Trans: Latin prefix implying "across" or "Beyond", often used in gender nonconforming situations – Scend: Archaic word describing a strong "surge" or "wave", originating with 15th century english sailors – Survival: 15th century english compound word describing an existence only worth transcending.

Category: Uncategorized (Page 2 of 2)

Mac OSX: Fixing GPT and PMBR Tables

My computer recently crashed very, very hard, while I was removing an small empty alternative OS partition I no longer needed.  This is a fairly mundane operation that I do now and again, and is a ongoing fight to keep at least a few gigs of space free for actual work on precious 250gb Mac SSD.  

The crash results?  Toasted GPT tables all around.   My 2015 computer’s next move was to reboot- only to find essentially no partitions of memory… at all.  What it did show was (wait for it) Clover bootloader of all things, with a single windows boot camp icon (nothing in there either).  That is so wrong…. On all levels!

I brought the machine to the local university repair.  They declared this machine bricked and offered to wipe it.  Back to me it came…

I scheduled an Apple support session with a phone rep, which after around 45 minutes of actually productive troubleshooting ideas (none helping though) was forwarded to a senior supervisor.  She was interested in this problem, and we scheduled a larger block of time. But, in the meantime, I still wanted to try again….

How to recover a garbled GPT table for Mac OSX:

Start with clean SMC and PRAM / NVRAM.

Clearing these actually made accessing internet recovery (how we get to a stand-in OS with a terminal) dozens of times faster.  2.5 hours to 7 minutes. I actually waited 2.5 hours twice on separate attempts before I cleared these.

Follow these Apple links to perform these operations:

Get the computer with a text editor open.

Restart the computer into internet recovery.  Command + R or Command + Shift + R.


Open a Terminal.  The graphical disk utility is useless because the disk / partition we want is unreachable(so it will say everything is great).


diskutil list

For me, I see disk0s2 is 180.6 gb.  That’s my stuff!

I also found /dev/disk2 → /dev/disk14 to be tiny partitions- don’t worry about those.

The syntax you are looking for is:

Name: “untitled” Identifier: disk#

(NOT disk#s#)

Write down ALL of the above information for the disk you are after.  That is probably disk0.


gpt -r show disk0

Copy the following readout in your terminal for all entries bigger than “32”.  The critical fields here are Start, Size, Index, and Contents. Each field is supremely important.

Here is mine (formatted for web):

# Disk0, with contents > “32” :

# First Table:

Start: 40  

Size: 409600

Index:  1

Contents: C12A7328-F81F-11D2-BA4B-00A0C93EC93B

# Second table, the one with my data:

Start: 409640

Size: 352637568

Index: 2


Note, this is the initial Contents.  I rewrote this once with the correct Apple Index 2 data but did not create a new table (leaving the rest of the broken bits broken).  We are replacing / destroying a table here, but not the data.     


# unmount the disk.  From here we are doing tables, not disks / data.

diskutil unmountDisk disk0

# Get rid of the GPT on the disk we are recovering.  We are not touching the data.

gpt destroy disk0

# Make a new one to start with some fresh values.

gpt create -f disk0

# perform magic trick


# we must add that first small partition at index 1.  Verbatim.

gpt add -i 1 -b 40 -s 409600 -t C12A7328-F81F-11D2-BA4B-00A0C93EC93B disk0

# index two (for me) is my data.  We are going to use the default OSX / Mac HD partition values.

# the Length of “372637568” is not as sure fire as the GPT Contents.  

# YMMV, but YOLO.

gpt add -i 2 -b 409640 -s 372637568 -t 7C3457EF-0000-11AA-AA11-00306543ECAC disk0

Again, that Contents value is 7C3457EF-0000-11AA-AA11-00306543ECAC.

