Blog

Restoring old DOS backups in 2023

The steps I took to recover data from some 30 year-old MS-DOS backup floppy disks.

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Restoring old DOS backups in 2023

The steps I took to recover data from some 30 year-old MS-DOS backup floppy disks.

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Restoring old DOS backups in 2023

The steps I took to recover data from some 30 year-old MS-DOS backup floppy disks.

Blog

SwiftUI errors with any View vs some View

Make sure that your SwiftUI View-returning methods return some View, not any View.

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SwiftUI errors with any View vs some View

Make sure that your SwiftUI View-returning methods return some View, not any View.

Blog

SwiftUI errors with any View vs some View

Make sure that your SwiftUI View-returning methods return some View, not any View.

Blog

SwiftUI errors with any View vs some View

Make sure that your SwiftUI View-returning methods return some View, not any View.

About

Coofdy Labs Coofdy Labs is the father-and-son development team of Martin Kenny (Marty), and Michael Kenny. We spend most of our time building software for iOS and macOS. Marty Marty has been playing around with electronics for nearly 50 years, and programming computers since 1977. When he’s not working with Michael, he can be found keeping up with RSS on his iPhone, pondering the future of computers as tools to assist with thinking, or coding on his Mac.

Blog

SceneKit: first steps — Part 1: Just a box

In the spirit of #showyourwork, and learning in the open, I’ve decided to document my journey as I teach myself about SceneKit on iOS and OS X, and modern 3D APIs.

Blog

SceneKit: first steps — Part 1: Just a box

In the spirit of #showyourwork, and learning in the open, I’ve decided to document my journey as I teach myself about SceneKit on iOS and OS X, and modern 3D APIs.

Blog

SceneKit: first steps — Part 1: Just a box

In the spirit of #showyourwork, and learning in the open, I’ve decided to document my journey as I teach myself about SceneKit on iOS and OS X, and modern 3D APIs.

Blog

SceneKit: first steps — Part 1: Just a box

In the spirit of #showyourwork, and learning in the open, I’ve decided to document my journey as I teach myself about SceneKit on iOS and OS X, and modern 3D APIs.

Blog

A fix for cwRsync ignoring --delete

Getting the --delete flag working with cwRsync on Windows.

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A fix for cwRsync ignoring --delete

Getting the --delete flag working with cwRsync on Windows.

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A fix for cwRsync ignoring --delete

Getting the --delete flag working with cwRsync on Windows.

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Network Not Starting on Migrated Virtual Machines

If you’ve recently migrated a Ubuntu virtual machine file from one computer to another, or from one virtualization product to another, you might have discovered that networking inside the VM was no longer working. As described in this Parallels KB article, what’s probably happened is that the random MAC address generated by the virtualization host has changed. The file: /etc/udev/rules.d/70-persistent-net.rules contains a record of the matching MAC address from the previous host.

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Explicit Congestion Notification (ECN) - Firewall Problems

I’ve just spent the afternoon trying to get a simple TCP connection established. The story is that I was configuring Nagios to check some HTTP services that are behind a Cisco PIX firewall. Nagios kept on getting timeout errors – when I tried by hand with telnet, I was getting the same problem, but only from the machine running Nagios. After setting up some logging on the firewall, I could see lines like:

Blog

A fix for cwRsync ignoring --delete

Getting the --delete flag working with cwRsync on Windows.

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Fixing 'could not find symbol value for runtime.buildVersion' Delve debugger error

Upgrade your Go installation to get the Delve and IntelliJ debuggers to work.

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This time it’s personal

The Apple Watch is such a personal device that it’s very enticing to create little, personal, information dashboards for it.

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Network Not Starting on Migrated Virtual Machines

If you’ve recently migrated a Ubuntu virtual machine file from one computer to another, or from one virtualization product to another, you might have discovered that networking inside the VM was no longer working. As described in this Parallels KB article, what’s probably happened is that the random MAC address generated by the virtualization host has changed. The file: /etc/udev/rules.d/70-persistent-net.rules contains a record of the matching MAC address from the previous host.

