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1. 29 30 31 32 33 34 35 36 37 38 39 40 41 Robert Leslie MAD MPEG audio decoder Online http www mars org home rob proj mpeg 2002 Current March 2002 Tsugio Makimoto Kazuhiko Eguchi and Mitsugu Yoneyama The cooler the beter New directions in the nomadic age Computer 34 4 38 42 April 2001 Matsushita Electric Industrial Co Osaka Japan Panasonic Electronic Modula Switch System Modem KX T206 Installation Manual 1993 Document code PSQX1158YA KW0796KM1027 David L Mills RFC 1305 Network time protocol version 3 specification implementa tion March 1992 Monty Cdparanoia an audio CD _ reading utility Online http www xiph org paranoia manual html 2002 Current March 2002 Elizabeth Mynatt Douglas Blattner Meera M Blattner Blair MacIntyre and Jennifer Mankoff Augmenting home and office environments In Proceedings of the third interna tional ACM conference on Assistive technologies pages 169 172 ACM Press 1998 Donald A Norman The Psychology of Everyday Things BasicBooks New York NY USA 1988 Donald A Norman The Invisible Computer MIT Press Cambridge MA USA 1998 Catherine Plaisant and Ben Shneiderman ON OFF home control devices Design is sues and usability evaluation of four touchscreen interfaces Interacting with Computers 3 1 9 26 1992 Larry Press Personal computing the post PC era Communications of the AC2. ISDN Terminal Adapter Motion Door and MP3 players PCs detectors window sensors N POTS modem Ethernet hub Information Furnace Figure 1 Information furnace connection diagram GSM phone Door phone POTS phones Relay and sensor board Sirens tively perform these standardised activities through a single command Thus the leave home command will turn on the answering machine switch off the internal artificial lighting and entertainment systems lower the central heating temperature light the en trance activate the burglar alarm and open the garage door On return a single pass word protected command will deactivate the burglar alarm turn off the answering ma chine play back any incoming messages provide caller id information on unanswered phone calls switch on the internal artificial lighting and entertainment systems raise the central heating temperature switch off the entrance light and close the garage door Similar sequences can be used for putting the house to sleep and preparing it for its owner s wakeup Other activities can trigger synergistic events As an example picking up the phone can cause the entertainment system to pause the music or video playback when the alarm system detects an unlawful entry it can begin flashing all the house s lights to frighten the burglar and attract
3. The systems I outlined in Section 2 are typically implemented using the following dis tinct communication networks 1 Voice Data Door interfacing Heating Security OY OS cR cue BS Light control There are expensive systems that integrate some of the above functions but the general case involves a waste of resources User Interface Each home system has its own user interface with its ergonomically challenged human interfacing devices Humans have to learn different dysfunctional interfaces to perform a limited number of tasks Power Each system needs line power and in the best case also has a separate backup power system typically a 9V battery Apart from the nuisance of maintaining the tens of dif ferent backup power systems the power requirements of all devices add up to a sizable power drain which is both expensive and environmentally unsound Space Finally many devices occupy space in living areas daily imposing their unsightly pres ence on us The ubiquitous table with the telephone answering machine and fax is one example the collection of the remote controls on the lounge table is another 4 The Information Furnace The Information Furnace supporting the post PC ubiquitous computing paradigm 49 34 is a basement installed PC type device that integrates existing consumer home control infotainment security and communication technologies to transparently pro vide user friendly access and sy
4. set the bit outb scp iobase PBIO CFG scp gt iomode ocfg portbit else return EACCES Figure 3 Configuring the PCL 724 I O ports 15 input or output as illustrated in Figure 3 Initially all ports are set for input to avoid damaging external circuitry When designing the device driver to minimise kernel context switches I specified three different ways I O would be performed Basic The read or write operation returns immediately after reading or writing the data to the port at bus speed Paced Data is transferred from or to the port at intervals specified by a separate ioctl 2 call Differential Only port values that differ from the previous port value are returned Modes can be set via ioctl 2 calls However experimenting with the basic mode I found that polling the input ports at one second intervals provided acceptable functionality most alarm sensors have their own latches with negligible impact on performance I therefore decided to handle the rest of the complexity through user mode polling realising however that other applications might benefit from a more sophisticated driver implementation The user mode alarm daemon is structured around an event driven driven loop Three types of events are handled external commands e g arm disarm panic sensor inputs and elapsed timers used for providing delays automatic re arming and notification intervals Different levels of logg
5. disks its power demands were or ders of magnitude lower than its rated capacity Having the information furnace utilise simple standards for organising and disseminating the content a text index and MP3 files exported via NFS as a directory tree allowed me to choose the operating systems opportunistically I selected FreeBSD to avoid the burden of configuring maintaining and provisioning disk space for another operating system the player shares the read only partitions of the information furnace and SuSE Linux because it was the first OS installation to run correctly on the laptop s idiosyncratic hardware 22 5 5 Security and Availability The information furnace is secured in a place that is not easily accessible continuously performing a number of critical functions For these reasons it is imperative that it runs unattended and recovers gracefully after any problem First of all I configured the machine s BIOS to let the machine boot without a keyboard and mouse However the most important part of the machine s reliability is the correct installation of a UPS I installed an additional serial card to connect the machine to the UPS The sharing of interrupts for serial cards is a notorious problem Thankfully the serial card I used was a 1985 vintage ISA card build around standard TTL and controller chips It was therefore relatively easy to follow the traces from the motherboard connector to the DIP switch and by cutting a trace
6. programming mode dial 62068 The examples we have seen illustrate that in many cases the user interface of consumer oriented home appliances and control devices is far from ideal Clearly hu man interface studies and approaches towards better interaction paradigms 32 33 have not yet found their way into widespread practice 3 2 Lacking Functionality One other problem with the devices we examined is that for a number of reasons they may impose arbitrary limits on their functionality or lack support for useful functions For many devices the available CPU power RAM or ROM are just not sufficient for implementing a given function For others the already complicated user interface would crumble under the cognitive load of the added functionality As an example there is no reason why the heating controller I described should support only three heating periods per day or not allow one to provide a schedule for the temperature of the running hot water as well as the temperature of the room Similarly a CD player may offer a facility to skip a boring track but will not remember to skip the same track in the future On another front an alarm unit could provide a precise report of the alarm triggering circumstances and allow its user to remotely probe and disable individual sensors Finally the PBX we examined could be more versatile if it supported different day and night mode start times for different days of the week A general lack of fun
