The family mainframe (by alaric)

I'm in the process of consolidation the home fileserver and the public Internet server - currently two separate bits of hardware - into a single physical device, virtualised to support multiple indepedent machine images. Having a single family mainframe will simplify the management of the complex web of computers and services that support our digital life.

For various reasons, the best place to build such a thing is at the office end of my workshop. Even though it's at the "clean" end, this is still a room that is prone to having fine conductive dust in the air, varying humidity and temperature, and (heaven forbid) a leaking roof. Also, I want a case with extensive room for upgrades, and which makes it easy to replace parts. Having used 1U rack-mounting servers for quite some time, I am sick of highly compact servers that are difficult to work with, requiring extensive dismantling to get to parts.

Clearly, I needed a rather special chassis for this new family mainframe, so I bought a load of steel, picked up my tools, and got to work. I've been working on this for months; I initially cut up the metal at home, then visited a friend's workshop to borrow his pneumatic rivet gun and his MIG welder. Since obtaining my own TIG welder, I've been able to continue at home.

The chassis is nearly structurally complete; this weekend, I've been attaching mounting brackets inside it for everything to attach. All that remains is to finish welding the upper panel on, then the whole thing can be cleaned and galvanised, and the exterior painted. Then I can fix it to the wall and start fitting the electronics and electrical systems!

The first thing I did this weekend was to fit mounting brackets for the processor frame. This is taken from a standard ATX case, and is the base plate with standoffs to mount the motherboard, the frame to attach expansion cards to, and the frame to hold the PSU. This is screwed into the chassis, so that I can use an existing frame (rather than having to make one myself), and so I can replace it if needed. The frame is held in place by two locating pins that fit into holes in it, and then two screws through the upper-left corner (I drilled and tapped holes in the top left bracket), and a little spacer at the top right to stop it from flexing:

With the frame in place, it looks like this:

Next came the expansion frames. I may need to add additional hardware inside the chassis in future, but once it's holding a running server and painted and bolted to the wall, I can't really take it down to weld additional brackets into. So I cut off one-inch lengths of square tube, drilled and tapped a hole in the centre of one side, and welded them to the inside of the chassis. I drilled holes in the ends of strips of steel, so they screw into the pairs of brackets, creating a metal strap that can be removed, things mounted onto (via welding etc), and then screwed back into place, without causing major disruption. There are two - one beneath the process frame, above where the UPS will go; and another right at the top, above the environment management system.

Here's the upper one:

And here's the lower one:

The welds were quite difficult, as I had to reach right down into a corner of the chassis. As such, they were either OK or awful, depending on whether I had to use my right (dominant) or left hand:

I also cut and drilled some mounting flanges, which will be what are used to bolt it to the wall:

When I made the sides of the chassis, I welded angle iron onto them, in order to attach said flanges:

(Note the plasma-cut hole, which will be where a removable plate with sockets for Ethernet, VGA, and USB will go).

The mounting flanges are quite thick (the wall is rough and bumpy, so the chassis needs to be spaced slightly from it), so it was good fun welding them to the much thinner angle iron. I think I did an OK job:

Then I mounted the internal frame for mass storage devices, which goes above the processor frame, below the environment management system. It's a metal plate drilled for lots and lots of 3.5" disk drives, which attaches (with screws) to brackets I welded into place:

With all the internal stuff done, I started to weld the top panel in place, which I'd avoided in order to enable me to get access into the top:

Annoyingly, I ran out of argon while doing the tack welds. A TIG welder without shielding gas is a lot like a plasma cutter, and I burnt a nice hole in a shower of sparks. It's only a small hole, so I'll be able to weld over it when I finish the job off.

Unable to do the final welding, I drilled a hole in the eaves, where clean outside air will be drawn in through a duct into the environment management system:

I also hefted the entire thing up to the wall where it will be mounted, propped it in position, leveled it, and drilled through the holes in the flanges to make the holes that will be used to anchor-bolt it in position:

Mary’s First Day at School (by sarah)

There has been truma - Mary is petrified of school. Jean couldn't wait but Mary...

