Programs generate a surprising amount of garbage, little pieces of memory that are used and then discarded. Low level programming languages like C require that the programmer manage the storage themselves, which is a surprisingly painful, time-consuming and error prone task. So these days application programs are written in languages like Java (or C#) where the system manages the storage and does the garbage collection. The result is much higher programmer productivity and much better and far more reliable programs.
The overhead of doing automatic garbage collection has always been a concern. However, another problem with automatic garbage collection is that up to now it has required that the system pauses, sometimes for a considerable length of time while parts of the garbage collector runs. A pause in a web application server stops customers from doing whatever they are trying to do. This can range from absolutely unacceptable in online stock trading to just very bad for customer satisfaction in a typical e-commerce application.
At the August meeting of the SDForum Java SIG, Cliff Click spoke on pauseless garbage collection. Cliff is part of Azul Systems, a startup that has developed an attached processor to run Java applications. As Azul Systems sells to large enterprises that run Java web applications to support their business, being able to do automatic garbage collection without pausing is an important feature.
Cliff is an engaging speaker who has spoken to the Java SIG before. Previously Cliff gave an overview of what Azul is doing. At this meeting, Cliff described the pauseless garbage collection algorithm in detail, and then went on to give us some indication of its performance. He had taken a part of the standard SPEC JBB Enterprise Java warehouse benchmark, modified it by adding a large slow-moving object cache and a much longer runtime that makes the benchmark more realistic and garbage collection more of an issue.
When the benchmark is run on an Azul system, the longest "Stop the world" pause is 25 milliseconds, whereas running the benchmark on other Java systems exhibited pauses of up to 5 seconds (yes seconds). On any platform almost all of the benchmark transactions run in under a millisecond. On the Azul system, no transaction took more than 26 milliseconds, which is very close to their maximum pause time, and well over 99% of the transactions ran in under 2 milliseconds. On the other Java systems, over half of the total transaction time could be taken up by transactions that took more than two milliseconds to complete.
While Cliff and Azul are proud of what they have done so far, they are not satisfied. So they are working on removing the last few vestiges of a pause from their system. We can expect even better performance in the future.
Wednesday, August 03, 2005
Monday, August 01, 2005
Aspect Ratio Hell
I returned from summer vacation with a large number of pictures which I am editing. Which leads to a difficult decision. When cropping the pictures, what aspect ratio do I chose for the images? This is not a clear cut question, and any investigation of which aspect ratio to use for cropping pictures leads to much confusion.
Last year, for example I had a beautiful picture of us getting Lei-ed as we arrived in Hawaii. I cropped the picture for a 4 x 6 print (aspect ratio 1.5) and then deciding that it made such a good picture, printed it on a 5 x 7 (AR 1.4) only to discover that the printer chopped off the tops of our heads. Looking further I see that it would get other results if I had tried to print an 8.5 x 11 (AR 1.294...) or a 11 x 17 (AR 1.545...) or a 13 x 19 (AR 1.461...). Fortunately the last two choices are moot because my printer cannot handle theses sized sheets.
There is more. I take a group of pictures and put them on a DVD that we can watch on TV. 60 pictures at 6 seconds each with a sound track will make a high energy 6 minute video of our vacation. However, this creates more aspect ratio choices. Currently TV's are changing their aspect ratio from 4 x 3 (AR 1.333...) to 16 x 9 (1.777...). (And why has the convention changed to putting the larger number first?) In practice TV's are even more difficult as they naturally chop off some lines at the top and bottom of the picture so that a video of still images introduces even more uncertainty when deciding how to crop the images.
If we want to see the whole image in the video, we can look at it on a computer monitor which does not lose scan lines from the top and bottom and will scale everything to fit. But there is a problem even in the logical world of computers. Most of the standard display settings have an aspect ratio of 1.333... (800 x 600, 1024 x 768, 1600 x 1200) however the majority of computer displays sold today are LCD panels at 1280 x 1024 (AR 1.25).
More confusing yet, the display size of 1280 x 768 (AR 1.666...) is becoming popular in both laptops that can be used for watching DVD's on long flights and with LCD TV's where the aspect ratio seems to match what is shown on a 16 x 9 TV even although 1.66... is not 1.77...
There is a lot more to aspect ratio and it only gets worse. For example, the above discussion assumed that the pixels were square which they do not need to be. I have some ideas on what can be done which will have to wait until another time.
