Technical details

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BPOS is a compiled "xBase" program. The xBase bit refers to "Dbase III" an MS-DOS based program written by "Ashton-Tate" in the early 1980s. It grew to be one of the premier "Database" development tools used on early PC's. It incorporated a language which made it easy to write table based applications. The one issue with dBase III was the programs were "Interpreted" which meant that if you wrote a world shattering application then you had to distribute your source code and a "run-time" (which cost money) to you potential customers. This made it simple to "use" your code. Interpreters were also slow as they considered your program a line at a time.


In the early 80's some innovative companies started to produce "compilers" for DBase III code. A compiler takes your source code and compiles it into an executable file which then executes. Developers could then send just the executable and there was no need for source code and runtime files. The pre-eminent compiler of the mid 1980's and early 1990's was "Clipper" from Nantucket Corporation. Look up Wikipedia for more information on Clipper.


BPOS is written in Clipper compatible code however Nantucket was sold to Computer Associates and as DOS was fading in the 1990's there was no direct upgrade to the world of Windows for the thousands of Clipper developers. This void was progressively filled by the clever, open source people on the "Harbour" project. Harbour has been "Forked" several times, the most noted was "XHarbour". This current version of BPOS is compiled using xHarbour mainly because I can't get the EPSON printer escape sequences to work correctly using the Harbour GDI printer drivers.  One day it will move back to Harbour....


BPOS therefore uses dBase III compatible files. There are no "FPT" style files in the system.

The indexes are "CDX" combination indexes using the DBFCDX drivers. These are lightning fast and simple to manage.

BPOS DBF files can be opened using Excel.


So - to build BPOS you will need


  1. BPOS sources
  2. xHarbour.org windows MSVC 9 version
  3. One of the free "MS Visual C Express" versions


I've compiled it using the GTWVW GDI driver. You also need to obtain the "mainwin.obj" file - this shim starts the GDI driver.

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