Orchestra-90/PC 1.0a is a simple, no frills program that plays original Orchestra-80/85/90 files on a PC using a sound card. It is launched from the command line with "orch filename.orc" or via a file association that runs orch.exe when an .ORC file is selected.

Hitting any key will terminate the program. (WinNT & Win95, only. Win3.x can't be stopped, sorry)

Continuous play is possible by using a batch file containing this line:
	for %%f in (*.orc) do orch %%f

If Orchestra-90/PC finds an error in the music file it displays a message with an error number similar to the original TRS-80 program. Any other problem results in an error exit. The exit code may give you a clue as to what the problem is.

exit(1)	file: not found/can't open/can't read/etc.
exit(2)	memory: can't allocate/etc.
exit(3)	error: compilation error.
exit(4)	wave: can't open/etc.

Caveats:
Orchestra-90/PC is a Win32 program. It was developed and tested on Windows NT 3.51 and in that environment it is rock solid.  Orch90PC's performance with Windows 95 seems to depend on the quality of the sound card drivers. Windows 3.x needs the Win32s kernel and Orch90PC runs as an extension of the Program Manager. That means that while Orch90PC is playing music the Program Manager will queue and not act upon any mouse and keyboard input. However, any other open window will multi-task with Orch90PC. 

Orchestra-90/PC computes every digital sample of sound in real time at a rate of 22,050 samples per second per stereo channel. If your CPU is not fast enough to maintain this data rate the music will have noticeable glitches in it. Another potential problem for small PC systems is that Orchestra-90/PC commits over 1MB of RAM to music buffers and wave tables. If either CPU speed or usable memory is a problem you can use the companion orch11.exe which uses fewer buffer and halves the sample rate. Of course, the slower sample rate will be prone to aliasing.

Overall, I think you will find the quality of the sound significantly better than the original TRS-80 versions. This is due to more advanced circuitry in the PC sound card and the vastly increased computational power of the today's CPUs. For example, where the TRS-80 versions used 8-bit, integer arithmetic to generate the wave tables, the PC version uses double precision, floating point math. This improvement comes at a price, though, and some Orchestra-90 transcriptions that pushed the limits with percussion effects may not sound the way they did on the TRS-80.

A large collection of Orchestra-90 music files can be found on the World Wide Web in Ira Goldklang's TRS-80 pages at: 	http://w3.infonorth.com/~ira/trs80-o.htm.

Enjoy,

Jon Bokelman
jmlpartners@nmhu.campus.mci.net
