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Satchel: Providing Access to Any Document, Any Time, Anywhere

1. Network C gt Service Software Apache Web Server File Server Satchel Server Fig 1 The basic components of the Satchel system to the device with velcro in an easily accessible location Specialized software converts between infrared protocol and Internet Protocol IP and adds the contextual information to the request so that an appropriate service is offered to the user The infrared transceiver along with its associated software we refer to as the infrared Gateway Note that although there are printers with integral infrared transceivers the trans ceiver cannot be accessed by external software To enable radio communi cations a standard dial in connection from the Nokia 9000 to a Communi cations Server is made using the GSM cellular radio network we refer to the dial in connection and the GSM network as the Radio Gateway The Communications Server provides access to the Satchel Server and the rest of the Satchel system Document Service Software and an Apache Web Server Laurie 1999 are located on the Satchel Server In addition each users own PC runs a Satchel Personal Web Server that provides access to documents accessible from the user s own PC e g documents stored on the local C drive or a shared file server This specialized Web server only provides access to the specific document referenced by the token Each user s PC is also equipped with an infrared transceiver
2. Services for Wordsworth Services Apache Directory Servi Web Server Print request TVICC Print request b form in Halibut form in HTML Satchel enabled printer Wordsworth Infra red _ Fetch i Personal lt Gateway service ice J Web Server Satchel enabled in HTML J Print queue for Wordsworth printer Fig 7 Invoking a print request Wordsworth or commercially available conversion utilities Our current solution sup ports several hundred end to end conversion possibilities This service is completely transparent to the user When a document is selected for printing for example the user does not even need to know or own the application that created the document the Satchel Conversion Service will carry out the appropriate conversions and print it on the selected printer The Conversion Service helps streamline the user inter face by carrying out these conversions behind the scenes 5 6 Using the Print Service An Example Figure 7 shows a schematic diagram of browsing through a directory and printing a document Figure 7 a shows what happens after the user presses Open with a noncached directory selected Because the user does not happen to be near an infrared transceiver the mobile client sends the token for the selected directory using the Radio Gateway The Fetch Service is invoked and the directory listing is retrieved via the Personal Web Serve
3. El Pendo Consulting 1 Expense Claims Open Satchel E 8Jan97_Workshop Services E Forms ese C Merger Plans Update E Logging page a Close PHONEOFF Status Ready Fig 5 The contents of the El Pendo Consulting folder with the document Merger Plans selected that created it its size etc The document itself cannot be opened and displayed on the Nokia 9000 5 3 3 Implementation The Satchel mobile client is a specialized Web browser that has been designed specifically to support Satchel functional ity For example the mobile client makes infrared and GSM requests to the Satchel system and implements the Beam Service see Section 5 4 4 It makes all requests using HyperText Transfer Protocol HTTP Berners Lee et al 1996 but it does not render HyperText Markup Language HTML Berners Lee and Connolly 1995 but a condensed and simplified proprietary format called Halibut Flynn et al 2000 This approach reduces communication time and computational load on the mobile device and improves its battery life Tokens are basically Universal Resource Locators URLs Berners Lee et al 1994 that are encapsulated in HTTP requests Unlike URLs though tokens incorporate a digital signature created by public key cryptography e g see Salomaa 1990 Each mobile device contains a private key and a corresponding public key is used by the Satchel system When a token is sent by the mobile client it
4. Networking Forrester Report Forrester Research Inc Cambridge MA SALOMAA A 1990 Public key cryptography EATCS monographs on theoretical computer science Springer Verlag New York NY SELLEN A AND HARPER R 1997 Paper as an analytic resource for the design of new technologies In Proceedings of the ACM Conference on Human Factors in Computing Systems CHI 97 Atlanta GA Mar 22 27 S Pemberton Ed ACM Press New York NY 319 326 UNWIRED PLANET 1997 Handheld Device Markup Language Specification Unwired Planet Inc Redwood City CA WIRELESS APPLICATION PROTOCOL FORUM LTD 1998 Wireless Markup Language WHITTAKER S FROHLICH D AND DALY JONES O 1994 Informal workplace communication what is it like and how might we support it In Proceedings of the ACM Conference on Human Factors in Computing Systems Celebrating Interdependence CHI 94 Boston MA Apr 24 28 ACM Press New York NY 131 137 ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000
5. When printing via infrared no navigation to find networked printers was required since the correct printer form was automatically presented to the user Although the Scan Service was used infrequently see Table I those who did use it 10 of 26 were unanimous in their positive comments with one user describing it as brilliant The Scan Service was seen as particularly easy to use compared to other methods of scanning that require using unfamiliar interfaces with many unexplained options and sometimes unex pected results In addition some users commented that when using other scanning methods it was notoriously difficult to store the document contents away to a remote location and storing a document locally at a different site was impractical Scanning was used for a number of reasons One user who had never scanned before the trial because he said it was too difficult used the Scan Service to scan in forms so he could later edit them and send them electronically Two users said it was useful for them personally one for scanning invoices the other for scanning forms received from other people in hard copy Although users found access to devices particularly easy using Satchel there were some specific problems in the implementation of some services though these were not in general perceived to be very serious For example many users 12 of 24 felt there were not enough print options on the ACM Transactions on Computer Human I
6. i e tokens on the mobile device To the user there are few important distinctions between the tokens and the documents themselves So for example many thousands of documents can apparently be stored in the small portable device Since portable devices are often unable to display many document formats the documents themselves are never transferred to the mobile device The mobile device only transmits and receives tokens and because these are very small they can be transmitted very quickly When there is a requirement to see the content of the document the secure token is transmitted to a device on the wired network e g a printer or a personal workstation and Satchel dereferences the token to yield the real document So the tokens can move around very quickly in the wireless world and the wired network is used only when the document s content is required ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere e 331 5 1 2 A Specialized Context Sensitive User Interface Another funda mental idea in the design of Satchel is the highly specialized context sensitive user interface In order to provide a streamlined user interface we have removed all functionality that is not expressly required to support accessing documents and document services Thus Satchel does only a few things but does them efficiently We have also designed Satchel
7. ELDRIDGE M BARNARD P AND BEKERIAN D 1994 Autobiographical Memory and Daily Schemas at Work Memory 2 1 51 74 ELDRIDGE M LAMMING M FLYNN M JONES C AND PENDLEBURY D 2000 Studies of Mobile Document Work and their Contributions to the Satchel Project Pers Tech 4 105 115 ELDRIDGE M SELLEN A AND BEKERIAN D 1992 Memory Problems at Work Their Range Frequency and Severity Tech Rep EPC 1992 129 Xerox Research Centre Europe Cambridge UK ETSI 1997 ETS 300 607 1 Digital cellular telecommunications system Phase 2 Mobile station MS conformance specification Part 1 Conformance specification GSM 11 10 1 version 5 5 1 ETSI Sophia Antipolis France FLYNN M PENDLEBURY D JONES C ELDRIDGE M AND LAMMING M 2000 The Satchel System Architecture Mobile Access to Documents and Services Mob Netw Appl 5 4 FROHLICH D 1995 Requirements for interpersonal information management In Mobile Personal Communications and Co operative Working P J Thomas Ed Alfred Waller Ltd Publishers Oxfordshire UK GUARDIAN 1991 RAF officer reprimanded over Gulf secrets theft Guardian Jun 29 HARPER R AND SELLEN A 1995 Collaborative tools and the practicalities of professional work at the international monetary fund In Proceedings of the ACM Conference on Human Factors in Computing Systems CHI 95 Denver CO May 7 11 I R Katz R Mack L Marks M B Rosson and J Nielsen Eds ACM Pre
8. Transactions on Computer Human Interaction Vol 7 No 3 September 2000 324 M Lamming et al She is concerned someone else will see her confidential report on the printer We believe that this should not be so difficult Ann should be able to concentrate on the business at hand she should not be distracted by grappling with the technology In contrast to current solutions Satchel was designed specifically to support the work of mobile professionals Because of this specialization Satchel overcomes many of the problems illustrated in the opening sce nario In Section 2 we will present evidence that the situations and problems faced by Ann are pervasive in mobile document work In Section 3 we discuss our high level design goals and how they are derived from our discussions of mobile document work Section 4 discusses how current technical solutions fail to address these high level design goals Section 5 describes the Satchel system itself Section 6 describes a trial of Satchel and summarizes some of our major findings Section 7 discusses some implications of our findings and some future enhancements 2 MOBILE DOCUMENT WORK For our purposes we consider a mobile worker to be a person who spends a substantial percentage more than 20 of work time away from the desk or immediate work area We are interested in supporting mobile profession als rather than nonprofessionals since they are typically engaged in more doc
