All posts by John Purvis

Mac OS X: WI-FI Fix for Yosemite

I came across this fact yesterday. Some, but not all, Macs may be experiencing slow Wi-Fi connections. The cause could well be a new feature of OS X Yosemite and iOS 8 called Apple Wireless Direct Link (AWDL). This technology is used for AirDrop,
AirPlay, and direct-play gaming connections. It is also known for causing Wi-Fi problems.

A quick solution can be applied through your terminal (Finder >> Go >> Utilities >> Terminal). Enter this command in your terminal window
sudo ifconfig awdl0 down

You will be prompted to enter your OS X administrator password. This command should clear up the wireless problems, but it DOES disable AirDrop on your Mac.

To re-enable AirDrop, simply go to your terminal again and enter
sudo ifconfig awdl0 up

What this Unix command ifconfig is doing is turning off/on respectively the network interface named awdl0.
Note that changes applied from the command line like described here will not persist after a system reboot.

Some older Macs may not be using AWDL so this command will result in an error message, something like “interface awdl0 does not exist”. I tried this on my Mac Mini (Mid 2011) and found that it was not supported. If you try it and if fails with this kind of error there is no harm done.

See my other Mac OS X articles

Book Review of “Fatal Puzzle”

“Fatal Puzzle” was published in 2015 (January) and was written by Catherine Shepherd. This was Ms. Shepherd’s first publication and the first of her “Zon” series. She has now published five books.

I obtained a galley of this novel for review through I would categorize this novel as ‘R’ as there are instances of Mature Situations and Violence. This Mystery novel is set in Zon, now a part of the city of Dormajen, Germany. The story is split between part that takes place in contemporary times, and part that takes place in the medieval city of Zon in 1495.

The primary character in today’s world is Emily Richter, a graduate student of journalism at Cologne University. Richter picks up a contract to supply a local paper with a multipart story about murders that happened in Zon back in 1495. As she researches the article, she is drawn into murders in today’s world, some of which mirror those of 500 years earlier.

The other primary character is Bastian Muhlenberg who has, in 1495, been appointed to the City Guard because of his skill at solving problems. After only a few months in the Guard, he is faced with the brutal rape, torture and murder of a young woman. His investigation leads to a man with a dark history. Because of the ritualistic nature, Muhlenberg fears that more deaths with follow. What seems to be a puzzle left behind by the killer, numbers and characters carved into his victims scalp, seem like a puzzle. Meulenberg races to prevent another brutal murder, trying to figure out what the puzzle can mean.

I really enjoyed the three hours I spent reading this novel. I liked how the plot was tied together between medieval and current day times. I think that part of the reason that this book resonates so well with me is that I was in southern German in December and visited a few medieval sites, though not Zon. There is a touch of Romance to the story and a hint at a possible Paranormal aspect as well. The characters were well developed in the story, though frankly I think the book should have been a little longer. I give this novel a 4.5 (rounded up to 5) out of 5.

My book reviews are also published on Goodreads (

The Threat of Thunderstrike

UPDATED 2/3/15 – When Apple released OS X 10.10.2 a week or so ago, the vulnerability to Thunderstrike was patched!

Those of us who use Macs have been more or less safe from Malware. However as the Mac has grown in popularity recently and the number of Macs in use has risen, we have finally become more of a target. Recently a new attack vector for the Mac has been discovered and it has been named Thunderstrike.

So far this is only a proof of concept discovered by security researcher Trammell Hudson. Apple is reported to be taking this threat seriously and is working on a fix. At present it DOES NOT offer much of a threat to most users.

The Bad – There are several features of Thunderstrike that are serious threats

  1. It is the first known OS X firmware bootkit, there is nothing currently scanning for its presence
  2. It controls the system from power up and can log every keystroke, including disk encryption keys
  3. It can open a backdoor directly into the kernel bypassing firmware passwords
  4. Once it is on your system it is very hard to remove
  5. It can infect subsequent Thunderbolt attached devices, spreading the Malware

The Good – So far this is only a prof of concept. To infect your Mac someone has to:

  1. Have Thunderstrike-enabled hardware — a modified Thunderbolt-to-Ethernet dongle was used in the proof of concept
  2. Have physical access to the Mac under attack
  3. Be able to reboot the Mac so as to modify the system firmware

Action You should take – even though the threat currently is low, you should keep in mind that if your Mac is left alone it could be subject to attack. The most common time this might happen is when traveling and your Mac is left in your hotel room. If you feel that you might be a target, take advantage of the safe in your room to store your Mac when you are out or keep it with you.