- Jess

written in the recovered computer xD

Evaluating Ubuntu Pop OS: Dual Boot Setup

Dual OS on a 2015 MacBook pro

As the costs of Apple computers continue to skyrocket and the price of useable amounts of storage zoom past a neighboring galaxy (for a college student at least), I am always on on the hunt for cost effective solutions to house and process big projects and large data.

Pop OS (a neatly wrapped Ubuntu) is the in-house OS from System76.  After looking through their catalog of incredible computers and servers, I thought it would be a good time to see how far I can go with an Ubuntu daily driver.  Of course, there are many major and do-not-pass-go downsides- see the below list:

  • Logic Pro X → There is no replacement 🙁   A killer DAW with fantastic AU libraries. I am versed with Reaper and Bitwig, but neither is as complete as Logic Pro.  I will be evaluating POP with an installation of Reaper, but with so few plugins (I own very few third party sets) this is not a fair replacement.
  • Adobe PS and LR:  I do not like Adobe, but these programs are... ...kind of crucial for most project of mine that involve 2d, raster graphics.  I continue to use Inkscape for many tasks, but it is irrelevant when it comes to pixel-based work and photo management / bulk operations.
  • AutoCAD / Fusion 360 / Sketchup:  I like FreeCAD a lot, but it is not at all like the other programs.  Not worse or better, but these are all very different animals for different uses.
  • Apple notes and other apple-y things:  OSX is extremely refined. Inter-device solutions are superb.  I have gotten myself used to Google Keep, but it is not quite at the in-house Apple level.
  • XCode and IOS Simulator environments:  I do use Expo, but frankly to make products for Apple you need a Mac.

Dual Boot (OSX and Pop Ubuntu) Installation on a 2015 MBP:

This process is quite simple, and only calls for a small handful of post-installation tweaks.  My intent is to create a small sandbox with minimal use of “extras” (no extra boot managers or anything like that)


Partition separate “boot”, “home”, and other drives

  • I am using a 256gb micro sd partitioned in half for OSX and Pop_OS (Sandisk extreme, “v3” speed rating version card via a BaseQi slot adapter)

Use the partition tool in Mac disk utility.  Be sure to set these new partitions as FAT 32- we will be using ext4 and other more linux-y filesystems upon installation, so these need to be as generic as possible.

Get a copy of Pop_OS from System76.

Use Etcher (recommended) or any other image burning tool to create a boot key for Pop.  

The USB key only has one small job, in which Pop_os will be burned into a better location in your boot partition made in the previous step.  If you are coming from a hackintosh experience, fear not: everything will stay in the Macbook Pro, not extra USB safety dongles or Kexts, or Plist mods…!


Restart your computer and hold down the alt-option Key.  THIS IS HOW TO SWITCH from Pop_os, OSX, Bootcamp, and anything else you have in there.  You should see an “efi” option next to the default OSX. (note- at least in my case, the built-in bootloader defaults to the last used OS at each restart.)

Once you are in the Pop_OS installer, click through and select the appropriate partitions when prompted.  After this installation, you may remove the USB key and continue to select
“efi” in the bootloader.


You are now in Pop_OS!  Using the alt/option key will become second nature… but some Pop key mappings may not.  Continue for a list of Macbook Pro - specific tweaks and notes.

First moves:

Go to the Pop Shop and get the “Tweaks” tool.  I made one or two small keymap changes, but this is likely personal preference.  

Default, important Key Mappings:

Command will act as a “control center-ish” thing.  It will not copy or paste anything for you.

Control does what Command did on OSX.  

Terminal uses Control+Shift for copy and paste, but only in Terminal:  if you pull a Control+Shift+C in Chrome, you will get the Dev tool GUI...  The Shift key thing is needed unless you are inclined to root around and change it.

Custom Boot Scripts and Services:

In an effort to make things simple, I made a shell script to house the processes I want running when I turn on the computer- this is to streamline the “.service” making process.  While it may only take marginally more time to make a new service, this way I can keep track of what is doing what from a file in my documents folder.

