Hi Steve,
I'm taking the discussion from the tracker to the mailing list ...
URL: http://tracker.squeakland.org/browse/SQ-708 Reporter: Stephen Thomas
Saw problems with Tick Rate while running random number tests. Created a simple project (see attached) to check tick rate by having a script to increment a counter and another to start it and then stop it after N seconds. Below are some of the results Tick Rate - Counter Value After 10 seconds 1 - 10 2 - 20 5 - 50 8 - 72 10 - 98 25 - 230 50 - 384-405 100 - 500 Also ran at tick rate of 100/sec for 100 seconds and got counter values of 4975 to 5000
Etoys is not a real-time system. The ticking rate is the desired number of script executions per second. The actual number can be lower depending on how much else is going on. Faster machines will run closer to the desired number of ticks, slower machines less so.
To expand on this:
The default rate is set to only 8 ticks per second to allow more objects to be animated at that rate. This is not "smooth", but then, the major purpose of Etoys is not pretty animation, but learning how things work (*).
Etoys is limited to a rate of 50 frames per second by default (we developers call that "world cycles"). That means it checks at most 50 times per seconds if scripts should be run. If it finds any that are due, it executes those scripts, and then redraws the screen. This may take well more than 20 ms, so there will be less than 50 world cycles per second.
That's the reason you don't get more than 500 ticks in 10 seconds no matter the tick rate.
Just for fun, look at the current frame rate by dragging out a "FrameRate" counter from the Object Catalog's "Just For Fun" category. This lets you see how various operations affect the frame rate. E.g., make a big object rotate, and then duplicate it a few times.
Enabling the "higherPerformance" preference removes the 50 fps cap. This basically has no effect on e.g. the OLPC XO-1 (except for draining the battery even more), because it can barely keep up even 50 fps. On faster machines you'll see the frame rate go up to hundreds of fps. If the system load is otherwise low, you'll get pretty accurate ticking, but again because sampling is involved, it's not guaranteed to be accurate. Having the 50 fps cap in place makes the timings actually more consistent over a wider range of machines.
So, long story short, you cannot use the tickings for accurate timing. If you let us know what you actually need this for, I'm sure we can find a way to help you :)
- Bert -
(*) I tend to forget that myself. E.g. my cars-on-an-intersection project works really nicely on my home machine, but rather poorly on slower machines - the cars don't even make it across the intersection in one light cycle: http://squeakland.org/showcase/project.jsp?id=9655 That's because I increased the tick rate of the cars to get smoother animation. Not a good idea in this case. The light ticks independently of the cars, so on slower machines you get many less car ticks per light tick than on a fast machine. The light advances when the car has barely reached the middle of the intersection. This could be worked around by having only a single ticking script in the world that would trigger all other scripts at appropriate intervals. That would guarantee much more reproducible behavior independent of the computer speed.
Bert, thanks for the explanation.
So if the default max Tick Rate is 50, should remove 100 from the list of selectable tick rates?
"Other..." still makes sense (especially 0.1 for ticking every 10 seconds), but we should have some warning so folks know the limitations. The warning could be when you select Other in the dialog box that pops up. ex: "Max Rate is 50 per second, can change in preferences").
My major purpose for using Etoys is playing around ;) no specific need at this point in time. I noticed the problem when running Randy's Dice Roll project and was simply trying to figure out how things worked.
Stephen
On Wed, Jun 2, 2010 at 6:46 AM, Bert Freudenberg bert@freudenbergs.dewrote:
Hi Steve,
I'm taking the discussion from the tracker to the mailing list ...
URL: http://tracker.squeakland.org/browse/SQ-708 Reporter: Stephen Thomas
Saw problems with Tick Rate while running random number tests. Created a
simple project (see attached)
to check tick rate by having a script to increment a counter and another
to start it and then stop it after N seconds. Below are some of the results
Tick Rate - Counter Value After 10 seconds 1 - 10 2 - 20 5 - 50 8 - 72 10 - 98 25 - 230 50 - 384-405 100 - 500 Also ran at tick rate of 100/sec for 100 seconds and got counter values
of 4975 to 5000
Etoys is not a real-time system. The ticking rate is the desired number
of script executions per second. The actual number can be lower depending on how much else is going on. Faster machines will run closer to the desired number of ticks, slower machines less so.
To expand on this:
The default rate is set to only 8 ticks per second to allow more objects to be animated at that rate. This is not "smooth", but then, the major purpose of Etoys is not pretty animation, but learning how things work (*).
Etoys is limited to a rate of 50 frames per second by default (we developers call that "world cycles"). That means it checks at most 50 times per seconds if scripts should be run. If it finds any that are due, it executes those scripts, and then redraws the screen. This may take well more than 20 ms, so there will be less than 50 world cycles per second.
That's the reason you don't get more than 500 ticks in 10 seconds no matter the tick rate.
Just for fun, look at the current frame rate by dragging out a "FrameRate" counter from the Object Catalog's "Just For Fun" category. This lets you see how various operations affect the frame rate. E.g., make a big object rotate, and then duplicate it a few times.
