[linux-dvb] Organizing ALL device data in linuxtv wiki

H. Langos henrik-dvb at prak.org
Thu Nov 12 18:31:30 CET 2009


Hi there,

Like most wikis of the linuxtv wiki is plagued with duplicate 
and out-of-sync information. It is most apparent for devices, 
their features, their hardware, and most of all their status 
in regard to linux support.

If you need an example of the mess take a look at
http://www.linuxtv.org/wiki/index.php/TerraTec or 
http://www.linuxtv.org/wiki/index.php/DVB-T_PCI_Cards
and try to find devices where the information on the
page is consistent with the information on the device 
specific page.

I've collected and concentrated data on about 150 devices
(mostly DVB-T USB) in one place and experimented a lot
with "wiki template voodoo". The result is a kind of minimalistic
database application within the wiki (retaining the advantages 
of the wiki, like mature history and undo function, 
low entry threshold for new users....)

Having _one_ article that holds the data means that there is
just one place to update and maintain while the information 
can be shown in lots of articles (or inside the same article
with different levels of detail).

That article can be thought of as one big table with columns
for attributes and rows for devices. 

Selection of columns is done by choosing the appropriate 
table templates (there are currently three different ones 
for different levels of detail).

Selection of rows is done by passing selection 
attributes and selection values.


It is roughly the equivalent of this sql statement:
  SELECT a1,a2,a3... FROM datatemplate 
  [ WHERE s1 LIKE '%v1%' [ AND s2 LIKE '%v2%'
    [AND s3 LIKE '%v3%' [AND s4 LIKE '%v4%' ]]]]; 


Recently I expanded the "database schema" to contain 
the host interface(s) and the supported broadcasting standard(s).
This way the same infrastructure can be used to hold information 
on anything from PCIe DVB-S2 to ISA NTSC devices and even
fm radio devices. 

The current "database schema" is documented in 
http://www.linuxtv.org/wiki/index.php/Template:DVB-T_USB_Devices_ListData#Syntax_and_Semantics

It is still geared towards DVB-T USB devices but I am sure 
it can be expanded/modified with little effort to support
other types of hardware with the level of detail needed.

What I'd like to get is 

A) Some feedback from users and developers in regard to
   additional attributes needed or attributes (or 
   values) that can be merged. 

   E.g. I don't have a clue 
   * if satelite receivers have special attributes, or 
   * if ANALOG-PAL /-NTSC /-SECAM should be listed separately or
   * if it would make sense to include links from a device
   straight to the linux kernel's driver blob via 
   kernel.org's gitweb.

   Please, keep in mind that the table is not there 
   to replace device specific pages with all their 
   detail but definetly should be part of the device's
   page.

B) Ideas about how to handle oem devices (clones). My 
   idea is to include them with just the "vendor" and 
   "device" attribute (so that users can easily find the
   device in the table looking for the vendor) and to 
   use the "supported" attribute to indicate that this
   device is just a clone of some other device. Problem 
   here is that you can't really link to that other 
   device directly or use data from that other device.
   (Sorry, no sql JOIN operation on tables :-))


Here are some examples of stuff that already works:

Differnet views on same device in one article.

  http://www.linuxtv.org/wiki/index.php/MSI_DigiVox_mini_II_V3.0
  http://www.linuxtv.org/wiki/index.php/Pinnacle_PCTV_nano_Stick_(73e)


Selection on demodulator af9015

  http://www.linuxtv.org/wiki/index.php/Afatech_AF9015


Selection on hostinterface USB and stadard DVB-T 
(still a rather messy page as lots of old devices still 
need to be merged/moved into the "database")

  http://www.linuxtv.org/wiki/index.php/DVB-T_USB_Devices


Some more examples and experiments:

  http://www.linuxtv.org/wiki/index.php/HLPlayground2
  http://www.linuxtv.org/wiki/index.php/HLPlayground2/doubleselection


I hope the outlook of having just one place to update
will inspire and motivate developers and wiki users alike 
to keep information on their device/driver up to date.

cheers
-henrik




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