7. secondary warm water circulating circuit in the house does not hurt the floors and walls where the running hot water pipes run act as secondary radiators When however the central heating is switched off on warm days or during an absence the circulator actually cools the stored warm water by continuously running it through the house In my experience modern heating controllers do not deal with this complication The natural light entering a building is often controlled through external blinds or stores These also play an important role in regulating the heat flowing into or out of the building In addition a heliostat device can be used to track the sun movement and actively reflect sunlight into the building Artificial lighting can be electronically controlled through a system such as X10 or LonWorks in the United States and the European Installation Bus EIB in Europe Perversely in the case of the EIB at least it is currently cheaper to control lights using 230V switches and individual switch to appliance power carrying cables than to use a signal and power bus cheaper control switches and the associated electronics This is clearly a case where the silicon econ omy has not yet done its work Other interesting elements of modern artificial lighting include light fixtures with integrated motion and light detectors that are increasingly used outside homes as burglar deterrents time switches used for the same purpose in side the house and
8. winnt system32 cmd exe 6 Facilitators and Roadblocks In the previous section we saw that the concept of the information furnace is indeed realisable if only with a subset of the functionality we prescribed in Section 4 Here I will describe the most important factors that facilitated and hampered the develop ment and are likely to affect future similar endeavours open source software hardware standards cost and maintenance 6 1 Open Source Software Clearly the most important aspect that affected the development was the availability of open source software The information furnace and its appendages were based on three different open source operating systems The stability and clear structure of FreeBSD provided the platform for the main unit NetBSD with its multiple architecture support was at the time the only OS that supported the Shark s StrongARM architecture while the aggressive development model of Linux resulted in an installation procedure and the existence of device drivers that could revive an old laptop as an MP player The existence of these systems in source form allowed me to easily write and add a device driver to support the PCL 724 I O card under FreeBSD and Mark Foster to patch NetBSD to provide audio and infrared support A number of times I found myself going over the source code to verify elements that were not clearly documented documentation can not possibly cover everything Some early failed experiments for disk
9. 999 57es 7 1999 5 T Berners Lee and D Connolly RFC 1866 Hypertext Markup Language 2 0 Novem ber 1995 6 Rocco Caputo CDDB high level interface to the internet compact disc database Online http www cpan org modules by module CDDB 2002 Current March 2002 7 Goran Devic Home entertainment linux MP3 player Linux Journal 2000 71es 8 2000 27 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Gert Doering Mgetty sendfax archive documentation centre Online http alpha greenie net mgetty 2002 Current March 2002 Amitava Dutta Roy Networks for homes IEEE Spectrum 36 12 26 33 December 1999 Marc Eberhard Vgetty documentation center Online http alpha greenie net vgetty 1998 Current March 2002 Robert E Filman Editor s introduction Embedded internet systems come home IEEE Internet Computing 5 1 52 53 January February 2001 R Finlayson RFC 906 Bootstrap loading using TFTP June 1984 Mark J Foster AV An audio visual equipment device driver for NetBSD Online ftp ftp talix com pub av 1999 Current March 2002 Armando Fox Brad Johanson Pat Nanrahan and Terry Winograd Integrating information appliances in an interactive workspace Computers Graphics and Applications 20 3 54 65 May June 2000 Robert Fulghum All I Really Need to Know I Learned in Kindergarten Uncommon Thoughts on Commo
10. M 42 10 21 24 October 1999 J Christopher Ramming editor USENIX Conference on Domain Specific Languages Santa Monica CA USA October 1997 Usenix Association Jef Raskin The Humane Interface New Directions for Designing Interactive Systems Addison Wesley 2000 Conrad Sanderson Notlame LAME command line front end Online http hive me gu edu au not_lame 2002 Current March 2002 Ben Shneiderman Designing the User Interface Strategies for Effective Human Computer Interaction Addison Wesley third edition 1998 Siemens Building Technologies Room Units for Use with Heating Controllers QAW70 June 1999 Document code CE2N1637E K Sollins RFC 1350 The TFTP protocol revision 2 July 1992 Diomidis Spinellis Palmtop programmable appliance controls Personal Technologies Personal and Ubiquitous Computing 2 1 11 17 March 1998 29 42 43 44 45 46 47 48 49 50 Diomidis Spinellis Reliable software implementation using domain specific languages In G I Schu ller and P Kafka editors Proceedings ESREL 99 The Tenth European Con ference on Safety and Reliability pages 627 631 Munich Garching Germany September 1999 ESRA VDI TUM A A Balkema Diomidis Spinellis Notable design patterns for domain specific languages Journal of Systems and Software 56 1 91 99 February 2001 Diomidis Spinellis and V Guruprasad Lightweight languages as softwar
11. P3 ID3 structures A separate Perl script crawls the content directories gathering metadata and creating the content directory in plain text HTML and LaTeX file formats Each CD is identified by a three digit number and each individual track is identified by a five digit number Figure 7 These numbers are again stored in one plain text file index txt for each CD The numbers increase monotonically as new CDs are added and are never reused thus providing numbering persistency so that bookmarks and music collections are not rendered invalid when CDs are added or deleted The CD and track identification numbers are also needed for selecting a particular CD or track using a simple remote control I reserved two digit numbers for creating bookmarks to particular songs and single digit numbers for identifying a music type e g Rock Jazz or Classical from which an MP3 player would randomly shuffle tracks The last option proved to be the most popular The plain text file forms the track database It simply contains track and CD identification numbers as comments followed by the respective file name 5021 10297 vol music Classical Bach FrenchSuites cdl track01 mp3 10298 vol music Classical Bach FrenchSuites cdl track02 mp3 10299 vol music Classical Bach FrenchSuites cdl track03 mp3 This format allows simple sed scripts to select data based on a CD or track identi fication number and feed the resu
12. The Information Furnace User friendly Home Control Diomidis D Spinellis Department Management Science and Technology Athens University of Economics and Business Greece email dds aueb gr Abstract The Information Furnace is a basement installed PC type device that integrates existing consumer home control infotainment security and communication tech nologies to transparently provide user friendly access and value added services A modern home contains a large number of sophisticated devices and technolo gies Access to these devices is currently provided through a wide variety of dis parate interfaces As a result end users face a bewildering array of confusing user interfaces access modes and affordances In addition as most devices function in isolation important opportunities to exploit synergies between their functionalities are lost The information furnace distributes data provides services and controls an apartment s digital devices Emphasis is placed on user friendliness and on ex ploiting the synergies that inevitably come up when these technologies and services are housed under a single roof The prototype implementation I outline integrates on a FreeBSD server the distribution of MP3 encoded music to DNARD NetBSD thin clients an answering machine a burglar alarm an Internet router a fax server a backup server and intelligent control of a PBX 1 Introduction Although our complex lives are not necessarily im
13. after opening the door A small Perl 47 script transforms the alarm specification into an efficient C loop structure 5 3 Telephone Integration The answering machine fax server PBX programming and alarm notification functions of the information furnace are handled by software written on top of the vgetty 10 extension a voice handling add on to the mgetty 8 package which in turn replaces the Unix getty S terminal handler to handle data and fax calls I wrote the incoming 17 and outgoing modem interaction scripts in Perl using the Modem Vgetty 3 21 Perl package We often access the answering machine through the phone using a DTMF voice menu The interaction of the answering machine software with the PBX poses an inter esting problem During normal use we want to be able to access the answering machine voice menu but we do not want it to answer incoming calls This was solved by having the answering machine setup the PBX to direct external incoming calls to all extensions but the modem during normal use and only to the modem extension when the answering machine is enabled The PBX provides a global 100 phone quick access memory feature By using these memories one can access the same number from all extensions without having to indi vidually program and maintain the memories of each different telephone Apart from offering a centralised point for storing the quick dial numbers this approach obviates the need to handle the disp