Enabling the "higherPerformance" preference removes the 50 fps cap. This basically has no effect on e.g. the OLPC XO-1 (except for draining the battery even more), because it can barely keep up even 50 fps. On faster machines you'll see the frame rate go up to hundreds of fps. If the system load is otherwise low, you'll get pretty accurate ticking, but again because sampling is involved, it's not guaranteed to be accurate. Having the 50 fps cap in place makes the timings actually more consistent over a wider range of machines.
So, long story short, you cannot use the tickings for accurate timing. If you let us know what you actually need this for, I'm sure we can find a way to help you :)
- Bert -
(*) I tend to forget that myself. E.g. my cars-on-an-intersection project works really nicely on my home machine, but rather poorly on slower machines
- the cars don't even make it across the intersection in one light cycle:
http://squeakland.org/showcase/project.jsp?id=9655 That's because I increased the tick rate of the cars to get smoother animation. Not a good idea in this case. The light ticks independently of the cars, so on slower machines you get many less car ticks per light tick than on a fast machine. The light advances when the car has barely reached the middle of the intersection. This could be worked around by having only a single ticking script in the world that would trigger all other scripts at appropriate intervals. That would guarantee much more reproducible behavior independent of the computer speed._______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote:
Bert, thanks for the explanation.
So if the default max Tick Rate is 50, should remove 100 from the list of selectable tick rates?
"Other..." still makes sense (especially 0.1 for ticking every 10 seconds), but we should have some warning so folks know the limitations. The warning could be when you select Other in the dialog box that pops up. ex: "Max Rate is 50 per second, can change in preferences").
My major purpose for using Etoys is playing around ;) no specific need at this point in time. I noticed the problem when running Randy's Dice Roll project and was simply trying to figure out how things worked.
Just FYI, there is a hidden feature called "fires per tick" (only present in the scriptor menu when etoyFriendly preference is off) to specify how many times the script should be executed per tick. For example, if you set the number high in Randy's Dice Roll, the bar graph grows more rapidly.
-- Yoshiki
Why is it hidden? It seems like a very nice feature to me.
Richo
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima yoshiki@vpri.org wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote:
Bert, thanks for the explanation.
So if the default max Tick Rate is 50, should remove 100 from the list of
selectable tick rates?
"Other..." still makes sense (especially 0.1 for ticking every 10
seconds), but we should have some warning so folks
know the limitations. The warning could be when you select Other in the
dialog box that pops up. ex: "Max Rate is 50 per
second, can change in preferences").
My major purpose for using Etoys is playing around ;) no specific need at
this point in time. I noticed the problem when
running Randy's Dice Roll project and was simply trying to figure out how
things worked.
Just FYI, there is a hidden feature called "fires per tick" (only present in the scriptor menu when etoyFriendly preference is off) to specify how many times the script should be executed per tick. For example, if you set the number high in Randy's Dice Roll, the bar graph grows more rapidly.
-- Yoshiki _______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
At Thu, 3 Jun 2010 01:07:57 -0300, Ricardo Moran wrote:
Why is it hidden? It seems like a very nice feature to me.
No doubt that it is useful in some cases, but the "repeat" tile provides the same behavior to the "fires per tick" feature but in a scriptable way.
Also, setting the tick rate is already somewhat hidden (holding the button on a clock is not discoverable). With a hidden feature there and a special-case menu item here and many combinations of these two produce pretty much the same end result. We thought it is confusing enough to explain them to the end user.
Removing the "100" option from the tick rate menu and making a tile to set tick rate in the scripting category would be nice. Trying to convince the edu team to reinstate the "fire per tick" feature might do it also^^;
-- Yoshiki
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima yoshiki@vpri.org wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote: > > Bert, thanks for the explanation. > > So if the default max Tick Rate is 50, should remove 100 from the list of selectable tick rates? > > "Other..." still makes sense (especially 0.1 for ticking every 10 seconds), but we should have some warning so folks > know the limitations. The warning could be when you select Other in the dialog box that pops up. ex: "Max Rate is 50 per > second, can change in preferences"). > > My major purpose for using Etoys is playing around ;) no specific need at this point in time. I noticed the problem when > running Randy's Dice Roll project and was simply trying to figure out how things worked. Just FYI, there is a hidden feature called "fires per tick" (only present in the scriptor menu when etoyFriendly preference is off) to specify how many times the script should be executed per tick. For example, if you set the number high in Randy's Dice Roll, the bar graph grows more rapidly. -- Yoshiki _______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
Yoshiki, Was "fires per tick" removed because of the way the OLPC works? BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075 Regards, Kathleen
---- Original message ----
Date: Wed, 02 Jun 2010 22:26:22 -0700 From: Yoshiki Ohshima yoshiki@vpri.org Subject: Re: [squeakland] Re: Tick Rate not accurate To: "squeakland@squeakland.org list" squeakland@squeakland.org
At Thu, 3 Jun 2010 01:07:57 -0300, Ricardo Moran wrote:
Why is it hidden? It seems like a very nice feature to me.
No doubt that it is useful in some cases, but the "repeat" tile provides the same behavior to the "fires per tick" feature but in a scriptable way.
Also, setting the tick rate is already somewhat hidden (holding the button on a clock is not discoverable). With a hidden feature there and a special-case menu item here and many combinations of these two produce pretty much the same end result. We thought it is confusing enough to explain them to the end user.