9. access their docu ments remotely using currently available solutions encountering many of the problems faced by Ann in the opening scenario Satchel provides streamlined access to remote documents and document services and is specialized for supporting mobile document work it supports a limited set of activities very well and is simple to use We believe along with many of the mobile professionals from our trial that there is a need for a document appliance such as Satchel ACKNOWLEDGMENTS We would like to thank Phil Barnard and William Newman for reviewing early drafts of this article as well as our three anonymous reviewers We would also like to thank Shilpa Datar Lorraine Hinds Ian Hutchison Mike Kleyn Douglas Reay and Abi Sellen for helping with the trial and Mark Stringer for helping us with later system enhancements We are also grateful to the 26 people at Xerox who gave up much of their time to help us try out our system REFERENCES BERNERS LEE T AND CONNOLLY D 1995 Hypertext Markup Language 2 0 RFC 1866 BERNERS LEE T FIELDING R AND FRYSTYK H 1996 Hypertext transfer protocol HTTP 1 0 RFC 1945 BERNERS LEE T MASINTER L AND MCCAHILL M 1994 Uniform Resource Locators URL RFC 1738 CHEN E 1998 101 Business Travel Tips Mobile Comput Commun Rev Nov EASTER L E 1999 Bulletproof Installs A Developers Guide to Install Programs for Windows Prentice Hall PTR Upper Saddle River NJ
10. and its associated software as well as addi tional software to support viewing documents on the PC ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere e 333 Fig 2 The Nokia 9000 Communicator lt gt Satchel E Hotlist Open Satchel Inbox Services EI My Computer aU E Network Neighbourhood Update 4837 page Close PHONEGFF status Ready Fig 3 The opening view of Satchel on the Nokia 9000 5 3 The User Interface 5 3 1 Appearance Figure 3 shows a screen shot of the opening view of the Satchel mobile client software when it is selected from the suite of Internet applications One important feature of the user interface on the mobile device is that it presents the user with a view of file structures that is familiar for example in this prototype the view on the Nokia 9000 is consistent with the Windows NT file structure For example the My Computer folder provides access to all the documents stored on the hard disk of the user s PC as well as access to other documents stored on file servers that have been mapped to drive letters The Network Neigh bourhood folder provides access to all documents that are stored on any network that is accessible from the user s own PC Two special folders are the Hotlist and Inbox The Hotlist functions in much the same way as a set of bookmarks in a Web b
11. course of their work This was not surprising since in data collected on pretrial questionnaires the reported frequencies of scanning were extremely low and nonexistent for many users Because beaming from Nokia to Nokia was not logged Table I shows a lower bound estimate of beams derived from an analysis of the detailed service logs This was inferred by looking in each user s Inbox at the end of the trial and by examining service requests made using tokens signed by other users The frequency of beaming of course was limited in that it could only occur between people in the trial group since no other people had Satchel enabled portable devices ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere e 345 6 4 2 Remote Document Access Is Easy In total there were 587 fetch requests made to support browsing Note that a fetch request is logged only when the user presses Open and the selected directory is not cached Of these browsing requests 74 were made within either the My Computer or Network Neighbourhood folders The remaining 26 were made when browsing in the Hotlist Thus most users relied on browsing through their directory structures although a few 4 of 23 reported adding tokens to their Hotlists before trips to make access even quicker This may have been partially due to the fact that scrolling through very long directories was pain
12. in a customer s organization it is unlikely that casual use would be tolerated because of compromises with security Like the laptop these solutions require using a general purpose computer that is not specialized for mobile document work and has proba bly been customized to reflect local conventions They do not have stream lined or specialized user interfaces 5 THE SATCHEL SYSTEM In contrast to the current solutions summarized above our solution was specifically designed to provide access to any document any time any where it aims to satisfy all of our high level design goals 5 1 Fundamental Ideas Satchel provides support for specialized document services including print ing faxing scanning and exchanging documents In order to provide these services everywhere and to address our goal of ubiquity we embed Satchel software in familiar wireless mobile devices e g mobile phones that people already carry around However as we discussed in the previous section these devices have physical limitations that prevent them from being able to store process and communicate many documents e g Microsoft Office documents One of the most fundamental ideas in the design of Satchel is the use of tokens or references to represent the documents in the mobile device 5 1 1 Tokens Satchel mimics the directory structures and documents that reside in the wired network with a parallel structure of directory and document references
13. is signed using the private key The public key is used by Satchel to verify the signature e g when documents are requested via the Personal Web Server So unlike a URL a token cannot be edited by a fraudulent user to produce a valid token for another document or directory See Flynn et al 2000 for more details on security features 5 4 Specialized Document Services Our current Satchel system provides the following specialized document services Print View Fax Beam and Scan These services are explicitly invoked by the user by pressing a Services button that is visible on the Nokia 9000 Figure 5 shows a folder called El Pendo Consulting opened on the Nokia 9000 screen the document called Merger Plans is currently selected When Services is pressed the mobile client sends an infrared service request If this request is received by a nearby infrared transceiver Satchel returns a service form appropriate for that specific device and service to the mobile client Thus Satchel provides a service that is appropriate for the ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 336 M Lamming et al Satchel Thumbnail 5 gt No Print 1255 Print all pages gt Yes 4 6 97 O Endpage 136 002 PHONEGFF Status Ready Close Fig 6 The Satchel Print Service form for the printer named Wordsworth user s physical context a print service form is displayed if the user i
14. machine back in the Cambridge lab Some users also spontaneously used the Short Messaging Service SMS on the Nokia 9000 to ask for help Reported problems were dealt with as quickly as possible usually within a matter of minutes Newslet ters were also distributed to relay information about software upgrades and progress on fixing problems likely to be experienced by many users 6 3 3 Collecting Observational and Questionnaire Data Throughout the trial period fieldworkers visited each of the three trial sites at least weekly partly to maintain interest in the trial but also to observe people and record problems Occasionally users were questioned about their activities but for the most part they were left to go about their work uninterrupted Fieldworkers also attended six important meetings involv ing trial group members Particular attention was given to observing if and when Satchel was used during meetings and whether users traveling from other sites to attend the meetings used any Satchel enabled devices Notes were kept of all observations and meetings and most of the meetings were video recorded All users were interviewed about one week after the start of the trial The primary aims of these interviews were to detect any early problems not reported through the problem reporting procedures and to collect initial reactions to Satchel Questions focused on the user interface use of Satchel services use of Satchel during meetings
15. progress of the print request The Print Service detects that the document needs to be converted say from Microsoft Word to PostScript and invokes the Conversion Service The Conversion Service then retrieves the document via the Personal Web Server converts it and forwards it to the Wordsworth print queue 6 TRIAL During the course of the design and development of Satchel we carried out two small scale trials on early prototypes These trials were carried out within our own laboratory and provided data mainly on the design of the user interface In the summer of 1997 the current version of Satchel was evaluated in a larger scale trial carried out within Xerox The trial started the second week of June and finished at the end of July The primary goals of this trial were to understand whether implementing and deploying a complete Satchel system was technically feasible and to see whether people found Satchel useful More specifically we wanted feedback on the user interface and the design of the specialized Satchel services and we wanted to see whether people could adapt their work practices to make use of Satchel s functionality 6 1 The Users The major requirement for selecting the trial group was that they be relatively mobile people within Xerox In addition we hoped to find a community of people who had access to common sets of documents and who had a need to exchange documents with other people in the trial group A technic
16. users 16 of 24 users felt beaming should be even simpler and should require only one button press rather than two It is not clear why users thought this one possibility is that they were comparing it to handing over a piece of paper since there was no obvious equivalent in the electronic domain Another possibility is that it involves two users and people might feel more impatient in this social situation The Beam Service was the most novel of the Satchel services since it allowed users to send electronic documents while face to face with another user Because of this novelty some users 6 of 24 reported having difficulty deciding when beaming a token would be useful and others 11 of 24 felt they needed more experience with Satchel to know when to use the Beam Service In addition many users 16 of 24 reported that potential recipi ents of beamed tokens were not Satchel users which was not surprising since there were only 26 Satchel users in the trial group 7 CONCLUSIONS 7 1 Factors Affecting Utility The findings from the trial provided us with a better understanding about how the utility of Satchel is affected by its design and by other external factors One crucial factor is to target those users who can most benefit from the technology i e those that are highly mobile and rely heavily on using and exchanging documents For example in our trial group five users were relatively desk bound and rarely wandered around the co