14. and a bit of soldering rewire the interrupt line to a different free PC interrupt More tricky was the software configuration of the UPS a task that has not yet been solved to my satisfaction To power down a UPS after its batteries signal that they are close to empty by expecting it to switch off when the batteries are completely drained is incorrect due to a number of subtle race conditions Consider first of all the following innocent scenario 1 Mains power is interrupted 2 Computer is now powered by the UPS 3 UPS batteries signal a low condition 4 Computer gracefully halts 5 UPS dies as batteries are completely drained 6 Computer switches off as UPS power is interrupted 7 Mains power is restored 8 Computer restarts Consider now the first race condition mains power is restored between steps 4 and 5 The UPS will restore power and the computer will wait idly in its halted state One can counter that many computers have automatic power management so that in step 4 they can be shut off instead of halted when power is restored the computer will correctly restart Enter now the second race condition power is restored during the shutdown sequence this sequence can last for several minutes on servers running database applications The computer will now complete its shutdown sequence and switch itself completely off despite being fed with mains power How can one handle these problems The communication protocol of most UPSs
15. arate user interface each device has for storing phone num bers is the programming sequence code AUTO number store or MEM code number hangup Of course this approach solves one user interface problem by replacing it with another since the quick access programming sequence for the PBX is hold your breath 6206206 00codeOnumber 6206 Thankfully having the PBX connected to the information furnace one can easily package this functionality as a shell script vm shell 1 ttydl S usr bin perl call pl 00S 1 0 2 and have another script program the PBX quick access memories to a known state John Doe Home setmem 10 0105554321 John Doe mobile number setmem 11 0935551234 John Doe Office setmem 12 0105556789 Since this script is rarely used I did not provide a more elaborate interface to it al though the script could easily be generated by mining the PDA phone database backups or through web forms However even in the format it currently is it proved a time saver when the country s numbering plan changed a simple global replace operation in the editor resulted in a new script that when run correctly programmed the PBX memories for the new plan You will probably have noticed that many different operations may compete for accessing the modem at a given time To solve this resource contention problem I wrote a command queue handling daemon as a simple shell script illustrated
16. berAll project 2 This includes the music collection stored in MP3 form synchronised copies of PDA contents the digital camera photographs and in the future the video collection 11 Finally the information furnace integrates the home s communication interfaces by per forming the functions of a firewall a router an intercom and a PBX When some type of functionality can not be directly implemented by the hardware at hand the information furnace shall at least communicate with the respective dedicated device so that it can indirectly control it As an example by communicating with a PBX using a simple modem one can provide a decent user interface to the functionality I described in Section 3 1 All integration shall of course be performed with an eye on safety and security Where appropriate the information furnace should work in parallel with dedicated hard ware providing redundancy or be isolated from it Elevators fire monitors and emer gency lighting should probably be left to work on their own tapping an elevator s call button or a fire alarm s output should be the limit to the type of coupling that should be considered safe Similarly control of mains voltages should be performed by ded icated hardware leaving to the information furnace the task of issuing the respective commands 4 4 3 Synergies The most effective user interface is the one that does not exist Centralising all home control con
17. ctionality witnessed in all the devices we examined is a facility to backup and restore the tediously entered program data True many devices have a power backup system for their memory contents but in my experience that inevitably 7 one day will fail typically long after the user has forgotten how to program the device and has lost the respective user manual 3 3 Lost Synergies I will fully expand the synergies made possible when all home systems communicate and cooperate with each other in Section 4 3 at this point I will illustrate my thesis with a simple example The blinking clock syndrome refers to the myriads of device clocks flashing 12 00 all over our planet Even in households where these are correctly set after a power failure twice a year they need to be re adjusted following the daylight savings time settings However a correct time signal enters a modern home from at least three different sources RDS radio teletext TV and the Internet 28 In addition modern operating systems can correctly interpret and adjust the time following the local daylight savings rules Our wonderful devices however fail to cooperate to correctly set their time 3 4 Provisioning Related to the lost synergies is the duplication of hardware and functionality we witness in the modern home Provisioning communication user access power and space for all different devices is simply an unproductive use of resources Communication
18. d 2 nominal operation 8 End of heating period 2 reduced operation 9 Start of heating period 3 nominal operation 10 End of heating period 3 reduced operation Operating a Digital Answerer The state of this particular digital answerer is indicated by a single messages indicator light Its behaviour is to be interpreted as follows 45 p 5 On Answerer is on and there are no messages Flashing Number of flashes indicates number of messages Off Answerer is off but there might still be messages Flashing rapidly Outgoing announcement is invalid or memory is full For remotely accessing the messages the device s owner is provided with a paper cut out remote access card that lists the eleven different commands five are to be used during message playback and six at all other times the answering machine supports Programming a PBX This low end PBX can be programmed from a DTMF phone connected to the extension 2 only The PBX allows the specification of different extension ringing patterns for day and night use To specify the day or night starting time the following procedure has to be followed 27 p 25 To enter the system programming mode dial 6206206 To set the day night switching time dial 71 A BB CC D where Ais to specify the day start time to the specify the night start time BB is the hour 01 12 CC is the minute 00 59 D is 0 for AM and 1 for PM To exit the system
19. d Maintenance Perhaps the biggest roadblock to the universal deployment of information furnaces is their installation testing and maintenance The subtle interactions of multiple systems can result in many subtle and difficult to find bugs Some of them can be amusing the first visitors to ring the doorbell after the information furnace was deployed were greeted with an telephone answering machine message More than a year after the 25 furnace s deployment we are still tuning its operation and correcting minor by now inconveniences Most people would not regard the existence of a resident system administrator an acceptable solution to this problem The availability of stable software rather than its organic home growth the adoption of the domain specific languages we saw in Sec tion 5 2 and the initial configuration of the furnace by a qualified professional can help in this direction However the above process although similar to other processes fol lowed for building homes is completely different from the ad hoc procedure typically employed when purchasing and deploying consumer oriented hardware plug it in play with the buttons avoid reading the manual Unless the widespread deployment of in formation furnaces is coupled with an appropriate installation and maintenance process significant problems will ensue 7 Conclusions There is tremendous scope for making the devices found in a modern home more user friendly and sy