Blog

Explicit Congestion Notification (ECN) - Firewall Problems

I’ve just spent the afternoon trying to get a simple TCP connection established. The story is that I was configuring Nagios to check some HTTP services that are behind a Cisco PIX firewall. Nagios kept on getting timeout errors – when I tried by hand with telnet, I was getting the same problem, but only from the machine running Nagios. After setting up some logging on the firewall, I could see lines like:

Blog

Network Not Starting on Migrated Virtual Machines

If you’ve recently migrated a Ubuntu virtual machine file from one computer to another, or from one virtualization product to another, you might have discovered that networking inside the VM was no longer working. As described in this Parallels KB article, what’s probably happened is that the random MAC address generated by the virtualization host has changed. The file: /etc/udev/rules.d/70-persistent-net.rules contains a record of the matching MAC address from the previous host.

Blog

Explicit Congestion Notification (ECN) - Firewall Problems

I’ve just spent the afternoon trying to get a simple TCP connection established. The story is that I was configuring Nagios to check some HTTP services that are behind a Cisco PIX firewall. Nagios kept on getting timeout errors – when I tried by hand with telnet, I was getting the same problem, but only from the machine running Nagios. After setting up some logging on the firewall, I could see lines like:

Blog

Network Not Starting on Migrated Virtual Machines

If you’ve recently migrated a Ubuntu virtual machine file from one computer to another, or from one virtualization product to another, you might have discovered that networking inside the VM was no longer working. As described in this Parallels KB article, what’s probably happened is that the random MAC address generated by the virtualization host has changed. The file: /etc/udev/rules.d/70-persistent-net.rules contains a record of the matching MAC address from the previous host.

Blog

Snowflakes on a Razer Blade

The magnificent set of snowflake photos by Russian photographer Alexey Kljatov (recently featured by kottke.org) make for some wonderful desktop images. Michael and I have both just recently updated our desktop images to these snowflake macros. Michael’s Razer Blade features an 800x640 display as the trackpad. A resized snowflake makes an ideal trackpad background. Pro Tip: If you’re trying to turn one of these images into a 16:9 or 16:10 wallpaper, Photoshop’s Content-aware Fill (Shift+F5) is your best friend.

Blog

Snowflakes on a Razer Blade

The magnificent set of snowflake photos by Russian photographer Alexey Kljatov (recently featured by kottke.org) make for some wonderful desktop images. Michael and I have both just recently updated our desktop images to these snowflake macros. Michael’s Razer Blade features an 800x640 display as the trackpad. A resized snowflake makes an ideal trackpad background. Pro Tip: If you’re trying to turn one of these images into a 16:9 or 16:10 wallpaper, Photoshop’s Content-aware Fill (Shift+F5) is your best friend.

Blog

Snowflakes on a Razer Blade

The magnificent set of snowflake photos by Russian photographer Alexey Kljatov (recently featured by kottke.org) make for some wonderful desktop images. Michael and I have both just recently updated our desktop images to these snowflake macros. Michael’s Razer Blade features an 800x640 display as the trackpad. A resized snowflake makes an ideal trackpad background. Pro Tip: If you’re trying to turn one of these images into a 16:9 or 16:10 wallpaper, Photoshop’s Content-aware Fill (Shift+F5) is your best friend.

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The People's Search Service

Jason Fried asks “Would you pay $5/month for Google if it wasn’t free”? Dave Winer says “Clone the Google API”. I’d like to join those together and ask “Would you pay $80/month to own a part of the infrastructure that powered a free implementation of the Google API”? In other words, rent a dedicated (low-end) server from the likes of Layered Technologies, or EV1Servers, and use it to run a distributed part of the crawling, indexing, or querying part of a full-on search engine.