17. wanted to be sure it was the correct document before invoking a service Sometimes the infor mation contained in the file name was enough sometimes the summary information was enough but sometimes more information was required Our users felt that either the first few lines of text or a thumbnail of the first page might be enough information to correctly identify the document Providing such a document identification service would improve the usefulness of Satchel and we are currently running experiments to deter mine how this service might be designed Providing useful services is obviously important to the overall utility of Satchel The services provided by the current Satchel prototype may be extended For example since the trial we have implemented an email service that allows Satchel users to email any document selectable on the portable device This provides users with an alternative way of exchanging electronic documents that can extend to non Satchel users thus increasing the system s usefulness One service that was not found to be particularly useful during the trial was the View Service However many users felt that a service for viewing documents on a projection screen for use during meetings would be useful A projection service requires only minor changes to the existing View Service and we have implemented such a service within our own laboratory Adding other new specialized document ser vices such as language transla
18. CM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere e 325 reasons for trips taken by all mobile professional workers and all of them required face to face collaboration of some kind In addition a large amount of working time is spent in meetings or conversations with estimates varying from 25 to 70 of working time e g Eldridge et al 1994 and Whittaker et al 1994 In a survey we carried out in 1995 of 103 managers within our own company we found that 40 of the managers had meetings outside their own building more than five times per week and 67 had meetings more than five times per week within their own buildings Eldridge et al 2000 2 1 2 Work Is Paper Based Paper is a pervasive aspect of the work of mobile professionals Sellen and Harper 1997 found that a group of 25 workers economists and administrative support people at the Interna tional Monetary Fund spent about 80 of their time working with paper documents in contrast to about 50 spent working with electronic docu ments What is particularly interesting in their study is the very heavy reliance on paper by the economists during face to face collaborative work Paper as opposed to electronic documents were used in about half of the conversations and in the majority of the meetings Frohlich 1995 also found a heavy reliance on paper in face to face interactions Accordin
19. Satchel Providing Access to Any Document Any Time Anywhere MIK LAMMING MARGE ELDRIDGE MIKE FLYNN CHRIS JONES and DAVID PENDLEBURY Xerox Research Centre Europe Current solutions for providing access to electronic documents while away from the office do not meet the special needs of mobile document workers We describe Satchel a system that is designed specifically to support the distinctive features of mobile document work Satchel is designed to meet the following five high level design goals 1 easy access to document services 2 timely document access 3 streamlined user interface 4 ubiquity and 5 compliance with security policies Our current prototype uses a Nokia 9000 Communicator as the mobile device it communicates to the rest of the Satchel system using wireless communi cations both infrared and radio A fundamental Satchel concept is the use of tokens or small secure references to represent documents on the mobile device The mobile client only transmits small tokens over the wireless channels leaving the wired network to transmit the contents of documents when and only when they are required Another fundamental Satchel concept is the highly specialized and context sensitive user interface on the mobile device The user s interactions are streamlined because of this specialization and through the use of contextual information gained by using infrared communications We report the results of a trial of S
20. Satchel or perhaps leading to the design of new mobile document appliances The token format is also extensible We believe that one useful addition would be the inclusion of a timestamp to alleviate replay attacks whereby communications are snooped on the network and when later replayed have the same effect thus giving the interloper undesired access to data or services Another would be the ability to sign a token for a specific recipient so only that recipient can retrieve the document to which it refers analogous to writing a cheque to a payee in that only the payee can cash the cheque Clearly to be maximally useful Satchel should be integrated with many different document repositories including Microsoft Exchange the World Wide Web Xerox DocuShare and Lotus Notes We have built prototype services to access documents in Exchange and Docushare we have not yet investigated options for integrating Satchel with Lotus Notes or other document repositories Since we implemented much of the Satchel system several years ago starting in 1994 a number of new developments have occurred For example several years ago specialized markup languages for use by mobile clients such as Handheld Device Markup Language HDML Unwired Planet 1997 and Wireless Markup Language WML Wireless Application Protocol Forum 1998 have been developed These markup languages require content to be specially designed for mobile clients in contrast Halib
21. States where some of the users traveled 6 4 3 Access to Document Devices Is Easy The Print Service was one of the most widely used services with just over 90 of the requests made at the user s home site though some of these were to printers outside of the user s own building This high percentage was partly due to increased opportunities to print at the home site since users on average spent only 15 of their time away It should be noted however that printing using Satchel while away from the site was the only viable method of printing available to the users at least without encountering many of the problems illustrated in our opening scenario For printing at the home site though there were other available meth ods Despite this some users 5 of 23 reported using Satchel to print documents because it was even faster and easier to access printers using Satchel than finding and selecting them from their own PCs This was because of poor network connections to printers at two of the sites and in some cases because printers could not be accessed at all from users PCs The Print Service was reported to be the most valuable service 11 of 23 respondents This is probably partially due to printing in general being very common However much of the value stems from Satchel s automatic and transparent conversion services because users did not need to worry about the document s format or how it needed to be converted for printing
22. al requirement was that they would be using Windows NT 4 0 before the start of our trial Xerox was then in the process of migrating to NT This requirement proved to be impossible to achieve since no groups within Xerox had migrated to Windows NT before the start of the trial After initial meetings and presentations a suitable trial group was identified There were 26 people in the group all working together to launch a large digital networked printer in Europe They held various jobs ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere 341 including product delivery managers launch managers training manag ers and technical specialists The users were based in three Xerox sites located in different cities in southern England There were 13 people at one site with seven and six people at each of the other two sites Some users traveled extensively among the three sites and around Europe others traveled mainly within their own buildings A few people were included because they were naturally part of the work community even though they could not be properly classified as mobile workers i e spending more than 20 of their time away from their desks Within the user group there were subsets of people who had access to common sets of documents and who interacted with each other 6 2 Deployment Activities A number of changes to the design of
23. an immediately select the token and invoke other services such as printing or faxing Beaming comes very close to being as easy as handing over a piece of paper The Beam Service also has the added advantages of allowing the sender to confirm the delivery of the document to discuss the document with the recipient at the time of the exchange and to exchange it when it is required rather than having to remember to do it later 5 4 5 The Scan Service To use the Scan Service the user loads a paper document into a Satchel enabled scanner and selects a suitable directory on the Nokia 9000 in which to store the document When the user presses Services an infrared request is sent and then the mobile client receives a Scan Service form A default name for the new document is provided by Satchel but the user may type in a new name if this is desired When Scan is pressed a request to scan is sent via infrared the paper document is scanned and its contents are stored in the specified directory subject to access rights wherever that directory is located A token for the new document appears on the user s Nokia 9000 once that directory is updated ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 338 M Lamming et al see Section 5 3 2 The user can then select this document and invoke other services Accessing the Scan Service is very easy and quick and enables the user to avoid carrying large heavy paper