She has always been clingy. She cried, Alaric was relieved that they didn't have to pry her physically off of him in the end - something that was on the cards. Fortunately I found hello kitty school shoes.

She is very excited about these and agreed to go to school if it meant she could wear them. They have little ears 🙂

She doesn't want to sit still and she want to go climbing, part of her panic was she thought she'd never get to go climbing again. But hello kitty shoes and matching scrunchy and heart buttons on her dress... and a promise that will do dancing when she gets home resulted in reluctant grin.

Of course she does have big sis who was lovely with helping Mary to get ready even with screaming and kicking. It's also Jean's last year of primary school - something that she is not that happy about though she does seem resigned.

Reading Jean (by sarah)

I took Jean to a midnight book launch - I debated weather it was appropriate as she is still 9 though will be ten by the weekend.

But it was the last discworld novel and I phoned Waterstones to check and she was desperate to be a feegle - Tiffany Aching was introduced to her last year by me. She was desperate for people like herself in books - she fell in love with the discworld.

Terry Pratchett got given a place next to Neil Gaiman and RL Stien as favourite authors. Then he died.

Jean went as Tiffany to World Book Day. Jean loves books, Jean often stays up far later than she should reading and gets twitchy if she doesn't have a book to hand.

She announced the Waterstones smelt of new books and though tired did say today she wished we'd stayed longer at the launch, last night we left when she said she wanted to go - she thought they should have read more of the book out.

As we queued she read the last book of Tiffany, The Shepherds Crown, it is also the last book of Terry. She would like it known that she is not reading the book in the above photo but was just looking through it at this point.

The beehives made bee noises - she was impressed and someone gave her a crotchet feegle - she loves it and fell asleep with it last night. We were in the newspaper and there will be more write ups on this 🙂

We don't have the sparkly book as Mummy was a cheap skate and got the £10 tickets. I made the right decision in taking her.

Her feegle outfit was cobbled together from a spock outfit and Rincewind had a tricorder. Don't cross the fandoms!

When asked why she was there she replied with "I like books", she is supposed to be asleep now but is reading.

Workshop progress (by alaric)

Setting up my workshop has been a long battle, thanks to the roof leaking (and everything getting covered in slime mold because of the damp, and ivy growing in through the holes in the roof and shedding sticky sap and dead leaves on everything, and a cat getting in there and pooing on the floor...). Things got rusty, everything got grimy, and stuff was moved around willy-nilly to get it out of the water; and then because everything was in the wrong places, stuff couldn't be put away properly, and so things ended up piled wherever they could go. This was quite distressing for me; by nature, I'm a person who makes things, but I've not been able to do anywhere near as much making as I'd like for years, because I didn't have a nice place to work and didn't have easy access to my equipment.

But, now the roof is fixed, and everything's had about a year to dry out. I've had time to continue painting the floor (it's all now covered in paint, but some parts need a second coat); I've cleaned and tidied;0 and thrown away wood and metal that was too rusted to be of any use, and scraped up the remains of cardboard boxes that had dissolved into fungus, and found and removed all the cat turds and scrubbed the floor with disinfectant; thrown away computer parts that were covered in disturbing fungal blooms; and cleaned and tidied the computer desk. I've made racks to store the wood and metal stocks that are still usable, and put down linoleum under the computer desk so the chair can roll around freely (it didn't do too well on the rough concrete) and I have a nice surface to rest my feet on.

I put up a bracket with hooks for my boiler suit and lab coats, by the door, as the place they used to hang now interferes with the material racks:

I've got the compressor installed under the workbench, rather than kicking around the floor:

And my computer desk is all set up nicely; you can't really see it here, but there's a desktop PC, with a nice set of speakers and an amplifier so I can listen to music - or the audio from my wide-band scanner, seen to the right of the monitor, which picks up the FM broadcast band nicely:

What's next? I still need to assemble some shelving, as there's still stacks of flimsy plastic crates holding a lot of stuff. And put a second coat of paint on some bits of the floor (which will be easy to get to when the crates are gone). And I've got a metal garden waste incinerator I was going to turn into a furnace (but which is far too large, and now I've helped somebody else build a furnace that he lets me use), which I need to find a new home for. And I need to find a place to store the festival trolley, which currently kicks around on the workshop floor (getting in the way and offering plenty of shin-scraping opportunity). And I need to finish the meter-and-a-quarter-high heavy steel server chassis standing in the middle of the room (which will be fixed to the wall next to my computer desk when it's finished).

