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I've been asked how easy/hard/ugly it was to write
C code to interface with the Technical Tools database.
(Technical Tools is a data provider in Deerfield Beach,
Florida, USA. Their homepage is http://www.techtool.com )
I found it relatively easy, to tell you the truth.
TechTools provides all kinds of support for this;
go to their web page and click "Developers Area"
and you can download their SDK and their API.
I decided to partition my software into a "front end"
and an "analysis engine". Only the front end touches
the TechTools data files. I just did a linecount on
the front end and found it was 412 lines of declarations
and source code. I estimate that 80% of this is
stuff I copied verbatim out of the SDK, and the other
20% is customization stuff I put in myself. I think
I probably spent a total of 3 solid hours reading the
SDK docs and studying the code they supplied, 2 more
hours copying the relevant parts out of the SDK (while
deleting the rest), 2 hours adding my personalizations,
and 2 hours debugging.
TechTools had a great idea: take advantage of
the HIERARCHICAL FILE SYSTEM of MS-DOS (now called
Windows) to organize the data. So, for example,
the price data for the common stock of International
Business Machines Corporation, is stored in this file:
C:\TECHTOOL\STOCKS\I\IBM.TTD
(the suffix ".TTD" is Tech Tools Database format -- it
is an extremely efficient way to compress price data).
Similarly, the price data for the September 1986 contract
of the S&P 500 futures is stored in this file:
C:\TECHTOOL\FUTURES\SP\SP___86U.TTD
You don't have to look in a "Qmaster" file or a "cdb.adm"
file to discover that "F014.DTA" is really "British Pounds"
(as you do with brand XX's datamanager); instead, in Tech Tools,
it's simply encoded in the file's pathname. I like it.
But then I'm a C programmer so of course I would like it :-).
The I/O code provided in the SDK for reading and writing
.TTD files is *fast*. Why? It does fread and fwrite
(ultra low-level system calls) plus buffer-ahead. This
makes it practical to run a trading system backtest
on all >20,000 stocks (and remember, 1 stock == 1 file)
in the database. And indeed I did this very thing.
I don't know much about the _quality_ of Tech Tools's
stock data; I have only been getting it for about a year.
However I am a relatively happy customer of their *futures*
data; my only complaint is that they often screw up their
calendar of market-holidays and so they insert an
"all-zeroes day" (open=0, hi=0, low=0, close=0) on the
holiday. Generally this gets cleared up in about a week
and the customer doesn't need to "do" anything; the
offending day just disappears [upon command from mission
control in Deerfield Beach].
They are good about handling brand-new tradeables; the
new symbol is created and data is automatically downloaded
without requiring the user to do anything.
They run "low price specials" from time to time; if you
are thinking of perhaps trying them out, you may wish to
wait for one of their frequent "deals".
Mark Johnson
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