24. and major benefits and problems Notes were kept of all interviews A workshop was held at each site at the end of the trial to collect feedback about the trial itself and to have users reflect on their use of Satchel More specifically users were asked to rate all problems reported during the course of the trial each problem was rated for severity using a four point scale not a problem low medium or high severity Nearly all users completed these ratings 24 of 26 There was a discussion about ideas for new services and features and possible future product offerings A final questionnaire was also distributed that included ques tions about Satchel functionality and the trial process These were filled in and returned several weeks later by 23 of the 26 users 6 3 4 Collecting Usage Data During the entire period of the trial usage logs were kept of all Satchel service requests except beaming from Nokia to Nokia These logs provided us with data on all service requests A suite of analysis tools was developed to parse the logs extract the key data and store them in a database The database was then queried to extract frequencies of various types of service request e g the number of infrared ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 344 M Lamming et al Table I Frequency of Service Requests Carried Out Using Infrared and GSM means lower bound estimate I
25. atchel that was carried out within our own company and discuss how well Satchel met our design goals We call Satchel a document appliance because it provides a stream lined solution to the problem of remote document access it aims to support only a limited set of activities but supports them very well Categories and Subject Descriptors C 2 4 Computer Communication Networks Distrib uted Systems Distributed applications H 1 2 Models and Principles User Machine Systems Human factors H 5 2 Information Interfaces and Presentation User Inter faces Evaluation methodology 1 3 6 Computer Graphics Methodology and Techniques Interaction techniques General Terms Human Factors Additional Key Words and Phrases Mobile computing mobile work document processing document access information appliance document appliance Authors addresses M Lamming and M Eldridge Cambridge Laboratory Xerox Research Centre Europe 61 Regent Street Cambridge CB2 1AB U K email lamming xrce xerox com eldridge xrce xerox com M Flynn Internet Designers Limited Compass House Vision Park Chivers Way Histon Cambridge CB4 9AD U K C Jones Apama Limited 17 18 Millers Yard Cambridge CB2 1RQ U K D Pendlebury Aspect Capital Limited 9 Mandeville Place London W1M 5LB U K Permission to make digital hard copy of part or all of this work for personal or classroom use is granted without fee provided that the copies ar
26. ch user from a central database The configuration data included the user s name the location of the user s home page the initial page displayed by the mobile client software server and proxy addresses and the dial in access point used for GSM communications In a few cases some configuration data was entered manually onto the Nokia 9000 In addition to installing the Satchel mobile client software as a conve nience we also downloaded contact information for all of the people involved in the trial both users and our own team members This informa tion was downloaded into the Contacts application on the Nokia 9000 using a Nokia connectivity application Nokia 1995 ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 342 M Lamming et al 6 2 3 Satchel Enabling Office Equipment Satchel enabled devices were provided at all three trial sites Printers commonly used by the people in the trial group were Satchel enabled by physically attaching an infrared transceiver to the printer and connecting the serial cable from the trans ceiver to a nearby networked PC running the associated software In total eight printers of various types and manufacturers were Satchel enabled at the three sites e g an HP IIIsi several Xerox 4920s and a Digital LN17 The printers were prominently labeled with Satchel logos so they could be easily located by the users Scanners were similarly Satchel enabled and lab
27. ctions were formal scheduled meetings others were initiated by one person or were completely spontaneous Anticipating the documents required for a formal meeting with a set agenda may not be too difficult although chance encounters or unexpected questions do occur even during such formal events ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 326 M Lamming et al Correctly anticipating all of the documents required for unplanned meetings may be impossible In addition anticipating documents required when preparing for a long trip or for an afternoon working at home can be very difficult Whether the need for a document is the result of a request from another person or by the self realization that the critical document is not available the need is unanticipated This is not an infrequent occur rence in our survey of managers within our company 59 reported not having a document they needed from one to five times per week and 24 reported this occurring six or more times per week Eldridge et al 2000 2 1 4 Accessing Remote Documents Is Difficult Typically while sitting in an office in front of one s own desktop PC accessing electronic docu ments is relatively easy The supporting infrastructure is readily available and the PC is set up to access this infrastructure People who carry around laptops can also access documents stored on them But accessing other remote electronic documents is more
28. d are indicated with an asterisk following the name of the directory on the Nokia 9000 screen see Figure 4 If a noncached directory is selected when Open is pressed the mobile client sends an infrared fetch request If this request is received by a nearby infrared transceiver the selected directory is retrieved and returned to the mobile client via infrared If no infrared reply is received the mobile client automatically strikes up a GSM connec tion to retrieve the selected directory To the user there is a time delay from 2 30 seconds depending on whether a connection has already been established but the user s action is simply to press Open regardless of whether the directory is cached or retrieved via infrared or GSM Over time the number of items stored in the cache increases so browsing requires less contact with the PC Cached directories can become out of date Users can retrieve an up to date view of a directory if they suspect that the current one is out of date This is done by pressing Update page on the Nokia 9000 see Figure 4 Once again the directory or page will be retrieved using either infrared or GSM If the user presses Open when a document is selected some summary information about the document is displayed e g the name of the application ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere e 335 y _
29. difficult e g see Eldridge et al 2000 Chen 1998 outlines 101 general business travel tips about one third of which are focused on preparing your laptop and peripherals Following all of these tips would certainly be time consuming and for some people impractical People who do not carry laptops often carry paper documents instead printing out those documents they believe might be required while away from their desks Carrying paper documents when traveling around the office building may be acceptable however when traveling long distances reducing the bulk of paper documents carried is often a primary consider ation with some people mailing support documents in advance of a trip e g see Chen 1998 2 1 5 Environments Are Unfamiliar and Stressful As we described earlier working away from the desk occurs in many different locations and situations These work environments will necessarily be less familiar than working in your office on your own personal machine In particular the procedures for accessing document devices such as photocopiers fax ma chines and printers are unfamiliar The opening scenario illustrated some of the problems encountered by a mobile professional when trying to print a document in another organization Not only do these problems add to the complexity and time required but they may lead to feelings of stress perhaps compounded by tiredness or jet lag Opportunities for making mistakes increase unde
30. documents These electronic docu ments will be available for editing and further processing when the user returns to the office The Scan Service is not currently included in the list of services available in any context i e it is not available using GSM 5 4 6 Implementation All of the specialized document services as well as the others described in Section 5 5 are implemented as a set of Common Gateway Interface CGI scripts running on a standard Web server In the current implementation the scripts are written in Python a popular freeware scripting language Lutz 1996 and are executed by either the Personal Web Server or the Apache 1 3 Web Server Laurie 1999 running on Windows NT 4 0 PCs See Flynn et al 2000 for more details on the implementation of services 5 5 Implicit Services In addition to the specialized document services described above there are three other implicit Satchel services that are transparent to the user the Fetch Service the Services Directory Service and the Conversion Service 5 5 1 Fetch Service The Fetch Service supports browsing see Section 5 3 2 and is transparent to the user When Open is pressed and the selected directory is not cached the mobile client makes a fetch request either via infrared or GSM and the Fetch Service is invoked This service retrieves the directory listing via the Personal Web Server converts the HTML to Halibut and returns it to the mobile client The Fetch Se
31. e it is not available using GSM 5 4 3 The Fax Service The Fax Service is a very important Satchel service because it requires only an ordinary fax machine for output rather than a Satchel enabled printer The Fax Service is selected from the list of Satchel services available in any context On the Fax Service form the user must enter in the fax number of the target device since Satchel is integrated with the Contacts application on the Nokia 9000 the fax number can easily be entered into the form by simply selecting a recipient s name The user then presses Fax to send the request via GSM Once again the selected document is converted automatically to fax format and is printed on the fax machine 5 4 4 The Beam Service Satchel supports the easy exchange of elec tronic documents by providing a novel infrared Beam Service Beaming is invoked in the same way as all other services When Services is pressed near another Nokia 9000 or any other mobile Satchel device the recipi ent s Nokia sends a form specific for that recipient to the sender s Nokia The sender presses Beam and a token is instantly passed to the recipient s mobile client regardless of the size of the referenced document This token is signed using public key cryptography see Section 5 3 3 thus ensuring that the recipient can retrieve only the referenced document The signed token appears in the recipient s Inbox as mentioned earlier The recipient c
