Michael J. Knister and Atul Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proceedings of the ACM 1990.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....transformation costs, we o#er a powerful runtime system, a set of programming abstractions for distributed data management, and a set of group specific user interface elements. Before describing the necessary transformation steps in detail, we discuss related work. 2 Related Work DistEdit [4] and DistView [11] reuse existing single user application as multi user applications. DistEdit allows a transformation of editor programs. Although the transformation does not require much e#ort, it uses a floor control mechanism, which only allows one user at a time to edit a document and thus ....

Michael J. Knister and Atul Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proceedings of the ACM 1990.

....ours, but it encourages turn taking floor control because when running an open floor, the events are not guaranteed to arrive in the same order at all sites. On the other hand, MMConf is a toolkit, whereas the groupware features of our system are currently integrated in the application. DistEdit [Knis90] is a toolkit for programming multi user text editors. It relies on the ISIS toolkit [Birm89] for the distributed aspect of the architecture. This may cause performance problems, as stated by the authors, because of the concurrency control algorithms implemented by ISIS. GroupKit [Rose92] also is ....

. Knister, M. J., and Prakash, A., DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proc. Third Conference on Computer-Supported Cooperative Work (Los Angeles, CA, October 1990). ACM, New York, 1990.

....to keep the consistency of the distributed data. In GroupDesign events are sent to replicas describing commands carried out by each user. The protocol is asynchronous because a replica never waits for a reply from other replicas. Logic clocks are used to ensure proper consistency. The DistEdit [Knister 90] toolkit maintains a copy of the state of the editor for each user. The consistency is ensured by a reliable atomic multicast protocol. Duplex [Pacull 94] uses a reliable atomic multicast protocol to maintain consistency and also allows discontinued operation in case of network partition. In ....

M. Knister and A. Prakash. DistEdit: a distributed toolkit for supporting multiple group editors. In Proceedings of the Conference on Computer Supported Cooperative Work (CSCW '90), Los Angeles, California, 1990. ACM Press.

.... that modern window systems make this task very difficult to achieve [Lau90] However, emerging groupware toolkits make it possible to adapt singleuser applications to collaborative settings with only a few changes aimed to combat 182 1 Conferencing and Collaborative Computing these shortcomings [Kni90, Jef92, Ros92, Ben94, Pat90, Pa93a]. The resultant application is thus collaboration aware. With the migration to wide area environs, centralized workspace architectures are often supplanted by distributed ones. Although it might be easier to take a centralized approach, in a geographically distributed environment, the choice may ....

M.J. Knister, A. Prakash; DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors, Proceedings ACM Conference on Computer-Supported Cooperative Work, CSCW'90, pp.13-26, Los Angeles, CA, pp.343-356, Oct 1990.

....PES. A process that is not in the PES will not need to maintain all of the above state components, but rather will just need to maintain state related to the messages received. 5 A Detailed Example Let us consider a collaborative application that allows for document sharing, i.e. a group editor [7]. This application can be thought of as being made up of the following objects: a document object (denoted by obj doc ) a window object (denoted by obj win ) and a pointer object (denoted by obj ptr ) A copy of each of these objects exists at each of the processes in the multicast group. The ....

M. Knister and A. Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proc. of the ACM Conf. on Computer Supported Cooperative Work, pages 343--355, Oct. 1990.

....at the basic window system level [8] Applications for a certain window system do not need to be modified. Most problems with this approach result from window systems not being designed for such a purpose. A number of toolkits to implement multi user applications have been described. DistEdit [7] implements a minimal set of operations for text editors. These operations are distributed by the kernel to replicated editors. MMConf [3] also uses a replicated architecture, but broadcasts low level events. Both toolkits require minor changes to existing applications. LIZA [6] and Rendezvous ....

Knister, M.J. and Prakash, A., DistEdit: A distributed toolkit for supporting multiple group editors. In Proceedings of the Conference on Computer Supported Cooperative Work (CSCW '90) ACM Press, Los Angeles, California, 1990, pp. 343-355.

....cooperative editing systems. Keywords: concurrency control, consistency models, cooperative editing, distributed computing, CSCW. 1 Introduction Cooperative editing systems are very useful and intensively used tools in the rapidly expanding area of CSCW (Computer Supported Cooperative Work) [5, 8, 10, 11, 15, 16]. A cooperative editing system allows multiple users to view and edit a shared document simultaneously from different sites, which are connected by a communication network. Each site typically contains an user interface for generating editing operations and displaying shared documents, a local ....