In terminal, go to where your services live if you want to look:

cd /etc/systemd/system

Or, cut to the chase:

sudo nano /etc/systemd/system/

Paste the following into this new file:

_____________Begin _After_This_Line____________________


Description=Start at Open plz




_____________End _Above_This_Line____________________

Exit nano (saving as you go) and cd back to “/”.


sudo nano /Documents/

Paste the following (and any scripts you may want, see the one I have commented out for odrive CLI) into this new file:

_____________Begin _After_This_Line____________________


# Uncomment the following if you want 24/7 odrive in your system

# otherwise do whatever you want

#nohup "$HOME/.odrive-agent/bin/odriveagent" > /dev/null 2>&1 &

# end

_____________End _Above_This_Line____________________

After exiting the shell script, start it all up with the following:

sudo systemctl start

sudo systemctl enable

Cloud file management with Odrive CLI and Odrive Utilities:

Visit one of the two Odrive CLI pages- this one has linux in it:

Please visit this repo to get going with --recursive and other odrive utilities

These are the two commands I ended up putting in a markdown file on my desktop for easy access.  Nope, not nearly as cool as it is on OSX. But it works…

Odrive sync: [-h] for help


python "$HOME/.odrive-agent/bin/" sync


Odrive utilities:


python "$HOME/odrive-utilities/" sync --recursive


Next, Get Some Apps:

Download Chrome.  Sign into Chrome to get your chrome OS apps loaded into the launcher- in my case, I needed Chrome remote desktop.  DO NOT DOWNLOAD ADDITIONAL PACKAGES for Chrome Remote Desktop, if that is your thing. They will halt all system tools (disk utils, Gnome terminal, graphical file viewer…   !!See this thread, it happened to me!! )

Stock up!  

Get Atom editor:

...Or my favorites:



MySQL Workbench:

If you get stuck:  make sure you have tried installing as root ($ sudo su -) and verified passwords with ($ sudo mysql_secure_installation)  

See here to start “rooting around” MySQL issues:

Get some GIS tools:


sudo apt-get install qgis python-qgis qgis-plugin-grass

uGet for bulk USGS data download!

sudo add-apt-repository ppa:plushuang-tw/uget-stable

sudo apt install uget

That's all for now- Cheers!


INFO: Deploy a Shiny web app in R using AWS (EC2 Red Hat)

Info on deploying a Shiny web app in R using AWS (EC2 Redhat)

As a follow-up to my post on how to create an AWS RStudio server, the next logical step is to host some useful apps you created in R for people to use.  A common way to do this is the R-specific tool Shiny, which is built in to RStudio.  Learning the syntax to convert R code into a Shiny app is rather subtle, and can be hard.  I plan to do a more thorough demo on this- particularly the use of the $ symbol, as in “input$output”- later. 🙂


It turns out hosting a Shiny Web app provides a large number of opportunities for things to go wrong….  I will share what worked for me.  All of this info is accessed via SSH, to the server running Shiny and RStudio.


I am using the AWS “Linux 2” AMI, which is based on the Red Hat OS.  For reference, here is some extremely important Red Hat CLI language worth being familiar with and debugging:


sudo yum install” and “wget” are for fetching and installing things like shiny.  Don’t bother with instructions that include “apt-get install”, as they are for a different Linux OS!


sudo chmod -R 777” is how you change your directory permissions for read, write, and execute (all of those enabled).  This is handy if your server disconnecting when the app tries to run something- it is a simple fix to a problem not always evident in the logs.  The default root folder from which shiny apps are hosted and run is “/srv/shiny-server” (or just “/srv” to be safe).


nano /var/log/shiny-server.log” is the location of current shiny logs.


sudo stop shiny-server” followed by “sudo start shiny-server” is the best way to restart the server- “sudo restart shiny-server” is not a sure bet on any other process.  It is true, other tools like a node.js server or nginx could impact the success of Shiny- If you think nginx is a problem, “cd /ect/nginx” followed by “ls” will get you in the right direction.  Others have cited problems with Red Hat not including the directories and files at “/etc/nginx/sites-available”.  You do not need these directories.  (though they are probably important for other things).