Last year, for example I had a beautiful picture of us getting Lei-ed as we arrived in Hawaii. I cropped the picture for a 4 x 6 print (aspect ratio 1.5) and then deciding that it made such a good picture, printed it on a 5 x 7 (AR 1.4) only to discover that the printer chopped off the tops of our heads. Looking further I see that it would get other results if I had tried to print an 8.5 x 11 (AR 1.294...) or a 11 x 17 (AR 1.545...) or a 13 x 19 (AR 1.461...). Fortunately the last two choices are moot because my printer cannot handle theses sized sheets.
There is more. I take a group of pictures and put them on a DVD that we can watch on TV. 60 pictures at 6 seconds each with a sound track will make a high energy 6 minute video of our vacation. However, this creates more aspect ratio choices. Currently TV's are changing their aspect ratio from 4 x 3 (AR 1.333...) to 16 x 9 (1.777...). (And why has the convention changed to putting the larger number first?) In practice TV's are even more difficult as they naturally chop off some lines at the top and bottom of the picture so that a video of still images introduces even more uncertainty when deciding how to crop the images.
If we want to see the whole image in the video, we can look at it on a computer monitor which does not lose scan lines from the top and bottom and will scale everything to fit. But there is a problem even in the logical world of computers. Most of the standard display settings have an aspect ratio of 1.333... (800 x 600, 1024 x 768, 1600 x 1200) however the majority of computer displays sold today are LCD panels at 1280 x 1024 (AR 1.25).
More confusing yet, the display size of 1280 x 768 (AR 1.666...) is becoming popular in both laptops that can be used for watching DVD's on long flights and with LCD TV's where the aspect ratio seems to match what is shown on a 16 x 9 TV even although 1.66... is not 1.77...
There is a lot more to aspect ratio and it only gets worse. For example, the above discussion assumed that the pixels were square which they do not need to be. I have some ideas on what can be done which will have to wait until another time.
Wednesday, July 27, 2005
Going off the Net
The internet is a wonderful thing, it is also a very dangerous place. Any computer system connected to the internet can and will be attacked. There is also a viral aspect to the internet, which means that while it is difficult to do with the internet and it is also difficult to do without.
At work we are building a software product that when combined with a number of other complex software systems on a cluster with a SAN will do wonderful things. However, configuring and debugging all this stuff requires a lot of privileged access.
The company has a lot of rules to protect its computer systems from attack. Part of that is denying users privileged access, which is sensible for most users. However when we want anything privileged done, we have to ask the IT guys to do it as they are the ones with the privilege, and each request takes its own time.
The test system arrived and my first thought was that we could bypass all these rules that slow progress by taking it off the net. If the test system is not connected, it is safe from attack, we do not have to follow all the rules and we can have all the privileged access we need to get things done as and when we want.
I suggested this at our project meeting and the first question was "if it is not on the net, how do I telnet to it for debugging?" I described sneakernet, the secure alternative to the internet. You burn a CD, pop it out, walk across the room, pop it into the test system and "Robert est votre oncle".
Everyone looked at me like I was mad, or maybe they thought that I was just lost in another millennia. The notion that you needed to be in the same room as the test system seemed retrograde. As did the idea that you could not be browsing Slashdot while waiting for that conditional breakpoint to pop. So we are going to have to put up with the constant battle with IT to get simple things done because now it is impossible to go off the net.
At work we are building a software product that when combined with a number of other complex software systems on a cluster with a SAN will do wonderful things. However, configuring and debugging all this stuff requires a lot of privileged access.
The company has a lot of rules to protect its computer systems from attack. Part of that is denying users privileged access, which is sensible for most users. However when we want anything privileged done, we have to ask the IT guys to do it as they are the ones with the privilege, and each request takes its own time.
The test system arrived and my first thought was that we could bypass all these rules that slow progress by taking it off the net. If the test system is not connected, it is safe from attack, we do not have to follow all the rules and we can have all the privileged access we need to get things done as and when we want.
I suggested this at our project meeting and the first question was "if it is not on the net, how do I telnet to it for debugging?" I described sneakernet, the secure alternative to the internet. You burn a CD, pop it out, walk across the room, pop it into the test system and "Robert est votre oncle".
Everyone looked at me like I was mad, or maybe they thought that I was just lost in another millennia. The notion that you needed to be in the same room as the test system seemed retrograde. As did the idea that you could not be browsing Slashdot while waiting for that conditional breakpoint to pop. So we are going to have to put up with the constant battle with IT to get simple things done because now it is impossible to go off the net.
Tuesday, July 19, 2005
Open Source BI
Open Source Business Intelligence is hot. This month the SDForum Open Source SIG hosted a talk from JasperSoft about their open source reporting software. Tonight the Business Intelligence SIG heard from Sandeep Giri about their OpenI initiative to provide an Open Source BI application.
