Turn off tainting in brewed Perl.

I read that turning off tainting when building Perl can give you a speedup. Tainting also appears to be on the way out: it’s not needed for Mojolicious, for example. I brew my Perls so wondered how to do it. Some digging in the Perl distribution’s INSTALL file led me to a section on tainting. This suggested a flag. The next rabbit hole was how to get perlbrew to pass flags. Doing that and verifying with –verbose led me to:

perlbrew --verbose install perl-5.36.0 

And now some totally unscientific benchmarking using different Perl versions:

A simple benchmark suggested by David Farrell: https://www.perl.com/article/40/2013/9/29/How-to-benchmark-Perl-code-for-speed/

Perl-5.38.0 taint enabled:

equalsAssign: 11 wallclock secs 
(10.19 usr +  0.05 sys = 10.24 CPU) @ 200453.61/s (n=2052645)
shiftAssign: 10 wallclock secs 
(10.12 usr +  0.03 sys = 10.15 CPU) @ 202096.55/s (n=2051280)

Perl-5.38.0 taint disabled:

equalsAssign: 11 wallclock secs 
(10.52 usr +  0.02 sys = 10.54 CPU) @ 207983.40/s (n=2192145)
shiftAssign: 11 wallclock secs 
(10.51 usr +  0.01 sys = 10.52 CPU) @ 206375.10/s (n=2171066)
The code:

#!env perl

use strict;
use warnings;
use Benchmark qw/cmpthese timethese/;

timethese(-10, {
        shiftAssign => sub {    my @alphabet = ('A'..'Z');
                                for (my $i = 0; $i < 26; $i++){
                                    my $letter = shift @alphabet;
        equalsAssign => sub {   my @alphabet = ('A'..'Z');
                                for (my $i = 0; $i < 26; $i++){
                                    my $letter = $alphabet[$i];

So all-in-all about 10% in a handwaving kind of way.

Sad London Bicycles, slightly happier Amsterdam ones

In the time I was a “real” photographer and in the time since when I’ve been armed with an iPhone camera, sad bicycles have caught my eye. Back in the day in London, very often wheels were bent or stolen completely. More recently in Amsterdam, the bicycles have just been collateral damage from the crappy weather. Anyhow by special Reddit request, here are the pictures. I believe the EXIF data should be intact, so if you really care, the phone photos should locate themselves. Why couldn’t SLRs do GPS?




Taipei is less about bicycles, although they are present, than scooters. I couldn’t find the photo I really wanted which was of a swarm of scooters waiting for a light to go green, pouring out fumes. I believe now there are many more electric ones, with convenient battery swapping stations. I do love the guy with gas bottles stacked on the back of his scooter.


So there you have it. The people of Amsterdam clearly value their bicycles more than Londoners, which given how much the Dutch travel by bike is only to be understood. Given the amount I’m walking at the moment, I daresay I shall encounter more, especially if I go to particularly bike-dense areas.

Star Trek Physics

The funny thing about the Star Trek universe is how they pushed technology and some of it has even come true. Here, I look at some of the tech they use and how it relates to where we are.


I have one in my hand almost all the time: it’s called a smartphone. Not only can I make a voice call, but I can also use it to make a video call, I can use Skype or Signal. It’s with me 100% of the time. On earth, I think landlines are dead. I only have one because BT says I have to have one. It has Wifi.


On the subject of tricorders, see above. It knows where I am, what the weather is going to be like (more or less), can identify plants and birdsong, do my banking, if I were female, keep track of my periods. It can show stars in the sky. It can track my cycling and daily steps. When coupled with a smartwatch it can keep track of a lot more of my health data like blood oxygen.

Tablet Computers

The original Star Trek had these. Is this where the idea came from? This can store my photos, let me produce great art, play games, do my shopping, do office apps and so much more. Largely stylus-free.

Universal Translators

True story. About ten years ago we were in Hong Kong meeting friends who only spoke Cantonese. We only spoke English and Mandarin. Guess what, alongside a little writing, Google Translate got us through a meal and beers. I suspect ten years on now, it’ll be even better. I use it today to decipher Welsh. I want a Babelfish.


These are coming. The technology is asymptotically approaching something useful.

They’re just taking time to come to market.

Cloaking Device

This is almost here. I’ve seen cloaks that let us blend into backgrounds, not just blue screen effects. If anyone does it, it’ll be the military.