M. Knister and A. Prakash:"DistEdit: a distributed toolkit for supporting multiple group editors," In Proc. of ACM Conference on Computer Supported Cooperative Work, pp. 343-355, Oct. 1990.

.... to computational resources (single user databases can be instances of UNI QUEUE or MULTI QUEUE, while multi user ones can be classified as non collaborative MULTI NO QUEUE) ffl Single groupware applications aimed to the production of documents or of program source code, as for example DistEdit [31] that deals with group editing, or GroupDesign [28] that is oriented towards drawing in structured graphics, as is the LBL Whiteboard, a public domain product (all of these collaborative applications can be well representative of MULTI NO QUEUE) ffl Tool kits that support collaboration within ....

Michael J. Knister and Atul Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In CSCW90: Conference on Computer-Suppported Cooperative Work, pages 342--355, Los Angeles, California, October 1990.

....et al. 1988] The Capture Lab [Halonen et al. 1990, Mantei, 1988, Mantei, 1989] the Multi Device Multi User Multi Editor (MMM) Bier and Freeman, 1991, Bier et al. 1992] and Matrix [Jeffay et al. 1992] all conceptualize floor passing as passing a single, sharable keyboard. DistEdit [Knister and Prakash, 1990] and rIBIS [Rein and Ellis, 1991] both allow participants to alternate between working independently and taking exclusive global control of the shared space, using mouse input for explicit mode control. These are called the free and lockstep cursor modes in DistEdit, and the loosely and tightly ....

Knister, M. J. and Prakash, A. (1990). DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In

....functions are defined and discussed in detail. Key Words: cooperative editing, consistency, transformation algorithms, CSCW. 1 Introduction Cooperative editing systems are very useful and intensively used tools in the rapidly expanding area of CSCW (Computer Supported Cooperative Work) [3, 4, 5, 6, 8, 9]. A cooperative editing system allows multiple users to view and edit a shared document simultaneously from different sites, which are connected by a communication network. Each site typically contains an user interface for generating editing operations and displaying shared documents, a local ....

....old character OC is deleted from the document state iff OC is in the deleting range of an executed Delete operation. It has been shown that compound editing operations like Replace String in practical text editing systems, such as vi and Emacs, can been implemented on top of these two primitives [6]. To guide the design of the intention preserving transformation functions for the two primitive op3 erations, the following verification criteria is defined. Definition 1 Verification criteria The execution of a primitive operation O is intention preserving iff the following editing effects are ....

M. Knister and A. Prakash:"DistEdit: a distributed toolkit for supporting multiple group editors," In Proc. of ACM Conference on Computer Supported Cooperative Work, pp. 343-355, Octo. 1990.

....architectures can be found in the streaming based systems (such as video audio conference) the collaborative editors and multimedia systems. Examples of products with centralized architecture are NetMeeting [14] SharedX[7] and XTV [2] and with replicated one are GroupKit [17] and DistEdit [11]. The replicated approach is preferred when the e ciency is required, while the centralized one is a usual choice when simplicity is demanding. With regard to collaborative 3D graphics applications, the replicated architecture is mostly used. As examples for this mode we may cite the projects ....

M. Knister and A. Prakash. Distedit: A distributed toolkit for supporting multiple group editors. In Third Conf. Computer-Supported Cooperative Work, pages 343355, Oct. 1990.

....Computer Supported Cooperative Work (CSCW) systems: ad hoc development, use of CSCW toolkits and use of integrated CSCW environments. In the ad hoc development the system is usually built from scratch, making little or no use of elaborate components. CSCW toolkits, such as Prospero [3] DistEdit [10] and Groupkit [18] allows one to build a system based on a set of predefined building blocks that can be reused and combined in different ways. Integrated CSCW environments, such as the activity support system TACTS [21] and the locale support system Worlds [7] 8] are cooperative platforms in ....

Knister, M.J. and Prakash, A.: DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. Proceedings of the ACM 1990 Conference on Computer-Supported Cooperative Work (CSCW'90), pp. 343-355, 1990.

