Sunday, June 18, 2017

The Beacons Way - Walk 4

Walk 4: Garreg Las

[map] [photos]

Monday, 8th May 2017

I arrived at the Llyn y Fan Fach car park at 11:30am. The car park itself is 1km beyond the end of the road leaving the village of Llanddeusant to the east, along a rough track that passes two farms.

Today's walk would be more like a "normal" walk up a hill. Starting from a car park in the valley, I was going to ascend a 635m hill, and then return. Simple.

The car park is quite popular with people walking up to Llyn y Fan Fach, but the walk up Garreg Las is much less well travelled. The car park itself is about 1km off the route of The Beacons Way, so I crossed the river (there's no bridge, but there are plenty of stones in it to aid crossing), and picked up a track that crosses Brest y Fedw and joins on to The Beacons Way route, which I then followed back down to the road. The official route follows the road into the village of Llanddeusant, but on the way out to collect my stone I followed the track to Gorsddu and then a footpath to Blaensawdde (which may be muddy after a wet spell), to emerge on the road below Gellygron. If you don't have pressing business in Llanddeusant you could use this short cut to avoid some road walking (although the views of Picws Du from the road are worth the extra walk). From here I was able to follow the official route back to the summit of Carreg yr Ogof and then to Garreg Las to retrieve my journey-stone...

From the twin Bronze Age cairns on the summit of Garreg Las the route continues along the ridge northwards over greener terrain, until you reach the rocky pavements and quarried outcrops on the summit plateau of Carreg Yr Ogof. There is a trig point here (585m - but not quite at the highest point). If you look at the aerial photos of the summit on Google Maps [link] the jaggies are not digital artifacts, the summit is actually like that.

Picking your way down through the remains of quarrying on the northern slopes of the summit (the entrance to the cave the peak is named for is at the base of a quarry about 100m north of the summit), you join a bridleway that leads down the grassy northern spur of the mountain towards the village of Llanddeusant. You leave the open hillside at a gate onto a green lane, and here is the first Beacons Way waymark we have seen in 17 km.

The green lane descends into the valley, and becomes a rocky track, and then a tarmac road. We cross the river by a bridge (with a commemorative stone marking its opening on 15th April 1929), and then the road climbs to the graveyard and church at Llanddeusant.

Follow the road leaving the village to the east, and after about 2km of quiet road walking the route branches right, back over the river (by a bridge opened on 11th February 1913, but recently refurbished), and then follow a stoney track by the river, which then begins to climb out of the valley up Brest y Fedw. At this point I returned to the car park.

Walk Distance: 15.1 km (9.4 miles), 4.4 hours.
Total: 4 walks, 71.9 km (44.7 miles), 19.2 hours
Beacons Way completed: 34.7 km (21.6 miles), 22.1%.

The next walk will also start from Llyn y Fan Fach Parking.

Saturday, June 17, 2017

The Beacons Way - Walk 3

Walk 3: The Black Mountain

[map] [photos]

The official route on this section was amended in 2016 to avoid the environmentally sensitive area of the summits of Pen-y-clogau, Pen Rhiw-ddu, Garreg Lwyd and Foel Fraith, and now follows a route that contours around the northern slopes of these. I've previously visited the 600m summits of Garreg Lwyd and Foel Fraith, so I was happy to stick to the official route, rather than the "old" route marked on my maps

This part of the route is available in Google StreetView [link].

Wednesday, 3rd May 2017

I arrived at the upper car park on the A4069 by The Black Mountain Quarries at 10am. It was windy, but sunny.

I set off to find my journey-stone. The paths on this section are faint and I started by following a track that left the A road a little to north of the revised path. When this ended I followed faint paths running in the general direction I wanted to go. The route is bounded to the north by a road, and descends to join it at the far end, so you can't go too far wrong (at least in fine weather). The faint paths wind through the remains of quarrying, and eventually lead to a descending green ramp that takes you down to the minor road below, before splitting off on a stony track to join a bridleway, which brings you back to the road, by a parking area and the small disused quarry where I had left my journey-stone. The stone recovered I continued eastwards on The Beacons Way...