Currently OpenI is a BI application built on Open Source components that provides visualization of data from an OLAP source such as SQL Server or Mondrian. Sandeep has plans to expand OpenI to become a fully fledged BI platform.
I had asked Sandeep to talk about why they are making their application Open Source. Sandeep explained that his company, Loyalty Matrix, provides Software as a Service (SaaS). [This means that they can use most Open Source software to provide their service.] While there are several Open Source components with a BI flavor, there was no ready to run Open Source BI application or platform.
Loyalty Matrix has had to develop their own platform using Open Source software. By giving their application back to the Open Source community they get the implementation help, support and feedback of a large user group to complement their tiny development team.
Currently OpenI is a BI application built on Open Source components that provides visualization of data from an OLAP source such as SQL Server or Mondrian. Sandeep has plans to expand OpenI to become a fully fledged BI platform.
I had asked Sandeep to talk about why they are making their application Open Source. Sandeep explained that his company, Loyalty Matrix, provides Software as a Service (SaaS). [This means that they can use most Open Source software to provide their service.] While there are several Open Source components with a BI flavor, there was no ready to run Open Source BI application or platform.
Loyalty Matrix has had to develop their own platform using Open Source software. By giving their application back to the Open Source community they get the implementation help, support and feedback of a large user group to complement their tiny development team.
Wednesday, June 22, 2005
Show me the Numbers
Yesterday we had a great talk at the SDForum Business Intelligence SIG from Stephen Few called "Show me the Numbers". Stephen has created a career for himself teaching how to present business information in a way that is clear and understandable. And as he told us in the meeting he did this because he saw a crying need for better information presentation and nobody else was doing it.
One of the chief problems is that BI systems vendors compete by offering the most features and in the presentation space this is done by offering a wide variety of impressive 3-D graphs. We looked at and critiqued a number of graphs taken from vendors sales and education literature and we had a field day. For example, in one memorable graph, the months in the time dimension had been sorted in alphabetic order!
When it comes to selecting the type of graph to use, many people use "Eeny Meeny Miny Moe", or look through the list of graph types and select one because they have not used it for some time. I know that I have used this method in the past. Stephen has a well thought out methodology for designing information presentation and he started to go through it, although there was not enough time to go into depth. If you want to find out more you have to read the book.
One of the chief problems is that BI systems vendors compete by offering the most features and in the presentation space this is done by offering a wide variety of impressive 3-D graphs. We looked at and critiqued a number of graphs taken from vendors sales and education literature and we had a field day. For example, in one memorable graph, the months in the time dimension had been sorted in alphabetic order!
When it comes to selecting the type of graph to use, many people use "Eeny Meeny Miny Moe", or look through the list of graph types and select one because they have not used it for some time. I know that I have used this method in the past. Stephen has a well thought out methodology for designing information presentation and he started to go through it, although there was not enough time to go into depth. If you want to find out more you have to read the book.
Sunday, June 12, 2005
Apple's ISA Shift
The most extraordinary news last week was the announcement that Apple would drop the Power chip and adopt the Intel chip and Instruction Set Architecture (ISA). There was a lot of speculation and disbelief before the event, the announcement in its own reality distortion field, and generally positive or at least understanding reportage afterwards.
First I should disclose a couple of personal connections with this event. The first one involves my mother-in-law (God bless her soul). Many years ago she wanted to buy a computer and hearing that Mac's were easier to use, bought one of the last 68000 based systems that Apple made. A couple of years later she got fed up with it because cruising the web had become impossible. Most complicated web pages took a very long time to render and many caused her system to crash. Of course there were no software upgrades to help her, so she went out and bought a PC which worked well for several years. This last January it broke down and she asked me for advice on getting it replaced. I suggested buying the Mac Mini that had just appeared and she bought one. Now I hear that it is obsolete, so is she going to be in the same position as she was with her last Mac? And this time its all my fault!
The second disclosure is that I worked for DEC, and was tangentially involved in their disastrous dithering with ISAs. Firstly they decided that the VAX ISA had no horsepower left so they adopted the MIPS chip for a short time and then completely changed tack to use their own internally developed Alpha chip and ISA. Old DEC hands may have thought that as they already had 12, 16, 18, 32 and 36 bit systems that throwing a couple more ISAs to the masses was business as usual. In practice customers took it as a sign that the company did not know what it was doing. DEC had always been deliberately run at the edge of control and when the customers deserted, DEC crumbled.