20. e interfaces and an RS 232 or USB data port The data port is connected to the infor mation furnace for providing internet access and firewall functionality The two POTS interfaces are connected to an entry level analogue PBX I decided to use an analogue PBX instead of an ISDN model to minimise the system s cost and by reasoning that new upcoming telephony offerings such as xDSL or fixed wireless lines might not be com patible with an ISDN PBX The PBX connects to a number of plain phones a door entry phone a relay actuator for opening the door and a POTS modem used for programming the PBX and providing a voice DTMF interface The 40Gb hard disk is used to store mu sic content in MP3 form to distribute throughout the house and as intermediate storage for backup purposes PCs and MP3 players connect to the information furnace via an Ethernet LAN The GSM phone and a UPS both connected to the information furnace via serial links provide communications and power backup Connecting the alarm system devices to the furnace was more challenging Alarm sensors and actuators typically work with 12V voltage while the digital I O card I used provided an 8255 compatible TTL type interface on a 50 pin ribbon cable connector To match the physical form and electrical characteristics of the two systems I designed and implemented a simple PCB printed circuit board circuit that converts sensor signals into TTL compatible inputs uses relays to activate ext
21. e ID3 standard because the type of data available 19 bin sh NUM 50 while do NUM expr SNUM 1 mkdir SNUM cd SNUM Loop waiting for a disk to be inserted while cdcontrol f dev acd0c status media grep q No media do sleep 60 done cdrip C s done Figure 6 Automating the ripping process IE ix EE Ipixi File Edit View Go Communicator Help File Edit view Go Communicator Help oncerti Nei o kaip c 12303 CD 1 578 Oddc oveipwy 12304 CD 2 579 Ely antag ywpic prepa 12305 La Folia And Other Sonatas 978 Evive Tapeenynon 12306 H Kup 22307 Dvorak Eid 1payo ia 8a cou Tw 12308 ayartw 12309 Cello Concerto Scherzo Capriccioso 580 Fapugadao ot auii 22310 Symphony 7 Slavonic Dances 587 Mig Navayid 22317 Symphony 8 Slavonic Dances 582 T aot pl rou Bopna 22372 Symphony 9 From The New World Carnaval Overture 583 O rayu p yoc rr Bave 22313 To Bad twv yap vuv ovelpwy 12314 Gershwin Koupacp vo rraAAnk pr 22315 Aydt Trou yivec O korro paya pr 72376 Cuban Overture Second Rhapsody Song Book 6 Melodies 3 Preludes 584 H Aor pvo 22317 O apat c 12318 Gorecki ABfjva 12319 Tei puye ro rpa vo 72320 Symphony 3 Sorrowful Songs 585 Ta madia rou Dieipait 12327 Paschalies Mesa Pao Ti Nekri Gi n4 49299 Document Done b A Document Done Figure 7 CD and track level HTML playlists 20 from the public CD directories does not exactly match that maintained in the M
22. e bottom line of the burglar alarm and home monitoring industry A modern burglar alarm consists of a control unit an array of sensors and facilities for alerting whomsoever the owner can afford The sensors used include motion detectors based on passive infrared PIR microwave or hybrid technologies magnetic contacts that detect the opening of doors and windows and glass vibration sensors Sensors placed under mats and carpets and light beam detectors are less often used Contrary to the popular perception promoted by Hollywood films visible red intersecting laser beams used to test a burglar s agility are not a popular sensor option The control unit is typically an overpriced and underpowered microprocessor con trolled contraption It monitors the sensors due to a dearth of input ports these are often or wired into zones allows the owners to activate and deactivate it using a PIN distinguishes between a normal entry e g through a door that provides a delay for deactivating the system and an unexpected event e g motion entry through a window that immediately triggers an alarm offers a facility for operating with the occupants inside the house night mode and controls the alarm triggering and rearming process Alarms in most cases sound an internal siren that is supposed to frighten the burglars but will in most cases only frighten the poor owners when set off in a night mode operation activate an external s
23. e engineering tools In Ramming 35 pages 67 76 Thomson Consumer Electronics Indanapolis USA GE Digital Answerer 1996 Docu ment code 2 9865 Marcello Urbani dagrab Read audio tracks from a CD into wav sound files Online http web tiscalinet it marcellou dagrab html 2000 Current March 2002 Larry Wall Tom Christiansen Randal L Schwartz and Stephen Potter Programming Perl O Reilly and Associates Sebastopol CA USA second edition 1996 Roy Want and Gaetano Borriello Survey on information appliances Computers Graphics and Applications 20 3 24 31 May June 2000 M Weiser Some computer science issues in ubiquitous computing Communications of the ACM 36 7 74 84 October 1993 Elizabeth Zwicky Simon Cooper and D Brent Chapman Building Internet Firewalls O Reilly and Associates Sebastopol CA USA second edition 2000 30
24. e humble vacuum cleaner the microprocessor en gineer show off case microwave oven and the increasingly clever refrigerator oven washing machine drier and coffee machine 16 Unfortunately for this article s au thor and probably fortunately for their other users none of these devices offers a viable interface for controlling their operation 3 Modern Problems The coexistence of the devices and systems I described in the previous section under the same roof is a sad story of unattained potential lost opportunities and waste 3 1 User Interface The most important problem inflicting the systems is their often dysfunctional to put it politely user interface The reason behind this problem stems from the restricted human interaction devices the systems have at their disposal In most cases interaction devices consist of small numerical LCD displays sometimes capable of displaying some additional hieroglyphic symbols and a few domain specific buttons The systems I de scribed rarely follow the principles of a user centred design 31 p 188 It is thus difficult to determine what actions are possible at any moment the system s conceptual model and current state are hidden from the user and there are no natural mappings be tween a user s intentions the required actions and the resulting effect Similarly many of the user interface design Golden Rules 38 pp 74 75 are never followed inter faces are inconsistent require tediou
25. e purposes of this article Convenience ele ments associated with control units involve the ability to maintain different temperature settings for day and night manually set the system to day night or absence mode keep a weekly schedule of automatic switchovers between these modes and switch off for the prescribed duration of a trip Instead of a burner some systems are based on a heat pump and air circulation They are controlled by the same principles but can also lower the building s temperature during hot days Split type wall mounted room air conditioners feature an integrated opaque control circuit adjusted individually through a remote control The provision of hot running water to the bathrooms and kitchen is often controlled together with the central heating system The added complications this brings into the picture involve the possibility of heating the water on sunny days through a solar panel an electrical heater used as a backup measure a circulating pump to pass water through the solar panel and a second pump to bring hot water near the taps The first pump operates through a thermostat comparing the temperature difference between the hot water storage tank and the solar panel we can again regard the system as a black box that absorbs solar energy The operation of the second pump is more tricky its intention is to save water by bringing the hot water close to the taps When the central heating system is operating having a
26. economy type light bulbs that may take up to five minutes to reach their rated light output A case where the silicon economy has worked is exemplified by the availability of affordable devices to control plant and garden watering These often sport a bewildering array of daily and weekly watering programs apart from the one you really require that is can be directly fitted into a watering hose or can control multiple valves and can receive additional feedback from a soil humidity sensor 2 2 Infotainment The array of devices used for servicing our entertainment and supposedly our infor mation access needs covering the so called infotainment category is bewildering It involves CD MP3 and DVD players radios the increasingly digital and interactive 24 television tape or hard disk based video recorders digital photograph and video cameras game consoles and networked personal computers Across those devices we typically witness a gratuitous duplication of functionality and a lack of standardisa tion both are exemplified by the growing array of remote controls adorning the typical lounge table The last problem has spurned research 41 and development of universal configurable remote controls 2 3 Security Home owners not wishing to trust their security of the prized possessions I outlined in the previous paragraph to the watchful eye of the local cop or a bona fide man eating animal often end up contributing to th
