Planet Smalltalk

Stephen Travis Pope explains why he still uses Smalltalk - and calls for vendors and open source developers to add some of the features he thinks the system is missing.

I've recovered a bit now from the STIC 2013 conference. The video for my talk "Modern Web Programming with Dart" is now available. I give a very quick overview of Dart and Web Components as approaches to improving web programming. You can also download the slides, which are a bit hard to read in the video.

Other presentations are being added at Jim's site. The most recent is Dan Ingall's keynote talk. On the loose theme of "My Favorite Things" Dan talked a selection of things he's been involved in over the years, starting with some quite interesting history about very early Smalltalk versions and how much they differed from Smalltalk-80, and ranging up through various Squeak projects and a short bit on the Lively Kernel. It includes running versions of some remarkably old software doing some remarkable things. This was part of the historical theme of the conference on the 30th anniversary of Smalltalk-80 being released to the world.

There is Cade - a graphics framework for Pharo using Athens. Here is the link including a demo video.

At STIC 2013 Alexandre Bergel presented Roassal, a Smalltalk visualization engine. It looked like a nice fit for our project, where we build deeply nested Seaside views from VW window specs. Navigating the component structure can be confusing, so I decided to add a tree view using Roassal.

We have the ability to inspect individual components, and we added our own inspector subclass which gives us a place for a custom menu (in VW you can do that by overriding #inspectorClasses). The most used menu entry is 'Inspect Parent Path', which inspects an array of components built from walking the parent links from the selected component up to the root component.

The parent path is handy, but is does not provide enough context, and navigating to a component outside of the parent path is a pain. It would be better to see a parent tree, with siblings and labels. Each of our components answers #parentComponet and #components. For the parent tree we just added each parent and each parent's components (siblings) into a set. Coding it in Roassal was easy...


visualizeParentPath

| view list |

list := self parentPathWithComponents.
view := Roassal.ROMondrianViewBuilder view: Roassal.ROView new.
view shape rectangle 
if: [:each | each hasUpdates] borderColor:  Color red;
if: [:each | each == self] fillColor:  Color yellow;
withText: [:each | each displayVisualizationLabel].
view interaction 
item: 'inspect' action: #inspect;
item: 'visualize' action: #visualizeParentPath.
view nodes: list.
view edgesFrom: #parentComponent. 
view treeLayout.
view open.


And here is what it looks like (the mouse is hovering over the 'I' input field; the popup is the printString of the component)...


This has proven to be quite handy. A big thanks to everyone that contributed to Roassal.

Simple things should be simple. Complex things should be possible.  Alan Kay. 

This is my first official communication server in VASmalltalk – programmed in the graphical environment of VASmalltalk.

Communication is done via 0MQ. The server shown here is a service registration server for a local network. Local services (written in C#, Java, Smalltalk or …) deliver their service information to their local service registration server – and this information is spread over all service registrations servers in the local network.

The good thing is, that – due to 0MQ – VASmalltalk has no load due to network communication, because all stuff is done in an external C thread.

The system is embedded as a standalone software component (physically as a software IC) within my Portobello framework and has the “normal” jQueryMobile administration GUI.

Filed under: .NET, Smalltalk Tagged: 0MQ, Connections, Smalltalk

In need of some Smalltalk marketing - then get some stickers.

Read more here.

Dan Ingall's keynote address at STIC 2013 - "A few of my favorite things"

Presenty is a user interface framework for Pharo based on MVP (Model view presenter). Read more about it on Denis blog. Code is on SmalltalkHub.

As of this morning, builderCI supports Pharo-3.0 and GemStone 3.1.0.3.

The total number of versions that can be automatically tested using Travis-CI and GitHub is now 16 (6 Pharo versions, 3 Squeak versions and 7 GemStone versions).

For information on using builderCI, see the project README.

Photo by http://www.flickr.com/photos/encels/4059671027 / CC BY-NC-SA 2.0

Another image here. 

