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maxvt / hp-p1109w-on-ubuntu-1604.md
Last active Feb 22, 2019
Solution for a HP LaserJet P1109w not printing on Ubuntu 16.04 Xenial Xerus
View hp-p1109w-on-ubuntu-1604.md

As usual, Linux needs a bit of under-the-hood wrenching to get things working. HP is actually doing Linux support commendably compared to its peers (see hplip). However, in this case a bit of extra grease was needed.

Symptoms: Printer is detected automatically. A test page fails to print. CUPS logs say:

hp[14727]: io/hpmud/musb.c 2095: Invalid usb_open: Permission denied

Solution: Note that this will potentially mess up any HP scanners you have installed. If the P1109 is your only HP device, no problem. I do not claim this to be the correct, the most appropriate, or the

@maxvt
maxvt / scala-and-elixir-sf-meetup-notes.md
Created Jun 10, 2016
Notes on _Scala and Elixir_ - a talk by Jeff Alexander at Erlang&Elixir SF MeetUp (8-Jun-2016)
View scala-and-elixir-sf-meetup-notes.md

Notes on Scala and Elixir - a talk by Jeff Alexander at Erlang&Elixir SF MeetUp (8-Jun-2016)

Jeff uses mostly Scala at work, trying out Elixir mostly for personal education.

Both languages are VM based. Scala: everything is a function. Elixir: everything is an expression. Both have tail recursion and pattern matching.

Let's look at performance:

@maxvt
maxvt / infra-secret-management-overview.md
Last active Apr 17, 2019
Infrastructure Secret Management Software Overview
View infra-secret-management-overview.md

Currently, there is an explosion of tools that aim to manage secrets for automated, cloud native infrastructure management. Daniel Somerfield did some work classifying the various approaches, but (as far as I know) no one has made a recent effort to summarize the various tools.

This is an attempt to give a quick overview of what can be found out there. The list is alphabetical. There will be tools that are missing, and some of the facts might be wrong--I welcome your corrections. For the purpose, I can be reached via @maxvt on Twitter, or just leave me a comment here.

There is a companion feature matrix of various tools. Comments are welcome in the same manner.

@maxvt
maxvt / writeup-ictf15-temperature.md
Last active Aug 29, 2015
UCSB iCTF 2014-2015 writeup - service "temperature"
View writeup-ictf15-temperature.md

This is a warmup-level challenge written in Python. The service opens a TCP socket on port 56098 and listens for commands to store or read a temperature reading based on time and location. The data is stored into a single flat file.

Simply interacting with the service over telnet would not work, as the service only attempts to read once and telnet sends a packet per character. The protocol is very easy to reconstruct by reading the source, though, and writing a small client to store and load data takes all of two minutes.

This service was one of the first ones being exploited by many teams.

View keybase.md

Keybase proof

I hereby claim:

  • I am maxvt on github.
  • I am maxvt (https://keybase.io/maxvt) on keybase.
  • I have a public key whose fingerprint is DF96 1F5F 85D9 F81C E581 5DA9 B243 60C4 D7E6 ED09

To claim this, I am signing this object:

View generate_web_server_certificate.md

How to generate a web server certificate for signing with StartSSL

The authoritative version of this gist will be maintained at http://www.maxvt.net/2014/12/23/web-certificate-startssl.html

A lot of advice on the web is outdated. There are three critical points that might be out of date or wrong:

  • Use 2048 bit key length. 1024 bit length is no longer considered secure, but if your server software is old enough, it might still be the default setting.
  • Use SHA-256 hash. The default is the older SHA1, which is being phased out since it is considered less secure. Apparently, by choosing SHA-256, you will lose compatibility with Windows XP and Windows Server 2003. Hopefully you do not run those anymore and therefore don't care.
  • Create a CSR (certificate signing request), not a self-signed certificate. A lot of advice on self-signed certificates was written when SSL certs were e
@maxvt
maxvt / apple_tax.md
Last active Aug 29, 2015
Apple Tax 2015
View apple_tax.md

This table compares the current compact (13") Retina MacBook Pro to potential alternatives. The current price premium for buying Apple as compared to similarly configured other brands is only 2-6%, compared with 40% in my 2010 calculation.

Discussion follows below. Send in your comments, fixes, and updates--I only do research like this when I'm personally interested, which is about once every few years when I need to update my hardware, but I don't mind quickly integrating fixes for the benefit of all.

Maker, Model CPU RAM Ram tech Display SSD USB Eth Size Wt W Sticker Best Notes
Apple, rMBP 2.8 i5 16 DDR3L 1600 2650x1600, 13" 512 2 No 12.4x8.7x0.7 3.5 3 2248 2062 Education discount
Apple, rMBP 2.8 i5 16 DDR3L 1600 2650x1600, 13
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