zoneminder/README

ZONE MINDER
===========

Introduction
============

Welcome to ZoneMinder, the new all-in-one Linux GPL'd security camera solution. A few months back my garage
was burgled and they stole my wine and power tools! I realised shortly after that if I'd just had a camera
overlooking the door then at least I'd have know exactly when and who did the dirty deed. And so ZoneMinder
was born. It's still a baby but hopefully it can grow up to be something that can be genuinely useful and
maybe one day either prevent similar incidents or perhaps bring some perpetrators to justice.

ZoneMinder (hereafter referred to as ZM to save my fingers) is designed around a series of independant
components which only function when necessary limiting any wasted resource and maximising the function of
your machine. A fairly ancient Pentium PC should be able to track one camera iper device at up to 25 framess
per second with this dropping by half approximately for each additional camera on the same device, additional
cameras on other devices do not interact so can maintain this frame rate. Even monitoring several cameras
still will not overload the CPU as frame processing is designed to synchronise with capture and not stall
it.

As well as being fast ZM is designed to be friendly and even more than that, actually useful. As well as the
fast video interface core it also comes with a user friendly and comprehensive PHP based web interface
allowing you to control and monitor your cameras from home or even elsewhere. It supports variable web
capabilities based on available bandwidth. The web interface also allows you to view events that your
cameras have captured and archive them or review them time and again, or delete the ones you now longer wish
to keep. The web pages directly interact with the core daemons ensuring full co-operation at all times.

The core of ZM is the capture and analysis of images and there is a highly configurable set of parameters
which allow you to ensure that you can eliminate false positives whilst ensuring that anything you don't
weant to miss will be captured and saved. ZM allows you to define a set of 'zones' for each camera of
varying sensitivity and functionality. This allows you to eliminate regions which you don't wish to track or
define areas which will alarm if various thresholds are exceeded in conjunction with other zones.

ZoneMinder is fresh off the keyboard and so comes with no warranty whatsoever, please try it, send your
feedback and if you get anything useful out of it please let me know.


Requirements
============

ZM needs a couple of things to work. Firstly, it uses MySQL so you'll need that. Next is does things with
JPEGs so you'll need at least libjpeg.a which I think come as standard nowadays. It also uses the netpbm
utilities in a very limited way to generate thumbnails under certains circumstance though this can be
modified. ZM can generate MPEG videos if necessary, for this you'll need the Berkeley MPEG encoder, if you
don't have it don't worry the options will be hidden and you'll not miss much really. The web interface uses
PHP and so you need that in your apache or whatever as well. Finally there is quite a bit of image streaming
in the package so if you don't have Netscape I recommend you get the excellent Cambozola java applet from 
http://www.charliemouse.com/code/cambozola/ which will let you view the image streams in IE and others.
Otherwise you're limited to just refreshing still images.

Hardware wise, ZM has been used with BTTV cards and USB cameras with the V4L interface. I don't have a lot
of cameras so I've not had change to test it much. Please let me know if your camera works or not. You do
need to have Video 4 Linux installed. I've not got many machines so I've only really used it on Redhat 7.2
which does have everythign there by default I think. Please give me feedback on other distributions.


Building
========

Before you start building you have a couple of things to do. Firstly you'll have to create your ZoneMinder
database and users. You'll need to identify these in zmcfg.h and in index.php. You'll notice that in zmcfg.h
there are two sets of users and passwords. This is because the Streaming server and Utility binaries require
only read access to the database so you may wish to create both a full access user and a limited access
user. You can of course set both to the full access user. The included schema can be used to actually create
the tablles required. The database is usually called 'zm'. ZM also needs to know where it stores its events
relative to the web root directory in zmcfg.h and where in full path terms in index.php. There are also
several other paths in index.php but these can wait until later.

So to start, just type './configure --with-mysql=/usr' (or your MySQL install path).
Then just type 'make' and off you go.

I know what you are going to say next, it doesn't build. I hope it does but this is my first type with autoconf
and quite honestly I haven't a clue what I'm doing so if you do get any build problems then just let me know
and I'll try and tell you how to fix them. Alternatively if you are and automake/autoconf expert then please
let me know what to do!

There are a couple of files in the package that come from other packages, this is just to simplify the build
and reduce dependencies on other packages. Anything ZM specific is named as such.


