Smalltalk Conferences between June and September 2008 1 Smalltalk Conferences between June and September 2008 This document contains my reports of • the Smalltalk Solutions conference in Reno June 18 - 21, 2008 • the ESUG conference in Amsterdam, August 25 - 29, 2008 (and brief info of the Camp Smalltalk 23rd - 24th and Seaside Sprint 29th - 31st) • the VASmalltalk User Group conference in Frankfurt, September 23, 2008 I have combined my three conference reports into a single document. They follow in the order in which conferences occurred. An initial section ‘Shared Keynotes’ gives two talks that were given at both ESUG and Smalltalk Solutions. Style ‘I’ or ‘my’ refers to Niall Ross; speakers (other than myself) are referred to by name or in the third person. A question asked in or after a talk is prefixed by ‘Q.’ (sometimes I name the questioner; often I was too busy noting their question). A question not beginning with ‘Q.’ is a rhetorical question asked by the speaker (or is just my way of summarising their meaning). Author’s Disclaimer and Acknowledgements These reports give my personal view. No view of any other person or organisation with which I am connected is expressed or implied. The talk descriptions were typed while I was trying to keep up with and understand what the speakers were saying, so may contain errors of fact or clarity. I apologise for any inaccuracies, and to any participants whose names or affiliations I failed to note down. If anyone spots errors or omissions, email me and corrections may be made. My thanks to the conference organisers and the speakers whose work gave me something to report. Shared Keynotes Gilad’s talk on Newspeak and Georg’s talk on Bach were given at both Smalltalk Solutions and ESUG. A single write-up combining material and questions from both conferences tells the story better than two write-ups. How to find the Bach house in Cöthen, Georg Heeg (This combines the talks Georg gave at Smalltalk Solutions and at ESUG. Questions asked and answers given at either venue are included. Strictly, Georg’s talk was not billed as a keynote in either conference, but it presents Smalltalk in a context of much wider interest, so I think it is worth highlighting here.) Dinosaur bones have been found in Cöthen, and evidence of stone age occupation. More recently it was the capital of the independent state of Anhalt in Germany; there are city records going back 900 years. It was also the location of the second largest ESUG (in 2004, eclipsed only by this year in Amsterdam). 2 Shared Keynotes Johan Sebastian Bach worked for 7 years in Cöthen, during which time he wrote ‘The Well-Tempered Clavier’ among many other works: Georg played us an excerpt from the 10th piece. Prince Leopold of Anhalt was the reason Bach lived in Cöthen for many years. (Unlike those princes who just had parties every day and spent all their money) he was very musical, invited Bach to the city, founded societies for the study of the German language and so on. Even during his lifetime, Bach began to lose popularity and only 100 years later did the superb quality of his music begin to be recognised. Thus there are many open questions about his life, including where he lived in Cöthen. Today the city wants to improve its tourist trade by finding all it can about Bach’s time there. Their first question was, ‘Where did he live?’ They got EU funding for a suitably long-winded title (Feasibility study for ....) and asked for bidders; Georg Heeg won. The bidding started in 23 March 2006; Georg Heeg completed the task on 15th February of this year. They did it in 4 phases as an agile project. They knew from the start that if they used the same approach as all the historians had tried - looking for a piece of paper with an address on it - they would fail: if such a paper existed, it would have been found. Instead, they intended to use exclusion as their proof method (c.f. the computer proof of the four-colour problem). Phase 1 was drill down to brainstorm and identify key issues. Phase 2 was locating, scanning and OCRing all the old material they could find in archives, libraries, old bookshops, eBay. 736 documents in gothic, latin and handwriting fonts were scanned. For example, they copied all the city property records for 100 years. Phase 3 built the semantic network. There were two existing semantic network products written in Smalltalk. K- Infinity (see my ESUG reports in 2001 and 2002) is used by the police, publishers, etc. It had no interface to word. Atlas TI is an analysis tool for non-numeric data, but is not extensible (it easily could be but the company only sell the packaged software). Neither of these could be fitted exactly to their problem without some work. They therefore created a specific semantic network solution GHBachNets. It provided direct connections between the automatic procedures and the human decisions. The UI was a web browser, using Seaside on VW and GemStone. Two phone calls to Monty improved performance from hours to seconds. The coder and researcher worked closely so UI ideas were implemented quickly. The first thing they discovered was that the 18th century public treasurer was either a fraudster or very bad at arithmetic; they suspect the former but cannot pursue it as he’s been dead for over 2 centuries. They also found lots of simple writing errors. To do the searching, they went back to Thorsten’s JavaSpektrum tree implementation, porting it from VW to GemStone. They soon realised that a semantic network concept of an idea or a Notion (Begriff in German) was naturally a class so they made it a subclass of ClassDescription (at first of Behavior but they found they needed the Shared Keynotes 3 subclass’ abilities as well). Thus Notion (Begriff) is a sister class to Class and Metaclass (only Smalltalk can do this!). Special Notions are Values and Relations between two or more Notions. GemStone does not allow this extension of its metaclass so they had a mapping from a description of a network to the real network in VW. Next they needed TemporalObjects. “Bach lived in this house” is not useful information without knowing from when to when he lived there. They created a time framework that could handle vague and precise dates and historical ways of dating. For hundreds of years, tax registers showed who owned a house and how much they had paid (but not where the house was located). They had old maps to locate things and they had a princely homage accession record which was a few years too early, but useful because it lists who rented as well as who owned. Thus they had a tax register of householders in 1710, and in 1765, and of those houses with the right to brew beer (most useful data - and doubtless a much-prized right at the time, too :-). He showed one page of the thick one-per-year book of which they handled 100 years-worth of books. Georg showed some of this information in an Excel table for a single home: house built in 1738, first tax record in 1741, relationships, graphics, etc. All this was imported from Excel via COM connect (the VW7.6. implementation was driven by this project’s needs). Cöthen was in the postal system. Bach wrote from Cöthen to the city of Erfurt (120 miles, which cost 2 groschen which was about 10 dollars in those days); Georg showed a copy of the letter. As was typical for that time, it listed the title, profession and position of recipient and sender in great detail, but not the street address let alone a house number. Half of the houses in Cöthen were owned by the Prince and rented; the rest were owned mostly by their residents. They swiftly concluded that Bach neither owned a house nor rented from the Prince; those records are complete. The oldest city map dates from 1730, seven years after Bach left (and conveniently is oriented north, not always the case in those days). By comparing with Google earth, you can see that streets today are very similar to what they were then. A second map of 1778 also showed little change and was easier to work with. While Bach lived in Cöthen, the city was enlarged and its walls rebuilt to enclose a larger area. They started to build the new city wall on 24th February 1719. We know that Bach must have had a spacious home. He had a big family and students lived with him, and he needed four big waggons for his goods when he moved (this useful fact is recorded in a humble newspaper of the time). They looked at all the houses that had been proposed. They also looked for any other homes that could fit. The first candidate (Burgstasse 11) was built in 1721 (too late) and was too small (luckily, as it has now been knocked down and is a space between two very modern houses). The second was simply too small. A third one, Holzmark 12, is mentioned in a list of 1855 with the names Bach and Erhardt. However it had six or seven families living in several apartments 4 Shared Keynotes within it - not at all ideal for music practice all the time. Stifstrasse 11 has a sign ‘probable Bach home’ and famous historians have backed the claim but it is not so; the project systematically proved their arguments were wrong, and were a classic case of historians quoting each other so that an ‘astonishing’ document found by one such historian was in fact already well known and not persuasive.