I retraced my route along the bridleway, track, road and grassy ramp, and then tried to follow the official route more closely than my outward journey. I'm not sure it was worth it though - it's easier to follow the faint paths on the ground that are going in the right general direction, and eventually you will emerge on the A4069.

After crossing the A road, the route takes a track through the old quarries and passes through the abandoned quarry on the northern spur of Foel Fawr before leaving it behind on a good path that emerges from the extreme eastern end of the quarry. The path contours around the slopes of Foel Fawr and Moel Gornach and gradually gets fainter before joining a path that runs south towards the col between Garreg Lwyd and Foel Fraith. At some point you have to leave this path and strike out eastwards to keep on route, skirting the slopes north of Foel Fraith. I was glad to be crossing this area after a dry spell, as there were signs that the ground could get quite wet.

At this point the official route tells you to aim for a tree in a shakehole, but this is not visible when approaching from the west. I contoured around below the northern slopes of Foel Fraith before ascending the shoulder above Blaen y Cylchau to emerge in a small quarry. I stopped on a table sized block to have a break where the grass was scattered with daisies.

Setting off again I dropped down the pools at the col between Foel Fraith and the southern end of the ridge of Garreg Las, to rejoin the "old" route marked on my maps. Although I'm only 1h15m out from where I parked, the area feels quite remote. Just under a mile to the south west, across the Afon Twrch, lies Tyle Garw - reputedly the most remote summit in mainland Wales.

The eastern slopes of Garreg Las are a jumble of weathered gritstone boulders, but a small path winds up through them to the southern end of the ridge, and then faint paths run north through the rocks and crossing pavements to eventually arrive at the twin Bronze Age cairns at the summit of Garreg Las. The highest point on The Beacons Way so far (and a new 600m Welsh summit for my ticklist).

I left my journey-stone under one of the many thousands of rocks on the plateau, and hoped I would be able to find it again when I returned, then retraced my steps back to the parking area by the quarries on the A4069.

Walk Distance: 20.6 km (12.8 miles), 5.5 hours.
Total: 3 walks, 56.8 km (35.3 miles), 14.8 hours.
Beacons Way completed: 27.7 km (17.2 miles), 17.7%.

The next walk will start from Llyn y Fan Fach car park, beyond the village of Llanddeusant.

Saturday, May 20, 2017

The Beacons Way - Walk 2

Walk 2: Carreg Cennen Castle

[map] [photos]

Sunday, 23rd April 2017

I arrived at the Car Park at Carreg Cennen Castle at 9:50am. My first objective was to walk back along the route towards Bethlehem to find my journey-stone. This took me about 30 minutes, but the stone was still there. And so The Beacons Way continues...

The route passes through fields towards the farm of Cilmaenllwyd, and detours around to the west of the farm by a well marked route on a well made track that doesn't appear on the official route mapping, or on my OS maps. Either way you end up at Castle View Farm, from where you follow the road to the car park at Carreg Cennen Castle, with the castle itself looming on the skyline perched atop a green hill.

Just beyond the car park there is a café/shop and you can pay to visit the castle ruins (dogs allowed on leads), but that wasn't my reason for being here today (although apparently there is an interesting cave that provides the castle with access to a well, which can be explored with a torch). Instead the path skirts below the castle mound and then descends through Coed y Castell wood to a footbridge over the Afon Cennen.

The route crosses another footbridge and then uphill on a stony track to join a farm track which cuts diagonally across the slope. Here you see why the castle was positioned where it is. From the north it appears to be at the top of small green hill, but from the south you can see that it is perched on the edge of a 300ft limestone cliff.

We exit the farmland at the entrance to Brondai farm and emerge onto a tiny road (with grass growing in the middle) that runs through the open hillside of The Black Mountain. As we have entered Open Access Land the waymarks disappear and we're on our own when it comes to route finding.

The little road winds through a landscape of pillow mounds (marked on the map as Beddau'r Derwyddon, which means Druid's Graves, but they are the remains of medieval warrens used for rabbit farming). Just beyond a cattle grid, we leave the road by the remains of ancient enclosures. There is a faint path which contours it's way across the hillside, avoiding shake holes. In the middle section it's easy to lose the path, but it becomes better defined as it crosses a stony stream-bed below a pronounced gully on the hillside. The path becomes a track which joins the minor road.