Removing the "100" option from the tick rate menu and making a tile to set tick rate in the scripting category would be nice. Trying to convince the edu team to reinstate the "fire per tick" feature might do it also^^;
-- Yoshiki
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima yoshiki@vpri.org wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote: > > Bert, thanks for the explanation. > > So if the default max Tick Rate is 50, should remove 100 from the list of selectable tick rates? > > "Other..." still makes sense (especially 0.1 for ticking every 10 seconds), but we should have some warning so folks > know the limitations. The warning could be when you select Other in the dialog box that pops up. ex: "Max Rate is 50 per > second, can change in preferences"). > > My major purpose for using Etoys is playing around ;) no specific need at this point in time. I noticed the problem when > running Randy's Dice Roll project and was simply trying to figure out how things worked. Just FYI, there is a hidden feature called "fires per tick" (only present in the scriptor menu when etoyFriendly preference is off) to specify how many times the script should be executed per tick. For example, if you set the number high in Randy's Dice Roll, the bar graph grows more rapidly. -- Yoshiki _______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
On 03.06.2010, at 14:12, kharness@illinois.edu wrote:
BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075
Great :) But this is not correct:
"The upper limit on the number you choose is the processing power of your computer. If the number too big, the script may freeze."
As I tried to explain in this thread, if the ticking rate is higher than the computer can handle, it will simply be lowered. If you specify 100 ticks per second but your computer can only do 5 updates per second, then it will simply do those 5. But it will not freeze.
What you set there is the *desired* rate, not the real one, which will practically be lower, always.
- Bert -
Bert, I'll redo the guide, thanks for the suggestion. Kathleen
---- Original message ----
Date: Thu, 3 Jun 2010 15:41:20 +0200 From: Bert Freudenberg bert@freudenbergs.de Subject: Re: [squeakland] Re: Tick Rate not accurate To: "squeakland@squeakland.org list" squeakland@squeakland.org
On 03.06.2010, at 14:12, kharness@illinois.edu wrote:
BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075
Great :) But this is not correct:
"The upper limit on the number you choose is the processing power of your computer. If the number too big, the script may freeze."
As I tried to explain in this thread, if the ticking rate is higher than the computer can handle, it will simply be lowered. If you specify 100 ticks per second but your computer can only do 5 updates per second, then it will simply do those 5. But it will not freeze.
What you set there is the *desired* rate, not the real one, which will practically be lower, always.
- Bert -
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
Kathleen,
My vote on the EDU team is to remove 100, add a scriptable tile for "files per tick" and a scriptable tile for setting the tick rate".
In your quick guide you may want to ask "What would happen if you set the Tick Rate to less than 1?" or "Try setting your Tick Rate to less than 1, what do you think will happen?"
Stephen
On Thu, Jun 3, 2010 at 8:12 AM, kharness@illinois.edu wrote:
Yoshiki, Was "fires per tick" removed because of the way the OLPC works? BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075 Regards, Kathleen
---- Original message ----
Date: Wed, 02 Jun 2010 22:26:22 -0700 From: Yoshiki Ohshima yoshiki@vpri.org Subject: Re: [squeakland] Re: Tick Rate not accurate To: "squeakland@squeakland.org list" squeakland@squeakland.org
At Thu, 3 Jun 2010 01:07:57 -0300, Ricardo Moran wrote:
Why is it hidden? It seems like a very nice feature to me.
No doubt that it is useful in some cases, but the "repeat" tile provides the same behavior to the "fires per tick" feature but in a scriptable way.
Also, setting the tick rate is already somewhat hidden (holding the button on a clock is not discoverable). With a hidden feature there and a special-case menu item here and many combinations of these two produce pretty much the same end result. We thought it is confusing enough to explain them to the end user.
Removing the "100" option from the tick rate menu and making a tile to set tick rate in the scripting category would be nice. Trying to convince the edu team to reinstate the "fire per tick" feature might do it also^^;
-- Yoshiki
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima yoshiki@vpri.org
wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote: > > Bert, thanks for the explanation. > > So if the default max Tick Rate is 50, should remove 100 from thelist of selectable tick rates?
> > "Other..." still makes sense (especially 0.1 for ticking every 10seconds), but we should have some warning so
folks > know the limitations. The warning could be when you select Otherin the dialog box that pops up. ex: "Max Rate is
50 per > second, can change in preferences"). > > My major purpose for using Etoys is playing around ;) no specificneed at this point in time. I noticed the
problem when > running Randy's Dice Roll project and was simply trying to figureout how things worked.
Just FYI, there is a hidden feature called "fires per tick" (only present in the scriptor menu when etoyFriendly preference is off) to specify how many times the script should be executed per tick. For example, if you set the number high in Randy's Dice Roll, the bar graph grows more rapidly. -- Yoshiki _______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
On 03.06.2010, at 15:43, Steve Thomas wrote:
Kathleen,
My vote on the EDU team is to remove 100, add a scriptable tile for "files per tick" and a scriptable tile for setting the tick rate".
Removing 100 is sensible, adding the "fires per tick" less so IMHO. Adding a tick-rate tile is a bit challenging. Or not, just make the scriptor scriptable. File a ticket about it.