sudo rm -r” is a good way to destroy things, like a mangled R studio installation.  Remember, it is easy enough to start again fresh!  🙂


sudo nano /etc/shiny-server/shiny-server.conf” is how to access the config file for Shiny.  The fresh install version I used did not work!  There will be lots of excess in that file, much of which can causes issues in a bare-bones setup like mine.  One important key is to ensure Shiny is using a root user- see my example file below.  I am the root user here (jess)- change that to mirror- at least for the beginning- the user defined as root in your AWS installation.  See my notes HERE on that- that is defined in the advanced settings of the EC2 instance.


BEGIN CONFIG FILE:   (or click to download) *Download is properly indented

# Define user: this should be the same user as the AWS root user!
run_as jess;
# Define port and where the home (/) directory is
# Define site_dir/log_dir - these are the defaults
listen 3838;
location / {
site_dir /srv/shiny-server;
log_dir /var/log/shiny-server;
directory_index on;


Well, the proof is in the pudding.   At least for now, you can access a basic app I made that cleans csv field data files that where entered into excel by hand.  They start full of missing fields and have a weird two-column setup for distance- the app cleans all these issues and returns a 4 column (from 5 column) csv.

Download the test file here:   2012_dirt_PCD-git

And access the app here:  Basic Shiny app on AWS!

Below is an iFrame into the app, just to show how very basic it is.  Give it a go!


How to make a AWS R server

When you need an R server and have lots of data to process, AWS is a great way to go.   Sign up of the free tier and poke around!

Creating an AWS Rstudio server: - using both the R snippet (works but the R core bits are NOT present and it will not work yet) and the JSON snippet provided - the suite being installed

Follow most of the AWS blog AMI info, with the following items:

AMI:  Amazon Linux 2 (more packages and extras v. standard)  

  • t2.micro (free tier)
  • IAM policy follows AWS blog JSON snippet
  • Security Policy contains open inbound ports 22, 8787, 3838 (the latter two for R server specific communication)
  • Append user, username:password in the blog post’s initial r studio install text (pasted into the “advanced” text box when completing the AMI setup


SSH into the EC2 instance

sudo yum install –y

sudo yum-config-manager --enable epel

sudo yum repolist


sudo yum update -y

sudo yum install -y R

sudo rstudio-server verify-installation


Access the graphical R server:

In a web browser, tack on “:8787” to the end of the Instance’s public “connect” link.  If it doesn’t load a login window (but seems to be trying to connect to something) the security policy is probably being overzealous……..


Notes on S3-hosted data:

  • S3 data is easiest to use if it is set to be public.
  • There are s3-specific tools for R, accessible as packages from CRAN directly from the R interface
  • Note data (delimited text at least) hosted in S3 will behave differently than it does locally, e.g. spaces, “na”, “null” need to be “cleaned” in R before use.  


There we have it!



DIY CMoy headphone Amp, point to point: worth it?








This is an extraordinarily simple headphone amp, and has essentially reached legendary/history status at this point.  I decided to build the original design (there are countless mods and totally different amps that hark back to this one), though opting for a wall-wart desk form factor instead of the original 9v battery tin.


I am building from the the 2008 "williamneo" blog post, as I like that point to point layout of his.  (I also could not easily procure the now ancient radioshack proto board- yes, the one shaped like a crab)  🙂



opting for a desktop form-factor and 12 volts, my little amp works fine for easy to drive headphones.... But does it actually sound better than, say, an iphone?