Here is a web application using Colin Putney’s Altitude framework. It’s a mockup for a possible squeak.org website. The site uses Bootstrap to make the site with Altitude, as the underlying framework. If you open it with Cog, execute the first line in the Workspace, you’ll see the site at localhost:8624. If your computer is connected to the internet, it’ll pull down related files and present the site. I have to say that Colin intended a more sophisticated use of what he created. Some shortcuts were taken by me to make it have conventional RESTful-looking urls.

Just released FileTree 1.0.2 with a hand full of bugfixes and Pharo3.0 support.

To install, follow these instructions.

Photo by http://www.flickr.com/photos/rogersmith/3609429682 / CC BY-NC-ND 2.0

I guess I was so busy preparing for my STIC talk I forgot to announce the availability of a podcast on GemTalk Systems that I did with James Robertson and David Buck. I have to say that James and David run a pretty smooth interview. It was fun and (I hope) informative.

For the past 21 years, the European Smalltalk User Group (ESUG) has organized the International Smalltalk Conference, a lively forum on cutting-edge software technologies that attract people from both academia and industry. ESUG 2013 will be held on September 9-13, 2013 in Annecy, France.

Alan Knight talks about the Dart language, and how it can be used with Smalltalk, at STIC 2013

James and David talk about the conference on Wednesday evening, just after it all wrapped up

First video recorded by James from this months "STIC 13" conference, Wigwam resort, Phoenix Arizona (June 9-12). Expect more to come in the next days ...

Didnt know Barcodes are so easy to implement in Smalltalk. So I started with EAN13 barcode together with unit tests.

Project lives on: http://smalltalkhub.com/#!/~TorstenBergmann/Barcode

You can also load it using the config browser in Pharo 2.0 now. It is already usable - thanks to the power of Pharo.

Short Guide:

 To instantiate: BarcodeEAN13 value: '2109876543210'
You can get the binarySequence of a barcode:

(BarcodeEAN13 value: '2109876543210') binarySequence

calcuate the checksum (last digit):

 (BarcodeEAN13 value: '2109876543210') computeChecksum

 or visualize the barcode:

  BarcodeEAN13 example asForm asMorph openInWorld

 or to write to a file:

   PNGReadWriter putForm: BarcodeEAN13 example asForm onFileNamed: 'sample.png'

  Now includes EAN8 as well

David Graham ported Andreas Raab’s WebClient web server to Cuis on GitHub, as is shown here. I created a simple web framework a while ago by welding the canvas of Seaside to Goran Krampe’s HttpView2 chassis. The result is called GreenNeon, which I’ve ported to Cuis. You can download the image here.  Zipped it comes in at 5M. Start it wit Cog and you can go to localhost:9221 and it’ll say Hello World!. The Websela homepage uses GreenNeon and Bootstrap. I’m unfamiliar with GitHub and the .pck file format Cuis developers use in lieu of Monticello .mcz files, so I’ve just provided an image.

So let's say you are having internet issues that look like traffic drops.  The ISP's technician runs a speed test and shows you that your connection speed is ok.  But you know from your previous runs that the results are unstable.  A reason why is that several popular speed test sites measure speed by receiving files (download speed) and sending files (upload speed).  Some examples include http://www.speedtest.net/, http://www.speakeasy.net/speedtest/, http://speedtest.comcast.net/, http://www.bandwidthplace.com/, and http://whatismyipaddress.com/speed-test.  The issue with this procedure is that they also end up measuring file I/O and, particularly, how your browser does file I/O, and how your operating system caches file I/O.

Yes yes I know your SSD drive is fast, and yes yes your hardware RAID card is awesome.  But why should there be file[system] I/O at all when doing a network test?  Here's the net effect I have observed on OS X with Firefox, on a fast machine with plenty of RAM to cache disk reads.