In your quick guide you may want to ask "What would happen if you set the Tick Rate to less than 1?" or "Try setting your Tick Rate to less than 1, what do you think will happen?"
maybe better "to a fraction between 0 and 1" ?
- Bert -
Stephen
On Thu, Jun 3, 2010 at 8:12 AM, kharness@illinois.edu wrote: Yoshiki, Was "fires per tick" removed because of the way the OLPC works? BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075 Regards, Kathleen
---- Original message ----
Date: Wed, 02 Jun 2010 22:26:22 -0700 From: Yoshiki Ohshima yoshiki@vpri.org Subject: Re: [squeakland] Re: Tick Rate not accurate To: "squeakland@squeakland.org list" squeakland@squeakland.org
At Thu, 3 Jun 2010 01:07:57 -0300, Ricardo Moran wrote:
Why is it hidden? It seems like a very nice feature to me.
No doubt that it is useful in some cases, but the "repeat" tile provides the same behavior to the "fires per tick" feature but in a scriptable way.
Also, setting the tick rate is already somewhat hidden (holding the button on a clock is not discoverable). With a hidden feature there and a special-case menu item here and many combinations of these two produce pretty much the same end result. We thought it is confusing enough to explain them to the end user.
Removing the "100" option from the tick rate menu and making a tile to set tick rate in the scripting category would be nice. Trying to convince the edu team to reinstate the "fire per tick" feature might do it also^^;
-- Yoshiki
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima yoshiki@vpri.org wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote: > > Bert, thanks for the explanation. > > So if the default max Tick Rate is 50, should remove 100 from the list of selectable tick rates? > > "Other..." still makes sense (especially 0.1 for ticking every 10 seconds), but we should have some warning so folks > know the limitations. The warning could be when you select Other in the dialog box that pops up. ex: "Max Rate is 50 per > second, can change in preferences"). > > My major purpose for using Etoys is playing around ;) no specific need at this point in time. I noticed the problem when > running Randy's Dice Roll project and was simply trying to figure out how things worked. Just FYI, there is a hidden feature called "fires per tick" (only present in the scriptor menu when etoyFriendly preference is off) to specify how many times the script should be executed per tick. For example, if you set the number high in Randy's Dice Roll, the bar graph grows more rapidly. -- Yoshiki _______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
On Thu, Jun 3, 2010 at 9:49 AM, Bert Freudenberg bert@freudenbergs.dewrote:
maybe better "to a fraction between 0 and 1" ?
Agreed, being able to enter fractions in the tick rate would be nice. I
tried entering "2/5" and it set the tick rate to 2.
Stephen
- Bert -
Stephen
On Thu, Jun 3, 2010 at 8:12 AM, kharness@illinois.edu wrote:
Yoshiki, Was "fires per tick" removed because of the way the OLPC works? BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075 Regards, Kathleen
---- Original message ----
Date: Wed, 02 Jun 2010 22:26:22 -0700 From: Yoshiki Ohshima yoshiki@vpri.org Subject: Re: [squeakland] Re: Tick Rate not accurate To: "squeakland@squeakland.org list" squeakland@squeakland.org
At Thu, 3 Jun 2010 01:07:57 -0300, Ricardo Moran wrote:
Why is it hidden? It seems like a very nice feature to me.
No doubt that it is useful in some cases, but the "repeat" tile provides the same behavior to the "fires per tick" feature but in a scriptable way.
Also, setting the tick rate is already somewhat hidden (holding the button on a clock is not discoverable). With a hidden feature there and a special-case menu item here and many combinations of these two produce pretty much the same end result. We thought it is confusing enough to explain them to the end user.
Removing the "100" option from the tick rate menu and making a tile to set tick rate in the scripting category would be nice. Trying to convince the edu team to reinstate the "fire per tick" feature might do it also^^;
-- Yoshiki
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima yoshiki@vpri.org
wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote: > > Bert, thanks for the explanation. > > So if the default max Tick Rate is 50, should remove 100 from thelist of selectable tick rates?
> > "Other..." still makes sense (especially 0.1 for ticking every 10seconds), but we should have some warning so
folks > know the limitations. The warning could be when you select Otherin the dialog box that pops up. ex: "Max Rate is
50 per > second, can change in preferences"). > > My major purpose for using Etoys is playing around ;) no specificneed at this point in time. I noticed the
problem when > running Randy's Dice Roll project and was simply trying to figureout how things worked.
Just FYI, there is a hidden feature called "fires per tick" (only present in the scriptor menu when etoyFriendly preference is off)to
specify how many times the script should be executed per tick. For example, if you set the number high in Randy's Dice Roll, the bar graph grows more rapidly. -- Yoshiki _______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
At Thu, 3 Jun 2010 15:49:22 +0200, Bert Freudenberg wrote:
On 03.06.2010, at 15:43, Steve Thomas wrote:
Kathleen, My vote on the EDU team is to remove 100, add a scriptable tile for "files per tick" and a scriptable tile for setting the tick rate".Removing 100 is sensible, adding the "fires per tick" less so IMHO. Adding a tick-rate tile is a bit challenging. Or not, just make the scriptor scriptable. File a ticket about it.
