My GTWeb system demonstrates how trip diaries can be created and presented by exploiting the synergies of integrating a GPS,
a digital camera, and publicly accessible databases. A GTWeb site consists of a trip overview, timelines, maps, and annotated photographs. The site is created by processesing a user's GPS track log and digital camera pictures, linking them with a gazetteer database, topography, and coastline data.
The (research prototype quality) software I developed can be freely downloaded (GPLed Perl and C source).
An article
that appeared earlied this year in IEEE Pervasive Computing describes the principles of operation.
Now that you have SFU freely available go download and install outwit.
Outwit is a suite of tools based on the Unix tool design principles allowing the processing of Windows application data with sophisticated data manipulation pipelines. The outwit tools offer access to the Windows clipboard, the registry, the event log, relational databases, document properties, shell links, and the event log.
As an example, you can change all registry entries pointing to a user's home directory by running
winreg HKEY_CURRENT_USER | sed -n 's/C:\\home/D:\\home/gp' | winreg
A Usenix technical conference paper describes the tools and a number of applications.
Now that you have SFU freely available go download and install outwit.
Outwit is a suite of tools based on the Unix tool design principles allowing the processing of Windows application data with sophisticated data manipulation pipelines. The outwit tools offer access to the Windows clipboard, the registry, the event log, relational databases, document properties, shell links, and the event log.
A Usenix technical conference paper describes the tools and a number of applications.
I built a home application network I termed an Information Furnace a couple of years ago based on machines running slightly customized versions of FreeBSD, Linux, and NetBSD. My system handles Internet access, the PBX, MP3 music distribution, an alarm system, and a door opener. It can receive commands from remote controls, DTMF, and the web.
What I gained from connecting these systems under one roof was
a better user interface; e.g. no more cryptic PBX commands to change quick-dialing codes
enhanced functionality, as in globally distributed MP3 play lists
synergies; a single command turn on the answering machine and the alarm system
more efficient and elegant provisioning: most of the cable clutter is now concentrated in a single out-of-sight location
The biggest difficulty in setting up the system was not technical, but administrative.
Although I had to write a device driver and some custom software, these proved to be relatively stable once debugged. The problems were in correctly specifying our living requirements, translating them into specifications, and testing the result. The first friends to visit us after I installed the system rang the doorbell and were greeted by the answering machine message (oops!) Now the system is very stable, but I would never think of modifying its configuration less than a month before leaving for a vacation.
You don't necessarily need LEDs to locate bad RAM. I remember locating a bad RAM chip on a TI-99/4A computer in 1984 by finding that one of the eight 4116 (16K * 1 bit) memory chips was colder than the rest. I soldered in a new chip and the machine worked like new.
I have automated audio, security, internet access, and voice telephony using a central server box running FreeBSD and a couple of clients running Linux and NetBSD. I term this approach the Information Furnace. When I presented my work at the SANE 2002 conference a member of the audience asked me:
What job does your wife do?
Fortunatelly for me, my wife is an IT professional and can appreciate both the advantages of this setup (our CDs are instantly available throughout the house, we can remotely retrieve caller-id information on last calls, setup customized alarm response scenarios, and so on) and the inevitable bugs (the first friends to ring our doorbell were were greeted by an answering machine message).
However, getting the behavior of the system just right took us more than a year, I am still being very conservative when I tweak something (I am never introducing changes to it before leaving for a vacation), and there were times where we discussed the system's interface over a graphical depiction of state machine diagram. I am sure the/. crowd thinks this is the way to go, but I also think there will be people who might find such a setup a bit bewildering.
The POSIX compliance of Windows NT is a farce. It was only added as a marketing trick allowing Windows-based systems to compete in procurement contracts where POSIX compatibility is an obligatory specification. As implemented in Windows NT and Windows 2000 the POSIX subsystem is almost useless. According to Microsoft's documentation applications running in the POSIX subsystem applications have no direct access to any of the facilities and features of the Win32 subsystem, such as memory-mapped files, networking, graphics, or dynamic data exchange. Applications working in the POSIX subsystem essentially operate in an isolated text terminal island. The original POSIX subsystem was probably an embarrassment to Microsoft, so it was quietly dropped when moving to Windows XP and beyond in favour of the Interix technology.
If you want POSIX compatibility under Windows you are better of using Cygwin or - at the shell level - the native ports of GNU utilities to Win32. Add to the mix my Outwit tools for Windows interoperability and you are set.
The result of applying the ++ operator on a variable is a plain value, not an lvalue (an entity that can appear on the left side of an assignment). The ++ operator has to be applied to an lvalue. Thus C++++, ++C++, and so on are not legal constructs. Convince yourself:
$ cat t.c foo() { int C; C++++;} $ cc t.c t.c: In function `foo': t.c:1: invalid lvalue in increment
A neat trick to reverse engineer the communication between a serially connected embedded device and the proprietary software controlling it, is to force it to communicate via an man-in-the-middle hardware interceptor. Any old PC will do for that. The interceptor logs all comunication into a file that you can then examine at your leisure. The interceptor program is simplicity itself: fork, open the serial device and file, read/write (or write/read) a character and log it to the file. Someday I 'll have to program a similar setup for USB devices.