27. ements of the information furnace concept and its prototype implementation This paper contains more material than what would be strictly necessary to present and substantiate my thesis for the information furnace The reasons are twofold firstly I tried to extensively document the main aspects of the prototype implementation and secondly I wanted to demonstrate that all I really need to know about system admin istration I learned building the information furnace with apologies to Robert Fulghum USD 2 The Modern Home A modern home contains a large number of sophisticated devices and technologies Current and near future technologies and respective devices can be roughly categorised into the categories of home control infotainment security communication and special purpose devices 2 1 Home Control Contemporary central heating systems are regulated by one external and a number of internal temperature sensors in conjunction with a control unit occupants use to set the desired room temperature The system compares the internal room temperature to the setting of the control unit and using the external temperature as a compensating factor regulates the temperature of the water produced by the local heat generating plant or the valve bringing remotely heated water into the home Burners often have their own control circuits based on target temperatures for the burner and the circulating pump but we can regard them as a black box for th
28. entrally backed up on a regular basis Surprisingly the information furnace concept when applied as a replacement for the stand alone provision of the functions it supports increases all aspects of the figure of merit M originally proposed for nomadic computers 26 Intelligence Size x Cost x Power However the most important benefit of the centralisation is the synergies that can be exploited we will examine this aspect in Section 4 3 The final element of the information furnace architecture concerns its user interface I do not believe that a single user interface is appropriate for all occasions For this reason the information furnace offers a number of different access modes These can include web forms and Java applets telephone based DTMF commands infrared remote controls access via Bluetooth devices or even a command line interface Thus for se lecting a song to hear one will use an infrared remote control to start the hot water boiler when returning from a trip one will issue DTMF commands over the cellular phone to open the garage door one could use a Bluetooth interface of a PDA and to program or review the activity log of the PBX or the burglar alarm one would prefer to interact with a web form Ideally all functionality should be available from all devices at night one might prefer to use the bedside phone to check the burglar alarm sensors when work ing on a PC a web interface might be used to review the answering
29. ernal loads and provides screw clamp terminal blocks for connecting the sensors and sirens Figure 2 right 5 2 Home Security The information furnace s alarm subsystem consists of a device driver that interfaces to the PCL 724 card and a daemon that monitors sensors and reacts to signals and com mands The PCL 724 card emulates the Intel 8255A programmable peripheral interface chip running in mode 0 simple I O It provides two 8 bit ports port A and port B and two 4 bit ports port C upper port C lower Each port can be individually programmed for input and latched output and appears at a different offset of the device s base I O address One of the lines can also trigger an interrupt but I did not use that feature A separate register allows the configuration of ports for input or output The device is so simple that reliably probing for it when input data arrives at its terminals is impossible therefore the kernel configuration has to specify the device s base address The device driver provides four character devices that correspond to the card s I O ports Opening a device for read or write automatically configures the corresponding hardware port for 14 Figure 2 The information furnace left and the sensor connection PCB right if oflags amp FWRITE Writing output zero the bit outb scp iobase PBIO_CFG scp gt iomode ocfg amp portbit else if oflags amp FREAD Reading input
30. have you checked your answering machine message lately Finally an ap propriate UPS can be provisioned to constantly maintain power without worrying about its size noise or appearance or the distribution of power to multiple locations 9 As the furnace acts as a central hub for content communications and control we can eliminate wasteful duplication provide universal access to all its functionality from any local or remote location centralise our access and control policies effectively backup all data and most importantly exploit the synergies that the centralisation allows A single modern CPU can easily handle all the functions I described in Section 2 Thus the numerous underpowered specialised devices can be replaced with a single general purpose one When all functionality is housed in a centrally connected location it can be accessed from all networked locations Thus elements such as the family s music and photograph collection the answering machine messages lighting controls the bur glar alarm log and the heater programme are available from all rooms in the house and also from remote locations Naturally the centralisation of these important functions entails considerable risks these can however be effectively controlled if the associated policies are centralised reviewable and implemented under a reasonably secure operat ing system In addition all the programming and other information stored in the device can be c
31. in Figure 5 Modem accessing commands are deposited in the form of small shell scripts in the voice shell spool directory The queuing function is provided by Perl and C language libraries so that individual requests are uniformly named according to the date and time they were generated and therefore processed in the correct order The final name of each script is given using a rename 2 call ensuring the operation s atomicity 18 bin sh VMDIR var spool voice vmq cd xec amp amp 2 gt amp while do for i in VMDIR vm do i amp amp rm i done sleep 10 done amp echo var run vmd pid Figure 5 PBX access serialisation daemon 5 4 Content Distribution A motivating requirement that led to the information furnace s conception was the abil ity to access our music collection from any networked place in the house Converting CDs into a collection of MP3 compressed files is a relatively easy task these days I used dagrab 46 and cdparanoia 29 to extract raw content from audio CDs and the encoders bladeenc 19 and notlame 37 to convert that content into MP3 form More difficult were the tasks of organising the transfer of a set of CDs into MP3 format the so called ripping operation systematising the material s storage and access providing useful metadata and setting up an appropriate content directory Although a number of programs for ripping CDs and organising collections e
32. ing are provided by calls to the syslogd 8 daemon Apart from triggering the various sirens alarms cause the queuing of voice and data messages to kind unlucky individuals and the responsible authorities via the modem and the backup GSM phone The actual behaviour of the alarm is specified using a domain specific language 44 42 43 A domain specific language DSL 35 is a programming language tailored specifically for an application domain rather than being general purpose it captures precisely the domain s semantics Examples of DSLs include ex and yacc 20 used for program lexical analysis and parsing HTML 5 used for document mark up and VHDL used for electronic hardware descriptions Domain specific languages allow the concise description of an application s logic reducing the semantic distance between the problem and the program 3 44 As a design choice for implementing safety critical software systems DSLs present two distinct advantages over a hard coded program logic Concrete Expression of Domain Knowledge Domain specific functionality is not co ded into the system or stored in an arcane file format it is captured in a concrete human readable form Programs expressed in the DSL can be scrutinised split 16 leave set sensor active ALL OFF set sensor active Door ACTIVE wait for door open wait for door open syslog LOG INFO Waiting for door open ActiveSensor door open door o
