MythTV Woes: mythtv-users mailing list

One of the main beauties of MythTV is the fact that you are getting a wonderful implementation and an ever expanding user base who are all willing to ‘give back’ in some way.

At least, that is what it first appears to be like.

MythTV’s installation can be daunting, but the end result is very impressive. The provided support via the mythtv-users mailing list is enough to put some companies support structure to shame. Technical questions get quickly answered and, when they cannot be answered, a poster was quickly pointed in the right direction. Of course, there are always a couple of nasty responders, but that comes with the territory.

Or so one might think. After being on the list for 6 months, one realizes that there are two classifications of people on the mythtv users list: knowledgable (let’s call them “old-timers” since they have been on the list for a long time) and newbie (people who inistalled recently and are trying to get off the ground, or ones that have recent successful implementation and are trying to help the product grow). The dynamics of the two groups cause a fair amount of friction and noise in an otherwise prosperous mailing list.

As with any complex installation, you see a lot of the same questions show up on the mailing list. This is just natural. While efforts at a FAQ have been on-going, human nature is to simply ask the question rather than hunt for the right question/answer. Rather frequently, you see the more vocal of the ‘old-timers’ slap around an inexperienced poster for not checking the FAQ or misphrasing items. This is generally tolerated on a mailing list when you are trying to keep things moving and teach at the same time. Unfortunately, that also teaches the other posters that it is ok to be nasty in a response.

Over the course of the 6 months snippet in time, it was quite surprising to see a fair number of the responses to postings (not the majority, but a growing minority) were general ‘turn off’ messages that degraded in to flames, apologies, and more flames for posting apologies. It is silly and sad at the same time.

The mysterious class-like structure of the ‘old-timers’ is such that they expect that everyone else should know as much about MythTV and its history as they do. The impression is that if a poster has not read every past posting and article, then that poster has not properly researched their problem. You actually see a lot of references to the main author/project lead and “the mythtv-devs” in regards to history and rules of mythtv that ‘everyone should have known about’, in an effort to create some form of authority in the posting without actually mentioning the contents of the reference. In other words, the use of the main author’s name is done to create a sense of authority, and it seems unlikely that the main author nor the mythtv-devs even know about this. Additionally, several of the developers who frequent the mythtv-users list will lash out at a poster, clearly throwing weight around, all while the majority of the newbie (see definition above) portion of the community have no idea who that person is until they identify themselves as “one of the devs”.

In summary, as someone who wishes to help out others with their MythTV installs and share some of our experience so as to make their road a little easier to travel on, try to keep a level head and don’t get bitter.  Spread that wealth of knowledge you have gained.

Recovering lost images from a flash card

There are a lot of expensive recovery methods to restore images off of a camera’s flash card and they all work (in their own way).  However, this is really not something you need to be paying for, unless there is something horribly wrong with the card (physically damaged or very very old).

There are many situations that can cause a card, or even a portion of a card, to become unreadable.  Some of which are:

  • Corrupt block written to the directory.
  • Camera corrupted a single image.

There are many schools of thought as to the reasoning behind any corruption, but the general rule of thumb (aka: “Best Practice”) is to never delete individual images from the card.  There is the temptation, while taking pictures (and the card is in the camera), to delete a bad  (blurry, shot of the floor, etc) image from the card in order to regain that space.  Resist that temptation!  Cameras are good at taking pictures and storing them.  If you delete an image, you are now freeing up previously written blocks in the middle of a section of used blocks.  You an now asking the camera to do block-level file management.  Don’t do it.  Leave those bad images there, and, when you are ready, copy the entire card locally to your machine.  Then, delete the bad images from your local copy, and when you need to re-use the card, reformat the card.

Directory corruption is the one that usually causes the most panic, since the symptom is that you cannot access any of the contents of the card.  Don’t give up and simply reformat the card!!  This is actually an easy one to get out of.

Use the Windows tool called Zero Assumption Digital Image Recovery.  I have attached the free standalone verion (Zero Assumption Digital Image Recovery) of their image recovery tool here, but it looks like they have now integrated it in to their ZAR 8.0 tool, which does a heck of a lot more.  ZAR 8.0 is not free, but the digital image recovery portion of ZAR 8.0 is.

I have had a lot of success with the free standalone tool and see no reason to use anything else.  Feel free to give it a try.  Your mileage may vary.

Mounting an ISO image on Solaris

No doubt you’ve had experience with this under Linux (mount -o loop /root/animage.iso /mnt) or Windows (using Daemon Tools), but I had a need to do this under Solaris. Fortunately, it is a rather simple process using a relatively unknown command: lofiadm. (loopback file admin)
lofiadm is a Solaris tool which can be used to map a file to a block device id. With that, you can then use the mount command to mount that block device id to a directory.

Now, you can do this in two steps:

# lofiadm -a /export/temp/software.iso /dev/lofi/1

# mount -F hsfs -o ro /dev/lofi/1 /mnt

But that requires some cleanup afterwards (rm /dev/lofi/1) otherwise, over time, you end up with a bunch of mapped block devices pointing to files that are no longer on the system. It is a “best practice” to combine the commands in to a single command:

# mount -F hsfs -o ro `lofiadm -a /export/temp/software.iso` /mnt