How it works – In simple terms when a Mac boots it starts
to run the EFI firmware code in the boot EEPROM. By design, FireWire and Thunderbolt interact with the Mac firmware at a very low level. In this case, if a Thunderbolt device is present with the Thunderstrike Malware at bootup, the system firmware will be overwritten and the system compromised.


  1. Macs vulnerable to virtually undetectable virus that “can’t be removed”
  2. Thunderstrike Proof-of-Concept Attack Serious, but Limited
  3. Thunderstrike – Trammell Hudson’s Projects

See my other Mac and Security posts



Book Review of “Broken Skies”

“Broken Skies” was published in 2014 and was written by Theresa Kay ( Ms. Kay has written three novels or novellas, this being the first of her “Broken Skies” series.

I obtained a galley of this novel for review through I would categorize this novel as ‘PG13’ as there are a few instances of Mature Language and Violence. This Young Adult Science Fiction Romance novel is written in the first person and is set in a future where humanity has nearly pushed itself to extinction on Earth through war.

The primary character is 17 year old Jasmine ‘Jax’ Mitchell. It has been nearly 30 years since the war took most of humanity. Max and her twin brother Jace were raised by their father in a remote cabin in the woods after the death of their mother. After their father disappeared, Jax and Jace moved to the small community of Bridgelake.

Jax is not happy with the community leadership and does not hesitate to break their rules, including following her brother into the woods while he is hunting. A few years after the downfall of humanity, aliens came to live on Earth, and thus far, they have stayed separate from the humans.

On one of Jax’s adventures, she and Jace see an alien craft land nearby in the woods. When they investigate, Jace is taken prisoner, and a teenage alien boy, Lir, is left behind. Jax takes it upon herself to journey to the city occupied by the aliens to get her brother back. She rebels against the Bridgelake leaders and forms a tenuous partnership with Lir to get her to the city and reunited with Jace.

Along the way she discovers secrets that her brother has been hiding from her. She also finds the partnership with Lir becoming romantic. There are factions within both the human and alien communities that want to strike out and exterminate the other. Jax finds herself, her family, and friends caught in the middle.

This was an OK story and I see it targeted at teen or preteen girls. Post apocalypse scenarios where young women are faced with danger, grow into leaders and are exposed to romance seem to be popular for that genre. Thankfully the Romance was not too much of the plot. I was surprised at the touch of LGBT  that crept in to the end of the story. I was a little disappointed that the character of Jax did not grow as much as I would have liked. I give this novel a 3 out of 5.

My book reviews are also published on Goodreads (

USA, Washington, Seattle: The Yellow Leaf Cupcake Company

IMG_1490 - Version 2My wife and I were is Seattle, WA in the fall of 2013 after taking an Alaska cruise. One of the eating establishments we came across
was The Yellow Leaf Cupcake Company. They offered a wonderful assortment of cupcakes, including several featuring Bacon. We visited twice while we were in Seattle trying a variety of flavors and every one was exceptional.

If you like cupcakes and you are in Seattle, it is certainly a place
to visit.

See my other Food posts


Using the “Rule of 50” When Reading

I came across the “Rule of 50” a short time ago looking at the  Sword & Laser Top Stories on Flipboard and I immediately knew I would be putting it to use. I read over 100 books in 2014, and expect to do the same this year. Most are good to great, but there are a few that, frankly, the “Rule of 50” was designed for.

What is the “Rule of 50”? The Rule of 50 comes from from Nancy Pearl‘s book Book Lust. The essence of it is:

I live by what I call ‘the rule of fifty,’ which acknowledges that time is short and the world of books is immense. If you’re fifty years old or younger, give every book about fifty pages before you decide to commit yourself to reading it, or give it up. If you’re over fifty, which is when time gets even shorter, subtract your age from 100. The result is the number of pages you should read before deciding.

I have applied it once so far, and while I hope not to encounter any more books that I simply can’t get into, I will not hesitate to apply the rule if necessary. I hope that knowing about this rule will make reading easier for you.

FOSS Under OS X: Gramps

I have an on-going project to research my family history. A program that I have been using to help document that is Gramps. This is an active Open Source project with multiple releases per year. Gramps is cross platform with versions available for Linux, Windows, OS X and BSD.

Gramps includes a full set of features that anyone wishing to document their family history might want:

  • A dashboard to help you monitor the progress of your research.
    A variety of widgets provide quick analysis of your data and
  • A list of every individual in your records featuring
    birth/death dates and more.
  • A summary of the active person’s parents, siblings, spouses
    and children.
  • A list of every family group featuring parent names,
    relationship status and, if applicable, marriage dates.
  • A graphic representation of the active person’s ancestry
    featuring photos and birth/death dates.
  • A list of every event in your records featuring descriptions,
    event types, dates and places.
  • And much more

I have been entering my data now for about the past year and find this program comparable to the popular commercial software. The web site includes documentation as well as tutorials. If you are interested in documenting hour family history, this is a low cost, yet highly functional solution.