Although you are only navigating by yourself for half an hour, it is probably best to tackle this section where there is good visibility (and if you can manage it, after a prolonged dry spell).

I left my journey-stone in a disused quarry by the road, then retraced the path to Carreg Cennen Castle (where the car park had filled up).

Walk Distance: 17.8 km (11.0 miles), 4.4 hours.
Total: 2 walks, 36.2 km (22.5 miles), 9.3 hours.
Beacons Way completed: 17.9 km (11.1 miles), 11.4%.

The next walk will start from the Mountain Road Car Park on the A4069 by Herbert's Quarry.

Sunday, May 7, 2017

The Beacons Way - Walk 1

I've decided to do The Beacons Way - a hundred mile walk across the Brecon Beacons National Park.

I'm doing the walk in the opposite direction (from Bethlehem to The Skirrid) to most descriptions for a variety of reasons. Partly because I know The Black Mountain least, so I wanted to explore that area first, partly because as I progress along the route I will be getting closer to home, and also because last year, when walking on Hatterall Hill it struck me what an enticing finishing post The Skirrid makes. And surely Bethlehem is a place of beginnings.

Also, to make logistics easier, I have decided to split the walk into several manageable segments that will allow me to do walks of about about 10 miles (16 km) from a single start point with a dog. Mostly this means doing the route one way, and then retracing it in the opposite direction to return to the chosen parking spot. Which means I'll end up doing the route twice, once in each direction, and turns a walk that is just under 100 miles into a walk that is just under 200 miles.

Any of my walking chums who would like to join me for any of the walks are welcome to get in touch.

Walk 1: Carn Goch

[map] [photos]

Saturday, 8th April 2017

I arrived at the small car park below Carn Goch just before noon. At Carn Goch there are two Iron Age hill forts, the larger of the two is reputed to be the largest Iron Age fort in Wales. But before I visit them I have to return, back down the road to Bethlehem, to find the carved oak bench that marks the start of The Beacons Way (for me, in most descriptions this bench is actually the end of The Beacons Way). I took a photo of myself, Teasel and my "journey stone" (this is a marked pebble, which I will carry along The Beacons Way and hide at the end of each walk to ensure it makes a continuous unbroken journey from the start to the end of the route) on the bench, and then set off at 12:30pm.

The route follows the road out of Bethlehem, along a farm track, and across some (slightly soggy in places) fields to come out on another road by a chapel. We then follow this road to the car park at Carn Goch. Here the route enters Open Access land. The route is way-marked on footpaths across farm land, but where it crosses open country you are on your own, so it's best to know where the route goes on a map and how to follow it on the ground. (Note that the official route, created in 2005, was revised in 2016, and so differs from the route given on some OS maps. I'm following the route as given on the website).

The route follows the ridge of Carn Goch, passing a stone monument to Gwynfor Evans (the first Plaid Cymru MP) erected in 2006, and three stone benches, before arriving at the smaller of the two Iron Age forts. Drop down to the gap between the two forts (here I had my lunch in the shade of a small tree), and then ascend to the larger fort encircled the remains of its massive stone wall. Leave the fort at it's north-eastern edge and follow a path down to the minor road below, which passes Garn-wen and becomes an enclosed track traverses diagonally the slope below Trichrug.

Reaching Bwlch y Gors, the way-marked path crosses a very wet boggy area to get to a stile, but it is drier to continue along the track to a gate, and then follow a different track on the other side of a wall to arrive back at the stile. The route follows the edge of a field, and then enters the wood of Carreglwyd. A good path through the wood drops down steeply to a forest track and follows this to exit the west side of the wood, where it becomes a track along the edge of some fields (which are wet in places) below the ridge of Carn Powell.