Oops. (Of course) I didn't mean to add "fire per tick" tile. It was a copy and paste error^^;
-- Yoshiki
Steve, The project I attached is similar to projects I see from young students who experiment with huge numbers and find out they can't pause a script. It combines a large y increase by value and a large tickspersecond. I could take back control of Etoys with control-alt-delete or alt-period. I saved it with the debug info. Regards, Kathleen
---- Original message ----
Date: Thu, 3 Jun 2010 09:43:58 -0400 From: Steve Thomas sthomas1@gosargon.com Subject: Re: [squeakland] Re: Tick Rate not accurate To: kharness@illinois.edu Cc: Yoshiki Ohshima yoshiki@vpri.org, "squeakland@squeakland.org list" squeakland@squeakland.org
Kathleen, My vote on the EDU team is to remove 100, add a scriptable tile for "files per tick" and a scriptable tile for setting the tick rate". In your quick guide you may want to ask "What would happen if you set the Tick Rate to less than 1?" or "Try setting your Tick Rate to less than 1, what do you think will happen?" Stephen
On Thu, Jun 3, 2010 at 8:12 AM, kharness@illinois.edu wrote:
Yoshiki, Was "fires per tick" removed because of the way the OLPC works? BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075 Regards, Kathleen ---- Original message ---- >Date: Wed, 02 Jun 2010 22:26:22 -0700 >From: Yoshiki Ohshima <yoshiki@vpri.org> >Subject: Re: [squeakland] Re: Tick Rate not accurate >To: "squeakland@squeakland.org list" <squeakland@squeakland.org> > >At Thu, 3 Jun 2010 01:07:57 -0300, >Ricardo Moran wrote: >> >> Why is it hidden? It seems like a very nice feature to me. > > No doubt that it is useful in some cases, but the "repeat" tile >provides the same behavior to the "fires per tick" feature but in a >scriptable way. > > Also, setting the tick rate is already somewhat hidden (holding the >button on a clock is not discoverable). With a hidden feature there >and a special-case menu item here and many combinations of these two >produce pretty much the same end result. We thought it is confusing >enough to explain them to the end user. > > Removing the "100" option from the tick rate menu and making a tile >to set tick rate in the scripting category would be nice. Trying to >convince the edu team to reinstate the "fire per tick" feature might do >it also^^; > >-- Yoshiki > >> On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima <yoshiki@vpri.org> wrote: >> >> At Wed, 2 Jun 2010 13:18:19 -0400, >> Steve Thomas wrote: >> > >> > Bert, thanks for the explanation. >> > >> > So if the default max Tick Rate is 50, should remove 100 from the list of selectable tick rates? >> > >> > "Other..." still makes sense (especially 0.1 for ticking every 10 seconds), but we should have some warning so >> folks >> > know the limitations. The warning could be when you select Other in the dialog box that pops up. ex: "Max Rate is >> 50 per >> > second, can change in preferences"). >> > >> > My major purpose for using Etoys is playing around ;) no specific need at this point in time. I noticed the >> problem when >> > running Randy's Dice Roll project and was simply trying to figure out how things worked. >> >> Just FYI, there is a hidden feature called "fires per tick" (only >> present in the scriptor menu when etoyFriendly preference is off) to >> specify how many times the script should be executed per tick. For >> example, if you set the number high in Randy's Dice Roll, the bar >> graph grows more rapidly. >> >> -- Yoshiki >> _______________________________________________ >> squeakland mailing list >> squeakland@squeakland.org >> http://lists.squeakland.org/mailman/listinfo/squeakland >> >> >_______________________________________________ >squeakland mailing list >squeakland@squeakland.org >http://lists.squeakland.org/mailman/listinfo/squeakland _______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
For this I'd explain to the kids that computers are very capable and very stupid at the same time. They do as they are told, no matter the consequences. If a kid was elevated a hundred kilometers without precautions, it wouldn't be too much fun either ...
The question is how much safety net we need to provide to protect against accidental errors. E.g. "forward by" does fence-testing (the object bounces off the world's border), "set y" does not. That's because assigning coordinates is a more advanced concept than simple movement.
For intentional testing of boundaries (which kids should be encouraged to do) it's IMHO fine to have "not nice" behavior. The lesson is "don't do that" or it hurts.
- Bert -
On 11.06.2010, at 14:20, kharness@illinois.edu wrote:
Steve, The project I attached is similar to projects I see from young students who experiment with huge numbers and find out they can't pause a script. It combines a large y increase by value and a large tickspersecond. I could take back control of Etoys with control-alt-delete or alt-period. I saved it with the debug info. Regards, Kathleen
---- Original message ----
Date: Thu, 3 Jun 2010 09:43:58 -0400 From: Steve Thomas sthomas1@gosargon.com Subject: Re: [squeakland] Re: Tick Rate not accurate To: kharness@illinois.edu Cc: Yoshiki Ohshima yoshiki@vpri.org, "squeakland@squeakland.org list" squeakland@squeakland.org
Kathleen, My vote on the EDU team is to remove 100, add a scriptable tile for "files per tick" and a scriptable tile for setting the tick rate". In your quick guide you may want to ask "What would happen if you set the Tick Rate to less than 1?" or "Try setting your Tick Rate to less than 1, what do you think will happen?" Stephen
On Thu, Jun 3, 2010 at 8:12 AM, kharness@illinois.edu wrote:
Yoshiki, Was "fires per tick" removed because of the way the OLPC works? BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075 Regards, Kathleen ---- Original message ----
Date: Wed, 02 Jun 2010 22:26:22 -0700 From: Yoshiki Ohshima yoshiki@vpri.org Subject: Re: [squeakland] Re: Tick Rate not
accurate
To: "squeakland@squeakland.org list"
At Thu, 3 Jun 2010 01:07:57 -0300, Ricardo Moran wrote:
Why is it hidden? It seems like a very nice
feature to me.