I want to make a new welding bench, too - my current one is curved, as (in the wildness of youth) I tried to put far more welds between the top surface and the frame than was needed, causing it to warp. This means it's very hard to make flat things, as they don't lie flat when I'm lining them up to weld. And, as it stands on four rather thin angle-steel legs, on a rough concrete floor, it wobbles, so isn't much use to mount a vice on. Speaking of vices, while clearing up in the workshop, I came across this beast:

It's a "leg vice"; the long metal leg should be embedded into the ground to steady it. It's a blacksmith's tool, intended to hold something while it's battered with a hammer; thus the exceptionally sturdy construction. If I bolted it to my current bench, then the bench would fall over if I tried to use it in earnest. We found it in the stable where we lived before, which is the ancestral home of one side of my family; I was given it as I thought I could try and get it working, although I was expecting a long task ahead of me to rebuild seized parts. Thankfully, the screw thread was in perfect condition, and penetrating oil and elbow grease got the joint un-seized, and it's now working nicely. It still needs some rust removal to make it more pleasant to touch and to avoid contaminating everything I clamp with rust, but that won't take long.

I costed up materials to make one with a more rigid frame, bolted to the wall at the back and with two legs at the front so that it wouldn't wobble (and, with the wisdom of experience, only stitch-welding it to the frame, as that'll provide more than enough strength without curving it into a bow); making that will cost a little over sixty pounds (plus welding consumables and electricity). The design includes a mounting point for the leg vice, so that it protrudes out into the room (with the top of the vice level with the top of the bench, so it's not in the way of large things going on the bench), and converting the old bench into a shelf under the new bench to provide much-needed handy storage for grinding tools and welding clamps.

However, having just spent a bunch of money on welding gear I'm not going to be in a position to splash out sixty quid on a welding bench for another month or so (let alone buying metal for other metalwork projects needed around the house, such as a set of railings for the front of the house...). Thankfully, we've found a local scrap metal merchant who are willing to let us rummage around for cheap metal! When we get a chance, I'm going to head over there and see if they have any steel plate for the top and box/angle section for the frame and legs... It'll be nice to have a good welding project to focus on with my new TIG welder!

Learning things (by alaric)

I love learning new things. I'm usually struggling to find new things to learn; the last fun bit of computer science I learnt about was Bloom filters, and they didn't hold my attention for long. The last really fun bit of computer science I learnt about would be content-addressed storage, and I'm still having fun with that, but I can't find any more to learn about it. I'm having to make stuff up myself, which is rewarding in its own way, but much harder work.

Of course, this past week I've been learning TIG welding, which has been awesome. It's been a while since a whole new field of things to learn has opened up to me, and it's nice to work on a new class of physical skills. My routine physical learning is my weekly Krav Maga training, but I crave variety. My lust for learning benefits more from intensive two-week courses than an hour a week for years. I'd love to go and take a proper welding course at a college, but I can't spare the time; I have to practice when I can in the evenings and weekends. I'm getting good at horizontal/flat welds, but I'd like to master vertical and overhead (because if I work on anything large, such as the festival trolley, in my cramped workshop, I often can't rotate everything around to be nice and flat). Also, suspecting that the trouble I was hitting with stick welding is at least partly to do with the limitations of my old cheap AC welder, I want to use my new welder's capability to do nicely regulated DC stick welding and see if I can learn to do good stick welds. And I'd like to get some practice in welding aluminium and stainless steel, as I have applications for both of those.

