NDLI: Managing stored voice in the etherphone system

Please wait, while we are loading the content...

Scale and performance in a distributed file system

Caching in the Sprite network file system

Using idle workstations in a shared computing environment

Attacking the process migration bottleneck

Hashed and hierarchical timing wheels: data structures for the efficient implementation of a timer facility

The packer filter: an efficient mechanism for user-level network code

A name service for evolving heterogeneous systems

The duality of memory and communication in the implementation of a multiprocessor operating system

Time warp operating system

Synchronization primitives for a multiprocessor: a formal specification

Managing stored voice in the etherphone system

Fine-grained mobility in the emerald system

Recovery management in QuickSilver

801 Storage: architecture and programming

Implementation of Argus

Exploiting virtual synchrony in distributed systems

Log files: an extended file service exploiting write-once storage

A simple and efficient implementation of a small database

Reimplementing the Cedar file system using logging and group commit

Managing stored voice in the etherphone system

Content Provider	ACM Digital Library
Author	Swinehart, D. Terry, D.
Abstract	The Etherphone™ system was developed at Xerox PARC to explore methods of integrating voice into existing distributed personal computing environments. An important component of the Etherphone system, the voice manager, provides operations for recording, playing, editing, and otherwise manipulating digitized voice based on an abstraction that we call voice ropes. It was designed to allow:unrestricted use of voice in client applications,sharing among various clients,editing of voice by programs,integration of diverse workstations into the system,security at least as good as that of conventional file servers, andautomatic reclamation of the storage occupied by unneeded voice. As with text, we want the ability to incorporate voice easily into electronic mail messages, voice-annotated documents, user interfaces, and other interactive applications. Because the characteristics of voice differ greatly from those of text, special mechanisms are required for managing and sharing stored voice. The voice manager reduces the work generally associated with building voice applications by providing a convenient set of application-independent abstractions for stored voice.Clients view voice ropes as immutable sequences of voice samples referenced by unique identifiers. In actuality, a voice rope consists of a list of intervals within voice files that are stored on a special voice file server. A database stores the many-to-many relationships that exist between voice ropes and files. Maintaining voice on a publicly accessible server facilitates sharing among various clients. These facilities for managing stored voice in the Etherphone system were designed with the intent of moving voice data as little as possible. Once recorded in the voice file server, voice is never copied until a workstation sends a play request; at this point the voice is transmitted directly to an Etherphone, a microprocessor-based telephone instrument. In particular, although workstations initiate most of the operations in the Etherphone system, there is little reason for them to receive the actual voice data since they have no way of playing it.Adding such voice facilities to a diverse and complex software base presents challenging problems to the systems builder since much of the existing workstation and server software cannot be changed or extended. Manipulating stored voice solely by textual references, besides allowing efficient sharing and resource management, has made it easy to integrate voice into documents. The only requirements placed on a workstation in order to make use of the voice services are that it have an associated Etherphone and an RPC implementation.The Etherphone system uses secure RPC for all control functions and DES encryption for transmitted voice. These ensure the privacy of voice communication, which is important even in a research environment, although the network is inherently vulnerable to interception of information. Storing the voice in its encrypted form protects the voice on the server and also means that the voice need not be reencrypted when played. All in all, the voice manager provides better security than most conventional file servers.The performance of operations for editing and managing recorded voice must be compatible with human response times: sub-second response at a peak rate of several operations per second is more than adequate. Performance measurements confirm that the voice manager easily meets these requirements. In conclusion, the major technical contributions presented in this paper involve the use of simple databases to:describe the results of editing operations such that existing voice passages need not be moved, copied, or decrypted, andprovide a modified style of reference counting that allows the automatic reclamation of obsolete voice. Approximately 50 Etherphones are in daily use in the Computer Science Laboratory at Xerox PARC. We have had a voice mail system running since 1984 and a prototype voice editor available for demonstrations and experimental use since the spring of 1986.
Starting Page	103
Ending Page	104
Page Count	2
File Format	PDF
ISBN	089791242X
DOI	10.1145/41457.37510
Language	English
Publisher	Association for Computing Machinery (ACM)
Publisher Date	1987-11-01
Publisher Place	New York
Access Restriction	Subscribed
Content Type	Text
Resource Type	Article

Central Library (ISO-9001:2015 Certified)
Indian Institute of Technology Kharagpur
Kharagpur, West Bengal, India | PIN - 721302

See location in the Map
03222 282435
Mail: support@ndl.gov.in

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in