To see all of my Mac OS X related posts visit my MAC OS X page


Book Review of “Unbreakable”

“Unbreakable” was published in 2015 (January) and was written by W. C. Bauers ( This is Mr. Bauers first novel and is the first of his “Chronicles of Promise Paen” series.

I obtained a galley of this novel for review through I would categorize this novel as ‘R’ as there are instances some Mature Language and substantial combat Violence. This Military Science Fiction novel is written in the first person and is set in a far future. The primary character is Promise Paen.

Paen is from the fringe world of Montana, successful as fringe worlds go, but still behind the other planets that make up the Republic of Aligned Worlds (RAW). Her mother dies when Paen is young and she grows up with a pacifist father. She witnesses her father being killed by raiders and a short time later Paen joins the RAW Marines.

Pain does well, then her company is chosen to go back to Montana. It is made clear to Paen that her company was chosen because she came from the planet Montana. Their mission is as much public relations as it is military, and she is seen as an asset in winning the confidence of Montana’s very independent inhabitants.

RAW’s rival, the Lusitanian Empire, is thought to be behind the raiders that have plagued Montana and other fringe worlds. Montana lies at the edge of RAW space near Lusitania Empire space, and the Empire wants Montana as added buffer.

Pain is just newly promoted to Lieutenant when an encounter with Lusitania space craft leaves her in command of all that remains of the RAW military on Montana. Together with her few surviving RAW Marines, Paen prepares to confront an invasion by overwhelming Lusitania forces.

I thoroughly enjoyed the 12 hours I spent reading this novel. The characters were well developed, with Promise Paen reminding me a lot of David Weber’s Honor Harrington. I give this novel a 5 out of 5.

My book reviews are also published on Goodreads (

Book Review of “Truth Insurrected: The Saint Mary Project”

“Truth Insurrected: The Saint Mary Project” was published in 2014 and was written by Daniel Douglas. This is Mr. Douglas’ first published novel.

I obtained a galley of this Science Fiction Thriller novel for review through I would categorize this novel as ‘R’ as there are instances of Mature Language and Violence. The novel is written in the third person and is set in contemporary America. The two main characters are retired FBI agent, now a Private Investigator, William ‘Bill’ Harrison and Las Vegas, Nevada Police Officer Nick Ridley.

Harrison is drawn into an investigation by an anonymous source. The more he looks into it, the stranger and more outlandish the claims seem to be, yet the evidence he accumulates indicates that it is the truth – Aliens did crash in Roswell, New Mexico in the 40s and the government is behind a massive cover up. The further Harrison digs, the more his life, and that of those around him, seem to be at risk.

Ridley experiences a strange incident, then he is pulled in by his sister as her husband, an Air Force traffic controller, begins to act strangely. Before he knows what has happened, he meets Harrison and is confronted with the conspiracy theory. Soon, he too is in danger of being included in an effort to clean up loose ends in the cover up.

I thought that this novel had a good plot, one that was not too outlandish. I liked the characters and enjoyed the 11.5 hours I spent reading this novel. I give this novel a 4 out of 5.

My book reviews are also published on Goodreads (

Book Review of “Rome is Burning”

“Rome is Burning” was published in 2014 and was written by Roy A. Teel Jr. Mr. Teel has published six novels, with this being the third in his “Iron Eagle” series.

I obtained a galley of this novel for review through I would categorize this Fiction Thriller novel as ‘R’ as there is Mature Language, Mature Situations and Violence. The novel is written in the third person and is set in contemporary Los Angeles, California. The primary characters are FBI agent John Swenson and Sheriff Jim O’Brian.

John Swenson is The Iron Eagle who has appeared in the first two novels of this series. While an FBI Agent, he anonymously sees justice carried out when the system fails. He has assembled a tight knit group of fellow Special Operations combat veterans around him to help with imposing justice when needed. They hold back nothing to succeed, and are not hesitant to resort to torture to get the information that they seek.

Sheriff Jim O’Brian is added to his group as Swenson discovers a plot to take over the US government. He and his crew strike out against terrorists attacking the Los Angeles area, and move to block those who wish to overthrow the government.

The plot is full of conspiracy theories, some kind of far fetched in my opinion. I also felt that there was not a lot of depth to the characters. There is a lot of action. I give this novel a 3.5 (rounded up to 4) out of 5.

My book reviews are also published on Goodreads (