No doubt that it is useful in some cases, but
the "repeat" tile
provides the same behavior to the "fires per
tick" feature but in a
scriptable way.
Also, setting the tick rate is already
somewhat hidden (holding the
button on a clock is not discoverable). With a
hidden feature there
and a special-case menu item here and many
combinations of these two
produce pretty much the same end result. We
thought it is confusing
enough to explain them to the end user.
Removing the "100" option from the tick rate
menu and making a tile
to set tick rate in the scripting category would
be nice. Trying to
convince the edu team to reinstate the "fire per
tick" feature might do
it also^^;
-- Yoshiki
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima
yoshiki@vpri.org wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote: > > Bert, thanks for the explanation. > > So if the default max Tick Rate is 50,should remove 100 from the list of selectable tick rates?
> > "Other..." still makes sense(especially 0.1 for ticking every 10 seconds), but we should have some warning so
folks > know the limitations. The warning couldbe when you select Other in the dialog box that pops up. ex: "Max Rate is
50 per > second, can change in preferences"). > > My major purpose for using Etoys isplaying around ;) no specific need at this point in time. I noticed the
problem when > running Randy's Dice Roll project andwas simply trying to figure out how things worked.
Just FYI, there is a hidden featurecalled "fires per tick" (only
present in the scriptor menu whenetoyFriendly preference is off) to
specify how many times the script shouldbe executed per tick. For
example, if you set the number high inRandy's Dice Roll, the bar
graph grows more rapidly. -- Yoshiki
squeakland mailing list squeakland@squeakland.orghttp://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
<problemtickspersecond.001.pr>_______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
Bert, This is exactly what I explain to students in person and what I was trying to convey in the new Quick Guide on that subject. I do want them to experiment and when I am there with them in person, we can go back and try to figure out the path they took. The guides are for the not-in-person learners I hope are trying Etoys. Regards, Kathleen
---- Original message ----
Date: Fri, 11 Jun 2010 14:35:05 +0200 From: Bert Freudenberg bert@freudenbergs.de Subject: Re: [squeakland] Re: Tick Rate not accurate To: "squeakland@squeakland.org list" squeakland@squeakland.org
For this I'd explain to the kids that computers are very capable and very stupid at the same time. They do as they are told, no matter the consequences. If a kid was elevated a hundred kilometers without precautions, it wouldn't be too much fun either ...
The question is how much safety net we need to provide to protect against accidental errors. E.g. "forward by" does fence-testing (the object bounces off the world's border), "set y" does not. That's because assigning coordinates is a more advanced concept than simple movement.
For intentional testing of boundaries (which kids should be encouraged to do) it's IMHO fine to have "not nice" behavior. The lesson is "don't do that" or it hurts.
- Bert -
On 11.06.2010, at 14:20, kharness@illinois.edu wrote:
Steve, The project I attached is similar to projects I see from young students who experiment with huge numbers and find out they can't pause a script. It combines a large y increase by value and a large tickspersecond. I could take back control of Etoys with control-alt-delete or alt-period. I saved it with the debug info. Regards, Kathleen
---- Original message ----
Date: Thu, 3 Jun 2010 09:43:58 -0400 From: Steve Thomas sthomas1@gosargon.com Subject: Re: [squeakland] Re: Tick Rate not accurate To: kharness@illinois.edu Cc: Yoshiki Ohshima yoshiki@vpri.org, "squeakland@squeakland.org list" squeakland@squeakland.org
Kathleen, My vote on the EDU team is to remove 100, add a scriptable tile for "files per tick" and a scriptable tile for setting the tick rate". In your quick guide you may want to ask "What would happen if you set the Tick Rate to less than 1?" or "Try setting your Tick Rate to less than 1, what do you think will happen?" Stephen
On Thu, Jun 3, 2010 at 8:12 AM, kharness@illinois.edu wrote:
Yoshiki, Was "fires per tick" removed because of the way the OLPC works? BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075 Regards, Kathleen ---- Original message ----
Date: Wed, 02 Jun 2010 22:26:22 -0700 From: Yoshiki Ohshima yoshiki@vpri.org Subject: Re: [squeakland] Re: Tick Rate not
accurate
To: "squeakland@squeakland.org list"
At Thu, 3 Jun 2010 01:07:57 -0300, Ricardo Moran wrote:
Why is it hidden? It seems like a very nice
feature to me.
No doubt that it is useful in some cases, but
the "repeat" tile
provides the same behavior to the "fires per
tick" feature but in a
scriptable way.
Also, setting the tick rate is already
somewhat hidden (holding the
button on a clock is not discoverable). With a
hidden feature there
and a special-case menu item here and many
combinations of these two
produce pretty much the same end result. We
thought it is confusing
enough to explain them to the end user.