So that's physical skills sorted, for now. Mentally, I've been learning how antennas work. There's no particular reason for this; it's something that's always puzzled me somewhat, but what's triggered the recent interest was a birthday gift from an old friend, of the ARRL handbook, which goes into some detail; and then meeting an interesting guy at a Cheltenham Hackspace Open Evening who turns out to design broadcast transmission antennas for a living, who answered a load of questions left open by the books. I still want to get a better intuitive grasp of the quantities involved - how many volts and amps appear on an antenna feeder line? What field strengths in volts per meter would you expect to find at what distance from an antenna? Does that relate to a corresponding magnetic field strength in tesla?

I've also been learning Morse code. This is quite interesting. I thought I'd memorise that table of dots and dashes and that'd be that, but it turns out that this technique tends to maroon people at slow morse speeds, as they mentally record a sequence of dots and dashes then mentally look it up in the table to find the letter. To get fast Morse skills, which tend to tend towards one or two characters per second, you need to learn to recognise the sound - "di di dah" - as a letter directly. So I've been using a combination of the Farnsworth and Koch methods to learn Morse; growing my "vocabulary" a letter at a time, and using an enlarged inter-character spacing. The latter is because I was tending to find that I'd hear a character, and write it down, but while I was writing it another would have been and gone, which was confusing. I want to reduce that inter-character gap, but I might wait until I've learnt the entire alphabet via the Koch method, so I can mentally be writing entire words rather than concentrating on a letter at a time - with a reduced alphabet, Morse training tends to involve writing down random gibberish (so far, I know M, K, R, U, S and O; at least the old Nokia SMS beep now makes sense to me... di-di-dit dah-dah di-di-dit!). Again, I have no particular reason to learn Morse - I learnt it as a child, but then forgot it through not using it, which had always faintly irritated me. I've often wondered about using it as a crude interface to tiny embedded computers, although it'd be frustratingly slow for most uses. The usual reason to learn Morse is to do CW amateur radio; that's an idea I've toyed with in the past, but being able to talk to random people over radio holds little appeal (I can talk to random people over the Internet much more cheaply and easily). However, I'd be interested in getting an amateur radio licence as a mental challenge, or as a means to some other project that requires radio communications capabilities, so I might go for a course if one comes up at a good time. I'd like to be able to operate a radio transmitter in an emergency situation, too.

I love to learn things, but I feel sad about not using the skills I pick up. Ok, I don't want to use my Krav skills - they tend to involve hurting people, and are only useful when already under danger of harm coming to me or people I'm protecting, which is nothing to be happy about. But I practice welding because want to make metal things. But by no means do I only learn things when I have a need for them; I learn stuff because it looks interesting and the opportunity arises, then I try and find applications. I've already been excitedly thinking about how aluminium welding will simplify the construction of one of my old back-burner projects - making a hiking staff out of aluminium tubing, that has a stack of lithium-ion batteries inside it at the base, a computer with a keyer in the middle so I can interact with it, and a high-brightness LED lantern on the top so I can have a variety of illumination options (white all around, white forwards only, red all around, etc). I had been working out complex systems of brackets and bolts to hold it all together, but TIG welding it would be much easier, neater, lighter, and stronger. Now, I had considered having a button that could be used to strobe the lights for Morse emergency signalling - and the logical next step was to include a co-axial semiconductor laser in the top that could shine a bright beam for signalling in Morse (and, at a pinch, be used to light fires; you can get 2W laser modules off the shelf these days, and all those lithium ion batteries are going to be able to source a lot of power...). So perhaps I should get a ham licence, and make the staff in sections joined together with insulators, and make it be a two-meter band dipole antenna (which is one meter long) with a CW transceiver inside, so it can also send and receive Morse by radio? That might be fun, and not much extra hardware as it'll already have a decent ARM microprocessor inside.

For now, though, I'd better focus on finishing off my server chassis (which I'm building my welding skills up towards), and make a new welding bench (mine is curved, and wobbles because the floor is uneven and the legs are too weak), and do some metalwork that's needed around the house... I'd like to do some more focussed Lojban study, too; right now I'm just picking up vocabulary by looking for words for things I don't know yet when I need them, but re-reading the reference grammar to remind myself of bits I rarely use would be good!