Installation
============

Once the build has completed you should have several shiny new binaries. I will now briefly describe what
each of them do.

zmc - This is the Zone Monitor Capture daemon. This binarys job is to sit on a video device and such frames
off it as fast as possible, this should run at more or less constant speed.
zma - This is the Zone Monitor Analysis daemon. This is the component that goes through the captured frames
and checks them for alarming events. It generally keeps up with the zmc but if very busy may skip some
frames to prevent it falling behind.
zms - This is the Zone Monitor Streaming server. The web interface connects with this to get real-time or
historical streamed images.
zmu - This is the Zone Monitor Utility. Basically a handy command line interface to several useful
functions. Not really meant to be used by anyone except the web page (there's no 'help' in it yet) but can
be if necessary.

At this stage typing 'make install' will install these binaries to the desired location. However, it's not quite
this simple as in order to get the ZM web interface up you'll have to create a web directory and configure your
web server to point to it. Once you do you then copy 'index.php' to that directory, you can rename it if
necessary. The 'zms' daemon is designed to run as a CGI program so you may also need to copy that to a
/cgi-bin type place also. There are several paths that must be defined (or cleared) in index.php to point to
various other binaries and directories before it will work fully but that's pretty much it for now.

Start your web browser and point it at index.php and off you go.


Tutorial
========

To start with you should see the ZM Console window, this will resize itself to avoid being too intrusive on
your desktop. Along the top there are a set of links to configure your bandwidth, this allows you to optimise
your settings depending on where you are and the actual options relating to this are defined at the top of
the index.php file. If you are using a browser on the same machine or network then choose high, over a cable
or DSL link maybe choose medium and over a dialup choose low. You can experiment to see which is best. This
setting is retained on a per machine basis witha persistent cookie.

To use ZM properly you need to define at least one Monitor. Essentially a monitor is attached to a camera and
will continually check it for motion detection and such like. So click 'Add New Monitor' to bring up the
dialog. First choose a name for it, anything you like. The next field is 'Function' which essentially
defines what the monitor is doing. This can be 'None' meaning the monitor is currently disabled, 'Passive'
meaning you can watch the streams coming from the camera but no alarms or events will be generated, or
'Active' meaning all the images will be analysed as well as the stream being available to watch. Generally
you'll want 'Active' but for now leave this at 'None'. Next enter the device number that your camera is
attached to. If it's /dev/video0 enter '0' etc. Some video devices, e.g. BTTV cards support multiple cameras
so in the Channel box choose the appropriate channel, or leave it at zero <if you're using a USB camera or
one without channels. Next enter the video format, and dimensions of the video stream your camera will
supply. If your camera supports several just enter the one you'll want to use for this application, you can
always change it later. However I would recommend starting with no larger than 352x288 and then perhaps
increasing and seeing how performance is affected. This size should be adequate in most cases. Finally enter
the colour depth. ZM supports both greyscale and 24 bit colour, so enter 1 or 3 here. Currently it doesn't
support any of the more esoteric formats, like 15 bit etc. Click 'update' to add your monitor.

On the main console listing you will now see your monitor and some of it's vital statistics. Each column is
also a link and you get to other functions of ZM by choosing the appropriate one. For the most part I'll 
describe them left to right but lets start with the Device column which you'll see showing red. This means 
that that device has no zmc (capture) daemon running on it, if it were orange it would mean that a zmc 
daemon was running but no zma (analysis) daemon and green means both are running. In our case it is red 
because we defined the Monitor to have a Function of None so no daemons are required. To get the daemons up 
and running you can either click on the device listed in the Device column, and start the daemons manually 
yourself, or click on the Function listed and change it to 'Active' which will ensure that the appropriate
daemons are started automatically. Having a device status of red or orange does not necessarily constitute
an error if you have deliberately disabled a monitor or have just put it into Passive mode. If you have 
several cameras (and thus monitors) on a device the device status colour reflects all of them, so if just
one monitor is active then both daemons will be running even if all the other monitors are switched off.
Once you have changed the function of your monitor, the main console window will be updated to reflect this
change. If your device status does not go green then check your system and web server logs to see if it's
something obvious like a bad path etc.

You can now add further monitors if you have cameras set up to support them. Once you have one or more 
monitors you may notice a 'Watch All' link appears which allows you to cycle through a shot from each
of your monitors (unless they are switched off) and get a still image from each in turn. Clicking on the
image will take you to the monitor watch window which will be discussed shortly.

Returning to the main console window, if you click the Id of your monitor in the listing then you will have
the opportunity to edit any of the settings your originally defined your monitor to have.