32. e device that provided both infrared and radio communications The Nokia 9000 has ordinary cellular phone functions as well as a number of common Personal Digital Assistant PDA applications e g calendar notes contacts and a suite of Internet applications e g telnet email and a World Wide Web browser The Satchel mobile client software is implemented on the Nokia 9000 as one of the suite of Internet applications Figure 2 shows the Nokia 9000 Communicator opened to show the PDA interface It has a full qwerty keyboard and a 640 by 200 pixel liquid crystal display To the left of the display are up and down scroll buttons to the right of the display are four command buttons The labels for the four command buttons are soft coded on the display Our current solution provides the following specialized document ser vices printing viewing faxing exchanging and scanning To provide these services Satchel uses standard office equipment such as printers scanners and PCs To enable infrared communications to these devices i e to Satchel enable them we equip them with infrared transceivers that are connected to a nearby networked PC The infrared transceiver is attached ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 332 M Lamming et al Z Nokia 9000 Personal Network PC Printer Communications User s PC Satchel Enabled Printer Server
33. e not made or distributed for profit or commercial advantage the copyright notice the title of the publication and its date appear and notice is given that copying is by permission of the ACM Inc To copy otherwise to republish to post on servers or to redistribute to lists requires prior specific permission and or a fee 2000 ACM 1073 0516 00 0900 0322 5 00 ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Pages 322 352 Satchel Providing Access to Any Document Any Time Anywhere e 323 1 INTRODUCTION 1 1 A Scenario Have you ever found yourself away from the office without a crucial document If you have not imagine the following scenario Ann Smith is in London to meet her client Bob Green During the meeting she unexpectedly finds she needs to show Bob a confidential report She does not have the report with her but it is stored on her file server back at the San Francisco office Feeling stressed Ann spends many minutes unpacking and configuring her laptop and modem to establish a reliable connection back to her office Using a variety of utilities and applications she starts transferring the report to her laptop and while it finishes she goes out for lunch with Bob After lunch she wants to lead Bob through the report identifying the confidential sections and annotating it with recent changes She wants a paper copy for this and decides to transfer the file to Bob s computer for pr
34. eled To support the Scan Service the nearby PC was also installed with some special Satchel software In total four Xerox Doculmage 620S scanners 40 page per minute duplex black and white scanners were Satchel enabled In addition to Satchel enabling each user s PC see Section 6 2 1 the PCs supporting the Scan Service were also Satchel enabled to allow people to use the View Service on these public machines 6 2 4 Installing the Server Software One Satchel Server running Win dows NT 4 0 was located at each trial site Each PC was installed with all of the document processing and service software required to support all of the Satchel services To allow printing on each Satchel enabled printer the appropriate printer queue was made accessible from the Satchel Server 6 2 5 Providing GSM Communications To provide GSM communica tions requests were initially routed via a dial up commercial Internet service provider Pipex to the Xerox firewall in Grenoble France Requests were then passed to a server in our own lab in Cambridge for authentica tion and if accepted forwarded to the desired recipient These communica tions however were very slow due to an unanticipated reduction in service between Pipex and Xerox in the public Internet in Paris To solve this problem during the first week of the trial we installed an ISDN access point at our own lab in Cambridge thus avoiding the public Internet bottleneck in Paris 6 3 Tria
35. fully slow on the Nokia 9000 due to the mechanisms used to display and lay out screen elements In summary by using tokens to represent documents and wireless communications to fetch directories Satchel makes accessing documents very easy even when those documents have not been preloaded in the Hotlist Not only was access easy it was also valued Many users 14 of 23 reported that they felt more at ease when away from their PCs knowing they could access documents using Satchel They made comments such as it improves confidence of document availability and I never have to say I haven t got that document Some users 4 of 23 also commented that they carried less paper with them to trips and meetings because they knew they could access documents using Satchel During the course of the trial there were a number of situations in which unanticipated documents were accessed Most of these happened in con junction with scheduled meetings either during the meeting itself or in a chance encounter before or after a meeting On one occasion a user accessed and then beamed a report to four other people at a meeting because he had forgotten to take the paper document with him In several other cases a document was accessed and then printed in response to a request from another person One person when working at home accessed a document on his office PC and had it faxed to his home fax machine because he had forgotten to bring the document ho
36. g to Harper and Sellen 1995 paper has physical properties that make it well suited to support collaboration For example it can be easily handed over to someone while simultaneously having a discussion it can be easily shared during a conversation and it can be easily annotated Their analysis is supported by our own survey of managers where we found that when people preferred to exchange paper documents it was often for these reasons Eldridge et al 2000 Obviously some mobile professionals carry laptops and use electronic documents when they are away from their desks Editing presentations before a conference and exchanging documents via email are both common examples of document activities that might be carried out while away from the desk As we will discuss later though there are problems associated with the use of laptops in many mobile contexts It is of course also true that there are some disadvantages to carrying paper when traveling it is heavy and bulky and it cannot be edited In addition paper documents may be out of date by the time they are required if the electronic version has been recently updated 2 1 3 Document Activities Are Often Unanticipated Earlier we consid ered the frequency and importance of meetings Meetings can be either scheduled and relatively formal events or more informal and spontaneous ones e g a chance encounter in a corridor Kraut et al 1990 estimated that only 12 of face to face intera
37. he chance that anyone can access them particularly given the use of sophisticated search engines on the Web Other people copy private perhaps company sensitive documents onto their laptops a similarly risky procedure Lap tops and their cases can attract the attention of thieves and as Chen 1998 points out to protect confidential data the laptop should be pass word protected at boot up and files should be encrypted thus adding to the complexity of legitimately accessing documents stored on them An alternative to carrying electronic documents on a laptop is of course to carry paper an equally insecure practice An extreme case of this was reported in a national newspaper in the United Kingdom when a Royal Air Force officer had three briefcases full of paper and a laptop stolen from the boot of his car all containing details of Gulf War plans Guardian 1991 3 AIMS OF OUR DESIGN 3 1 The Vision In designing Satchel our aim was to provide a solution that would provide streamlined access to documents and document services Rather than grappling with technology at every step our vision was of a scenario like this Ann Smith is in London to meet her client Bob Green During the meeting she unexpectedly finds she needs to show Bob a confidential report She does not have the report with her but it is stored on her file server back at the office in San Francisco Ann takes out her PDA and using its Satchel software browses t
38. hrough several familiar directories of documents contained on her remote office file server Ann locates the confidential report and on the way out to lunch she beams a print request to Bob s departmental printer using infrared Within a minute or two the report is retrieved from Ann s office file server in San Francisco and is then printed on Bob s printer in London They discuss the report over a relaxed lunch 3 2 Design Goals Taking into account the distinctive features of mobile document work we derived five high level design goals These are described in the following sections ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 328 M Lamming et al 3 2 1 Easy Access to Document Services Because people rely heavily on paper for mobile document work and because paper is bulky to carry around it should be very easy to transfer electronic documents from person to person and to and from paper form This means that there should be a simple way to use document services such as printing without worrying about where such devices are located on the network or whether the correct drivers and applications are available Similarly if people acquire bulky paper documents that they do not want to carry around it should be very easy to transfer them into electronic form i e scan them Exchanging an electronic document should be as easy as handing over a paper document this simple task should not
39. inting despite the fact it is confidential Left on her own she spends the next half an hour unsuccessfully trying a variety of methods to transfer the file finally resorting to a series of floppy disks Using Bob s computer she first finds the correct departmental printer and then sends the report to it but not until she has tracked down and installed the latest version of Microsoft Word She dashes down the corridor looking for the printer so she can retrieve the confidential report before anyone else reads it 1 2 The Problems The scenario above illustrates many of the challenges faced by the mobile professional who needs to access documents when away from the desk During a scheduled meeting Ann finds she needs a hard copy of a document that she has in neither paper nor electronic form Her unantici pated need causes her to face the following problems She has to unpack her laptop and figure out how to plug it in and set it up in an unfamiliar environment She must wait for the file to be transferred to her laptop delaying her discussion until after lunch She must transfer a file from one computer to another using floppy disks which are too small She must store and hopefully remember to delete a confidential file on a computer in Bob s organization She must find and install the correct version of Microsoft Word on Bob s computer She does not know which printer to use or where it is located ACM