....used in the development of cooperative systems: ad hoc development, use of CSCW toolkits and use of integrated CSCW environments. In the ad hoc development the system is usually built from scratch, making little or no use of elaborate components. CSCW toolkits, such as Prospero [2] DistEdit [10] and Groupkit [17] allows one to build a system based on a set of pre defined building blocks that can be reused and combined in different ways. Integrated CSCW environments, such as the activity support system TACTS [20] and the locale support system Worlds [6,7] are cooperative platforms in ....

Knister, M.J. and Prakash, A.: DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. Proceedings of the ACM 1990 Conference on Computer-Supported Cooperative Work (CSCW'90), pp. 343-355, 1990.

....must handle issues such as concurrency control. Different replicated toolkits handle this in a variety of ways. For example, Share Kit [40] has no direct concurrency control, and it must be programmed infrom scratch if a programmer requires it. Others do provide concurrency capabilities. DistEdit [43] uses atomic broadcasts. ObjectWorld s shareable objects have the ability to detect messages that have arrived out of order, and allow programmers to do non optimistic locking [76] GroupKit [62] can force serialization for some actions by funneling selected activities through one of the ....

....(Lotus Inc. Even toolkits within the domain of real time interaction handle different niche problems. Dewan and Choudhary s Suite toolkit [10] applies only to highly structured text objects and investigates how flexible access control mechanisms are incorporated into them. Knister and Prakash s [43] DistEdit provides groupware primitives that could be added to existing single user text editors to make them group aware. DistView, produced by the same group, is oriented towards a fairly strict view sharing approach to sharing window components and underlying data via an object replication ....

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Knister, M.J. and Prakash, A. (1990) "DistEdit: A distributed toolkit for supporting multiple group editors." in Proceedings of ACMCSCW'90 Conference on Computer Supported Cooperative Work, p343--355, Los Angeles, California, October 7--10.

....by other users, while carefully avoiding the complexities involved in providing simultaneous access to documents and records. Broadly speaking, such tools are generally referred to as asynchronous collaborative editors. x# Another approach was taken by GROVE (Ellis et al. 1990) and DistEdit (Knister et al. 1990). These are examples of collaborative editing tools that support sessions of simultaneous access to a shared document as well as immediate awareness of interactions of other users with the shared document. Broadly speaking, these tools are referred to as synchronous collaborative editors. x# ....

.... shaped considerably by our decision to design and implement it as a collaborative extension of an existing compound document framework, rather than developing it from scratch, or as a compound document editing extension of a collaborative document editing framework or toolkit (such as DistEdit (Knister et al. 1990), GroupIE (Rdebusch, 1995) or IRIS (Koch, 1995) We considered both alternatives to be inefficient, as the development of compound document editing document facilities requires a significant amount of time without providing new insights compared to using existing compound document frameworks. We ....

Knister, M.J., and Prakash, A. (1990) DistEdit : A distributed toolkit for supporting multiple group editors. CSCW'90 : Proceedings of the conference on computer-supported cooperative work, October 7-10, 1990, Los Angeles, CA, USA: , (p. 343-354). Association for Computing Machinery, New York.

....applications (Lotus Inc. Second, even toolkits within the domain of real time interaction handle different niche problems. Shen and Dewan s (1992) Suite toolkit applies only to highly structured text objects and investigates how flexible access control mechanisms are incorporated into them. Knister and Prakesh s (1990) DistEdit provides groupware primitives that could be added to existing single user text editors to make them group aware. DistView, produced by the same group, is oriented towards a mostly strict WYSIWIS approach to sharing window components and underlying data via an object replication scheme ....

Knister, M.J. and Prakash, A. (1990) "DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors." in Proceedings of ACM CSCW'90 Conference on Computer-Supported Cooperative Work, October 7-10, Los Angeles, California, p343-355, ACM Press.

....executable components of T E X system. Target application was completely described in SYNOPSIS. SYNTHESIS was able to generate coordination code automatically. Collaborative Editor A system which extends the functionality of existing single user editors with group editing capabilities [7]. Micro Emacs [10] source code was used to implement single user editor. Same system description was specialized in two different ways to generate micro Emacs based group editors for Windows and UNIX. Table 1: Summary of experiments of using SYNTHESIS to facilitate the integration of ....

M. J. Knister and A. Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proceedings, CSCW 90, Los Angeles, CA, October 1990, pp. 343-355.

