[squeak-dev] Please add Robot support tools

Eliot Miranda eliot.miranda at gmail.com
Tue Feb 17 04:06:02 UTC 2015

Hi Kirk,

On Feb 16, 2015, at 9:17 AM, Kirk Fraser <overcomer.man at gmail.com> wrote:

> Here are improvements to make Squeak more useful for Robot control.
> 1) Add machine vision tools.  I'm told eToys has video camera access but more access to each frame is needed for autonomous robot control including "contour" to reduce the image to arcs and lines to start visual object identification and measurement of object speed and direction as the robot is moving, to either intercept or avoid an object.  The same arcs and lines may in some applications be processed into readable text, read your lips, or other interesting things.
> 2) Method to stop Garbage Collection.  I see Squeak 4.5 has a menu item to perform garbage collection so performing collections can be put under program control but there should also be a message to stop any garbage collection until requested or resumed.  Why?  Imagine you are in a self-driving car powered by Squeak.  You enter a curve, turn, or need to stop while going 60 MPH then encounter a 100 millisecond delay for garbage collection.  That scenario could put you 8 feet off course into a canyon, oncoming traffic, or a child chasing a ball.  So the only way is to use two Squeaks operating in separate cores and use socket communication to guarantee one Squeak is paying close attention to the road while the other collects its garbage, trading off as needed.  Perhaps a measure of the garbage pile and growth rate would also help decide which image gets to proceed.

Instead of turning off GC, which will mean that eventually you'll run out if memory, you should ask what is the maximum pause time you want.  Pause times for the scavenger in Sour are around a millisecond on typical hardware.  Spur will introduce an incremental global scan-mark to collect old space some time this year and it will be set to have similar pause times as the scavenger.  So how far would your car drift in 2ms?  If you could tune the VM to pause for less than this, what pause time would be acceptable?  Can you provide the  range of times that spans from marginal to more than satisfactory?

> 3) The Raspberry Pi has many pins to connect electronics to.  Supporting those could potentially provide control for many projects for children and adults.
> Thank you.
> Kirk W. Fraser
> www.JesusGospelChurch.com - Replace the fraud churches with the true church.
> http://freetom.info - Example of False Justice common in America
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