Blog

The People's Search Service

Jason Fried asks “Would you pay $5/month for Google if it wasn’t free”? Dave Winer says “Clone the Google API”. I’d like to join those together and ask “Would you pay $80/month to own a part of the infrastructure that powered a free implementation of the Google API”? In other words, rent a dedicated (low-end) server from the likes of Layered Technologies, or EV1Servers, and use it to run a distributed part of the crawling, indexing, or querying part of a full-on search engine.

Blog

The People's Search Service

Jason Fried asks “Would you pay $5/month for Google if it wasn’t free”? Dave Winer says “Clone the Google API”. I’d like to join those together and ask “Would you pay $80/month to own a part of the infrastructure that powered a free implementation of the Google API”? In other words, rent a dedicated (low-end) server from the likes of Layered Technologies, or EV1Servers, and use it to run a distributed part of the crawling, indexing, or querying part of a full-on search engine.

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Spammers Start Using Wildcard DNS

In his now-famous, A Plan for Spam, Paul Graham wrote: … the spam of the future will probably look something like this: Hey there. Thought you should check out the following: http://www.27meg.com/foo because that is about as much sales pitch as content-based filtering will leave the spammer room to make. (Indeed, it will be hard even to get this past filters, because if everything else in the email is neutral, the spam probability will hinge on the url, and it will take some effort to make that look neutral.

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The ongoing Effect

I've been ongoing'ed, or is that Tim'ed – the ongoing version of being Slashdotted. The main difference is the smaller number of visitors, and the fact they're an even more geeky bunch (so far they all use Firefox or Safari). Anyway, the link in question came from Tim Bray's Genx page. If you're looking for a way to generate well-formed XML from C/C++, and don't want to sprinkle your code with printfs, or equivalent, then check out Genx.

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Refactoring CSS - the need for a testing tool

Several times over the last couple of weeks, I've found myself refactoring CSS – making changes to simplify and group rules, but with the aim of not changing the appearance at all. To test my work, I've been taking screen shots and swapping backwards and forwards to look for differences. It suddenly struck me that what I really need is a CSS/HTML-specific diff tool. One that can take some CSS and some specific HTML, work out all the borders, margins, placements, etc.

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Google and Page Titles

A couple of recent weblog posts, at Microdoc News and Virtuelvis, have echoed something I've been meaning to write about for a while – that Google makes such heavy use of a page's contents when indexing a site. For a long time this site had a PageRank of zero, although for a few days now, it's been four. What I noticed was that, despite have a PR of zero, and being linked from a vanishingly small number of other places, my articles were often turning up in the first page of Google results for two-word queries containing words from my article titles.

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Zeldman presents: Designing With Web Standards

Recently, a bright orange book, with a beanied man on the front cover, arrived on my front verandah. I'm referring, of course, to Jeffrey Zeldman's new book, Designing With Web Standards, and the beanied man is none other than Zeldman himself. Forthwith, my mini-review of his book: I wasn't quite sure what to expect from this book – all I knew was that it had sold out it's first printing, before I could get my hands on a copy.

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Echo - an emergent syndication format

I've recently been playing around with RSS – first by trying a few readers, then by setting up my own feed. I wasn't entirely happy with any of the readers I tried, so I've been building my own to more closely match my own needs, and to learn about RSS issues along the way. It's pretty clear that everybody has a different idea about the semantics of any given version of RSS.

Blog

The People's Search Service

Jason Fried asks “Would you pay $5/month for Google if it wasn’t free”? Dave Winer says “Clone the Google API”. I’d like to join those together and ask “Would you pay $80/month to own a part of the infrastructure that powered a free implementation of the Google API”? In other words, rent a dedicated (low-end) server from the likes of Layered Technologies, or EV1Servers, and use it to run a distributed part of the crawling, indexing, or querying part of a full-on search engine.