....that distinguishes between textual and structural information. A text is partitioned into sections that are owned by each author. Like CES, Quilt [7] uses sections as editable granularity. On the other hand, editors like the Group Outline Viewing Editor (GROVE) 6] or toolkits like DistEdit [15] provide no structural information. GROVE is finegrained and supports real time updates on characterlevel using insert and delete primitives. A transformation algorithm based on priorities and semantics of the operations permits highly concurrent access. Floor passing in DistEdit allows a single ....

Knister, M.J., Prakash, A.: DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. Proc. 3rd Int. Conf. on Computer-Supported Cooperative Work, Los Angeles, CA, Oct. 1990. New York: SIGCHI/SIGOIS ACM, pp. 343--355

....the Search button is pressed to locate the next occurrence, and the cursor is returned to its default position to close the loop. ii) If the user presses the Skip button the animator presses Search to locate the next word as before and returns the cursor to its default position. DistEdit [3] is an example of a toolkit that allows heterogeneous applications to collaborate using a common language for application actions. Periodically, each site transmits updates (translated application actions) over the network to other sites, where they get buffered. For maximum flexibility ....

Knister, M.J. and Prakash, A. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors, in CSCW `90 Conference Proceedings (1992).

....Tools We decided to use the Suite user interface primitives [8] for implementing the form and view editors. Several other user interface tools also address some of our implementation needs. These tools include multi user window systems such as VConf [18] shared toolkits such as DistEdit [14], and shared user interface architectures such as Rendezvous [23] However, these tools either provided low level support for building the editors or did not address all our needs. Suite supports near automatic generation of multi user structure editors. An interactive Suite object can display ....

Michael J. Knister and Atul Prakash, "DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors, " Proceedings of ACM Conference on Computer Supported Cooperative Work, October 1990, pp. 343356.

....and to keep the consistency of the distributed data. In GroupDesign events are sent to replicas describing commands carried out by each user. The protocol is asynchronous because a replica never waits for a reply from other replicas. Logic clocks are used to ensure proper consistency. The DistEdit [30] toolkit maintains a copy of the state of the editor for each user. The consistency is ensured by a reliable atomic multicast protocol. Duplex [39] usesa reliable atomic multicast protocol to maintain consistency and also allows discontinued operation in case of network partition. In Ensemble [36] ....

M. Knister and A. Prakash. DistEdit: a distributed toolkit for supporting multiple group editors. In Proceedings of the Conference on Computer Supported Cooperative Work (CSCW '90), Los Angeles, California, 1990. ACM Press.

....a Unix tool kit called COeX [21] providing primitives for building diverse collaborative applications in a high level fashion, abstracting basic multi user issues and implementation details. Another effort, specifically directed towards group editing and using a similar approach, is DistEdit [19], which exploits the communication mechanism available in another tool kit, called ISIS [4] GroupDesign [18] allows group sessions and it is oriented towards drawing in structured graphics. It supports this kind of activity providing features as Tele Conference and means of recognizing actions ....

Michael J. Knister and Atul Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In CSCW90: Conference on Computer-Suppported Cooperative Work, pages 342--355, Los Angeles, California, October 1990.

....have also been proposed recently. They provide essentially some basic features to allow programmers to build exactly the system that suits their needs. For example, Bayou [11] lets programmers insert application specific code into the provided generic optimistic concurrency control. DistEdit [7] allows any text editor to be ported into CSCW by defining generic text editing primitives. These systems and toolkits provide only one concurrency control policy. This choice limits each of them to a few specific well suited uses. Some projects such as GroupKit [10] address this limitation by ....

Knister, M. J., and Prakash, A. DistEdit : a distributed toolkit for supporting multiple group editors. In Proceedings of the CSCW conference (Oct. 1990), pp. 343--355.

.... distributed computing systems [7] Various concurrency control approaches have been proposed for cooperative editing systems, including turn taking protocols which allow only one user at a time to edit the shared document [7, 21] lock based protocols which lock a data object before updating it [8, 11], transaction based protocols which encapsulate a collection of editing operations into an atomic transaction [1, 6, 8, 12] and optimistic execution protocols which allow responsive execution of editing operations and repair out of order executions by performing reversible operations [10, 19, 17] ....

M. Knister and A. Prakash:"DistEdit: a distributed toolkit for supporting multiple group editors," In Proc. of ACM Conference on Computer Supported Cooperative Work, pp. 343355, Octo. 1990.