40. l Activities 6 3 1 Training Users We trained the users in pairs at the start of the trial Because none of the users had ever used a Nokia 9000 they were first given a broad overview of the applications available They were then given detailed training on using all of the specialized document services Training was hands on with the users carrying out the activities themselves following instructions being relayed by the trainers The users were given no advice about how and when to use Satchel they were let loose with the technology and were free to use it when and where they felt it would be appropriate The rationale for this approach was that we were interested in observing how or whether people would adapt their working practices Thus we were unwilling to force Satchel use in any particular situations ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere e 343 6 3 2 Providing Technical Support Each user was provided with a user s guide for both the Nokia 9000 Nokia 1995 and the Satchel system along with a list of the physical locations of the Satchel enabled devices at each of the three sites In the first few days of the trial there was a Satchel technical support person at each trial site to sort out early problems Throughout the trial period users could either phone a dedicated help line or fill in a form and fax it to a dedicated
41. le work in mind but to perform a wide variety of office document processing tasks where the design assumes the undivided attention of the user Norman 1998 p 71 agrees describing a PC as being too big too expensive too complex demanding more and more attention It is a general purpose machine which means it can do anything A laptop distracts the user s attention from the task at hand because it is not specialized for the document activity the mobile professional is undertaking it does not have a streamlined user interface one of our fundamental design goals Although it is possible to access remote documents using a laptop and modem the opening scenario illustrated that it provided neither easy timely nor secure access Indeed many laptop solutions using remote access software and infrastructures do not provide access to corporate documents within firewalls thus severely limiting their ability to meet our goal of timely document access Although the laptop offers the mobile professional the convenience of a single suitcase of tools that is easy to take on a business trip it is heavy and inconvenient to carry everywhere just on the off chance that it might be needed Also as we mentioned earlier laptops pose security risks This means that people often do not carry them particularly when wandering around their own office buildings They do not therefore provide a ubiqui tous solution 4 2 Other Mobile Device Soluti
42. me with him Despite the overall ease and value of accessing remote documents there were several factors that limited accessibility two were due to the design of Satchel itself two were due to non Satchel issues First Satchel relies on the Personal Web Server running on the user s PC to provide remote access to documents For those users who had laptops as their primary PC when the laptop was disconnected from the network their documents were no longer accessible via the Personal Web Server Many of the users 17 of 24 particularly those who were more technically aware felt this was quite a serious problem Second Satchel did not provide access to the users Microsoft Mail messages or attachments This was highlighted as an issue before the start of the trial since some people used it as a means of permanent document storage A third limitation was due to the design of the Nokia 9000 It was considered by many users to be too bulky 11 of 23 or too heavy 6 of 23 and was not always carried around especially when users were wandering around their own buildings Fourth GSM coverage was still poor at the ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 346 M Lamming et al time of the trial In two sites it was nearly impossible to strike up connections in parts of the buildings In addition although GSM had been adopted in most countries it was not widely available in the areas in the United
43. nfrared GSM Total Print 201 40 241 View 258 258 Fax 42 42 Scan 43 43 Beam 58 58 Total 560 82 642 print requests sent to a given printer or the number of fetch requests made by GSM while browsing 6 4 Findings Enormous quantities of data were collected during this trial We will summarize some general results on frequencies of use extracted from the usage logs Then we will discuss our major findings relying on data collected during observations from the problem ratings and from the final questionnaire 6 4 1 Frequencies of Use A total of 642 service requests were made during the trial Table I shows the frequencies of use for each of the specialized document services The View and Print Services were used much more frequently than any others although most of the View Service requests 45 were carried out by only one person Nearly everyone used the Print Service this is not surprising since printing in general is a common activity Only nine people used the Fax Service This service was intended to be used when no Satchel enabled printers were available Thus the main opportunity for faxing was when the users were on trips to non Satchel enabled sites where GSM was available Some people said that if they had taken more trips during the course of the trial they would have used the Fax Service more often The Scan Service was used by 10 people with most others saying that they saw no need for scanning in the
44. nteraction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere 347 Satchel print forms see Figure 6 This limited the usefulness of printing especially when users wanted to set many print options on very large printers When using the Fax Service to fax documents to remote locations many users 15 of 24 complained that Satchel only provided feedback about sending a service request to a fax queue but provided no feedback on whether or not the fax was actually received at the other end In general users quickly learned how to use each of the Satchel services during the hands on training The number of steps required to carry out a service via infrared was minimal point the Nokia 9000 press Services and press the same button again labeled for the specific service e g Print Thus opportunities for errors were negligible and very few user errors were observed or reported And the time from the user invoking a service to receiving confirmation of the request was normally about 10 seconds These factors ease of learning nearly error free use and speed of operation contributed to the overall ease of accessing document devices and using Satchel in general 6 4 4 Sending Electronic Documents Is Easy Invoking the Beam Ser vice is identical to invoking any other Satchel service and required the same number of button presses by the sender see Section 5 4 4 Despite this consistency many
45. ons Cellular phones pagers and more recently personal digital assistants PDAs such as the 3Com Palm devices provide user interfaces that are specialized for a very small number of focused tasks If designed well such devices have limited features sets and streamlined user interfaces that are simple to understand In addition some devices provide easy access to some documents and some document services For example the Nokia 9000 Communicator Nokia 1995 provides easy access to a printing service by allowing the user to send a note to a suitable printer or a business card to another user by using infrared But physical limitations e g memory size processor speed and battery life make the Nokia 9000 and other similar devices unable to store typical office documents e g large Microsoft Office documents and transmitting such large documents over slow wireless channels would be far too slow Thus these smaller device solutions cannot provide timely ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 330 M Lamming et al access to any document that might be required nor do they provide easy access to many document services 4 3 Wired Solutions Current Web based or other network solutions can provide access to remote documents and document services These solutions are clearly not ubiqui tous since suitable computers are not available everywhere Even if a suitable computer is present e g
46. ortable device or they can beam a document to a nearby user However the inaccessibility of documents in certain respositories will set limits on timely document access see Section 7 1 The Satchel mobile client has a streamlined user interface because Satchel is specialized for only a limited set of mobile document activities Carrying out a service request is very easy requiring only a few key strokes provoking few user errors and requiring little training time The use of context sensitive service forms when using infrared and the trans parent conversion services also help streamline the user s interaction see Sections 6 4 3 and 6 4 4 For a variety of reasons Satchel does not meet its goal of ubiquity Two main limitations were the lack of radio coverage and the lack of Satchel enabled devices that communicate via infrared Radio coverage is improv ing although GSM is still not available globally and reception is poor in some areas Until Satchel systems become commercially available Satchel enabled devices will be in short supply Another factor affecting Satchel s ubiquity is the unwillingness of some people to carry around the Nokia 9000 because of its weight and bulk The newer Nokia 9110 Communicator now available in Europe is lighter and smaller and we have implemented the Satchel mobile client on it now Other smaller devices might be more acceptable and we have already prototyped Satchel on a keychain si
47. r converted to Halibut and then returned to the mobile client via the Radio Gateway The user then selects a document in the opened directory and walks to a printer called Wordsworth Figure 7 b shows what happens after the user presses Services Wordsworth has an associated infrared transceiver ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 340 M Lamming et al on it and the mobile client sends the service request using the Infrared Gateway The printer is identified by the gateway as Wordsworth and the Services Directory Service is invoked to retrieve the associated print form via the Apache Web Server The print form is converted to Halibut and returned to the mobile client via the Infrared Gateway The user then fills in any desired options on the print form e g number of copies pages to print etc Figure 7 c shows what happens after the user presses Print The mobile client again sends the Wordsworth print request containing the token for the selected document via the Infrared Gateway The Fetch Service forwards the print request to the Print Service and the Print Service immediately returns an acknowledgment to the Fetch Service This acknowledgment is then converted to Halibut and returned to the mobile client via the Infrared Gateway This asynchronous acknowledg ment allows the user to carry out other operations on the mobile device or to receive more detailed feedback on the