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The Federation

I’m probably the last person to see all these new North American political maps floating around the Web. But, just in case, here are three from: Richard Friedman, Mena Trott, and Tim Bray. If Australia’s going to be aligning itself closely with the U.S. (it is, and it does), then perhaps we should be joining the Federation – I’m sure they’d accept representation on the western rim of the Pacific :-).

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A Political Weekend

It turned into more of a political weekend than I’m accustomed to. First, my friend and former colleague, Bill Malkin, wrote asking if he could borrow my site design for a website he was setting up in support of Brian Deegan. Brian is contesting the Adelaide Hills seat of Mayo, against the incumbent member, federal minister Alexander Downer, in the upcoming federal election. Then, on Sunday evening, Theen had organized for us to see Michael Moore’s “Farenheit 9/11”.

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Magnatune are not vandals

Tim Bray recently likened MP3 encoding of music to Vandalism, and again made the point in more detail when discussing a New York Times article about online music purchasing. While I agree that 128Kbps MP3s are not really up to scratch, it's worth noting that at least one online music vendor, Magnatune, lets you download your music in a number of different formats, including two lossless formats, and a couple of higher-than-usual-quality lossy formats.

Blog

Magnatune are not vandals

Tim Bray recently likened MP3 encoding of music to Vandalism, and again made the point in more detail when discussing a New York Times article about online music purchasing. While I agree that 128Kbps MP3s are not really up to scratch, it's worth noting that at least one online music vendor, Magnatune, lets you download your music in a number of different formats, including two lossless formats, and a couple of higher-than-usual-quality lossy formats.

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Pervasive OFDM

Reading this article on Wireless USB, prompted me to think about just how pervasive the RF modulation known as OFDM is becoming. I'm someone who pretty much has to know how something works, once it enters my consciousness. So, in mid-2000, while researching Australia's chosen form of digital TV, Digital Video Broadcasting - Terrestrial (DVB-T), I discovered a fascinating form of RF modulation, known as Orthogonal Frequency Division Multiplexing (OFDM).

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Implementing Structured Text

I’ve started to implement my structured text ideas as PHP code. Currently it handles levels of indenting Python-style, and uses them to determine nesting of lists and heading levels. This allows me to do things like: Have individual list items. Some of which can contain sub-paragraphs like this one. As well as nested lists, like this. This section includes some gratuitous code: for (int i = 0; i < 10; i++) { sprintf("i: %d", i); } Some final closing remarks would go just about here.

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Thoughts on Structured Text

What do I really want from structured text for a CMS? My wish list, in a rough order of importance: The ability to just type normal text and get paragraphs and probably line breaks (not that I use them often). Lists–I tend to organize my thoughts in lists – often nested. So ideally lists should be nestable. It would be great if list items could contain whole multiple paragraphs too.

Blog

Spammers Start Using Wildcard DNS

In his now-famous, A Plan for Spam, Paul Graham wrote: … the spam of the future will probably look something like this: Hey there. Thought you should check out the following: http://www.27meg.com/foo because that is about as much sales pitch as content-based filtering will leave the spammer room to make. (Indeed, it will be hard even to get this past filters, because if everything else in the email is neutral, the spam probability will hinge on the url, and it will take some effort to make that look neutral.

Blog

Pervasive OFDM

Reading this article on Wireless USB, prompted me to think about just how pervasive the RF modulation known as OFDM is becoming. I'm someone who pretty much has to know how something works, once it enters my consciousness. So, in mid-2000, while researching Australia's chosen form of digital TV, Digital Video Broadcasting - Terrestrial (DVB-T), I discovered a fascinating form of RF modulation, known as Orthogonal Frequency Division Multiplexing (OFDM).

Blog

Optical Illusions

Norman Walsh recently posted a link to Akiyoshi’s illusion pages. I’ve got to say these are really fantastic. They are excellent illustrations of the physiological factors that make our vision work the way it does. I recently read Margaret Livingstone’s Vision and Art: The Biology of Seeing, and although it’s not the sort of book I would have bought for myself (my mother gave it to me as a birthday present), it’s excellent.