....provided support for the application information sharing needs of applications. Examples of these systems include Arjuna [99] 100] a system for supporting the low level distribution needs of applications; Rendezvous [77] which provides support for sharing of views and data structures; DistEdit [57], a domain specific tool for constructing shared editors based on the ISIS [4] framework; and SUITE [18] 20] a system that provides support for several dimensions of coupling between replicated data structures and views, based on the SUITE user interface management system [21] 22] Very few ....

Knister, M.J., and Prakash, A. "DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors." CSCW 90: Proceedings of the Conference on Computer-Supported Cooperative Work, Los Angeles, CA: ACM, 343-355.

....synchronisation schemes must be employed in order to ensure that members views remain consistent. In addition to the specific applications cited above a number of toolkits have been written to simplify the task of implementing certain classes of groupware application. GroupKit [17] and DistEdit [18] are examples of such toolkits and each is based on a fully replicated architecture and uses the atomic broadcasting facilities provided by ISIS [19] to communicate between replicas. ISIS provides two main atomic multicast protocols which allow group updates to be received by replica objects in ....

Knister, M., A. Prakash, "DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors", Proc. of Conference on Computer Supported Cooperative Work, Los Angeles, California, U.S., October 1990.

....collaboration. Locking If we can ensure by locking that each application object can only be updated by one user, then the updates they perform will commute with other updates. This is the traditional database approach to ensuring commuting updates. It is also the basis of several group editors [13, 4, 17, 23, 20], where various locking schemes are used. Giving undo attention 15 The most prevalent form of lock is the explicit lock. A user will obtain a lock on a section of a document, or a whole file, perform updates and then release the lock. During the period the lock is held, other users cannot update ....

M. J. Knister and A. Prakash. Distedit: a distributed toolkit for supporting multiple group editors. In CSCW'90 Proceedings of the Conference on Computer-Supported Cooperative Work, pages 343--355, 1990.

....as failure atomicity. However, the burden of validating the resulting executions then lies on the application programmers. We next explore several systematic approaches with well defined, but flexible, consistency semantics that could provide a unifying paradigm for robust collaboration. DistEdit [19] a group editor uses the Isis toolkit [5] which supports process groups and associated broadcast protocols that update the state encapsulated by processes corresponding to different users. Failure notification and message ordering guarantees provided by the Isis system can ensure consistency ....

M.J. Knister and A. Prakash. Distedit: A distributed toolkit for supporting multiple group editors. In Proceedings of the Conference on CSCW. ACM, 1990.

....other users. This may result in blocking of designers over long periods of time which is not acceptable in cooperative authoring. If this approach is combined with versioning mechanisms, new object versions can be derived concurrently but they need later to be merged manually by the users. GS87, KP90] introduced the notion of a floor to synchronize multiple users working with a set of shared objects. The floor is owned by one user at a time who has the exclusive permission to execute all modifications on the objects while other users can only observe his actions by means of read operations. A ....

M.J. Knister and A. Prakask. DistEdit: A distributed toolkit for supporting multiple group editors. In Proc. of the third ACM Conference on ComputerSupported Cooperative Work, pages 343--355, 1990.

....toolkits include: Rendezvous [25] an architecture and prototyping language designed to support the development of real time interfaces forcooperative# applications. Mead [7] a prototyping environment which supports the rapid construction of multiuser interfaces by direct manipulation. DistEdit [26]: a development toolkit to support the construction of shared editing systems. OVAL [27] a Lisp based object oriented toolkit which allows the rapid construction and reconfiguration of a range of cooperative applications based upon sharing structured information. 3.3.2. The use of space A ....

Knister, M.J. and Prakash, A. (1990) 'DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors', Proceedings of the Conference on Computer Supported Cooperative Work (CSCW '90), Los Angeles, CA, October 7-10 1990, ACM press , ISBN 0-89791-402-3.

....transport services coexisting with traditional point to point communication services are a pragmatic approach particularly interesting. The GTS system [5] is a reference for us in the way to build effective useful cooperative large scale infrastructures. Research provided by some projects [36] 37][38], 22] are examples of the replication approach we argue for synchronous groupware. But our work wish to achieve a more generic group oriented platform basis to support in a complementary fashion synchronous as well as asynchronous applications with different semantics criteria. The current ideas ....