The next important thing to do is set up Zones for your monitors to use. By default you'll already have one
created for you when you created your monitor but you might want to modify it or add others. Click on the
Zones column for your monitor and you should see a small popup window appear which contains an image from
your camera overlain with a stippled pattern representing your zone. In the default case this will cover
the whole image and will be red. Beneath that will be a table containing a listing of your zones. Clicking
on either the relevant bit of the image or on the Id or Name in the table will bring up another window where
you can edit the particulars for your Zones. As you can see there are quite a few, so now is a good time
to go through them. Firstly the zone Name appears, you can change this to be more representative if you like
though it isn't used much except for logging and debugging. After that is the zone Type, this is one of
the more important concepts in ZM and there are four to choose from. The one you'll use most and which will
be set for your deault zone if 'Active'. This means that this zone will trigger an alarm on any events that
occur within that meet the selection criteria. The next two options I'll cover shortly but the one at the 
bottom is the opposite to Active and is Inactive. In this zone type no alarms will ever be reported. Create
an Inactive zone to cover any areas in which nothing notable will ever happen or where you get constant
false alarms that don't relate to what you are trying to monitor. An Inactive zone can overlay other zone 
types and will be processed first. The next option is Inclusive and you'd use this zone type for any zones
that you want to trigger an alarm only if at least one other Active zone has already triggered one. This
might be for example to cover an area of the image like a plant or tree which moves a lot and which would
trigger lots of alarms. Perhaps this is behind an area you'd like to monitor though, in this case you'd
create an active zone covering the non-moving parts and an inclusive zone covering the tree perhaps with
less sensitive detection settings also. If something triggered an alarm in the Active zone and also in the
Inclusive zone they would both be registered and the resulting alarm would be that much bigger than if you
had blanked it out altogether. The final zome Type is Exclusive, this means that alarms will only be triggered
in this zone if no alarms have already been triggered in Active zones. This is the most specialised of the
zone types and you may never use it but in it's place it is very useful. For instance in the camera covering
my garden I keep watch for a hedgehog that visits most nights and scoffs the food out of my cats bowls. By
creating a sensitive Exclusive zone in that area I can ensure that a hedgehog alarm will only trigger if
there is activity in that small area. If something much bigger occurs, like someone walking by it will 
trigger a regular alarm and not one from the Exclusive zone. Thus I can ensure I get alarms for big events
and also special small events but not the noise in between. I mentioned above that Inactive zones may be
overlain on other zones to blank out areas however as a general principle you should try and make zones
abut each other as much as possible and not overlaps to avoid repeated duplicate processing of the same area.
For instance an Inclusive zone overlaying an Active zone when all other settings are the same will always
trigger when the Active zone does which somewhat defeats the object of the exercise.

The rest of the zone settings are slightly simpler to explain. The first is Units which details whether certain
of the following settings are in Pixels or Percent ofthe frame. In general pixels is more precise whereas 
percentages are easier to use to start with. If you change this setting all appropriate values below are
redisplayed in the correct context. A good tip would be to initially enter the settings in Percent and then
change to Pixels and refine any gaps. Repeated flipping between the settings will cause rounding errors as
ZM in general is not at home to Mr Floating Point for reasons of performance. Following the units the next
four settings define the bounds of the Zone in the monitor frame and are self explanatory with the exception
of the fact that the minima are at the top left of the frame and the maxima are at the bottom right rather
than Cartesian. The option after that allows you to specify what colour you'd like any alarms this zone 
generates to be highlighted on images, pick anything you like that will show up against your normal image
background. This and all following options are irrelevant for Inactive zones and you will be prevented from
setting them. The options that follow are all related to motion detection and now would be a good time to 
describe how that works. Once a stream of images starts coming through the zma daemon will begin analysing
them initially there will be a warm-up period where it does nothing except start to build up a reference 
image. This image is a composite of the previous images and by default is formed of by applying the current
image as 10% of the previous reference image. Thus each images part in the reference image will diminish 
by a factore of 0.9 each time round. So a typical reference image will be 10% the previous image, 9% the
one before that and then 8.1, 7.2, 6.5 and so on of the rest of the way. An image will effectively vanish
around 25 images later than when it was added. This blend value of 10% can be varied and if higher will
make slower progressing events less detectable as the reference image would change more quickly, similarly
events will be deemed to be over much sooner as the reference image adapts to the new images more quickly. 
In musical terms the higher this value the steeper the event attack and decay of the signal (or note). It
depends on your particular requirements what the appropriate value would be for you. Currently this value
is unfortunately a compile time global option and not monitor specific but this will change in the next
release.

