Below are the five most recent posts in my weblog. You can also see a chronological list of all posts, dating back to 1999.

My blog post about my Red Hat shell prompt proved very popular, although some people tried my instructions and couldn't get it to work, so here's some further information.

The unicode code-point I am using is "🎩", U+1F3A9 TOP HAT. My Terminal font of choice is Noto Mono Regular which does not contain a glyph for that code-point. Therefore the font system my Terminal uses (pango) is pulling it from another font. In my case, it's using OverPass Mono, an open source font created for Red Hat branding. The TOP HAT glyph in OverPass Mono is a Fedora. This is a nice little easter egg included by the font authors. (There's at least one other easter egg in the font, by the way!)

It's pure chance that my font system chose OverPass Mono to pull that glyph.

The simplest way to get this to work is (probably) to download and install "OverPass Mono" and set your Terminal font to it for all characters. Alternatively you may need to look at configuring Pango (or whatever font system you are using).

If your Terminal and font system support multicolour emojis, then the above alone may not work for you. Some of my colleagues got a nasty surprise when upgrading their systems: their red hats turned blue. It's possible to add a trailing Unicode modifying code-point that instructs the font system to not render the prior glyph using multicolour emojis. This reportedly fixes it:

hat="🎩"
combiner="$(perl -CS -e 'print "\N{VARIATION SELECTOR-15}"')"
# ^ alternatively, "$(printf '\xef\xb8\x8e')"
export PS1="\[\e[31m\]${hat}${combiner}\[\e[0m\]"

(Thanks ilmari for the perl trick)

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This is the fourth part in a series of blog posts. The previous post was part 3: preliminaries.

A500 mainboard

A500 mainboard

In 2015 Game 2.0, a Retro Gaming exhibition visited the Centre for Life in Newcastle. On display were a range of vintage home computers and consoles, rigged up so you could play them. There was a huge range of machines, including some Arcade units and various (relatively) modern VR systems that were drawing big crowds but something else caught my attention: a modest little Amiga A500, running the classic puzzle game, "Lemmings".

A couple of weeks ago I managed to disassemble my Amiga and remove the broken floppy disk drive. The machine was pretty clean under the hood, considering its age. I fed new, longer power and data ribbon cables out of the floppy slot in the case (in order to attach the Gotek Floppy Emulator externally) and re-assembled it.

Success! Lemmings!

Success! Lemmings!

I then iterated a bit with setting up disk images and configuring the firmware on the Gotek. It was supplied with FlashFloppy, a versatile and open source firmware that can operate in a number of different modes and read disk images in a variety of formats. I had some Amiga images in "IPF" format, others in "ADF" and also some packages with "RP9" suffixes. After a bit of reading around, I realised the "IPF" ones weren't going to work, the "RP9" ones were basically ZIP archives of other disk images and metadata, and the "ADF" format was supported.

Amiga & peripherals on my desk

Amiga & peripherals on my desk

For my first boot test of the Gotek adaptor, the disk image really had to be Lemmings. Success! Now that I knew the hardware worked, I spent some time re-arranging my desk at home, to try and squeeze the Amiga, its peripherals and the small LCD monitor alongside the equipment I use for my daily work. It was a struggle but they just about fit.

The next step was to be planning out and testing a workflow for writing to virtual floppies via the Gotek. Unfortunately, before I could get as far as performing the first write test, my hardware developed a problem…

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This is the third part in a series of blog posts, following Amiga floppy recovery project, part 2. The next part is Amiga/Gotek boot test.

The first step for my Amiga project was to recover the hardware from my loft and check it all worked.

When we originally bought the A500 (in, I think, 1991) we bought a RAM expansion at the same time. The base model had a whole 512KiB of RAM, but it was common for people to buy a RAM expander that doubled the amount of memory to a whopping 1 MiB. The official RAM expander was the Amiga 501, which fit into a slot on the underside of the Amiga, behind a trapdoor.

The 501 also featured a real-time clock (RTC), which was powered by a backup NiCad battery soldered onto the circuit board. These batteries are notorious for leaking over a long enough time-frame, and our Amiga had been in a loft for at least 20 years. I had heard about this problem when I first dug the machine back out in 2015, and had a vague memory that I checked the board at the time and could find no sign of leakage, but reading around the subject more recently made me nervous, so I double-checked.

AMRAM-NC-issue 2 RAM expansion

AMRAM-NC-issue 2 RAM expansion

Lo and behold, we don't have an official Commodore RAM expander: we were sold a third-party one, an "AMRAM-NC-issue 2". It contains the 512KiB RAM and a DIP switch, but no RTC or corresponding battery, so no leakage. The DIP switch was used to enable and disable the RAM expansion. Curiously it is currently flicked to "disable". I wonder if we ever actually had it switched on?

