Prev: Web based sequence diagram generator
Next: Design pattern to sync objects
From: John Carter on 27 Mar 2007 01:20
On Mon, 26 Mar 2007 16:30:03 -0700, steve.hanov wrote:

> I made this because I have to draw a lot of sequence diagrams at work, for
> documentation. We have special MS Visio templates for UML but they are not
> fun to use.
>
> Now I just type into my tool at:
>
> http://gandolf.homelinux.org/~smhanov/mscdraw/index.php
>
> Then it spits out the image, which I copy and paste into my documents.

Cool!

Suggestion...

Make the horizontal event lines with a gentle downward slope...

Instead of...

|--------------->|

Something like so (but perhaps a gentle 20 degrees instead of the
45degrees forced by ascii art)...

|\ |
| \ |
| \>|


Why? Because its a gentle reminder about the speed of light and latencies
in communication systems.

When people draw horizontal event lines they mistakenly think the creation
of the event and the reception of the event is instantaneous.

When the lines are gently sloping it reminds you... Hey! Between the left
of the arrow and the right, is a space of time during which another arrow
may be coming back at me....

|\ /|
| \ / |
| X |
| / \ |
|< >|


And whenever I can draw a diagram with crossing event lines like that, I
know I have a rich and fertile soil in which to go hunting race conditions
and deadlocks.

And boy oh boy whenever I have gone looking, I have many such subtle bugs
in the code of those who draw event lines horizontally!


--


John Carter Phone : (64)(3) 358 6639
Tait Electronics Fax : (64)(3) 359 4632
PO Box 1645 Christchurch Email : john.carter(a)tait.co.nz
New Zealand


From: steve.hanov on 31 Mar 2007 12:11
John, that's a really great idea. Concurrency isn't really something
that's emphasized with these types of diagrams, but it impacts every
system and causes bugs. I've added it to the list of things to do.

Also last night I added styles, so the output can look like rose,
quick sequence diagram editor (qsd) or mscgen. You can also do object
activation, deactivation, and destruction.

On Mar 27, 1:20 am, John Carter <john.car...(a)tait.co.nz> wrote:
> On Mon, 26 Mar 2007 16:30:03 -0700,steve.hanovwrote:
> > I made this because I have to draw a lot of sequence diagrams at work, for
> > documentation. We have special MS Visio templates for UML but they are not
> > fun to use.
>
> > Now I just type into my tool at:
>
> >http://gandolf.homelinux.org/~smhanov/mscdraw/index.php
>
> > Then it spits out the image, which I copy and paste into my documents.
>
> Cool!
>
> Suggestion...
>
> Make the horizontal event lines with a gentle downward slope...
>
> Instead of...
>
> |--------------->|
>
> Something like so (but perhaps a gentle 20 degrees instead of the
> 45degrees forced by ascii art)...
>
> |\ |
> | \ |
> | \>|
>
> Why? Because its a gentle reminder about the speed of light and latencies
> in communication systems.
>
> When people draw horizontal event lines they mistakenly think the creation
> of the event and the reception of the event is instantaneous.
>
> When the lines are gently sloping it reminds you... Hey! Between the left
> of the arrow and the right, is a space of time during which another arrow
> may be coming back at me....
>
> |\ /|
> | \ / |
> | X |
> | / \ |
> |< >|
>
> And whenever I can draw a diagram with crossing event lines like that, I
> know I have a rich and fertile soil in which to go hunting race conditions
> and deadlocks.
>
> And boy oh boy whenever I have gone looking, I have many such subtle bugs
> in the code of those who draw event lines horizontally!
>
> --
>
> John Carter Phone : (64)(3) 358 6639
> Tait Electronics Fax : (64)(3) 359 4632
> PO Box 1645 Christchurch Email : john.car...(a)tait.co.nz
> New Zealand

 | 
Pages: 1
Prev: Web based sequence diagram generator
Next: Design pattern to sync objects