Indeed they are all over it.


Another technology that appeared to arrive, was useful to a minority and seems to have faded. We can 3D print things (slowly) in plastic. I’ve seed 3D food printers, but more excitingly machines that can 3D print buildings. Scale that up and it’ll be a game-changer.

From a few years ago.

Sonic Showers

Some news fragments floating ideas a few years ago, but nothing since then. File under Too Hard (for now). Some cleaners use sonic cleaning but the item needs to be wet, defeating the point.


Beyond the quantum level, forget it.

Warp Drive

You cannae change the laws of physics. I’ve just been reading about space and learned that the vacuum of space is made of stuff and something about that prevents us from going faster than the speed of light. Ever wondered why aliens haven’t contacted us? It’s a long way, which means it’s a long time. That said, the stuff we know a fair amount about is only 5% of the universe. We know nothing about dark matter or dark energy. *Maybe* when we do, breaking the speed of light becomes possible. After all, during the big bang, the universe exceeded the speed of light. Briefly. Wormholes are an intriguing idea, too.

Tractor Beams

There were some news items 5-10 years ago about tractor beams on the micro-scale but nothing since.

NASA is on it. Don’t hold your breath.

Artificial Gravity

I don’t think that’s going to happen. Revolving spacecraft, maybe, but that’s not the same.

Again, NASA is thinking about it.


This is probably down to the military.

David HodgkinsonPosted on Categories Sci-FiTags , , , , , , , , , , , , ,

Rock Guitarists

This is by necessity a personal list of guitarists. I’m sure I’ve left some out, and I’ve left them out because I’m just not familiar with their work.

Ritchie Blackmore
Ritchie Blackmore

Banjo Players

This is by necessity a personal list of guitarists. I’m sure I’ve left some out, and I’ve left them out because I’m just not familiar with their work. Some I’ve put in because I really ought to get to know them better! But many of these are the guitarists who have touched me. Oh, by the way, the really good music stopped in 1976!

Ritchie Blackmore

We have to start with him. Of those of his era, like Jimmy Page, for me, Blackmore stands head and shoulders above them. Starting off playing pop-rock and doing sessions for Joe Meek, it all came together when Deep Purple was synthesized. Starting off with slightly psychedelic rock, and Hush which took America by storm, at Ritchie’s behest they sacked a couple of people, brought some others in and took the world by storm with Machine Head and Made in Japan. Ritchie has a reputation for being difficult (or a total asshole) and indeed in the Rainbow years, for terrible pranks and attempts to set keyboard players on fire. If he likes you, fine. If he doesn’t like you, watch out.

Tommy Bolin

One of Deep Purple’s other guitarists was, briefly, Tommy Bolin. After Blackmore left, they got together and suggested names and Tommy’s name kept cropping up. Tommy is the opposite of Blackmore: he’s a feel player, not a technician. I like him. His only album with Purple has a mixed fanbase but his solo albums are well worth checking out. I have them on vinyl.

Bernie Tormé

A guitarist who formed the backbone of Ian Gillan’s solo band, did an ill-judged but actually very good stint in Ozzy’s band, plus Atomic Rooster. I heard some of his later stuff with John McCoy which was rather good too.

Gary Moore

Here’s one I should know better. A great blues-rock player with a lovely, throaty voice.

Robin Trower

Another one I should know better. For example, I had no idea he was in Procol Harum!

Rory Gallagher

Same again. Listening to his stuff makes me wonder why it’s not part of my rotation.

Eric Clapton

He has to be on any list. To be honest, he’s like vanilla ice cream to me. He’s good, but to my mind, there are better. It did take me a while to “get” the outro to Layla though!

Jimi Hendrix

What’s there to say about him? He reinvented the style, stormed Woodstock, had a great band and came to the UK to get great management. I know at least two other guys trying to emulate his style! Deep Purple even covered one of his tracks.

Jeff Beck

Another guy I should listen to much more. He’s the master of understated playing and knows just how to hit the right note.

Honorable mentions

Jimmy Page, Dave Gilmour, Eddie Van Halen, Carlos Santana, Neal Schon, Joe Satriani, Steve Vai, Steve Morse, George Harrison, Lynyrd Skynyrd, Uli John Roth, Brian May, Michael Schenker, Peter Green and Lyndsey Buckingham from Fleetwood Mac, Scott Gorham and Brian Roberton from thin Lizzy, Paul Kossoff, Micky Moody and Bernie Marsden from Blusesnake and a few I’ve left off (which I’ve been reminded of).