First, there is the issue of where Firefox puts the files, which is the browser's cache.  If your cache is full, then Firefox will have to make space in the browser's cache as it's writing the file during the speed test.  The cleanup operation will cause random file I/O in the cache's hash bucketed directory structure to find the files, and then more random file I/O to delete the files.  OS X doesn't like caching a lot of disk writes while deleting files, so this means file I/O checkpoints.  If your file system is POSIX, that also means a number of atime updates as well.  Finally, I assume something will have to be done in the database that's holding which URLs correspond to what files.  And what if the cache is full of tiny (less than 4kb) files, as it usually is?  Then all this file I/O will happen every 4kb or less during your speed test measured in megabytes per second.  Oh, and did I mention there has to be file I/O to write the file to the browser's cache too?

Well ok you could at least clear the cache before beginning.  Try deleting 250k files out of a 1gb browser cache on OS X.  With an SSD drive, that can take a significant fraction of a minute (top speed on the order of 2k IOPS, usually less than 1k IOPS).  With a regular hard drive, that will cost you half an hour or more (top speed on the order of 300 IOPS, and a lot of audible seeking --- as if the OS was flushing disk buffers continuously).

But even if you flush the cache so the browser can write without deleting anything, that's not a guarantee of a proper test because OS X also buffers writes until the buffer fills, and then further I/O is effectively blocked until the buffers are flushed to disk.  You can see this effect by using the activity monitor app during the test.  The writes will flatline at zero most of the time, and at some point the buffers will be flushed (at hopefully much higher speeds than the speed test itself is receiving data).  While the flushing happens, most speed tests seem to get stuck and their fancy graphics don't update, etc.

I've yet to find a browser based speed test that simply allocates memory to do these things.  I'm not saying none exists.  Speed tests such as the above are not useful because of the problems described above.

Generally, the issue with the Firefox cache induced file I/O can be improved dramatically by creating an ExFAT disk image and mounting it where Firefox expects the hash bucketed directory structure to be.  Clearing the browser's cache is vastly improved with this approach.  Whereas it can take half an hour or more with a regular drive to delete 250k files and 1gb of cached data, the disk image approach can do the same thing in a few seconds.  Effectively, you get SSD performance out of your mechanical drive simply because you coax software to do a better job of file I/O.  The only hiccup will occur when OS X decides to flush disk buffers, at which point the machine might seem stuck for a couple seconds.

Can we please fix these underlying issues so that we can get proper performance out of SSD drives too?

Update: a Comcast technician suggests http://testmy.net, which doesn't look like it's writing stuff to the browser's cache.  Nice!

The Squeak wiki can be a reference for you on your desktop. Download this image. Open the image and execute the two commands in the Workspace one at a time. Then go to localhost:8666. You’ll have the Squeak wiki in a browser on your desktop.

You may want to leave a few seconds after the first command, as the image has to suck in ten thousand files. I removed a few things to make the download smaller. It is ~50M and expands to ~350M. There is no Croquet book or Swiki book (i.e. the Swiki wiki). There are no images. Getting it out of the server was 3G.

If you want to take a new Squeak 4.4 and load in the ComSwiki, you can find the source on the Gemstone SqueakSource here. You’ll need to install Comanche. (I recommend the near latest, but not the latest version of Kom.)

The only real change I made to make the ComSwiki work in 4.4 was to copy #readOnlyFileNamed: into UnixFileDirectory. ComSwiki wants StandardFileStream in XmlSwikiStorage. UnixFileDirectory readOnlyFileNamed: ’1.xml’ needs to produce a StandardFileStream and not MultiByteFileStream, which is what FileDirectory readOnlyFileNamed: will provide.

There are no tests for the ComSwiki. If it explodes on your desktop, perhaps you could say where.

• In a Computer A, a Test record (of a secure note) is modified to TestZZZ.
• In the Computer B, after a few instants, the PasswordsPro file get updated (synchronized)
• In the Computer B, the Test record is deleted.
• In the Computer A, after a few instants, the PasswordsPro file get updated (The Test record don't exist anymore).

by Satoshi Nishihara

John O'Keefe at STIC 2013, giving the VA Smalltalk Roadmap.