Removing the "100" option from the tick rate
menu and making a tile
to set tick rate in the scripting category would
be nice. Trying to
convince the edu team to reinstate the "fire per
tick" feature might do
it also^^;
-- Yoshiki
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima
yoshiki@vpri.org wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote: > > Bert, thanks for the explanation. > > So if the default max Tick Rate is 50,should remove 100 from the list of selectable tick rates?
> > "Other..." still makes sense(especially 0.1 for ticking every 10 seconds), but we should have some warning so
folks > know the limitations. The warning couldbe when you select Other in the dialog box that pops up. ex: "Max Rate is
50 per > second, can change in preferences"). > > My major purpose for using Etoys isplaying around ;) no specific need at this point in time. I noticed the
problem when > running Randy's Dice Roll project andwas simply trying to figure out how things worked.
Just FYI, there is a hidden featurecalled "fires per tick" (only
present in the scriptor menu whenetoyFriendly preference is off) to
specify how many times the script shouldbe executed per tick. For
example, if you set the number high inRandy's Dice Roll, the bar
graph grows more rapidly. -- Yoshiki
squeakland mailing list squeakland@squeakland.orghttp://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
<problemtickspersecond.001.pr>_______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
Ah, I see. Well, the freeze is unrelated to the ticking rate. It's the out-of-range coordinates that's causing the trouble.
- Bert -
On 11.06.2010, at 15:55, kharness@illinois.edu kharness@illinois.edu wrote:
Bert, This is exactly what I explain to students in person and what I was trying to convey in the new Quick Guide on that subject. I do want them to experiment and when I am there with them in person, we can go back and try to figure out the path they took. The guides are for the not-in-person learners I hope are trying Etoys. Regards, Kathleen
---- Original message ----
Date: Fri, 11 Jun 2010 14:35:05 +0200 From: Bert Freudenberg bert@freudenbergs.de Subject: Re: [squeakland] Re: Tick Rate not accurate To: "squeakland@squeakland.org list" squeakland@squeakland.org
For this I'd explain to the kids that computers are very capable and very stupid at the same time. They do as they are told, no matter the consequences. If a kid was elevated a hundred kilometers without precautions, it wouldn't be too much fun either ...
The question is how much safety net we need to provide to protect against accidental errors. E.g. "forward by" does fence-testing (the object bounces off the world's border), "set y" does not. That's because assigning coordinates is a more advanced concept than simple movement.
For intentional testing of boundaries (which kids should be encouraged to do) it's IMHO fine to have "not nice" behavior. The lesson is "don't do that" or it hurts.
- Bert -
On 11.06.2010, at 14:20, kharness@illinois.edu wrote:
Steve, The project I attached is similar to projects I see from young students who experiment with huge numbers and find out they can't pause a script. It combines a large y increase by value and a large tickspersecond. I could take back control of Etoys with control-alt-delete or alt-period. I saved it with the debug info. Regards, Kathleen
---- Original message ----
Date: Thu, 3 Jun 2010 09:43:58 -0400 From: Steve Thomas sthomas1@gosargon.com Subject: Re: [squeakland] Re: Tick Rate not accurate To: kharness@illinois.edu Cc: Yoshiki Ohshima yoshiki@vpri.org, "squeakland@squeakland.org list" squeakland@squeakland.org
Kathleen, My vote on the EDU team is to remove 100, add a scriptable tile for "files per tick" and a scriptable tile for setting the tick rate". In your quick guide you may want to ask "What would happen if you set the Tick Rate to less than 1?" or "Try setting your Tick Rate to less than 1, what do you think will happen?" Stephen
On Thu, Jun 3, 2010 at 8:12 AM, kharness@illinois.edu wrote:
Yoshiki, Was "fires per tick" removed because of the way the OLPC works? BTW I wrote a new quick guide to introduce the tick rate feature. http://www.etoysillinois.org/library.php?sl=1075 Regards, Kathleen ---- Original message ----
Date: Wed, 02 Jun 2010 22:26:22 -0700 From: Yoshiki Ohshima yoshiki@vpri.org Subject: Re: [squeakland] Re: Tick Rate not
accurate
To: "squeakland@squeakland.org list"
At Thu, 3 Jun 2010 01:07:57 -0300, Ricardo Moran wrote:
Why is it hidden? It seems like a very nice
feature to me.
No doubt that it is useful in some cases, but
the "repeat" tile
provides the same behavior to the "fires per
tick" feature but in a
scriptable way.
Also, setting the tick rate is already
somewhat hidden (holding the
button on a clock is not discoverable). With a
hidden feature there
and a special-case menu item here and many
combinations of these two
produce pretty much the same end result. We
thought it is confusing
enough to explain them to the end user.
Removing the "100" option from the tick rate
menu and making a tile
to set tick rate in the scripting category would
be nice. Trying to
convince the edu team to reinstate the "fire per
tick" feature might do
it also^^;
-- Yoshiki
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima
yoshiki@vpri.org wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote: > > Bert, thanks for the explanation. > > So if the default max Tick Rate is 50,
should remove 100 from the list of selectable tick rates?