Back to the story. The most interesting commentary came from Cringely. I do not believe his major thesis, that this in an opening move in a merger between Intel and Apple. I do think that he is right on the money with his "Question 4: Why announce this chip swap a year before it will even begin for customers?" Who is going to buy a Mac now, knowing that it will be obsolete when Apple changes their ISA next year? Apple has basically destroyed the market for their major product for the next year.
There are a couple of possible reasons for making the announcement now. Firstly Apple may have decided that it was not going to keep it a secret and so the announcement was inevitable and put the best possible spin on a difficult situation. Alternatively, it could be hubris. Jobs has a history of being very successful and then getting caught up in his own reality distortion field to the extent that he blows it big time. His last big failure was Next which was colossal. This could be his next, we will see.
One other vector is Intel. Cringely is on the money in that they have a big stake in this. Microsoft just announced their xBox 360, which uses an IBM chip. If the xBox 360 turns out to be the home media center in disguise, Intel has potentially lost the consumer part of their franchise. In this context a link up with Apple who also have their eye on the home media center makes perfect sense.
First I should disclose a couple of personal connections with this event. The first one involves my mother-in-law (God bless her soul). Many years ago she wanted to buy a computer and hearing that Mac's were easier to use, bought one of the last 68000 based systems that Apple made. A couple of years later she got fed up with it because cruising the web had become impossible. Most complicated web pages took a very long time to render and many caused her system to crash. Of course there were no software upgrades to help her, so she went out and bought a PC which worked well for several years. This last January it broke down and she asked me for advice on getting it replaced. I suggested buying the Mac Mini that had just appeared and she bought one. Now I hear that it is obsolete, so is she going to be in the same position as she was with her last Mac? And this time its all my fault!
The second disclosure is that I worked for DEC, and was tangentially involved in their disastrous dithering with ISAs. Firstly they decided that the VAX ISA had no horsepower left so they adopted the MIPS chip for a short time and then completely changed tack to use their own internally developed Alpha chip and ISA. Old DEC hands may have thought that as they already had 12, 16, 18, 32 and 36 bit systems that throwing a couple more ISAs to the masses was business as usual. In practice customers took it as a sign that the company did not know what it was doing. DEC had always been deliberately run at the edge of control and when the customers deserted, DEC crumbled.
Back to the story. The most interesting commentary came from Cringely. I do not believe his major thesis, that this in an opening move in a merger between Intel and Apple. I do think that he is right on the money with his "Question 4: Why announce this chip swap a year before it will even begin for customers?" Who is going to buy a Mac now, knowing that it will be obsolete when Apple changes their ISA next year? Apple has basically destroyed the market for their major product for the next year.
There are a couple of possible reasons for making the announcement now. Firstly Apple may have decided that it was not going to keep it a secret and so the announcement was inevitable and put the best possible spin on a difficult situation. Alternatively, it could be hubris. Jobs has a history of being very successful and then getting caught up in his own reality distortion field to the extent that he blows it big time. His last big failure was Next which was colossal. This could be his next, we will see.
One other vector is Intel. Cringely is on the money in that they have a big stake in this. Microsoft just announced their xBox 360, which uses an IBM chip. If the xBox 360 turns out to be the home media center in disguise, Intel has potentially lost the consumer part of their franchise. In this context a link up with Apple who also have their eye on the home media center makes perfect sense.
Thursday, June 09, 2005
What the Dormouse Said
An extraordinary event at the PARC last night. The SDForum Distinguished Speaker Series went out with a bang as John Markoff spoke about his new book "What the Dormouse Said: How the 60s Counterculture Shaped the Personal Computer Industry". The truly remarkable thing about the night was the audience, as many of the people featured in the book were in the room.
Sandy Rockowitz introduced several audience members. The names I recall are Doug Engelbart, Bob Taylor, Butler Lampson and Adele Goldberg. Sandy did not introduce everyone and I did not catch all their names, so this is a partial list of a partial list, but it gives a glimpse of who was in the room.
John Markoff presented his thesis. The conventional story of Personal Computers is a story about Xerox PARC and the two Steves. The real story goes back much further to the 1960s and involved Doug Engelbart, John McCarthy, LSD, and only later Stewart Brand, the Homebrew Computer Club, and Stanford institutions like Kepplers bookstore around which the grateful Dead also formed.
At the meeting several people denied their personal involvement with drugs. I have not read the book so I do not know whether drugs really played a part or whether they are there promote book sales. I will let you know my opinion when I have finished it.
Sandy Rockowitz introduced several audience members. The names I recall are Doug Engelbart, Bob Taylor, Butler Lampson and Adele Goldberg. Sandy did not introduce everyone and I did not catch all their names, so this is a partial list of a partial list, but it gives a glimpse of who was in the room.