33. iren often coupled with a strobe light that passers by typically try to ignore and notify via a modem or a recorded message a control centre or a list of pre assigned phone numbers The whole system has some redundancy and self monitoring capabilities Many sensors and sirens are equipped with a normally closed tamper switch opening the device s cover or cutting its connecting wire will be immediately registered by the alarm unit The control unit is equipped with a battery which supplies power during a power failure In addition many outdoor sirens come with their own battery and are wired for stand alone operation if the power supplied by the control unit is interrupted or the siren s tamper switch is activated the siren will begin to sound Some systems are also installed with wall mounted panic buttons or similar signalling tokens that an individual can wear These are also useful when elderly or disabled people wish to signal they need attention Some owners also combine their unit with fire detection sensors however fire detection equipment installed to satisfy building regulations falls outside the scope of this article Related to security are also the door phone and sometimes a TV camera the asso ciated door opener and the remote controlled garage door opener Note that the typical door phone and opener combination is an system cunningly designed to minimise the number of individual cables required for its installation Inte
34. less booting the Shark were based on an old Linux platform by comparing the NFS implementation of the Linux version I was using with that of the Shark s NetBSD I quickly found out that 24 the configuration would never work since the two were supporting different versions of the NFS protocol No less important were the various add on packages I used In some cases I experi mented with more than one package for a given task It was clear that the co existence and evolution of competing packages created evolutionary pressure that resulted in bet ter overall offerings A clear example of this case was the area of MP3 encoders and decoders The Shark with its StrongARM processor lacking floating point support is a tough platform for MP3 decoders I fortunately was able to choose and test several different packages until I settled for the MAD MP3 decoder the only one that run suc cessfully on the Shark A counterexample was the vgetty package as far as I could determine it is the only viable offering for handling voice modems and it has a lot of room for improvement At the start of the project I was somewhat ambivalent on binary and package distributions However I found that being able to quickly try pack ages without having to go through the configuration and manual compilation process outweighed the opacity problems of this distribution process 6 2 Standards and Costs The existence of open standards proved to be a blessing for the projec
35. lts directly as a playlist to MP3 players such as mpg 123 18 and mad 25 The first MP3 player connected to the information furnace was a network computer In 1997 Digital Equipment Corp now part of Compaq Computer Corp produced the DIGITAL Network Appliance Reference Design DNARD and published the hardware specifications for free use DEC used the code name Shark to refer to these NCs probably due to the plastic fins used to make them stand in an upright position Figure 8 The DNARD exploits the power of the StrongARM microprocessor combined with the flexibility and economy of industry standard busses and chips With the sale of Digital Semiconductor to Intel in early 1998 ownership of the StrongARM passed to Intel Since that time the DNARD design has no longer been supported by Digital or Compaq Using however a DNARD as an MP3 player connected to the information furnace was an attractive proposition because of the DNARD s attractive slim design silent operation it does not contain a disk or a fan infrared port and audio hardware The Shark runs NetBSD 1 5 patched with Mark Foster s AV package to support the audio hardware and the infrared port 13 The Shark gets its initial configuration from the information furnace dhcpd 8 server and boots using TFTP 12 40 it subsequently mounts its file systems and the MP3 disk volume over NFS A small shell script run at startup time allows us to use a remote control to select mu
36. machine messages Some of the access modes can be more user friendly than others however the process ing and storage power of the information service means that there will be no artificial restrictions to the usability of a particular access mode As an example a complete answering machine help menu can be made available as a voice message over a phone connection without requiring the user to rely on cut out cards or memorise the access commands 10 4 2 Functionality The functionality the information furnace provides encompasses everything it can reli ably and safely accommodate I take this maximalistic view because by my experience every system and function moving to the information furnace automatically benefits from universal multi modal access user friendly control and data backup while pro viding additional opportunities for synergies with other services Thus the information furnace can control the home s climate and hot water provision external and internal blinds artificial lighting alarm sirens and door openers It should receive input from the phone via DTMF commands web forms and Java applets remote controls internal and external temperature sensors motion detectors and opening sensors rain and moisture sensors and Bluetooth devices The information furnace should also act as the centralised repository for the home oc cupants data in a manner analogous to the one suggested by the Cy
37. metrical opposite to the PC s one application for each task design philosophy While my prototype implementation proves the concept its piecemeal implementa tion by a single developer has resulted in a wanting to put it politely software archi tecture If the information furnace concept is to be widely adopted major architectural challenges have to be overcome Already research approaches such as iRoom 14 demonstrate how the task of developing such an architecture could be approached The software architecture of a consumer oriented information furnace should be extremely reliable allow installator and end user customisation provide means for interfacing to many different proprietary devices and integrate the above with a modular multi 26 modal and user friendly interface What is not needed is a repeat of the PC usability and reliability debacle in a scale that will affect our entire family lives and home Acknowledgements Compaq Research contributed as a prize of the 2000 Usenix technical conference win a pet Shark contest the Digital Network Appliance Reference Design DNARD that I used as the system s first MP3 player Jeffrey Mogul kindly handled the tricky logistics for distributing the contest s Sharks and saved the day by explaining to me how a keyboard could be essential for its operation Eliza Fragkaki contributed the server s processing unit literally provided a helping hand during the CD rip
38. n Things Ivy Books reissue edition 1993 Fotis Georgatos and Annie Pinder Coffee HOWTO Online http www linuxdoc org HOWTOf mini Coffee html 2000 Current March 2002 Markus Gutschke Gero Kuhlmann Jamie Honan Martin Renters Bruce Evans Rob de Bath and et al Etherboot open source code for creating boot ROMs Online http etherboot sourceforge net 2002 Current March 2002 Michael Hipp mpg123 A fast MP3 player of Linux and Unix systems Online http www mpg123 de 2001 Current March 2002 Tord Jansson bladeenc MP3 encoder Online http bladeenc mp3 no 2002 Current March 2002 Stephen C Johnson and Michael E Lesk Language development tools Bell System Technical Journal 56 6 2155 2176 July August 1987 Jan Kasprzak Modem vgetty perl module Online http www cpan org authors id Y YE YENYA 1998 Current March 2002 Russell Kroll Network UPS tools Online http www exploits org nut 2002 Current March 2002 Markus Lauff and Hans Werner Gellersen Adapation in a ubiquitous computing man agement architecture In Proceedings of the 2000 ACM symposium on Applied computing 2000 pages 566 567 ACM Press 2000 Giorgos Lekakos Kostas Chorianopoulos and Diomidis Spinellis Information systems in the living room A case study of personalized interactive TV design In Proceedings of the 9th European Conference on Information Systems Bled Slovenia June 2001 28 25 26 27 28
39. neighbourhood attention watering the garden should probably be avoided when the garden lighting indicates that a party 1s taking place a visitor overstaying his welcome will cause a gradual lowering of the house s temperature and lighting 5 Prototype Implementation To experiment with the ideas I outlined in the previous sections I designed and imple mented a prototype of the information furnace In all honesty this is not an entirely accurate description of the causal relationship between the two aspects of my work but seems to be the generally accepted politically correct way of expressing it The implemented information furnace provides the functionalities of an alarm system an answering machine a fax server a PBX interface an internet firewall and router a con tent management and distribution point and a backup server 13 5 1 System Structure You can see a diagram of the information furnace connections in Figure 1 The informa tion furnace consists of a low end 100 MHz Pentium PC equipped with a 40Gb hard disk an additional serial port card and an Advantech PCL 724 24 bit digital input output card For the PC I was fortunate to acquire a surplus IBM Personal Computer 340 unit running FreeBSD 4 1 it proved to be a very stable platform with uptimes in excess of 200 days The national telecom operator provides with each ISDN connection a ter minal adapter with two POTS plain old telephone system traditional analogue phon
