> Was the landscape of signal processing solutions just so
> particular that trying to create a centralized interface didn't make sense at
> the time?  Or was it a simple matter of priorities, with things like language
> development and system design taking center stage, leaving a dearth of resources
> to direct towards these sorts of matters?  Was there ever a chance of seeing,
> say, the 5ESS handling of PCM, extended out to non-switching applications, 

In the early days of Unix there were intimate ties between CS Research and Visual and Acoustic Research. V&A were Bell Labs' pioneer minicomputer users because they needed interactive access to graphics and audio, which would have been prohibitively expensive on the Labs' pre-timesharing mainframes. Also they generally had EE backgrounds, so were comfortable  working hands-on with hardware, whereas CS had been largely spun off from the math department.

Ed David, who led Bell Labs into Multics, without which Unix might not have happened, had transferred from V&A to CS. So had Vic Vyssotsky and Elliot Pinson (Dennis's department head and coauthor with me of the introduction to the 1978 BSTJ Unix issue). John Kelly, a brilliant transferee who died all too young pre-Unix, had collaborated with Vic on BLODI, the first dataflow language, which took digital signal processing off breadboards and into computers. One central member of the Unix lab, Lee McMahon, never left V&A.

The PDP-7 of Unix v0 was a hand-me-down from Pinson's time in V&A. And the PDP-11 of v1 was supported by a year-end fund surplus from there. 

People came from V&A to CS because their interests had drifted from signal processing to computing per se. With hindsight, one can see that CS recruiting--even when it drew on engineering or physics talent--concentrated on similarly motivated people. There was dabbling in acoustics, such as my "speak" text-to-speech program. And there were workers dedicated to a few specialties, such as Henry Baird in optical character recognition. But unlike text processing, say, these fields never reached a critical mass of support that might have stimulated a wider array of I/O drivers or full toolkits to use them.

Meanwhile, in V&A Research linguists adopted Unix, but most others continued to roll their own one-off platforms. It's interesting to speculate whether the lack of audio interfaces in Unix was a cause or a result of this do-it-yourself impulse.

Doug