Tuesday May 9th, 2023 NCLUG Meeting

Bob Proulx bob at proulx.com
Wed May 10 01:41:28 UTC 2023

j dewitt wrote:
> What: Tuesday May 9th, 2023 NCLUG Meeting

We had several new faces in the group tonight.  AWESOME!  If you have
been contemplating meeting up then there is no time like the present.
Come on down!

Stephen started things off with an interesting tidbit about DHCP.

    watch ip addr show dev wlan0

    2: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UP group default qlen 1
        link/ether 20:1e:88:78:61:94 brd ff:ff:ff:ff:ff:ff
        inet brd scope global dynamic wlan0
           valid_lft 6387sec preferred_lft 6387sec
        inet6 fe80::221e:88ff:fe78:6194/64 scope link
           valid_lft forever preferred_lft forever

With the interesting bit being the valid_lft valid time left for the
DHCP leas.

           valid_lft 6387sec

That does seem to be new in my recollection.  This feature apparently
originated with Red Hat but then by popular demand was pulled into
other distros subsequently.  (The RFC this is defined in is for IPv6
not IPv4 but hey why not?  Extra can be okay.  I would rely upon it
for IPv6 and be cautious about IPv4. --rwp)

Stephen's second item was an X Window debugging tool "xtrace" to
display the communication between X clients and the X server.
Effectively xtrace is a proxy server which sits in the middle printing
out what the X client is doing as it talks to the actual X server.

The reason for this need was because Stephen was experiencing a
slowdown for some reason.  A particular VMWare client application was
tremendously slow.  Not every program.  Just that one program.  Every
time focus shifted the system was going out and probing everything to
determine the number of displays, the size, the display depth, and all
of the rest of the things that are important at start.  But probably
not each and every time focus changes.

To hack around this slowdown problem Stephen grabbed the source code
and hacked in a filter for these particular messages.  Filtered out
the slow egregious and slow commands.  GetScreenResources.  And
immediately the speed was much faster.  Problem worked around.  Maybe
the offending program can be fixed but that's a vmware program.

Alex and Sy then took the floor to talk about their Firefox
adventures.  It turns out that compiling Firefox from source takes a
while.  It takes a while on a fairly high performance machine.  This
adventure was because Firefox is the new OS and there are some
customizations which are possible by modifying the source but not
(yet) exposed to the user.  (Personally I would like to see my
keybindings uniformly applied.  I hate it when I have a textarea being
edited and I forget and hit Control-N a couple of times and it opens
up several new window frames.  Drat!  --rwp)

This was a fun discussion of several interesting points of the
internal data flow through Firefox.  Makes me want to get my source
compile going again.  I just haven't been playing with the source
enough lately.  Because that is where things can be truly customized.
Check out the 2023-04-05 blog posting for it!  Cool stuff!


Bob then gave an update on his NAS disk array recovery.  The TL:DR; of
it is that never give up if you think the data is still there.  The
problem looked like too many disk failures but the problem was my disk
controller which seems to have flaked out.  In the end figuring out
that it was the disk controller and replacing it allowed 100% of the
array to be recovered.  Whew!

Sy is doing some personal book archiving using a camera and software
to do OCR to convert the photo over to plain text.  Says that the
conversion is in the high 90's % of accuracy.  Which though not
perfect is quite good.


It was fun!  Come and show off your project next tim!  See ya!

More information about the NCLUG mailing list