48. r stress The consequences of making mistakes e g accidentally deleting a file at the start of a long trip may be more severe when the normal support and infrastructure are not available 2 1 6 Security Levels Are Low When working away from the desk levels of security are relatively low The opening scenario illustrated this with the problem of printing a confidential document in another organiza tion This scenario illustrated three security risks copying the file to a computer outside the user s corporation allowing an outsider access to a corporation s intranet and sending a confidential document to a printer in ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere e 327 an unknown and public location Sending confidential documents to fax machines is similarly insecure and in hotels the problem is compounded by the fact that many hotels are notorious for their inability to promptly inform recipients about incoming faxes or as experienced by one author to deliver them to the correct recipient Because it is sometimes very difficult to access corporate documents from outside the corporate intranet some people use workarounds to make private documents available publicly For example people may compromise the security of their own corporate documents by moving them to public places on the Internet e g a public Web site thus increasing t
49. require detailed knowledge of the recipient s email address or File Transfer Protocol FTP directory or of what applica tions they use or own 3 2 2 Timely Document Access Providing timely access to documents means providing access to documents when and where they are needed Since document needs cannot always be anticipated it is very difficult to ensure that one always has the correct documents to hand whether in paper or electronic form People should be able to access documents quickly They should not have to wait hours for a document to be transmit ted over a slow modem or sent by fax nor should they have to carry out numerous sometimes obscure steps to access them They should not have to extend meetings because of delays accessing critical documents Being able to access a document and give it to someone else at the moment of need also has the advantage of removing the need to remember to send it later a common problem for many people e g see Eldridge et al 1992 3 2 3 Streamlined User Interface In the face to face interactions that are so pervasive in mobile work the focus of attention is normally on the topic under discussion Any solution that supports work in such situations should not distract the user s attention from maintaining the conversation e g see Luff et al 1992 The user interface should be streamlined this means it should be specialized for the activities it supports in order to achieve simplicit
50. rowser or a set of ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 334 M Lamming et al Computer See p Open m CA Satchel Services ay D A Ta C F MARKETINGIEXTRAPRISE Update EI G WSALESIORDERS page fi awl a WINKINCDICCL an PHONEGFF Status Ready Fig 4 The contents of the My Computer folder shortcuts on a Windows NT desktop It is a user configurable list of tokens referring to documents or directories that the user wants to access quickly Using the Hotlist helps to streamline the user interface by allowing the user to make frequently accessed documents easily accessible rather than requiring browsing through multiple levels in the file structure see Section 5 3 2 The Inbox contains tokens that have been beamed using infrared from another mobile client see Section 5 4 4 5 3 2 Browsing To browse through directories on the Nokia 9000 the user simply moves the selection to a directory using the scroll buttons and then presses the command button labeled Open The contents page of the selected folder i e directory is then displayed Figure 4 shows the contents of the My Computer folder To return to the previous directory the user simply presses Close Browsing through any directory is done in the same way Once the contents page of a directory has been displayed on the Nokia 9000 it is stored in a nonvolatile cache Directories that are cache
51. rridors of their own buildings or traveled away from their home sites These people did not find Satchel to be very useful In contrast though those who traveled frequently both to other Satchel enabled sites and elsewhere ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 348 M Lamming et al found Satchel very useful Other factors such as the user s willingness to experiment with new technology affected the perceived value of Satchel In addition because Satchel provides new ways of working with documents e g the Beam Service some users were not able to adapt their working practices during the relatively short trial period To maximize utility the portable device must provide access to all of the documents normally accessible from the user s PC This means it is crucial to integrate Satchel with all document repositories particularly email systems Document access must be ubiquitous in other words documents should be accessible at any time and anywhere There are both design and external factors that bear on this issue For example Satchel should not rely exclusively on Personal Web Servers running on PCs that may be removed from the network i e laptops Important external factors affect ing ubiquity are radio coverage and the physical size of the portable device One problem encountered by several users during the trial was that once a document was selected on the portable device they
52. rvice is also used to retrieve the service forms used for the specialized document services if these forms are not cached 5 5 2 Services Directory Service The Services Directory Service is used during service requests it is invoked when Services is pressed If the service request was made via infrared 1 this service dereferences the contextual information i e the location of the device 2 the associated service form is fetched via the Apache Web Server on the Satchel Server and 3 the form is then converted to Halibut and returned to the user s mobile client If the request for services was forwarded via GSM no contextual information is added and a list of services available in any context is fetched and then returned to the user s mobile client 5 5 3 Conversion Service The Conversion Service is used by the Print Fax and View Services It includes conversions between many document formats and figures out the best conversion route to get from the selected document s format to the format required for the output device This may involve only one conversion or multiple conversions Some conversions use the original application e g Microsoft Word to PostScript others use free ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere 339 z gt Ea lt Ea Server Directory listing A REEE listing in Halibut in HTML
53. s but is not in front of a printer with an infrared transceiver the mobile client makes a request using GSM and Satchel then sends a list of services available in any context The user must then select the particular print service required When the print service form see Figure 6 is displayed the user simply presses Print and then the mobile client sends the print request Since the user is not necessarily near the printer when using GSM documents may be sent to a remote printer perhaps to be collected later 5 4 2 The View Service The View Service allows users to view docu ments on a Satchel enabled PC i e a PC with an infrared transceiver this PC may be either an individual s personal machine or a PC located in a public area This service is useful since the documents themselves cannot be viewed directly on the Nokia 9000 screen When the user presses ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere 337 Services while standing in front of a PC with an infrared transceiver the mobile client receives a View Service form The user then presses View to send the request via infrared As with the Print Service Satchel automat ically converts the document to a format that can be displayed using some available application installed on that PC The View Service is not cur rently included in the list of services available in any context i
54. s in front of a printer a scan service form is displayed if in front of a scanner and so forth If no reply is received by the mobile client from a nearby infrared transceiver the mobile client automatically makes a request using GSM and Satchel sends a list of services that can be used in any context The user must then select the particular service required perhaps brows ing through folders of services depending on the number of services offered 5 4 1 The Print Service When the user presses Services while stand ing in front of a printer with an infrared transceiver the mobile client receives a form for that specific print service as shown in Figure 6 All the user must then do is press the same button again now labeled Print to send the print request via infrared to the print queue the document is then printed This is very easy and requires only two presses of the same button by the user Of course the user could also choose to print multiple copies thumbnails or only selected pages Note that when printing the user does not need to worry about or even know what application created the document nor does the user need to know what format the printer requires This is all taken care of by the conversion service see Section 5 5 3 in the Satchel system These auto matic conversions are transparent to the user and help to achieve simplic ity of use and ease of access to document services When the user presses Service