> > "Other..." still makes sense
(especially 0.1 for ticking every 10 seconds), but we should have some warning so
folks > know the limitations. The warning could
be when you select Other in the dialog box that pops up. ex: "Max Rate is
50 per > second, can change in preferences"). > > My major purpose for using Etoys is
playing around ;) no specific need at this point in time. I noticed the
problem when > running Randy's Dice Roll project and
was simply trying to figure out how things worked.
Just FYI, there is a hidden featurecalled "fires per tick" (only
present in the scriptor menu when
etoyFriendly preference is off) to
specify how many times the script should
be executed per tick. For
example, if you set the number high in
Randy's Dice Roll, the bar
graph grows more rapidly.
-- Yoshiki
squeakland mailing list squeakland@squeakland.org
http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
<problemtickspersecond.001.pr>_______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
On Friday 11 Jun 2010 5:50:44 pm kharness@illinois.edu wrote:
The project I attached is similar to projects I see from young students who experiment with huge numbers and find out they can't pause a script.
Before they start running scripts, you may want to introduce them to "All Scripts" controller from Supplies. Let them step through scripts to see inner workings. This helps them build a mental model of what is happening in their project. Otherwise, students will feel lost when scripts run at full tilt.
It combines a large y increase by value and a large tickspersecond. I could take back control of Etoys with control-alt-delete or alt-period. I saved it with the debug info.
Place value encoding of a number is so compact that even elders can lose track of its implications (cf. wheat and chessboard story). One way to introduce the concept is to get students to play an outdoor game: a) Think of a digit (say 2) and write it down "2". Take this many steps in one direction and count each step. b) Think of another digit (say 7). Write it down before the previous one ("72"). Now take this many steps in the same direction, counting each one. c) Repeat step b till exhaustion ;-).
For indoor purposes, the student can jiggle up and down or simply count the numbers.
FWIW .. Subbu
Thanks, I forgot about the "repeat" tile :)
Richo
On Thu, Jun 3, 2010 at 2:26 AM, Yoshiki Ohshima yoshiki@vpri.org wrote:
At Thu, 3 Jun 2010 01:07:57 -0300, Ricardo Moran wrote:
Why is it hidden? It seems like a very nice feature to me.
No doubt that it is useful in some cases, but the "repeat" tile provides the same behavior to the "fires per tick" feature but in a scriptable way.
Also, setting the tick rate is already somewhat hidden (holding the button on a clock is not discoverable). With a hidden feature there and a special-case menu item here and many combinations of these two produce pretty much the same end result. We thought it is confusing enough to explain them to the end user.
Removing the "100" option from the tick rate menu and making a tile to set tick rate in the scripting category would be nice. Trying to convince the edu team to reinstate the "fire per tick" feature might do it also^^;
-- Yoshiki
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima yoshiki@vpri.org
wrote:
At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote: > > Bert, thanks for the explanation. > > So if the default max Tick Rate is 50, should remove 100 from thelist of selectable tick rates?
> > "Other..." still makes sense (especially 0.1 for ticking every 10seconds), but we should have some warning so
folks > know the limitations. The warning could be when you select Other inthe dialog box that pops up. ex: "Max Rate is
50 per > second, can change in preferences"). > > My major purpose for using Etoys is playing around ;) no specificneed at this point in time. I noticed the
problem when > running Randy's Dice Roll project and was simply trying to figureout how things worked.
Just FYI, there is a hidden feature called "fires per tick" (only present in the scriptor menu when etoyFriendly preference is off) to specify how many times the script should be executed per tick. For example, if you set the number high in Randy's Dice Roll, the bar graph grows more rapidly. -- Yoshiki _______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
There is no visible indication if this is enabled. If you want a script to run multiple times per tick, use a times-repeat block. At least there it is in plain sight what's happening.
I think this obscure "feature" comes from a time when there was no repeat block.
- Bert -
Am 03.06.2010 um 06:07 schrieb Ricardo Moran richi.moran@gmail.com:
Why is it hidden? It seems like a very nice feature to me.
Richo
On Wed, Jun 2, 2010 at 5:53 PM, Yoshiki Ohshima yoshiki@vpri.org wrote: At Wed, 2 Jun 2010 13:18:19 -0400, Steve Thomas wrote:
Bert, thanks for the explanation.
So if the default max Tick Rate is 50, should remove 100 from the list of selectable tick rates?
"Other..." still makes sense (especially 0.1 for ticking every 10 seconds), but we should have some warning so folks know the limitations. The warning could be when you select Other in the dialog box that pops up. ex: "Max Rate is 50 per second, can change in preferences").
My major purpose for using Etoys is playing around ;) no specific need at this point in time. I noticed the problem when running Randy's Dice Roll project and was simply trying to figure out how things worked.
Just FYI, there is a hidden feature called "fires per tick" (only present in the scriptor menu when etoyFriendly preference is off) to specify how many times the script should be executed per tick. For example, if you set the number high in Randy's Dice Roll, the bar graph grows more rapidly.
-- Yoshiki _______________________________________________ squeakland mailing list squeakland@squeakland.org http://lists.squeakland.org/mailman/listinfo/squeakland
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squeakland@lists.squeakfoundation.org
-
Bert Freudenberg -
K. K. Subramaniam -
kharness＠illinois.edu -
Ricardo Moran -
Steve Thomas -
Yoshiki Ohshima