code>-<code>exec()</code> pattern is so common there's a C library to do it more easily
### <code>popen()</code>
## Takes either "r" or "w" to define which end of the pipe it is supposed to be.
## Named pipes
### Literally files
### <code>mkfifo</code>
### creates a file in <code>/tmp/</code>
### Multiple processes can interact with it because it's just a file
## Questions
### How does <code>popen()</code> handle the input command?
#### Ron checked the manpage
#### Apparently just passes it to: <code>/bin/sh -c <arg></code>
### What <code>popen()</code> ('r' or 'w') do you start first?
#### Left side (input) of pipe is the "write" side, and is what you create first
#### Right side (output) is the "read" side, and is created second
### Freya got clickbaited, still doesn't know how to fix her sink
### A lot of things in Linux/UNIX 'pretend' to be files
#### Plant can turn off her GPU by <code>echo 0 > /proc/<some_thing></code>
#### KVM pretends to be a file you interact with through <code>ioctl</code>'s
### Windows named pipes are in <code>\\?<thing></code>
#### Related to how NFS is <code>\\<share_name></code>
# Chris swung by just to shill XCP-NG
## Proxmox has its... 'issues'
## LUG Proxmox incident earlier today
## Went down in #general in the LUG discord
## Three "Proxmox moments" in a row
### Random disk I/O lockup on node, VMs froze on all r/w operations
### Rebooting that node made the cluster lose quorum since two nodes were already offline
#### All nodes webUI unavailable
#### After a while, quorum was finally restored
## Wiki VM got migrated to a node that didn't have its VM storage image, then failed to start
### Required manual intervention
## Then finally after all that ''cluster''fuck everything is back online
# October 8th, 2025 6:55PM: The LUG AI incident
## Anti-AI versus Pro-AI forces in the LUG discord
## Sarten X misquoted something, came off as calling someone "princess"
### It all went downhill from there
## Simone submitting an essay on favorite digital space
### Chose LUG Discord
### Said "ultimately a place where people can put aside their differences"
### Then the AI incident happened
### Needs to append essay with "except in matters of Artificial Intelligence"

[[Category:Meeting Minutes]]

← Older revision		Revision as of 21:19, 10 October 2025
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	### <code>grep</code> just takes from stdin		### <code>grep</code> just takes from stdin
	#### If you run <code>grep</code> without providing a filename, you can just type into it to have strings recognized		#### If you run <code>grep</code> without providing a filename, you can just type into it to have strings recognized
	#### <code>grep</code> doesn't ''know'' we're typing its input, it just ~~received~~ it through stdin		#### <code>grep</code> doesn't ''know'' we're typing its input, it just receives it through stdin
	#### The developers didn't have to do anything special to enable this to happen		#### The developers didn't have to do anything special to enable this to happen
	## ~~Pipe~~()		## <code>pipe()</code>
	### Pipe just takes in an array of integers		### Pipe just takes in an array of integers
	### Populated the array with two file description		### Populated the array with two file description
Line 83:		Line 83:
	### Multiple processes can interact with it because it's just a file		### Multiple processes can interact with it because it's just a file
	## Questions		## Questions
	### How does <code>popen()</code> handle the ~~input~~ command?		### How does <code>popen()</code> handle the inputted command?
	#### Ron checked the manpage		#### Ron checked the manpage
	#### Apparently just passes it to: <code>/bin/sh -c <arg></code>		#### Apparently just passes it to: <code>/bin/sh -c <arg></code>

Minutes 2025-10-09 - Revision history

D2wn at 21:19, 10 October 2025

D2wn: initial commit