55. ss Addison Wesley Publ Co New York NY 122 129 ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 352 M Lamming et al HENNING J AND BRAGEN M 1994 Mobile Professionals in Focus BIS Strategic Decisions Norwell MA Kraut R FisH R Root R AND CHALFONTE B 1990 Informal Communication in Organizations Form Function and Technology In Proceedings on The Claremont Sympo sium on Applied Social Psychology People s Reactions to Technology In Factories Offices and Aerospace S Oskamp and S Spacapan Eds Sage Publications Inc Thousand Oaks CA 145 199 LAURIE B 1999 Apache The Definitive Guide 2nd ed O Reilly and Associates Sebastopol CA Lurr P HEATH C AND GREATBATCH D 1992 Tasks in interaction paper and screen based documentation in collaborative activity In Proceedings of the ACM Conference on Computer Supported Cooperative Work CSCW 92 Toronto Canada Oct 31 Nov 4 M Mantel and R Baecker Chairs ACM Press New York NY 163 170 Lutz M 1996 Programming Python O Reilly amp Associates Inc Sebastopol CA Moore G 1966 Keynote Speech IEEE International Electronic Devices Meeting Dec 10 San Francisco Nokia 1995 Nokia 9000 Communicator User s Manual Nokia Corporation Espoo Finland Norman D A 1998 The Invisible Computer MIT Press Cambridge MA RUTSTEIN C Howe C CussEN M PATEL S AND WAKEMAN M 1999 Nomadic
56. the Satchel system were required before it could be deployed outside of our own laboratory These included tidying up all software components to simplify the deployment process providing tools to configure and acceptance test each installation and adding functionality to support remote testing and debugging 6 2 1 Installing Software on the Users PCs Before the Satchel Personal Web Servers could be installed on the users PCs Windows NT 4 0 was installed Based on our experience running Windows NT and Satchel in our own laboratory we defined the minimum specification for PCs to be an Intel Pentium PC or high end Intel 486 processor with 32MB of memory and at least 50MB of free hard drive space At that time many of the users PCs fell well short of this and so we had to upgrade and in some cases replace their PCs Python Lutz 1996 was installed on each machine to support the service software and then the Personal Web Server and other Satchel support files were installed using InstallShield Easter 1999 In addition each PC was equipped with an infrared transceiver and the associated software to support viewing documents browsing and updating directories 6 2 2 Installing Software on the Nokia 9000s The Satchel mobile client software was downloaded onto each Nokia 9000 via a serial cable from an installers laptop Most of the user configuration information was down loaded automatically by retrieving the appropriate data for ea
57. tion or summarization could also improve the usefulness of the system for some users 7 2 Does Satchel Meet Our Design Goals In Section 4 we discussed how alternative solutions to providing remote access to any document any time anywhere fail to meet our design goals In this section we will summarize how well Satchel addresses these goals Providing easy access to document services requires both that accessing the documents on the portable device is easy see Section 6 4 2 and that accessing document devices is easy see Section 6 4 3 Easy access to ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere 349 documents is achieved by using tokens to represent the documents on the portable device thus many documents are accessible and the small tokens can be transmitted quickly over wireless channels Accessing docu ment devices is similarly easy particularly when infrared is used to provide a form specific to the nearby device Providing timely document access is possible using Satchel since it does not rely on users accurately predicting what documents they have to hand When the document is required the Satchel mobile client is ready to go without worrying about connections to networks using modems and wires By using the specialized document services users can get hard copies of any document that is accessible from the p
58. to work fast it is almost as fast to send a token from one portable device to another as it is to hand over a piece of paper It is also fast to send tokens from a portable device to a device such as a printer Thus accessing document services is easy requiring only a few simple button presses using Satchel requires no wires no obscure commands no swapping applications no setting up communications no logging in no passwords no smart cards for authentication We have also designed Satchel to use knowledge of the user s physical context to figure out the most likely thing the user wants to do For example if a token is beamed via infrared to the printer in front of you it probably means you want to print the document on that printer There is no need to navigate through tree structures of printers to discover the name and location of the printer that is just in front of you Using knowledge of context thus helps achieve simplicity of operation and speeds up access to documents and document services 5 2 Basic Components Over the last few years we have developed a number of Satchel prototypes using various mobile clients and platforms see Flynn et al 2000 Figure 1 shows the basic components of the current Satchel system Our current solution uses a Nokia 9000 Communicator Nokia 1995 as the mobile device and Windows NT 4 0 as the platform The Nokia 9000 was chosen because at the time it was the only programmable wireless mobil
59. ument intensive work There are many millions of mobile professionals worldwide and these numbers are expected to increase as organizations become larger and more distributed and as international trade increases A recent Forrester report for example surveyed network managers who estimated that 23 of their user populations were mobile and this percent age is expected to increase to 35 in the next two years Rutstein et al 1999 Mobile document work can be carried out in a wide variety of geographi cal locations and in many different contexts For example on a business trip we observed a mobile professional working with documents on an airplane during a formal presentation during an informal meeting while waiting for a taxi in a reception area and while waiting for a flight in an executive lounge at a foreign airport Eldridge et al 2000 Even on a day in the office a mobile professional is often away from the desk working with documents in meeting rooms in other peoples offices or in corridors 2 1 The Distinctive Features of Mobile Document Work In this section we describe six features of mobile document work that distinguish it from document work carried out while at the desk These distinctive features give rise to the design goals that are outlined in the next section 2 1 1 Work is Collaborative and Face to Face Face to face collaboration is a major feature of mobile work Henning and Bragen 1994 analyzed the A
60. ut content is not expected to be authored All content is authored in HTML and converted to Halibut on the fly when requested by a Satchel mobile client However we will investigate the use of these specialized markup languages for future prototypes There are certainly alternative solutions to providing access to any document any time anywhere though in our opinion these alternatives fail to address our design goals see Section 4 The likelihood that laptops could store all documents is improbable since even though the costs of electronic storage are decreasing and storage capacities are doubling every 18 months Moore 1966 documents are getting bigger today routinely occupying tens of megabytes of storage space There seems to be no reason why these trends will not continue and increases in storage capacities will be offset by the increasing size of documents In addition although wireless communication rates are increasing dra matically with predictions of data rates approaching two megabytes per second by the year 2002 with wide band GSM ETSI 1997 they will remain slower than wired rates Thus even if portable devices could store ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere 351 all documents the rates of transmitting them over wireless channels would be unbearably slow In conclusion mobile professionals may continue to
61. y of operation A streamlined user interface will also help to reduce opportunities to make mistakes in the unfamiliar and perhaps stressful environments encountered by the mobile worker 3 2 4 Ubiquity Mobile work occurs in a wide variety of contexts and document needs are often unanticipated The solution therefore should literally work anywhere wherever people are 3 2 5 Compliance with Security Policies In providing the mobile profes sional with access to remote documents and document services current levels of security should not be compromised and ideally they should be improved Levels of security should comply with corporate policies and they should be acceptable to the information technology managers within the organization Of course any security features must also meet our design goal for easy access to document services ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 Satchel Providing Access to Any Document Any Time Anywhere 329 4 DO CURRENT SOLUTIONS MEET OUR DESIGN GOALS Although technologies currently exist that provide remote access to docu ments and document services we believe that none of them meets our design goals In this section we describe the limitations of solutions using laptops and other smaller portable devices We also briefly describe other wired network solutions 4 1 Laptop Solutions The ancestor of the laptop the desktop PC was not designed with mobi
62. zed device There are however additional challenges in streamlining the user interface for such small devices We have no evidence that Satchel fails to address the goal of compliance with security policies we had no complaints either from users or network support people during our trial Our solution provides secure per document access through the use of tokens without compromising the streamlined user interface In addition there is no need for documents to be stored on an external server since Satchel provides secure access through firewalls We do not know however whether a system with the current security features would be widely acceptable by corporate information technology managers 7 3 Future Enhancements Satchel s system architecture easily supports the addition of new services see Flynn et al 2000 for a discussion of this extensibility We mentioned ACM Transactions on Computer Human Interaction Vol 7 No 3 September 2000 350 M Lamming et al several new services in Section 7 1 some that we have already imple mented e g the email service and others that we are investigating e g a document identification service Other services designed to support docu ment work in general e g summarization may also be useful for support ing mobile document work One of our current research themes aims to identify other important document services perhaps to be added to the suite of services provided by

Satchel: Providing Access to Any Document, Any Time, Anywhere

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