I 've used this trick to reverse engineer the proprietary communication protocol of a (now ancient) Ericsson GH-388 mobile phone and write a program to query the phone for battery level, reception level, IMEI, and phonebook contents.
The proprietary program was running on a Windows laptop; a Linux machine was sitting between the program and the phone busilly recording every byte they exchanged.
In my recent column in the Communications of the ACM (Inside risks: Reflections on trusting trust revisited 46(6):112, June 2003) I describe two parallels: twenty years ago Ken Thompson showed us that one cannot trust an application's security policy by
examining its source code if the platform's compiler (and presumably also its execution environment) were not trusted. The recent 007 Xbox attack demonstrated
that one cannot trust a platform's security policy if the applications running on it cannot be trusted. (The Xbox is a specialized trusted computing platform.) The moral of the Xbox attack is that implementing on a trusted computing
platform, a robust DRM, or mandatory access control, or an even more sinister security policy involving outright censorship will not be easy. It is not enough to
certify the hardware and have a secure operating system; even a single carelessly written but certified application can be enough to undermine a system's
security policy. As an example, a media player could be tricked into saving encrypted content in an unprotected format by exploiting a buffer overflow in its
(unrelated) GUI customization (skin) code.
the timecoded track log of a consumer-grade handheld GPS,
maps generated from publically available topography and coastline data,
a gazetteer (place names and locations) database, and
links to map web sites
to create a geocoded picture album and trip log.
You can view such an example at http://www.spinellis.gr/geoweb/Chalkidiki/. An article titled Position-annotated Photographs: The Geotemporal Web to appear in IEEE Pervasive Computing presents the technical aspects of Geoweb's design and implementation.
Slashdot Mirror
An article that appeared earlied this year in IEEE Pervasive Computing describes the principles of operation.
Diomidis Spinellis - #include "/dev/tty"
As an example, you can change all registry entries pointing to a user's home directory by running
A Usenix technical conference paper describes the tools and a number of applications.#include "/dev/tty"
#include "/dev/tty"
What I gained from connecting these systems under one roof was
The biggest difficulty in setting up the system was not technical, but administrative. Although I had to write a device driver and some custom software, these proved to be relatively stable once debugged. The problems were in correctly specifying our living requirements, translating them into specifications, and testing the result. The first friends to visit us after I installed the system rang the doorbell and were greeted by the answering machine message (oops!) Now the system is very stable, but I would never think of modifying its configuration less than a month before leaving for a vacation.
Diomidis Spinellis - Code Reading: The Open Source Perspective
#include "/dev/tty"
Diomidis Spinellis - Code Reading: The Open Source Perspective
#include "/dev/tty"
What job does your wife do?
Fortunatelly for me, my wife is an IT professional and can appreciate both the advantages of this setup (our CDs are instantly available throughout the house, we can remotely retrieve caller-id information on last calls, setup customized alarm response scenarios, and so on) and the inevitable bugs (the first friends to ring our doorbell were were greeted by an answering machine message).
However, getting the behavior of the system just right took us more than a year, I am still being very conservative when I tweak something (I am never introducing changes to it before leaving for a vacation), and there were times where we discussed the system's interface over a graphical depiction of state machine diagram. I am sure the /. crowd thinks this is the way to go, but I also think there will be people who might find such a setup a bit bewildering.
Diomidis Spinellis - Code Reading: The Open Source Perspective
#include "/dev/tty"
If you want POSIX compatibility under Windows you are better of using Cygwin or - at the shell level - the native ports of GNU utilities to Win32. Add to the mix my Outwit tools for Windows interoperability and you are set.
Diomidis Spinellis - Code Reading: The Open Source Perspective
#include "/dev/tty"
Diomidis Spinellis - Code Reading: The Open Source Perspective
#include "/dev/tty"
I 've used this trick to reverse engineer the proprietary communication protocol of a (now ancient) Ericsson GH-388 mobile phone and write a program to query the phone for battery level, reception level, IMEI, and phonebook contents. The proprietary program was running on a Windows laptop; a Linux machine was sitting between the program and the phone busilly recording every byte they exchanged.
Diomidis Spinellis - Code Reading: The Open Source Perspective
#include "/dev/tty"
Diomidis Spinellis
Code Reading: The Open Source Perspective
#include "/dev/tty"
- the date/time stamp of a digital camera,
- the timecoded track log of a consumer-grade handheld GPS,
- maps generated from publically available topography and coastline data,
- a gazetteer (place names and locations) database, and
- links to map web sites
to create a geocoded picture album and trip log.You can view such an example at http://www.spinellis.gr/geoweb/Chalkidiki/. An article titled Position-annotated Photographs: The Geotemporal Web to appear in IEEE Pervasive Computing presents the technical aspects of Geoweb's design and implementation.