Blog

Zeldman presents: Designing With Web Standards

Recently, a bright orange book, with a beanied man on the front cover, arrived on my front verandah. I'm referring, of course, to Jeffrey Zeldman's new book, Designing With Web Standards, and the beanied man is none other than Zeldman himself. Forthwith, my mini-review of his book: I wasn't quite sure what to expect from this book – all I knew was that it had sold out it's first printing, before I could get my hands on a copy.

Blog

O'Reilly's Safari Rocks

OK, there, I've said it. O'Reilly's Safari Bookshelf is great. I'd been thinking about giving Safari a go for a while, but it wasn't until Slashdot ran a review of it that I gave in and signed up for a 14-day trial. I had some intial misgivings. I'm an avid technical book reader; I have a large library that dates back to the days of 8-bit microprocessors. I read myself to sleep every night with a book, often an O'Reilly one.

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Refactoring CSS - the need for a testing tool

Several times over the last couple of weeks, I've found myself refactoring CSS – making changes to simplify and group rules, but with the aim of not changing the appearance at all. To test my work, I've been taking screen shots and swapping backwards and forwards to look for differences. It suddenly struck me that what I really need is a CSS/HTML-specific diff tool. One that can take some CSS and some specific HTML, work out all the borders, margins, placements, etc.

Blog

Gratuitous Iris Photo

Now that I have a camera I carry everywhere, I'm more likely to catch a photo of something incidental. Here's a photo of raindrops on a small iris outside the front door. Click it for the original high-resolution image (my current desktop image).

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Beechwood Autumn Colours

On Easter Monday, we went for a picnic in the Beechwood Heritage Garden. Beechwood was a private garden that is now managed by the Mount Lofty Botanic Gardens, and is only open to the public for six weeks in spring and again in autumn. It's well worth a trip in both seasons, and is definitely an excuse for a few photos.

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KneeHIGH Puppets

Last weekend we went to the Adelaide Zoo for the closing event of the children’s festival known as “Come Out”. We watched a number of musical events with an environmental or animal theme, put on by primary school children, but the highlight of the visit was an appearance by the “KneeHIGH Puppets”. From their name we imagined these would be puppets that were, well, knee-high. We couldn’t have been more wrong.

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Patent Madness

It seems nearly every day brings news of some new software patent that is pretty damn obvious and for which there should be easily locatable prior art. Today it's browser cookies, a few days ago it was web advertising. It's so common that Slashdot has a whole category for it ! As someone who, as a youth, applied for a patent with a friend (for a non-software idea), I can sort of relate to patents, but as a software developer I'm just plain scared and annoyed by most (all) software patents.

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Don't do stuff while you're sick or tired

I was reminded, yesterday, of an old rule of mine; “don't do important things when you're feeling sick or tired”. My rule dates back to some time in my mid-teens when I spent an evening soldering up a kit for what was then known as a VDU (in this case a single board that acted as the display part of a dumb terminal). Unfortunately I was already tired and excited (I'd been waiting for this thing for a couple of months).

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Interlacing and double-buffering

Having discovered that while everything was working quite well for MPEG content in ‘film mode’, like the feature film on a DVD, I hadn’t really tried things with stuff in interlaced mode. Things like the ‘making of’ programmes on DVDs tend to have been made for television, and contain frames made up of two fields that may have movement between them. The end result was a horrible juddering, where the fields were sometimes being played in reverse order.

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Thermal Problems

For a while now, the power supply has been heating up quite a bit. It seemed as though insufficient air was being pulled through the power supply by its fan. It turns out the the problem was the positioning of the PSU and its fan relative to the heatsink of the CPU. The fan was positioned exactly level with the heatsink at a distance of about 12mm. Instead of air being sucked into the PSU and out its vents at the other end, I believe this was causing air to circulate between the middle of the fan and the outside of the fan; needless to say, it was getting fairly hot inside there.