The footpath emerges at a crossroads and follows the road toward Trapp, past a couple of forestry plantations, the second one marked as Helgwm on the map. It was here that I planned to end the first leg of my walk, but I didn't find anywhere obvious to leave my journey-stone, and the onward path seemed to cross a marshy field, so I thought it best to get that out of the way, so I set out across it, and as we reached the far side the way became drier. Crossing a ladder stile brought us into a drier field, containing the remains of an old quarry, and at the far side of this field, by the stile into the next field I left my journey-stone in a pile of stones, and returned back to the Carn Goch car park.

Walk Distance: 18.4 km (11.5 miles), 4.9 hours.
Total: 1 walk, 18.4 km (11.5 miles), 4.9 hours.
Beacons Way completed: 9.1 km (5.7 miles), 5.8%.

The next walk will start from Carreg Cennen Castle.

Tuesday, December 8, 2015

Ada Lovelace, Charles Babbage and the First Computer Program

The 10th of December 2015 will be the 200th Anniversary of the birth of Ada Lovelace.

In 1842, in Italy, Charles Babbage gave his only public lecture on The Analytical Engine. The lecture was transcribed, in French, by an Italian military engineer. Ada translated the transcript into English, and subsequently Babbage suggested she add her own commentary on the transcript.

This she did, and in 1843 she published the translation of the lecture, along with a copious set of her own notes (that were twice as long as the translation of the lecture). In one of these notes is a diagram that is considered to be the earliest published computer program.

I was intrigued as to what this program looked like, and how we could run it today. So I explored this in the following three articles:

Part 1: Starting with the diagram, I wrote my own version of the algorithm in a modern programming language (Python). Then I wrote a transliteration of the diagram (also in Python) that could be run directly, and produced an "assembly language" listing that corresponds to the cards that would be used to program the Analytical Engine (if it had been built).

Part 2: I wrote an emulator for the Analytical Engine, which could run the assembly language program produced in Part 1.

Part 3: I code up an assembler that reads a mnemonic format corresponding directly to the diagram in Ada's note and produces the appropriate sequence of cards needed to program the Analytical Engine Emulator from Part 2. Finally we produce a program that corresponds directly to Ada's diagram and runs on the Analytical Engine Emulator.

The end result is an emulator for the Analytical Engine in Python that lets you run Ada's program to generate Bernoulli Numbers, or you can write your own programs for it.

Thursday, October 22, 2015

Downgrading a Package in MacPorts

MacPorts installed a new version of XEmacs and it broke things. So instead of fixing it I just went back to the previous version.

Here's how I did it:

  1. Create a local repository in ~/lib/macports/local:

    % mkdir ~/lib/macports/local

  2. Add the local repository to /opt/local/etc/macports/sources.conf:


  3. Find the previous revision of XEmacs:

    % svn log

    It's r141410.

  4. Check it out (into ~/lib/macports/local):

    % svn co --revision r141410 editors/xemacs/

  5. Run portindex on the local repository:

    % portindex ~/lib/macports/local

    It should report: "Ports successfully parsed: 1"

  6. Now port list xemacs shows both versions.

    xemacs  @21.4.22  editors/xemacs
    xemacs  @21.5.16  editors/xemacs

  7. Install the local version

    # port install xemacs @21.4.22

That's it.

Tuesday, December 16, 2014

Cabin Pressure Advent Calendar

Inspired by this site, I've been listening to an episode of Cabin Pressure every day since 28th November, so that I'm ready for the final episode ("Zürich") to be broadcast in two parts on 23rd and 24th December (6:30pm, BBC Radio 4).

Of course there are many brilliant lines in each episode, but here are my particular favourites (to be updated each day):

Abu Dhabi

Douglas: Again, I fear you flatter my knowledge of cat pathology.


Martin: Where's Carolyn?
Douglas: Sharpening her teeth.
Arthur: Brushing.
Douglas: Brushing her teeth. Yes, sorry.
Arthur: I didn’t know you for very long, Mr. Leeman, but I'll always remember you as ... as a shouty man. You loved to shout; shout and smoke – those were your twin passions. And so, in a way, I suppose you died doing what you loved: shouting and smoking, and covered in foam. I don't know if you liked that. You probably didn’t. 


Arthur: The thing is, is it unprofessional to tell a passenger that you once made a collage of her face out of pasta shapes?
Douglas: Hmm, I really don’t know.
Arthur: You see, part of me thinks ...
Douglas: Oh, I’m sorry. Did I say "know"? I meant "care". I don’t really care.