40. nergistic The isolated location all inclusive scope and multi modal interface attributes of the information furnace offer a potential roadmap for achieving these goals By implementing a prototype I discovered the pivotal role that open source software standards and the deployment process will play in such an endeavour Some may counter that my thesis for a centralised information furnace contradicts the proposed move from a complex general purpose personal computer towards user friendly simple and versatile information appliances 32 48 I can defend my po sition on two grounds Firstly the systems my proposed information furnace is set to replace do not exhibit any of the information appliance design axioms simplicity ver satility pleasurability 32 p 67 Secondly my solution although based on personal computer technology does not entail at least in the form I designed it the two damn ing characteristics of PCs creeping featurism and an application oriented mindset 32 pp 80 87 I propose that application furnaces be individually configured by experts to match the needs to a home s occupants in the same sense as the house itself is archi tected Secondly the information furnace I propose is in fact an information appliance albeit one with a rather large scope to integrate the home s control information and communication systems This integration aspect necessary to exploit the synergies I discussed is the dia
41. nergistic value added services The use of integrated intelligent devices in the home automation area is not a new concept 30 4 7 14 the information furnace differs however from other approaches by prescribing concrete architectural guidelines expressly adopting a maximalistic approach towards its func tionality and aggressively targeting and exploiting the resulting synergies 4 1 Architecture The architecture of the information furnace is based on three basic premises The device 1 is located in the basement or in a cupboard 2 acts as a central hub for content communications and control and 3 offers multi modal user friendly access to all its functions The location of the device in a secure non accessible place is central to our design having a number of important repercussions Firstly the same location will be used to terminate the various connections These often include home networks telephone lines reception antennas network lines and cable TV connections The unsightly presence of all these cables can only be accommodated in a specially provisioned place In addi tion the noise the system will generate can be effectively isolated Rotating hardware hard disks and fans and other noise generating components such as electromagnetic relays can be brought together into a single place keeping the rest of the house serene Furthermore the system can be physically secured deterring burglars minors or even pranksters
42. pen Syslog LOG INFO Door opened 10s day arm Figure 4 DSL specification of the leave command combined shared published put under release control printed commented and even be automatically generated by other applications Direct Involvement of the Domain Expert The DSL expression style can often be de signed so as to match the format typically used by the domain expert This results in keeping the experts in a very tight software lifecycle loop where they can di rectly specify implement verify and validate without the need of coding inter mediaries Even if the DSL is not high level enough to be used as a specification language by the domain expert it may still be possible to involve the expert in code walkthroughs far more productive than those over code expressed in a gen eral purpose language The DSL used for specifying the alarm daemon behaviour describes a state machine Each state description consists of its name actions to perform when it is entered written on lines starting with a symbol and events that lead to other states denoted using a gt symbol Actions are simply C function calls To enhance the DSL s expressiveness a state can also transfer immediately to another state without waiting for an event I use this feature to modularise the specification by defining subroutine states As an example the sequence in Figure 4 is used to specify that a leave command will arm the system 10s
43. ping operation and patiently endured the prototype system s alpha and beta testing period Lorenzo Vicisano came up with the idea of using the Shark as an MP3 player Isidoros Kouvelas and Vasilis Prevelakis offered encouragement help and interesting ideas dur ing the prototype s implementation and Giorgos Gousios contributed valuable comments on an earlier draft of this paper Finally my colleagues at the Athens University of Economics and Business eLTRUN research group provided me with numerous opportunities to enrich my view and expectations of ubiquitous computing appliances and applications Software Availability The source code for the PCL 724 device driver and the Shark MP3 player script is avail able at lt http www dmst aueb gr dds sw ifurnace gt References 1 Christoph Bartelmus Pablo d Angelo Heinrich Langos Tom Wheely Karsten Scheibler Jim Paris Pawel T Jochym and Milan Pikula LIRC Linux infrared remote control Online http www lirc org 2002 Current March 2002 2 Gordon Bell and Jim Gray Digital immortality Communications of the ACM 44 3 28 30 March 2001 3 J Bell F Bellegarde J Hook R B Kieburtz A Kotov J Lewis L McKinney D P Oliva T Sheard L Tong L Walton and T Zhou Software design for reliability and reuse a proof of concept demonstration In Conference on TRI Ada 94 pages 396 404 ACM ACM Press 1994 4 Stewart Benedict X automate Linux Journal 1
44. proved by each new technological widget we adopt uncooperative devices and appliances with deficient user interfaces can certainly conspire to frustrate us Over the past three years I have experimented In SANE 2002 3rd International System Administration and Networking Conference Proceedings SANE 2002 pp 145 174 Maastricht The Netherlands May 2002 NLUUG This is a machine readable rendering of a working paper draft that led to a publication The publica tion should always be cited in preference to this draft using the reference in the previous footnote This material is presented to ensure timely dissemination of scholarly and technical work Copyright and all rights therein are retained by authors or by other copyright holders All persons copying this information are expected to adhere to the terms and constraints invoked by each author s copyright In most cases these works may not be reposted without the explicit permission of the copyright holder with a number of technologies that gave birth to the information furnace concept a basement installed PC type device that integrates existing consumer home control in fotainment security and communication technologies to transparently provide user friendly access and synergistic value added services In the following sections we will examine the devices and appliances lurking in the modern home overview the prob lems associated with the current breed of devices and go over the basic el
45. rfacing with such a system can be very difficult however many small private box exchanges PBXs offer a door phone door opening option and can be easier to interface 2 4 Communication The modern home s communication needs are served by the phone and an Internet con nection using POTS and a modem ISDN and a terminal adaptor or another digital net work technology e g DSL and the associated terminator box Sharing of phone lines and internal communication can be facilitated via a PBX while the corresponding shar ing of data connections can be facilitated by a network and hub or wireless network and a router PCs are also increasingly used to share network collections Phone lines are often terminated on an answering machine and a fax the more exotic ISDN offer ings trumpeted by the incumbent telecom providers videophones digital faxes have been persistently snubbed by consumers Connected to the data lines are PCs holding valuable personal data and in dire need of regularly scheduled backups and connected to the PC are various PDAs holding the owner s telephone number directory and other personal data A baby monitor typically functions independently of the above setup A variety of wired and wireless home networking technologies aim at interconnecting the systems I described 9 2 5 Special purpose Devices Finally inside a modern home there is a number of electronically controlled special purpose devices These include th