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Infra-red Remote

Having built a simple serial infra-red receiver compatible with the LIRC project, some time ago, I finally got around to configuring it and testing it in the TVapp. It’s all working nicely with an old Sony remote that was lying around.

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Comparing mplayer and VideoLAN

In trying to get mplayer to play pause-free, I decided to have a look at VideoLAN. Having perused the main loop in mplayer, while trying to figure out my timing problems, I’d seen that it’s code’s not pretty :-). Looking through the VideoLAN code, and looking at the development documentation shows me that the VideoLAN code is more approachable. I’ve now got the VideoLAN client (vlc) running on the TVapp, but not without some hassles.

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Interlace Problems

A lot of the problems getting smooth, quality, TV output from the Trident have revolved around the fact that television timing is interlaced. It looks as though no-one has really tried to use the Trident Xv driver in an interlaced mode. The problems I’ve had are: Initially all video was stretched out vertically to twice the correct height. After some digging I found a register bit named MC Interlace Display, that fixed that.

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Vertical Retrace Revisited

Well it turns out there was another solution to eliminating tearing, while using no extra CPU time. It turns out that the Trident display controller has built-in anti-tear support. Basically, this amounts to double-buffering where the controller lets you update the pointers to the next page to display, while not actually changing pages until the vertical retrace is in progress. It took quite a bit of messing around to actually get it to work, because the data-sheet was short on details, and somewhat misleading, but I’ve finally got a version of the Trident Xv driver that works tear-free with mplayer.

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The Vertical Retrace Problem

The essential problem of trying to play a video stream correctly on TV in a tear-free and jump-free way is to synchronize the delivery of new frames with the vertical retrace period; the time around the vertical sync pulse when the monitor is moving the beam from the bottom back to the top of the screen. So far my attempt at achieving this has been to hack my video card’s X11 XVideo driver to sit in a polling loop until the bit in the video controller registers indicates that retrace is in progress.

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TVapp Project Status

As at 20-Nov-2002: The first milestone for me, is to be able to sit down and watch through a whole DVD without having any noticable problems. I don’t necessarily need a remote control, or anything fancy, but I need to be able to forget about my creation enough to enjoy the film. To that end, the current remaining obstacles are: the Pioneer DVD is really quite noisy. The DVD-116 seems not to slow down in response to using the hdparm utility with the -E parameter.

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Weblog

In order to keep a track of the progress of the TVapp PVR project, and other stuff, I need a weblog that can help me keep track of, and organize, my thoughts. I’ve been sitting paralyzed on this one for a couple of months now, trying to work out just the right database model that fits my plans for how I believe it should work. I want some of it to be organized hierarchically, outline style, and other parts to be more like a traditional weblog with small, quick posts.

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TVapp Software

The software components of the TVapp currently consist of: Linux Terminal Server Project for network booting and NFS mounting of all persistent volumes (the TVapp has no hard-disk), mplayer for playing the MPEG-2 streams from the server and DVD, XFree86 and the Trident CyberBlade driver for video output. I’m currently in the process of patching the Trident driver to correctly handle XVideo overlays in interlaced modes. Currently planned are: Linux Infra-Red Controller for IR control,

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TVapp Hardware

The TVapp hardware currently consists of: Celeron II 1.1GHz with 64MB RAM, MSI MS-6368 motherboard with on-board Trident video and 10/100 LAN, Pioneer DVD-116/2 DVD-ROM drive, custom VGA-composite PAL converter board, 19" rack-mount 2U case, AOpen Micro-ATX power supply. Also planned are: Infra-Red receiver for LIRC use, Noritake 128x32 graphics vacuum fluorescent display (VFD) for menus and status display, several push-buttons to go with the display.