The follow-on Amiga models A500+ and A600 featured the RTC and battery directly on the machine's mainboard. I wonder if that has resulted in more of those units being irrevocably damaged from leaking batteries, compared to the A500. My neighbours had an A600, but they got rid of it at some point in the intervening decades. If I were looking to buy an Amiga model today, I'd be quite tempted by the A600, due to its low profile, lacking the numpad, and integrated composite video output and RF modulator.

Kickstart 1.3 (firmware) prompt

Kickstart 1.3 (firmware) prompt

I wasn't sure whether I was going to have to rescue my old Philips CRT monitor from the loft. It would have been a struggle to find somewhere to house the Amiga and the monitor combined, as my desk at home is already a bit cramped. Our A500 was supplied with a Commodore A520 RF adapter which we never used in the machine's heyday. Over the Christmas break I tested it and it works, meaning I can use the A500 with my trusty 15" TFT TV (which has proven very useful for testing old equipment, far outlasting many monitors I've had since I bought it).

A520 RF modulator and external FDD

A520 RF modulator and external FDD

Finally I recovered my old Amiga external floppy disk drive. From what I recall this had very light usage in the past, so hopefully it still works, although I haven't yet verified it. I had partially disassembled this back in 2015, intending to re-purpose the drive into the Amiga. Now I have the Gotek, my plans have changed, so I carefully re-assembled it. Compared to enclosures I've used for PC equipment, it's built like a tank!

The next step is to remove the faulty internal floppy disk drive from the A500 and wire up the Gotek. I was thwarted from attempting this over the Christmas break. The Amiga enclosure's top part is screwed on with T9 Torx screws, and I lacked the right screwdriver part to remove it. I've now obtained the right screwdriver bit and can proceed.

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A Debian package of ZDBSP is now available in the unstable distribution.

I mentioned ZDBSP when I wrote about glBSP. It's my hope to remove glBSP from the archive, leaving ZDBSP as the sole Doom nodebuilder in Debian. I might try to do this in time for the next stable release. That means probably actioning the removal before the 12th March.

If you use glBSP for any purpose, please give ZDBSP a look and make sure it works for you.

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I'm sad to belatedly witness the apparent demise of Maker Faire UK: an annual event for (mostly) amateur makers of all skill-levels that ran from the Centre for Life in Newcastle.

The Centre was always packed out for the Maker Faire, which attracted a huge range of people from all over the UK, and beyond. I was proud that this was taking place in my city. I always enjoyed attending the Faire, although it was often bitter-sweet: none of my own Making was of the kind of that you could show off at an exhibition like this. I often found myself wondering if I should try my hand at more physical hobbies.

The Centre for Life is remodelling itself this January, and as part of that project or planning, they seem to have decided that the Maker Faire was not a good fit for their new direction. They talk about opening a new space for "crafting, tinkering and creativity" within the Centre in the Spring, but I very much doubt it will attract the breadth and depth of talent that the Maker Faire did.

The decision was announced back in September, but they've already pulled the plug on the website hosting the announcement (https://makerfaireuk.com/), which was up so briefly it was not captured by either https://web.archive.org/ or https://archive.is. Their defunct twitter account points cryptically at this dead website with a final tweet of "We have posted important news about Maker Faire UK on the homepage of the website: https://makerfaireuk.com/".

At the last event in April, 2018, a friend from the Paper Jam Comics Collective demonstrated an incredible Lego Mindstorms-powered Comics drawing robot:

Other things that stuck out to me at the last Faire were some of the non-computer, non white-male-dominated crafts, such as creative stitching, knitting, crocheting and similar. Some of the exhibitors there seemed to feel like they were outsiders, but I felt they were as deserving to be there as anyone else (and more so than some of the purely vendor tables); some of them proudly exclaimed as such, and their work was a refreshing change of pace from the more dominant themes.

I recall enjoying music-related stalls in years gone by. There was usually a table of synthesizers which was fun to noodle with. I'm not sure what making they were exhibiting, perhaps the intention was their own music: there was no sign of DIY synth building. But it was fun. Various other stalls tended to have DIY synths or novel musical input devices wired up to Arduinos, or Raspberry Pis. The Centre itself has a permanently installed reactive table set up as a synthesizer which my daughter and I both enjoy playing with when we visit. One year a company was demonstrating reactive lighting boxes that I'm fairly sure were designed with (or in collaboration with) Brian Eno.

I was also impressed to see a stand demonstrating a mini replica of a PDP-8 minicomputer (it might have been this one), which reminded me of the Newcastle University Computing History Committee, and made me ponder whether any of our activities in that committee would be worthy of a stall at the next Maker Faire. For the last couple of years I've also weighed up whether or not my daughter was old enough to enjoy attending. I was fairly sure that 2019 would have been the first year that she might be, but alas, it will not come to pass.

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