46. s sequences of data entry and often lack shortcuts informative feedback and the ability to reverse actions Other important user interface problems include non intuitive interaction sequences the operation in various different modes 36 pp 30 57 the overloading of buttons for different purposes cryptic display messages lack of localisation and accessibility for disabled people and a non ergonomic design Appreciating that I might be accused of shooting a lame duck I illustrate these points with three representative examples Programming a Heating Controller The room unit in question allows programming a weekly schedule for the controller s operation Programming is performed by switching between 17 different modes each indicated on the panel by a different number The following excerpt from the operation manual outlines the weekly programming procedure 39 p 5 With the heating program you can predetermine the temperature switch over times for one week The weekly program consists of seven 24 hour programs One 24 hour program may include up to three heating periods each of which is defined by a start and an end time If you do not require a certain heating period you need to enter the same time of day as start and end time 4 Select the required day for the heating period 1 Monday 7 Sunday 5 Start of heating period 1 nominal operation 6 End of heating period 1 reduced operation 7 Start of heating perio
47. sic The irw command from the LIRC distribution 1 reads remote control messages These can be a number forming a CD track or music type code play stop previous next or pause The play command 21 Figure 8 The Digital Network Appliance Reference Design DNARD left and the Shark as an MP3 player right starts an MP3 player process All other commands are handled by sending signals to the MP3 player process stop kills the player process pause pauses it previous and next send it the USR1 and USR2 signals respectively I contributed patches to the MAD and mpg123 development efforts that enable both players to recognise these signals to move backwards and forwards in the current playlist Playlists are generated by a sed 1 command that prints the master playlist from the music part selected until its end As music is sorted and traversed according to its content when the player finishes the selected track or CD it will continue playing roughly similar content Shuffling of music tracks is simply accomplished using the NetBSD s Auffle 1 command The two other MP3 players we deployed use similar concepts but run on less pol ished hardware and software configurations One consists of an Intel 100MHz Pentium PC that boots a copy of FreeBSD diskless from the information furnace using etherboot 17 the other is an old laptop running SuSE Linux 7 0 To minimise the noise of the PC I switched its fans to 5V reasoning that with no hard
48. supports a software command to switch off the UPS Thus the last action of step 4 is to soft switch off the UPS and consequently the computer if the UPS is running on batter ies or restart the computer if the UPS is at that point running on mains power If the UPS 29 is switched off when power is restored both the UPS and the computer will correctly restart Note that the implementation of this sequence is not trivial the excellent NUT 22 UPS software I used operates as a user process when the computer is ready to halt user processes have died and filesystems are unmounted making it difficult to send that last command to the UPS The information furnace acts as an internet router and as a firewall by means of the native FreeBSD user mode ppp 8 package running with network address translation NAT enabled This approach while not perfect is adequate for the profile of the users living inside the firewall Configuring the filters was relatively easy once I had refer ence 50 at hand Despite my earlier thoughts to the contrary I found that protecting a dial up connection can be worthwhile I do not have time to maintain the various MP3 players with the latest security patches and as the following excerpt from the informa tion furnace s apache log shows dial up connections are actively scanned for security holes Tue Sep 18 20 35 49 2001 error client 195 158 192 25 File does not exist usr local www data scripts xcl x9c
49. t s success the lack of standardisation a curse Specifically the lack of open standards ruled out having the information furnace controlling the home s heating in the form I described the heating controller was clearly attached to a form of a network bus but its operation at all the network stack levels was apparently a secret closely guarded by its manufacturer i e the standard was not available on the web Similarly in the domain of artificial lighting controls it being an area where a number of incompatible proprietary standards compete there are expensive solutions that do not deliver the economies they could Efforts for integrating arbitrary communication protocols such as 23 could help so would adopting TCP IP for communicating with all devices 11 On the other hand the standards and the resulting economies of PC manufacturing coupled with the rapid obsolescence of PCs provided me with a number of cheap and viable platforms for deploying the infrastructure I described While scavenging obso lete hardware can be a viable strategy for a researcher or a hobbyist it can not form a long term technology adoption plan However the above forces can also result in the development of affordable hardware platforms based on established components and processors like the DNARD Shark These platforms based on cheap industry standard busses and chips can form the base of the future s mass produced information furnaces 6 3 Deployment an
50. tent and communications in a single place allows us to exploit synergies that make many control functions redundant or provide new and more versatile features First of all the collocation of all services in a powerful processing and storage device makes it possible to provide centralised backup universal and multi modal access to all functions and user friendly interfaces Consider the alarm system motion detectors These can detect activity in rooms and can therefore be used to start the running hot water circulation pump when an occupant approaches the bathroom or kitchen close the blinds when the owners are in a room to protect their privacy and oth erwise open them in cold summer nights and sunny winter days to improve the home s climate control turn artificial lighting on and off as the owners move across rooms additional hints such as entertainment system or communications activity can be used to improve the heuristics of this approach avoid ringing the phone in a bedroom with no activity where presumably an occupant might be sleeping when activity in another room indicates that someone else might prefer to pick up the phone Note that reversing the above conditions does not yield a heuristic many adults would agree with When leaving the home and on return the activities we perform can be compa rable to walking through a jet pilot s checklist The information furnace can collec 12 ISDN line
51. xist most of them appear bloated and resource hungry I decided to handle the task flexibly by piecing together existing tools and see where this approach would lead me I ripped CDs by piping the output of an audio extraction program into an MP3 encoder I encoded most material at 192kbps some older historic CDs were of such low quality that they could be encoded at 128kbps without audible problems variable rate encoding was not universally supported at the time of the ripping operation The ripping script saved each track into a separate file named t rackNN mp3 and also created an text file containing the CDs track information To increase the throughput of the ripping process I used the script shown in Figure 6 to rip each CD into a directory named with an ascending integer number After each CD was ripped the disk was ejected and the script would wait for a new disk to be inserted Thus whenever we would see an ejected CD in the tray we could just feed the furnace with a fresh CD At periodic intervals we would move the ripped directories into a hierarchical struc ture made up out of the music type the composer performer or band name the album name and the CD number Also a script would crawl the directory structure and create a metadata file for each CD info txt by pulling information out of the cddb com and later the freedb org server using the CDDB Perl module 6 I decided to store the meta data into a separate file and not use th
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