Blog entries from May, 2007

As of this morning Nathan, my nephew, has a little brother.

Yesterday a bunch of books arrived from Amazon:

• Working Effectively with Legacy Code was recommended by Leif at a perl mongers meeting where he talked about testing.
• I first read about Designing Interactions at Coding Horror and it sounded worthwhile to get.
• Hackers: Heroes of the Computer Revolution isn’t a recent book, but it sounds like it provides an excellent account of the early days of computers.
• In contrast What the Dormouse Said: How the 60s Counterculture Shaped the Personal Computer Industry is a recent book that also tells of the early days of computers, in particular the sixties.
• Where Wizards Stay Up Late also describes the early days of computers, specifically the origins of the internet.
• i, Woz is the story of Steve Wozniak, one of the founders of Apple
• The Areas of My Expertise appears to be an almanak of irrelevant knowledge.

Today I recieved more books. This time a dozen secondhand novels that I bought off eBay that worked at at AU$4 each including postage.

Now I need to cover them, add them to my catalog on LibraryThing, and then find some time to read them.

Today Damien and I followed through on my recent ride idea.

The return trip from my place ended up at 67km in 3.5 hours. I found it quite easy, however Damien was struggling towards the end. Not surprising since this is the first actual ride he has gone on since he got his new bike back in January…

In order to use up some leave I have been taking Thursdays off work. Today I decided to go for a ride and initially I considered following up on my idea involving the Hallam Bypass I posted a few days ago.

As I didn’t want to go that far I went for a ride that incorporated parts of the idea, but in the reverse direction:

This ended up a total of 48km measured (compared with the 44 km bikely estimates). The strong northerly was good initially as a tailwind, became an annoyance as a sidewind, and finally was difficult as a headwind. Apart from that it could be considered a perfect day for a ride, sunny apart from a few clouds and just the right temperature.

(If you are reading this you are seeing the new host.)

I have just changed web hosting provider. Astute readers would be aware that it is less than a year since I last changed hosts. Although I haven’t mentioned anything, I was growing unhappy with the service:

• There was a period of a few days at the start of May where nine out of ten requests to my sites were getting a zero sized response. The problem was also affecting the support site which made reporting it difficult. Eventually I just emailed them and the next day I was informed that the servers had had to be rebuilt with higher security which was breaking a number of things. So why didn’t they send out an announcement.
• The same server rebuild upgraded the version of cPanel they were running to the latest version. However this introduced some new ‘features’ that messed up how I manage my email forwarders and the online file manager no longer listed my .htaccess files. These weren’t show stoppers, but they were adding up.
• The final straw was that they ran out of disk space for MySQL which caused WordPress to complain that it got error 28 from storage engine. It did get fixed after I reported it, but as I type I can see that it has reoccurred.

At a couple of melbourne.pm meetings Kirrily has mentioned that she uses DreamHost if the conversation turns towards web hosting. So I decided to check it out.

Read the rest of this entry…

I picked up the latest edition of the Victorian bike paths guide earlier in the week and while I was comparing it to my older edition it reminded me that there were some paths down where the Monash Freeway was extended past Hallam, specifically the Hallam Byass Trail.

After a few hours of studying the bike paths guide, the online version of the Melway and Google Maps (inside Bikely) I have the following:

This is a 33km route that starts at the Dandenong Creek Path in Dandenong. From there it heads east along the Eumemmerring Creek, along the Monash Freeway, past Fountain Gate Shopping Centre and along other paths to the Wilson Botanic Park in Berwick. Heading back west along the Princes Highway it passed Fountain Gate Shopping Centre again then turns north along off road paths, through Endeavour Hills, until it eventually meets up again with the Dandenong Creek Path in Dandenong North.

The total journey from my place and back would be around 50km, something for an afternoon.

This afternoon I install the flat panel adapter (that arrived earlier in the week) into my SGI O2 so it can natively run the 1600SW display. It took around ten minutes to install the adapter and then an hour and a half to update Irix to 6.5.2 using the included patch CDs.

Unfortunately the power adapter for the display decided to release its magic smoke when I plugged it in. At least it wasn’t plugged into the display at the time so the damage was constrained.

I was able to test it out using the power adapter for the MultiLink adapter, but as it is rated lower (1A instead of 3A) the display didn’t run properly. Oh well. Time to find a replacement.

Last night Kirrily mentioned that she had created a flowchart about eating lunch at your desk so tonight I went off to find it on her Geek Etiquette site. Anyone who works in a shared office will see the truth in it, however I feel it is missing something. It doesn’t cover the case where you have a lunch that is stinkiest while being reheated and you take back to your desk because you do not want to eat in the now stunk out kitchen…

In the process of all this I checked out Kirrily’s profile on Library Thing. I started thinking that, although I built my own simple catalog, this could be useful in the same way that del.icio.us has been for my bookmarks. So I created an account…

…to find that I had already done so when I first got my barcode scanner and forgotten about it. The couple of books that were in the account were the ones that I had used when first playing around with a catalog of my own.