In the overrated department, I’d put John Sykes. It was lovely seeing him guest with Deep Purple for Smoke on the Water, throw his guitar in the air at the climax and have it land on his head!


I used to do photography. I did some at the University of Bath, a year of nights at three different Central St. Martin campuses and I’ve taught in London and Taiwan. When I was in Camden I’d be out a few nights a week shooting people from Logan Plant to Midge Ure. Obviously, I’ve travelled around following Deep Purple, the US, Canada and much of Europe. I gave up my camera and lenses a few years ago and now rely on my phone and for zoom a Canon point and click. Well, here are a few of my better photos from the past. I *do* have a load of Cardiff, as you can see from this blog of Cardiff tourist stuff. I think my best is printed on Moo business cards but I can’t find the originals.

First the Camden ones:

Staqbles Market
Stables Market. The top-end by Morrisons.
Legalise Tea
On the balcony above the West Yard.
Regents Park
Regents Park. Lens wide open.
Crafty fag.
Crafty fag.
Chalk Farm.
Chalk Farm. I had a queue of people behind me.
Lous Floyd Henry.
Lous Floyd Henry. Brick Lane.
Entertainer. South Bank I think.
Book stall.
Book stall, South Bank.
Bubble guy.
Bubble guy, South Bank.
Sweet corn.
Sweet Corn, Taipei.
Transporting gas.
Transporting gas, Taipei.
LA sunset.
Sunset Venice Beach, LA.

Fresh Ubuntu networking and host directories


When I installed ubuntu 20.04.3, I expected the ubuntu networking to Just Work. That was wrong. And apparently, there’s a new network management subsystem to worry about. A quick Google search led me to the Ubuntu docs and thence to create the file /etc/netplan/01-netcfg.yml:

  version: 2
  renderer: networkd
      dhcp4: true

Then this line enabled the interface:

sudo netplan apply

Host directory

I put all my GitHub/GitLab checkouts in ~/workspace, a hangover from BBC days, along with using VMWare Fusion. Although I tend to use docker more these days. I tried mounting it from within VMWare but no luck. A pointer from a chap on Reddit led me to these lines:

mkdir /mnt/hgfs
sudo mount -t fuse.vmhgfs-fuse .host:/ /mnt/hgfs -o allow_other

Or alternatively, add the following to /etc/fstab:

.host:/	/mnt/hgfs    fuse.vmhgfs-fuse	auto,allow_other	0	0

And there we go. Disappointingly everything I wanted didn’t work out of the box, but I got it working in the end.

Cardiff Tourist Stuff

This is an initial list of Cardiff Tourist Stuff. Assume most places here, except the really remote ones, have cafés, and even some of the remote ones have pubs close by. It’s also biased towards the West of Cardiff because that’s where I live. Look on Google maps for interesting green spaces and interesting (hopefully free) things to do.

Do check opening times, things are currently higgledy-piggledy because of the plague. If you want to do many of these, it’s worth getting Cadw or National Trust membership, depending on where you want to go.

Bear in mind you can always do a Google search and get the information I’ve left out, like the official sites for these attractions.

Main Attractions

Cardiff Castle

Cardiff Castle

If you only see one thing in Cardiff, let it be Cardiff castle. The original Norman keep is impressive in itself and it’s well worth climbing up to take in the view over the city. Cardiff uses the castle periodically to host other concerts or Welsh language events. It’s well worth a trip to see.

Cardiff Castle Apartments

Obviously, the castle got taken over by a rich mining family who took it upon themselves to build apartments. These are well worth a guided tour, through bedrooms, offices, sitting areas and at the end, the library which, like many places in Cardiff, has starred in Dr Who. There are also leftover WWII bomb shelters set in the walls that are well worth a look.

The castle and Bute park were given to the City after WWII to avoid death duties and are well worth a look. Again, events take place here from theatre to horticultural events to street food. At the top end are sports fields.

Insole Court

Owned, built and extended by another mining family, this house, this little gem in the Fairwater/Llandaff borders is well worth a visit. You can look in the house into the kitchen and various drawing rooms. You can pay to go upstairs to see a history exhibition. The gardens are lovely and they have a nice allotment at the side.