John Markoff presented his thesis. The conventional story of Personal Computers is a story about Xerox PARC and the two Steves. The real story goes back much further to the 1960s and involved Doug Engelbart, John McCarthy, LSD, and only later Stewart Brand, the Homebrew Computer Club, and Stanford institutions like Kepplers bookstore around which the grateful Dead also formed.
At the meeting several people denied their personal involvement with drugs. I have not read the book so I do not know whether drugs really played a part or whether they are there promote book sales. I will let you know my opinion when I have finished it.
Saturday, June 04, 2005
Spom?
I was using Google to do some research at work the other day, and I noticed that whatever I searched for I got lots of useless results from the likes of eopinions.com and bizrate.com. In fact, for some searches, the pollution of off-topic search sites was so high that I found nothing useful in the first few pages of search.
Personally, I have found sites like eopinions.com and bizrate.com to be completely worthless, even when I am looking to buy something. Whatever I am looking for they seem to offer something slightly different and whatever they present is jumbled and difficult to comprehend. The Google sponsored links are on target, easy to digest and much more likely to be useful than any of these sites.
The problem is that the usefulness of internet search is being destroyed by these sites. So can we do about it? The first step in any campaign is to name the enemy. I propose we call it Spom. We have Spam polluting our email and Spim polluting instant messaging, so Spom polluting searches seems to fit. We could even explain it by saying that SPOM is the contraction of Search POlution Menace. Well it is a bit forced, but it will do. Finally Spom is so far unused (mostly).
Personally, I have found sites like eopinions.com and bizrate.com to be completely worthless, even when I am looking to buy something. Whatever I am looking for they seem to offer something slightly different and whatever they present is jumbled and difficult to comprehend. The Google sponsored links are on target, easy to digest and much more likely to be useful than any of these sites.
The problem is that the usefulness of internet search is being destroyed by these sites. So can we do about it? The first step in any campaign is to name the enemy. I propose we call it Spom. We have Spam polluting our email and Spim polluting instant messaging, so Spom polluting searches seems to fit. We could even explain it by saying that SPOM is the contraction of Search POlution Menace. Well it is a bit forced, but it will do. Finally Spom is so far unused (mostly).
Wednesday, May 18, 2005
Collaborative Filtering Hell
I was at Amazon.com getting some stuff and clicked on "Richard's Store" tab which of course led me to their "Recommended For You" page. Suddenly I was lost in collaborative filtering hell. All I could find was stuff that I already had or that I had already considered and rejected. I could not find anything that interested me in the slighest and the further I looked the worse it got. Have you ever been lost in a maze of twisty little web pages with no idea of how to get out? The only cure was to exit completely and come back in through the front door.
I will never visit my personal store again!
I will never visit my personal store again!
Friday, May 13, 2005
Interesting Times
Wow, things are getting hot. So many things happened this week. Microsoft announced the new xBox home media center. Yahoo came out with their Napster/iTunes killing music service. Google is up to something that is not fully revealed yet. Gates dissed the iPod, claiming that the converged cell phone, camera, music player, PDA will be Microsoft powered. Could things get more interesting?
Cringely has a great column that covers the first three and some Apple rumors. I am surprised that Microsoft happened to announce a double pronged attack on the home PC and the pocketable information appliance in the same week.
After writing that all information task could be done by a single Information Appliance, I was going to write about how we really need three different types of information appliance with different form factors. There is the information appliance with a 42" or larger screen that is mostly for passive shared use. Next there is the personal information appliance with a 14" or larger screen for information intensive tasks like editing and composing media and emails, shopping and bookkeeping. Finally, there is the pocketable information appliance is small enough to be taken everywhere, even the bathroom.
Microsoft won the battle for the middle one and has been going after the other two for some time. Will they have more luck this time? We will just have to wait and see.
Cringely has a great column that covers the first three and some Apple rumors. I am surprised that Microsoft happened to announce a double pronged attack on the home PC and the pocketable information appliance in the same week.
After writing that all information task could be done by a single Information Appliance, I was going to write about how we really need three different types of information appliance with different form factors. There is the information appliance with a 42" or larger screen that is mostly for passive shared use. Next there is the personal information appliance with a 14" or larger screen for information intensive tasks like editing and composing media and emails, shopping and bookkeeping. Finally, there is the pocketable information appliance is small enough to be taken everywhere, even the bathroom.
Microsoft won the battle for the middle one and has been going after the other two for some time. Will they have more luck this time? We will just have to wait and see.
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