Gestion d'un convertisseur numérique-analogique sous UNIX

Abstract : The implementation of a digital audio device (DAD) under Unix V7(1) is presented. The device is intended to be used by a speech signal Processing package. The converter is connected to a minicomputer PDP11/24 (2) by an alternate buffer DMA interface DRU11-C (2). This interface is designed for double buffering to handle continuous data transfers at high rate. A new Unix system-call is used as driver for the DRU11 interface which also handles the double buffering and initiates the reliated disk transfers (on a special file in the Unix sense, using the standard disk driver). In a standard multi-user/multi-task context where the disk drive can handle any disk transfers, the maximum sampling rate without disk time-out was 20 kHz (40 kbytes/s). It is possible to set a special mode where the disk drive is restricated to the transfers of the DAD, and as a result, all the other processes needing disk access remain in a sleeping state until the completion of the DAD request. Consequently the maximum sampling rate without disk time-out increased up to 65 kHz (130 kbytes/s) in this mode.
(1) Unix is a trademark of Bell Laboratories.
(2) PDP, DRU11-C are trademarks of Digital Equipment Corporation.
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Contributor : Robert Espesser <>
Submitted on : Friday, November 16, 2018 - 2:59:08 PM
Last modification on : Wednesday, November 28, 2018 - 1:22:02 AM
Long-term archiving on : Sunday, February 17, 2019 - 2:16:38 PM


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  • HAL Id : hal-01925173, version 1



  • requires hal-01925590 - hal-01925590 décrit la composante "hardware" du dispositif


Robert Espesser. Gestion d'un convertisseur numérique-analogique sous UNIX. séminaire GALF/GRECO "traitement du signal de parole", GALF Groupe Communication parlée; GRECO 39 CNRS Groupe Analayse du Signal de Parole, Dec 1983, PARIS, France. p155-163. ⟨hal-01925173⟩



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