St. Fagans

St. Fagans, owned by the Earl of Plymouth after whom Plymouth Great Woods is named, is the bane of any Welsh schoolchild’s life. Set in 100 acres, it encompasses Welsh life from Iron age roundhouses to more recent prefabs with a visitor centre and museum rooms packed with Welsh history.

The house/castle itself is worth a viewing and the Italian gardens are pretty. This place is worth a day of anyone’s time. Beautiful gardens, interesting reconstructed buildings and a decent pub in the village.

Cardiff Museum

The main museum in Cardiff is well worth a look, filled with fossils and art and so much more.

Llandaff Cathedral

Llandaff Cathedral in the heart of Llandaff village heading down to the Taff is impressive. It’s been there since 500AD or so, fell into disrepair and was rebuilt into the form we see today. If you can get it on a Cadw open day get the guided tour and have your mind blown. Like much CofE it has military connections. There are cafés in the village. And pubs. One of which is very good.

It also has a Rosetti. With it comes a story.

The Bay


The seat of Welsh democracy, important for making decisions that don’t matter when the real stuff happens in Westminster. Still, it’s how a modern parliament should look.

Norwegian Church Arts Centre

Another historic little building built for sailors back in the day when Cardiff was a throbbing port. It usually has arts and crafts displays and a café obviously.


Another Bute building, this was once the beating heart of the docks. Currently home to some historic exhibitions and the occasional conference.

Cardiff Bay Wetlands Reserve

A little patch of land tucked away in the docks, supposedly home to rare birds and even most recently a seal. I’ve never seen more than pigeons, ducks and swans. Oh, well.


Cefn Onn Park

To the north of Cardiff in Lisvane, straddling the M4 and reassuringly close to Ty Mawr a good pub, this is a lovely garden heading towards Caerphilly founded by Ernest Prosser, Director of the adjacent Rhymney Valley Railway.

It’s lovely when the rhododendrons are out. Also good for collecting golf balls apparently.

Llanishen Reservoir

There’s not a lot to say about this. It’s a reservoir and probably good for walking the dog. I’ve heard mutterings about building a visitor centre and having boating of some sort on it, but we’ll see.

Grangemoor Park, Cardiff

Despite this being practically on my doorstep, I’ve never been. The river Ely here used to be a lot twiddlier but there was a landfill and now it’s an IKEA and a trading estate.

FForest Farm/Radyr Hydro Scheme/Melingriffith Water Pump

Supposedly this is one of the more radioactive areas of Cardiff (there were metalworks here back in the day), this is one of my favourite places in Cardiff, on the Taff. Park your car in Radyr railway station for free, go under the railway and over the Taff then turn left and walk up to the weir.

There are birdwatching hides here and the old canal water pump.

Roath Park

Opened in 1894, it’s well worth a circumnavigation. You can even go boating on it if you’re brave. There’s a café there and some more locally if you fancy a stretch.

Caerau Fort

Set on top of a hill in unromantic Ely, bordered by the A4232 with a commanding view of the City lies an Iron Age hill fort that was in use until Roman times and beyond. Having had Time Team do geophys and had several archaeological digs, it’s recently acquired a visitor’s centre. The story of the church ruins is a sad one.


Castell Coch/Fforest Fawr Car Park

Another Bute property, this time North of the M4 and close to Taff’s Well railway station. There might be a café, but Tongwynlais has one or more pubs and maybe some cafés. Further up the hill is a car park with a nice walk and a sculpture trail.

And the sculpture trail…


Chapter Arts Centre

Previously a secondary school, it became an arts centre showing films, live performances and so on. There’s a decent café with a well-stocked bar. I’ve been to various meetups there. Canton is a throbbing little village.

Thompson’s Park

An oasis at the back of Canton opened to the public in 1891 with ponds, birds and set on two levels. Nice. Take a coffee and peruse.


Penarth Pier Pavilion

The Esplanade, Penarth – Wales, United Kingdom

Penarth is lush. It has a pier, a pavilion with a café and a theatre/cinema. The estuary front is nice for a stroll with shops and cafés.

Not Quite Cardiff

Caerphilly Castle

Another one of South Wales’ great castles, this is well worth a visit. Pay Cadw and go inside and wander around. Caerphilly has a rail station.