The truth is, while it gets much louder than a phone, the OPA jfet op amp powering the whole thing is simply NOT high end.  it will distort with too much input (after a few clicks on a phone before the phone is maxed out for reference- well below standard line/"dac" level in both home and pro audio voltage wise) and will incrementally break up with hard/loud songs on bigger headphones, as the volume and rocking out goes up- in my case, the current fostex RP evolution I have been mangling is the big cheese candidate.  the planar drivers in the RP series are definitely "very hard" to drive in the scheme of things, but anything "heavy weight" will simply not do when pushed to an accessible limit.  I CAN use smaller dynamic/efficient  headphones with ease, such as my ported and open hifiman edition S without experiencing distortion.  Still here though, it is clear this amp is a "diy/cheap access to power"- slated against the fiio e12 for example, the CMOY seems a bit.... Loose?  Not any better, that is fore sure!  (granted, the e12 is a fantastic budget amp)


Note of op amps:   the NTE and other non-OPA brand-name look alikes and electrical analogues sound terrible.  I was fussing around with the NTE variants after needing the short out resistors "R5" (very important when building:  do not use R5) when they actually blew out from my using a inversely-poled power supply by accident, and was getting frustrated as the amp was working but sounded like a making TIDAL streaming gurgle out from a cheese grater.  eventually, after a ebay shipment of brand name OPAs came, I popped one in cautiously and it turned out the opamp was the source of the.... cheese grating.

In all, a good project for skill building but falls short of anything "hifi".


Wolf Pine @ Fox Park #1 +Bonus Winter Birds

Today and yesterday, 2.19.17 - 2.20.17, have officially kicked off my first real visits to my "sit spot" (required for all adventure ed students at PSU) and commutes around campus armed with my bird rig, ready for the warmer-weather inclined birds.

Observations from the Wolf Pine @ Fox Park:

Snowshoed into Fox Park around 2:15 on Sunday, 2.19.17.

Weather:  After repeated heavy snow falls, Sunday was the first day solidly above freezing- thus a large amount of dripping and snow-condensing was happening.  My wolf pine was in a bit of a freezing puddle, with ~2 feet of snow accumulation surrounding its base.   High pressure day, bluish-grey skies and scattered wispy clouds.  Light breeze, and fairly quiet.

Upon quieting myself and my raucous snow-hoverboards, it became apparent how few birds and squirrels were about.    I could hear "whispers" and chips from passerines, but they sounded far away, likely to be lower on the hill, near the squishy earth and faux-pond.  Squirrels maybe rustled a branch or two during my sit- note the trees where about half evergreen and probably not a food source for these little mammals.  These trees  would, however, provide good coverage from avian predators...  I wonder if the squirrels have thought of that.

Perhaps the surrounding homes and intermittent (not on Sunday) construction sounds provided a safer space park wide.  Owls and to a lesser extent hawks are irked to no end by these sounds and regular but unpredictable human activity.  I have observed elsewhere in MA owls are not put off by circadian dog walkers at all;  in fact, I would glean most of my "big bird" info from the unperturbed 2 - 3 times a day dog walkers of my neighborhood.   Great horned families, bald eagles, and belted kingfisher pairs could care less about 2 dozen or more dogs pass under their homes a day, but the moment a motor boat, police cars, or loud parties occurred these unbelievable species would vanish.   I make this digression because this is a college town, and the park is surrounded by active dwellings of different sorts, including development sites.  THUS:  there were essentially no rodents/lagomorphs/etc.  (easily findable ones that is)

Speaking of which, the tracks were tough to figure out.  Heavy dogs?  Yes.  beyond that, the melting snow and dripping was creating a fairly non-descript blanket over any crazy prints.

I noticed remarkable BIG woodpecker activity, i.e. Pileated and Red Bellied/flicker- especially on my way out of the park.  Holy smokes are the pileated OCD around here!

Also Note the intersting spiraling growth pattern on this Wolf Pine limb.  It is long dead, but appears and felt denser than "ye average" pine tree.  ??

I plan to get back to my spot ASAP for more warm weather observations.  I believe this is the forecast all week!


A loud house finch and a lovely Bohemian waxwing.

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