So back to the settings, the next is an alarm threshold, this represents the difference in value between a pixel
and it's predecessor. For greyscale images this is simple but for colour images the colours are averaged
first, originally this used an RMS (root mean squared) algorithm but using sqrt mugs performance and does not
seem to improve detection. Using an average does means that subtle colour changes without any brightness
change may go undetected but this is not the normal circumstance. The following two settings define the
minimum and maximum number of pixels that exceed this threshold that would cause an alarm. If the units are
Percent this (and following options) refer to the percentage of the frame and not the zone, this is so 
these values can be related between zones. The minimum value must is matched or exceed for an alarm to be 
generated whereas the maximum must not be exceeded or the alarm will be cancelled. This is to allow for 
sudden changes such as lights coming on etc which you may wish to disregard. In general a value of zero 
for any of these settings causes that value to be ignored, so you can safely set a maximum to zero and it
will not be used. The use of just a number of pixels is however a very brute force method of detection
as many small events dispered widely are not distinguished from a compact one. To combat this ZM applies
several other functions to the data to improve its ability to distinguish interesting signals from uninsteresting
noise. The first of these is a filter which removes any pixels that do not participate in a continguous
block of pixels above a certain size. The options that control this are the Filter Width and Height settings
which are always pixels and which should be fairly small. Application of this filter removes any tiny
or discontinuous pixels that don't form part of a discrete block. Following that are two further bounds which
specify the limits of pixels which would cause an alarm after this filtering process. As the filtering
process only removes pixels it makes no sense for the Minimum and Maximum Filtered Area to be larger than the
equivalent Alarmed Area and in general they should be smaller or the same. The next step in the analysis
phase is the collation of any remaining alarmed areas into contiguous blobs. This process parses the 
image and forms any pixels that adjoin other alarmed pixels into one or more larger blobs. These blobs may
be any shape and can be as large as the zone itself or as small as the filtered size. The Minimum and Maximum
Blob Size settings allow you to define limits within which an alarm will be generated. Of these only the
Minimum is likely to be very useful. Finally the Minimum and Maximum Blobs specify the limits of the actual
number of blobs detected. If an image change satifies all these requirements it becomes an alarm event.

As this point you should have one or more Monitors running with one or more Zones each. Returning to the
main Console window you will see your monitors listed once more. The columns not explored so far are the
Monitor name, and various event totals for certain periods of time. Clicking on any of these will bring
up a variation on the same window so click on the Monitor name for now. On doing so up will pop another window
which should be scaled to contain a heading, an image from your monitor, a status and a list of events if
any have been generated. Depending on whether you are able to view a streamed image or not the image frame
will either be this stream or a series of stills. You have the option to change from one to the other (if
available) at the centre of the top heading. The image should be self explanatory but if it looks like
garbage it is possible that the video configuration is wrong so look in your system error log and please
report anything unusual. The centre of the window will have a tiny frame that just contains a status, this
will be Idle, Alarm or Alert depending on the fnction of the Monitor and whats going on in the field of
view. Idle means nothing is happening, Alarm means there is an alarm in progress and Alert means that an 
alarm has happened and the monitor is cooling down, if another alarm is generated in this time it will
just become part of the same event. By default if you have minimised this window or opened other windows in
front it will pop up to the front if it goes to Alarm state. This behaviour can be turned off in configuration
at the top of the index.php file. Below the status is a list of events that have occurred, by default this 
is a listing of just the last 12 but clicking on 'All' will give you a full list and 'Archive' will take
you to the event archive for this monitor, more on this later. If you arrive at this window by clicking one
of the event totals from the console window then the listing will reflect that period. Clicking on any
of the column headings will sort the events appropriately. From here you can also delete events if you wish.
The events themselves are listed with the event id, and event name (which you can change), the time that 
the event occurred, the length of the event including any preamble and postamble frames, the number of
frames comprising the event with the number that actually contain an alarm in brackets and finally a score.
This score lists the average score per alarm frame as well as the maximum score that any alarm frame had.
The score is an arbitrary value that essentially represents the percentage of pixels in the zone that are
in blobs divided by the number of blobs and then divided by the size of the zone. This gives a nominal
maximum of 100 for a zone and the totals for each zone are added together, Active zones scores are added
unchanged, Inclusive zones are halved first and Exclusive zones are doubled. In reality values are likely
to be much less than 100 but it does give an simple indication of how major the event was.