Cowbridge Physic Garden, The Butts, Cowbridge CF71 7BD

Cowbridge is a cute little town just a short bus hop or a drive from Cardiff. This picture is of the physic garden, but there are lots more things to see. Cowbridge has a ruined castle and a Waitrose. What more do you need?

Cosmeston Country Park

Cosmeston is a former quarry now turned into lakes and a wildlife refuge. It has a visitor centre with a café (obviously) and is good for a wander.

Dyffryn Gardens

Though dating back to the seventh century it was bought by the wealthy John Cory in 1891 whose son collaborated in making the gardens. The house itself is well worth a look. Again, easy access by bus or car, it’s halfway to Cowbridge.

National Trust – Lanlay

Out in Peterson-super-Ely, there’s very little to say about this except it’s nice to walk there and there are a couple of decent pubs in the village. There are even occasional buses.

Pysgodlyn Mawr

In the vicinity of Hensol or the A48, you can park up and take a nice walk to this fishing lake. Take a thermos and some chocolate.

Tredegar House

Situated towards Newport, this was the home of the Morgan family since the 17C. Lovely rooms, amazing gardens. This one is another National Trust property.

Nash Point

This one is definitely a drive although there might be a weekly bus. Actually hourly to either Llantwit or Bridgend. It’s nice to see the lighthouse buildings, the sheep and maybe clamber down the cliffs to the estuary.

There is potentially more to come!

2021 – Climate change and Welsh independence.

Cefn Onn

2021 has been an odd year.

Despite the supermarkets staying open during the lockdown, we’ve been getting far more food delivered; not just supermarket food but heat-at-home restaurant meals and fruit and veg from Wellocks, suppliers to Michelin-starred restaurants.

That said, two things have been standout in the last 12 months: climate change and Welsh independence.

Climate change podcasts

I don’t know whether it’s that I’ve been listening to many more podcasts and been adding scientists to my Twitter feed (thanks @robinince), such as Helen Czerski, Brian Cox, Alice Roberts, Katie Mack, Mya Rose Craig, Hugh Warwick and podcasts from the likes of 5×15, The Science and Media Museum and many more. It seems to me that scientists and amateurs are getting much noisier about climate change. Of course, it’s turned out that Greta Thunberg was right all along. Also maybe it’s just awareness but there seems to be so MANY more podcasts too.

Living in a country that contributed hugely to the increase of CO2 into the atmosphere helps concentrate the mind. Because of the lockdown, we’ve been taking that car out only once or twice a week and I see an electric car in our future. As it is, we live in a wood-clad “green” flat and are surrounded by trees in a borderline countryside area. Wales is 3rd in the world for recycling. I’m not sure what more we could do for the environment.

Welsh Independence

On the subject of Wales, in the last year, the subject of Welsh independence has started to gain traction. The non-political group yes.cymru have gone from nothing to nearly 20,000 paying members and 50,000 Twitter followers. Welsh Labour and Plaid Cymru supporters are behind the idea too. The electorate polls at 25%-40% in favour.

As I’ve said before, Wales has a GDP per head which puts it on a par with Spain. We’re shy between £5-£10 billion pounds a year but hey, with European support we can claw our way back as Ireland did. I’ve blogged about Wales’ potential before. Also, accounting properly for water, electricity and HS2 would help by a few billion in our favour. Oh, and we pay a disproportionate amount for defence, another £1.9 billion. It doesn’t help their case that we appear to have a bunch of incompetents in Westminster.

So there you have it. These are two things that are now occupying much more news space, internet space and headspace.

MySQL 8.0 oddity – passwords and password policy

These are all things you can find elsewhere but a couple of password issues came as a surprise to me

These are all things you can find elsewhere but a couple of password issues came as a surprise to me when a legacy system got the MySQL 5.7 upgraded to 8.0.

Firstly, password policies are much tighter. There’s a plugin that by default demands an uppercase letter, a number and a punctuation character. That foxes our legacy system whose installer just generates lowercase letters and numbers. Uninstall it.

UNINSTALL COMPONENT 'file://component_validate_password';

Another good one was the the library I was using, and didn’t want to upgrade, didn’t know the default authentication to connect to MySQL. That was easily fixed:

mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'xxxxxx';
Query OK, 0 rows affected (0.03 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

Having gone from a Centos 7 MySQL accidentally to MySQL 8.0 and back again, that’s a world of pain involving the recompiling of the Perl DBD::MySQL and finding the correct .so library.