After I saw that the import function could extract ISBNs from an arbitrary chunk I test I copy and pasted the output from my catalog into it. 449 ISBNs were found and it is added 202 of them to my catalog as 200 is the limit for a free account (is that a boundary error?). Even though it does not satify my fundamental need for a catalog I may still pay the US$25 for a lifetime membership as it is yet another way to have an internet presence.

So what is my fundamental need for a catalog? Sorting by series and series order.

Along with the title, author and ISBN of each novel, I also have a series name and a number to represent the place the novel has in the series. Sorting by author, series, series number, then title gives me a list with two benefits; first it makes it easy to see which books in a series I do not have, and second, when printed out, this made rearranging my bookshelves signifigantly easier as I prefer to have them in chronological order.

Now that my bookshelves are mostly in order the second benefit is no longer as important and it limits the catalog to novels. I have plenty of other books that I should catalog.

Tonight was the first Melbourne Perl Mongers meeting since March. A few weeks ago I realised that the last time I posted about one of these meetings was at the start of last year so I decided that I would make an effort this month.

So…

Thre was a decent turnout of around 15 people to listen to Paul talk about “Doing Stupid Things with Perl” and Jacinta talk about greediness and regular expressions. In between there was a sysadmin question (I didn’t get the name of who asked it) about the best way to go about rolling back system processes (eg creating a user account) midway if there was a failure. This turned into an interesting discussion of both how to reliably run a system process and various ways of keeping track of where the overall process was up to in order to run other processes to revert changes that had already been made.

I recall Paul, Leif and Kirrily contributing the most with suggestions of IPC::System::Simple to reliably run the processes and various state tracking and/or nesting structures to know how to roll back.

So what is with the title of this post?

The discussions in the pub briefly turned to confidence tricks and at the time I couldn’t remember the name of an excellent book on the subject.

First published in 1940, The Big Con is a book I picked up a few years ago that is considered to be a definitive work on the subject. I find the social engineering aspect of it all to be fascinating and I would cite the following two things as the source of my interest:

• The Sting – the 1973 movie staring Robert Redford and Paul Newman that features the wire as the main con in order to get revenge for a murder
• Hustle – a contemporary television show from the UK that “follows the fortunes of a gang of five expert con artists let loose on the streets of London”

There are other influences (such as the 2003 movie Matchstick Men), but those are the first ones that come to mind.

In Perl, PHP and shell (maybe others as well) the “`” character (informally known as the backtick and formally known as a Grave accent) is used to execute a shell command and return the output as a string.

Perl and PHP have other methods of achieving the same result that are not elements of syntactic sugar. These are less likely to surprise you, as I found today when I noticed that the computer collection section of this site was breaking in a strange way.

For those pages I use PHP to build up the page based on the directory structure and the existence of certain files. The first thing I checked was that the files were actually present. They were.

The next thing to check was the error log and here I found a number of messages telling me that shell executions were disabled. That made sense in relation to a recent change in the security configuration that the hosting people had made, but what was I executing on the shell?

As the error message was nice enough to tell me the specific file and line number I quickly found this call:

trim(`pwd`) 

This is running pwd in a shell to get the current directory and then using trim() to remove excess whitespace. This is stupid. Especially since the following does exactly the same thing:

getcwd()

This has a crucial difference; it is built into the language, no shell execution (and potential security hole) is required.

To answer the original question: Use backticks to execute a shell command only if, for some bizarre reason, there is nothing built into the language or a module cannot be loaded to achieve the same result.

A few weeks ago Thomas Hawk posted about using external hard drives to back up photos. The post and the comments that followed provide a lot of good ideas and advice, but none of them address a fundamental issue I have with external USB drives:

• They use an external power supply.

I have problems with this:

• The power supply is an additional part that must be carried with the drive. This reduces the convenience of the drive unless there is a power supply at each location the drive is to be used.
• The pins on the power connector are too fragile. Between myself and people I know there are at least a half dozen times where a drive has become useless because the connector or the socket became faulty.
• The power supply adds to the clutter if the drive needs to be connected for an extended period of time.

A few years ago, before USB, the option for external drives was SCSI and those cases came with internal power supplies. Simply connect an IEC power lead and the SCSI cable and the drive was ready to go.

Why can’t that be the case for USB cases? You could transport a single item which could be used anywhere that had a standard power cable and a standard USB cable.

I can think of two possible solutions which both involve sacrificing a USB drive case:

• Fit the hard drive, USB interface and the (previously) external power adapter inside another case.
• Fit the USB interface inside a SCSI hard drive case in place of the SCSI connector.

For now I’m just going to keep my eye out for cheap SCSI cases on eBay.