Once you have one or events displayed in this listing you can now click on one to view it in more detail.
If you have streaming capability you will see a series of images that make up the event. You will also see
a link to allow you to view the still images themselves. If you don't have streaming then you will be taken
directly to this page. The images themselves are thumbnail size and depending on the configuration and
bandwidth you have chosen will either be the full images scaled in your browser of actual scaled images. if
it is the latter, if you have low bandwidth for example, it may take a few seconds to generate the images.
If thumbnail images are required to be generated, they will be kept and not re-generated in future.
Once the images appear you can mouse over them to get the image sequence number and the image score. You will
notice for the first time that alarm images now contain an overlay outlining the blobs that represent the
alarmed area. This outline is in the colour defined for that zone and lets you see what it was that 
caused the alarm. Clicking on one of the thumbnails will take you to a full size window where you can see
the image in all it's detail and scroll through the various images that make up the event. Should you determine
that you don't wish to keep the event, clicking on Delete will erase it from the database and file system.
Returning to the event window, other options here are renaming the event to something more meaningful, 
refreshing the window to replay the event stream, deleting the event, switching between streamed and still
versions of the event (if supported) and generating an MPEG video of the event (if supported). These last 
two options require further explanation. Archiving an event means that it is kept to one side and and not
displayed in the normal event listings unless you specifically ask to view th earchived events. This is 
useful for keeping events that you think may be important or just wish to protect. Once an event is archived
it can be deleted or unarchived but you cannot accidentally delete it when viewing normal unarchived events. 
The final option of generating an MPEG video is experimental and not likely to be highly useful. It uses
the Berkeley MPEG encoder and will generate a short video which will be downloaded to your browsing machine
to view. Due to the relatively slow frame rate that ZM will capture at and the high minmimum frame rate
that the encoder uses, each image is included twice. This has the useful effect of making the video watchable
and not too quick while having the unfortunate side effect of increasing file size and generation time.
Building an MPEG video, especially for a large event, can take some time and should not be undertaken lightly
as the effect on your host box of many CPU intensive encoders will not be good. However once a video has 
been created for an event it will be kept so subsequent viewing will not incur the generation overhead.
I will be the first to admit that this area of the package is not particularly well implmented and needs 
work, and probably a better encoder.

That pretty much is it for the tour. You should experiment with the various setting to get the results
you think are right for your. Naturally letting thousands of events build up is not good for the database
or your filesystem so you should endeavour to either prevent spurious events from being generated in the
first place or ensure that you housekeep them strictly.

Have fun, please report any bugs or features you'd like to see and hopefully ZM can be your camera monitoring
friend!

Philip Coombes (philip.coombes@zoneminder.com) - September 2002


Troubleshooting
===============

Life eh? Nothing ever works first time does it? In case you are having problems here are some things to try.
If these don't work then feel free to get in touch and I'll see if I can suggest something else. The best
places to look for errors are in your system eror log (/var/log/messages on RedHat) and your web server
log (/var/log/httpd/error_log). There should be something in one of those that gives you some kind of tip
off.

Some things to check.
1. Device configuration. If you can't get your cameras to work in ZM, firstly make sure that you have the
correct settings. Use xawtv or something like that to check for settings which work. If you can't get them
to work with that then the likelihood is they won't work with ZM.
2. Device permissions. As the ZM daemons are started by your web server, you need to ensure that your video
devices can be opened by the associated user.
3. Web server. Ensure that your web server can serve PHP files. It's also possible that your php.ini file
may have some settings which break ZM, I'm not a PHP expert but setting safe mode may prevent your index.php
file from runningcertain programs. You may have to set configuration to allow this. Also as the daemons are
started by your web server, if it dies or is shut down then the daemons will disappear. I suspect this is
a bug in ZM.
4. Use debug. ZM has various debug which by default will go into your system log (via syslog). These will
be of the form of "Sep 14 14:50:11 localhost zma-0[1975]: INF [Front: 221000 - Processing at 4.26 fps ]"
where the zma-0 part identifies the daemon and the device it is running on. Entries with INF in are 
informational and not an error, if you see ERR then it is one, though not all are fatal. You can prevent 
this information from being emitted by setting the DLVL_zmc environment variable to -1 or less once things
are working. If you want to run any of the daemons from the command line to test, setting DBG_PRINT to 1
will output the debug on the console and setting DLVL_zmc (or DLVL_zma etc) to a number between 0 and 9 
will emit progressively more debug though theres not a lot in there at present.
5. Paths. I admit it, the various paths in ZM are a bit of a nightmare. Make sure that they are all correct 
and that permissions are such that the various parts of ZM can actually run.

