High Tech Sorcery


storing money in decimal fields in MySQL

by on Jun.15, 2011, under Uncategorized

I haven’t found a lot of advice about what precision values to use for storing money in decimal fields.  Here’s what I calculated.  The scale is going to be 2 for US currency which requires 1 byte of storage.

  • precision 4, scale 2 = 2 bytes of storage, 99.99 to -99.99
  • precision 6, scale 2 = 3 bytes of storage, 9999.99 to -9999.99
  • precision 8, scale 2 = 4 bytes of storage, 999999.99 to -999999.99 (I’ve tended to suggest this as a starting point)
  • precision 11, scale 2 = 5 bytes
  • precision 13, scale 2 = 6 bytes
  • precision 15, scale 2 = 7 bytes
  • precision 17, scale 2 = 8 bytes
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Encoding webm with ffmpeg

by on Mar.11, 2011, under Uncategorized

It was pretty easy.  At it’s most basic:

ffpeg -i infile -f webm outfile.webm

Some resources to get fancier:

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Alternatives to the ASUS M4A785TD-V EVO

by on Jan.11, 2011, under Uncategorized

There seems to be a small market for consumer motherboards with ECC.  I had planned on purchasing a new system with the ASUS M4A785TD-V EVO motherboard which got excellent reviews, was reasonably priced, and supported ECC DDR3 memory.  As this motherboard has been discontinued I took some time to find its successor.  I’m not sure the M4A78T-E counts as a successor but it is a reasonable alternative.  Finding it was somewhat difficult as ECC is not a feature many places seem to list (including newegg).  The main difference between the M4A785TD-V EVO and the M4A78T-E is the chipset combo: AMD 785G/SB710/RADEON 4200 on the former, AMD 790GX/SB750/RADEON 3300 on the latter.  For an additional $50 the ASUS M4A89GTD PRO/USB3 brings a bump to AMD 890GX/SB850/RADEON 4290 as well as USB 3 and 6Gbps SATA.  That makes it a little more future-proof but as to whether that’s worth a 50% price jump I’m skeptical.

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Getting more entropy for virtual servers

by on May.04, 2010, under Uncategorized

It is not uncommon for people to have performance problems with the their virtual servers and chalk it up to virtualization as the problem instead of insufficient entropy.  Running a mail server or SSL web server are particularly vulnerable to virtual servers without much entropy.  I have noticed that my virtual servers have had a lot less entropy in the past 6 months or so.  I decided to revisit what simple and effective solutions exist to solve this problem.

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Chromium Extensions

by on Apr.22, 2010, under Uncategorized

I’ve been playing with the beta builds of chromium for a while.  There are not nearly as many useful extensions are there are for firefox but these have helped:
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Open Source Search Engines with Web Crawling and HTML Indexing

by on Jan.19, 2010, under Uncategorized

The term search engine is particularly vague.  It can mean an online search engine, or it can mean software that provides something similar to the online search engines, or it can mean software that does fulltext indexing and querying.  I specifically wanted to find a tool that could be used to create a niche search engine without having to write the whole thing myself as a ruby on rails app.  Here’s what I found:

  • mnoGoSearch – seems very actively maintained, packages present in Debian and Ubuntu, written in c
  • DataparkSearch – seems fairly actively maintained, apparently a branch of mnoGoSearch, written in c
  • Nutch – seems fairly actively maintained,written in java, built on top of Lucene

And that’s really it.  There is a product called ASPseek but it has long since been abandoned.  There is also ht://Dig but it has not been updated in years and is not really in the same league as the above.  So, at least for anyone trying to research this area there are not a whole lot options to try.

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Another year, another blog

by on Jan.19, 2010, under Uncategorized

I believe this is my 6th blog.  So far I have never taken the time to migrate articles from one to another and I am continuing that tradition.  Not so good for the internet perhaps but better for me to not have to take the time to get a migration right.  I may go back and report some of my older content as appropriate though.  I decided to use wordpress this time because I’m supporting some other wordpress users.  I haven’t been the biggest wordpress fan in the past but I’m willing to give it another try.

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