Knister,M., Prakash,A., "DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors", Proceedings of the CSCW'90, (October 1990)

....check out policy with merge support, but uses a line based textual representation and a state based differences approach. This development is encouraging since it supports our fundamental decision of regarding the copy merge strategy as viable. The work on groupware and synchronous editors [EGR91, KP90, MO92] are other interesting efforts to support the group related activities discussed above, but does not solve the problems during asynchronously performed tasks. These editors also do not provide any mechanisms for revision and variant control since the metaphor is that there is only one shared ....

Knister, M.J., Prakash, A., DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors, Proceedings of CSCW'90, ACM 1990 Conference on Computer Supported Cooperative Work, Los-Angeles, 1990.

....[22] With synchronous interaction, modifications to the document context (the body of all data such as text, figures, messages, directives, etc. produced using the three facilities) can be observed in real time by all members of the collaboration. For example, several systems (GROVE[6] DistEdit[12], Mule[21] propose a synchronous collaborative editor. In contrast, the DUPLEX environment incorporates a collaborative editor with asynchronous interaction between users through a shared kernel which maintains the document context. Synchronous interaction, if required, is achieved using the two ....

M.J. Knister and A. Prakash. DistEdit: A distributed toolkit for supporting multiple group editors. In Proceedings of the ACM Int. Conf. on Computer-Supported Cooperative Work (CSCW '90), pages 343--355, October 1990.

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# M. Knister and A. Prakash, "DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors," Proc. Third Conf. ComputerSupported Cooperative Work, pp. 343--355, Oct. 1990.

....to keep the state of the replicas consistent. Most group editors adopt a replicated approach in which text buffers are replicated at each site, and editor processes run a synchronization algorithm among themselves in order to maintain the consistency of the replicated buffer. For example, DistEdit [8] provides locks of varying granularity that can consist of any number of consecutive characters, and the size of a lock dynamically grows as a user continues to type. The dOPT algorithm of Grove [9] uses an optimistic strategy in that it locally transforms remote operations based on the state of ....

M. Knister and A. Prakash, "DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors," in Proc. of the Third Conference on Computer-Supported Cooperative Work, Oct. 1990, pp. 343--355.

....to catch up on the activities that occurred during the session. This paper presents the paradigm, its applications, its design, and our preliminary experience with its use. Introduction Many approaches to computer supported collaboration have been centered around synchronous collaboration [4, 5, 9]. In synchronous collaboration, users of a multi user application first find a common time and then work in a WYSIWIS (What You See Is What I See) collaborative session. However, a synchronous mode of collaboration can often be too imposing on the schedule of the participants. It requires that ....

M. Knister and A. Prakash. DistEdit: A distributed toolkit for supporting multiple group editors. In Proceedings of the Third Conference on Computer-Supported Cooperative Work, pages 343--355, Los Angeles, California, October 1990.

....etc. execute processes that perform operations (e.g. read, write, etc. on objects (e.g. files, printers, etc. The permissions of a principal to perform operations on system objects are called the access rights of the principal in the system. As an example, consider the DistEdit [12, 13] system. DistEdit is a toolkit for building collaborative editors using a replicated process architecture. In a collaborative editing session, each user in the collaboration has an editor process (see Figure 2) When a user edits the buffer, the DistEdit sends a copy of the command to each editor ....

M. Knister and A. Prakash. DistEdit: A distributed toolkit for supporting multiple group editors. In Proceedings of the Third ACM Conference on Computer-Supported Cooperative Work, pages 343--355, October 1990.

....and else it returns 0, and a method unlock( to release the lock. Application designers can provide their own application specific object classes to implement more sophisticated locking schemes, For instance, to allow simultaneous editing on a text user interface object as in the DistEdit toolkit [9], application designers can provide a text specific object that maintains a lock table containing portions of text that are locked. DistView provided lock objects would then be used only to control access to the lock table, rather than to the text object itself. An alternative strategy would have ....

....of replication. Furthermore, the application writer is given mechanisms to handle concurrency control through the use of locks an issue which is typically not adequately addressed in existing toolkits. The replication approach used in DistView builds on our work on the DistEdit toolkit [9, 10], in which the underlying data objects representing editors text buffers were replicated. DistView goes further because arbitrary interfaces can also be replicated, providing not just consistent but identical displays of data in windows that are shared. Furthermore, DistView is designed to ....

M. Knister and A. Prakash. DistEdit: A distributed toolkit for supporting multiple group editors. In Proceedings of the Third Conference on ComputerSupported Cooperative Work, pages 343--355, Los Angeles, California, October 1990.