To Do
=====

Seeing as ZM is so young and has kind of evolved rather than being planned there are a bunch of improvements
and enhancements still to do, here is just a sample.

1. Sort out the class structure - Frankly it's a bit of a mess at the moment with too many 'friends', it needs
rationalising.
2. Perhaps split out devices - I think devices should probably be a separate table and class from monitors. Not
critical but would represent a better model.
3. Comments - Needs many more, but that's just me I'm hopeless at commenting things out. I'll get round to it
soon though honest! You're lucky to even get this document.
4. Optimised zones - The zones could do with being sorted out a bit to optimise the processing of overlapping
ones, at the moment you can waste resource unless your zones are kept very tidy.
5. Create zones using server side image maps - This would make it easier to precisely define and see where your
zone is going to go. Not critical but handy but a bugger to do.
6. Zone Bitmaps - Allow zones to be defined according to a colour coded bitmap. Currently all zones are 
rectangular this would add a bit of flexibility. Would need a bit of a rewrite though.
7. Security - I think I need to give the php file a bit of a good going over as I'm sure it's not done in the
most secure way regarding passing things onto command line, exposing file paths and other stuff. I'm a bit of
a php novice, as I'm sure you can tell so might need help here. I should have done it in perl!
8. Mouseover help - A bit more help popping up when you mouseover things would be handy. A bit more help full
stop actually.
9. FTP uploads - It's no good if your nice cameras and linux box records a perpetrator busting into your place
if they then proceed to nick your computer. So need an additional, probably perl, daemon to keep an eye on
things and tar, zip and upload qualifying events to an external server.
10. WAP interface - A bit of a crusade of mine I'm afraid. I'd like to put a WMl interface on to allow you
to view event listing and perhaps the most significant image from each event on your phone. Also simple
management.
11. Email and SMS notifications - As with the FTP uploads, probably event the same daemon to let you know when
something happens, perhaps configurable to report only certain types of events.
12. Templatise the php file. Personally I hate mixing up HTML and logic, perhaps use Smarty or something and 
separate the screens out from the rest.
13. Automatic device configuration - Video 4 Linux supprots various device queries, it should be possible to
get most of the device capability information from the device itself.
14. X-10 integration - A handy feature would be to allow a generated event to trigger some other action
perhaps to an attached X-10 interface, for instance turn lights on or make a dog barky noise!
15. Extend the API. Well ok it's not really got an API yet but the image datais held in shared memory in a
very simple format. In theory you could use the capture daemon to gab the images and other things could
read them from memory or the analysis daemon could read images from elsewhere. Either way this should be 
done through an API, and would need a library I think. Also the zmu utility could probably do a whole lot
more to enable other things to manage when the daemons become active etc.
16. Finish implementing customisable image timestamps. There is proto support for this and it would be
easy to do to allow the timestamp to be defined as a strftime string and allow it's position to be moved.
Possibly also revamp the fonts a bit.
17. Access control should probably be built in rather than relying on htaccess etc.
18. I've got lots of ideas for enhancing the motion detection part with optional algorithms etc. Just got
to find the time somewhere!


Bugs
====

1. The shared memory segment(s) are not cleaned up properly. It's difficult to decide how perisistent to make
them really as they could still be of use even when nothing is using them, or at least writing to them.
2. Sometimes there is a sync error and very rarely a capture daemon just stops. Probably need a watchdog to 
restart it when this happens.
3. I'm not sure if this is a bug or by design but the timestamp is added to the image by the capture daemon.
I _think_ this isn't necessary as it may contribute to alarms, plus the time is associated with the image 
anyway. So I think this should be moved to the analysis daemon.

Probably a bucket load more, just fire them at me.


Non-Bugs
========

1. Yes, those are tabs in the indents, I like tabs so don't go changing them to spaces or else. Also yes I
also like my opening braces on their own line most of the time, what's the point of brackets that don't line up?

Everything else that isn't definately broken is probably deliberate, or was once anyway.


License
=======

Zone Monitor is released under the GPL, see below.

Zone Monitor README, $Date$, $Revision$
Copyright (C) 2002  Philip Coombes

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.