Martin: Right. Well, I've made my point anyway.
Jutteau: You've made it. I 'ave disagreed with it. I'm going to do nothing about it.


Birling: (To the tune of "Cwm Rhondda") Bread of heaven, bread of heaven, yum yum-yum-yum-yum-yum-yum! Bread of heaven, here I come!


Martin: Well, we can sit in the plane, or we can sit in the rain.
Douglas: Can't we sit in the car or sit in a bar?
Martin: Douglas.
Douglas: I'm sorry, I thought we were staging an impromptu tribute to Dr. Seuss.


Carolyn: This is my son Arthur, and I promise you he couldn't hurt a fly...
Arthur: Thanks Mum!
Carolyn: ... because the fly would outwit him.


Carolyn: Oh, my goodness! Well, you certainly have surprised me with a cake.
Douglas: Thought we might.
Carolyn: Perhaps what's most surprising about it is that it's a fishcake.


Martin: I've had one. One is the correct dosage of quiche for the adult human male.


Douglas: Carolyn, you're really not helping.
Carolyn: I know! I'm not trying to. 

Kuala Lumpur

Carolyn: (Pretending to be a passenger) It means I'm gluten-intolerant.
Arthur: Well, I'll, I'll try not to be too gluten annoying.


Martin: Is this the famous Admiral's pie?
Arthur: Yep.
Douglas: The admiral's not a fussy eater, is he?


Douglas: You took my Petrus '05, and you ... mulled it?


Martin: (cabin address) So, we should be taking off in ... about an hour.
Carolyn: (shouting from the cabin) Martin! What have you done now?
Martin: (cabin address) So sorry about the delay – which is not, incidentally, because of anything I've done now.

Ottery St Mary

Arthur: Well, I was the one who thought of putting an otter in the fridge!


Arthur: Can I tell you in my own words?
Douglas: Who else's words had you planned to use? Winston Churchill's?


Arthur: Bears! Bears, bears, bears, bears! Polar bears! Look! On the ground.
Douglas: Of all places!


Douglas: I'm not being childish, but if I can't go to the Grand Prix I'm not being in the film.

St Petersburg

Arthur: Here you are, Skip. Nice hot cup of coffee.
Martin: Oh. (takes a sip) Ugh! It's cold!
Arthur: Nice cup of coffee.
Martin: It's horrible!
Arthur: Cup of coffee.
Martin: I'm not even sure it is coffee.
Arthur: Cup. 


Douglas: It's been a topsy-turvy sort of Birling Day, hasn't it? We flew away from the rugby; Mr. Birling got soberer and soberer; and Arthur ruined everything with his knowledge and erudition.


Arthur: You know, between the dames and the horses, sometimes I don't even know why I put my hat on.


Herc: I didn't realise you were in such thrall to royalty.
Carolyn: I don't give two hoots for royalty!
Herc: I think you give four or five hoots.
Carolyn: I do not.
Herc: And not just any old hoots: low and reverent hoots, like an owl at a Jubilee.


Arthur: I've brought Boggle, Guess Who?, Connect Four and Kerplunk.
Wendy: Are they ... rappers?


Arthur: It's not "Have a banana", it's "'ave a banana!" - like the song!
Carolyn: What song?
Arthur: The "'ave a banana!" song. I don't really know it, except for one bit.
Douglas: (sings) Let's all go down the Strand.
Arthur: Are you alright, Douglas?


Martin: ... but it's not brilliant for anyone else, is it?
Arthur: Oh, don't say that, Skip. The Swiss guys'll get used to you!
Martin: I'm like a capsized duck. 

Zurich (Part 1)

Theresa: Was that the time Martin landed with one engine?
Carolyn: That's right.
Theresa: Yes, he's often told me that story.
Martin: Not that often.
Theresa: Quite often.

Zurich (Part 2)

Arthur: Don't worry Skip - Douglas always saves us. Like remembering the brake pads.
Martin: That was me!
Arthur: Well, yeah, but you were being Douglas. 

OK. Bye.