....its Things or Places. On the other hand, the Corona server does not support the Facade like capabilities for viewing the shared states of groups before actually joining the groups; users should obtain the names of groups to join externally through our session manager [14] Coast [22] and DistEdit [12] fully replicate their shared states as well as various administrative components among client applications. As discussed earlier, a fully replicated approach may not be suitable for collaboration over a unreliable, longhaul collaboration environment such as the World Wide Web where clients may ....

M. Knister and A. Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proc. of the Third Conference on Computer-Supported Cooperative Work, pages 343--355, Oct. 1990.

....duration, even up to several days. Many of the issues of fault tolerance and real time propagation of updates are not important in such systems. The DistEdit toolkit concentrates on providing more closely coupled real time interaction. An earlier version of the DistEdit toolkit is described in [12]. Several major features have since been added. Unlike the earlier version, the present version allows several users to edit the same file simultaneously in a single session, provides support for locking of regions, allows users to undo the globally last as well as their own last actions, handles ....

....The lightweight process system in ISIS allows broadcasts to be received while waiting for keyboard input; also, events, such as a group member failing, can be handled by triggering a lightweight process. 7. 2 Dealing with Concurrent Updates Unlike the earlier version of DistEdit described in [12], the current version of the DistEdit toolkit provides support for concurrent updates. To keep response time low, any update is performed locally first and then broadcast to other sites. It is well known that concurrent updates can Table 3: DistEdit Protocol Messages LOCK(previous lock id, ....

M. Knister and A. Prakash. DistEdit: A distributed toolkit for supporting multiple group editors. In Proceedings of the Third Conference on Computer-Supported Cooperative Work, pages 343--355, Los Angeles, California, October 1990.

....and proves several useful properties of the algorithm. Section 6 suggests ways of improving the performance of the algorithm for many common situations. Section 7 discusses the design and implementation issues we faced in incorporating the undo scheme in the group text editor toolkit, DistEdit [21, 22]. In the same section, based on our experience with DistEdit s undo facilities, we also discuss some important user interface design issues, for instance the utility of providing both a per user undo and a global undo in a groupware system. Finally, Section 8 summarizes our conclusions and future ....

....undo is quite reasonable, avoiding the need for handling conflicts. 8 Future Work and Conclusions We have presented a framework for group undo which is simple and generally applicable to a variety of documents. The techniques proposed in this paper have been implemented in the DistEdit toolkit [21]. The techniques are presented in the context of history undo; however, many aspects of the techniques, such as the notions of Transpose and Conflict, are also applicable to implementing undo based on the linear and US R models. The focus of the paper was on developing a general framework for ....

M. Knister and A. Prakash. DistEdit: A distributed toolkit for supporting multiple group editors. In Proceedings of the Third Conference on Computer-Supported Cooperative Work, pages 343--355, Los Angeles, California, October 1990.

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Michael J. Knister and Atul Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proceedings of the ACM 1990.

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Michael J. Knister and Atul Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proceedings of the ACM 1990.

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Michael J. Knister and Atul Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proceedings of the ACM 1990.

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Michael J. Knister and Atul Prakash. DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. In Proceedings of the ACM 1990.

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Knister, M.J. and Prakash, A. DistEdit: A distributed toolkit for supporting multiple group editors. In Proceedings of CSCWU90, Los Angeles, CA, Oct 1990. p. 343-355.

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Knister, M.J. and A. Prakash. "DistEdit: A distributed toolkit for supporting multiple group editors.", Proc. ACM CSCW'90 Conference on Computer Supported Cooperative Work, pages 343-355, Los Angeles, California, October 7-10 1990.

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Knister, J. Michael; Prakash, Atul. "DistEdit: A distributed Toolkit for Supporting Multiple Group Editors." CSCW 90 Proceedings, ACM SIIGCHI & SIGOIS, L.A. Oct/90.

No context found.

Knister, M.J., Prakash, A.: DistEdit: A Distributed Toolkit for Supporting Multiple Group Editors. Proc. 3rd Int. Conf. on Computer-Supported Cooperative Work, Los Angeles, CA, Oct. 1990. New York: SIGCHI/SIGOIS ACM, pp. 343--355

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Knister MJ, Prakash A (1990) DistEdit: a distributed toolkit for supporting multiple group editors. Proceedings of the ACM Conference on CSCW, Los Angeles, Calif., ACM Press: 343--355

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