Posts by J.G.Harston 3725 publicly visible posts • joined 4 Mar 2009
Most of the Hong Hong Stock Exchange was run on Beebs, and the Hong Kong Harbour Authority modelled water flows using a network of Beebs connected to monitoring equipment. And then all those factories where, under half an inch of oil, grime, and metal shavings, was a Beeb controlling the processes.
I had one job where I was brought in after the senior engineer had been fired, taking his knowledge with him. They had recruited a replacement, but he couldn't start for a couple of months. Nothing was documented, everything was in his head. I spent the time getting everything documented with backup printouts, and was confident that J. Random Stranger could walk in and take over and know how the system worked.
I have a vague memory of some old TV drama where this was exactly the denument. I'm sure it was black&white, and it involved bank staff and mechanical adding machines. Everybody was kept behind to find who had been diddling the accounts. At the last point, one character frustratedly said "It's a simple as two" punches in 2 on the calculator "plus two" punches in plus 2 and cranks the handle - which displays 5.
More than that, you're thinking of transactions in a universe that functions differently to the one we live in. This is a well-known long-know problem, there is no way to know a message has not arrved at its destination. It's variously called The Two Generals Problem, or Caesar's Generals Problem. yes, understanding it is that old.
I wrote up this almost four years ago. While it is likely to not be the exact problem with Horizon, it is a near enough description to explain the problems:
In my understanding, what it was was:
Correct functioning:
PO sends ‘credit £x’
HQ receives ‘credit £x’
HQ credits account
HQ sends ‘acknowledge credit £x’
PO receives ‘acknowledge credit £x’
PO removes item from queue
Failed functioning:
PO sends ‘credit £x’
HQ receives ‘credit £x’
HQ credits account
HQ sends ‘acknowledge credit £x’
PO /doesn’t/ receive acknowledge
PO retries
PO sends ‘credit £x’
HQ receives ‘credit £x’
HQ credits account
HQ sends ‘acknowledge credit £x’
PO receives ‘acknowledge credit £x’
PO removes item from queue
PO now has one ‘credit £x’ recorded, but HQ has two ‘credit £x’ recorded.
It’s a classic network transaction confirmation problem. In fact, a Networking 001 problem. It’s not even undergraduate level concepts. How do you know where a failed message has failed? Has the message to HQ failed, or has the acknowledge failed? The solution is to either use a sequence chain, or *not* transfer ‘change’ messages, but transfer ‘updated balance’ messages:
PO sends ‘account balance is £x’
HQ receives ‘account balance is £x’
HQ updates account
HQ sends ‘acknowledge account balance is £x’
PO /doesn’t/ receive acknowledge
PO retries
PO sends ‘account balance is £x’
HQ receives ‘account balance is £x’
HQ updates account
HQ sends ‘acknowledge account balance is £x’
PO receives ‘acknowledge balance is £x’
PO removes item from queue
This results in the PO recording a balance update to £x and HQ recording a balance update to £x.
Of course, this has it’s own problems of multiple access/single resource (what happens if somebody else does a ‘balance is X’ between your retries) but is solid if you have exclusive access during the whole transaction. To do that you’d wrap it in ‘open for exclusive access’/’close for exclusive access’.
Tom Scott described it quite well here where it happened with ordering pizzas.
Not just Ed.
Margaret Beckett 1997 to 1998
Peter Mandelson 1998 to 1998
Stephen Byers 1998 to 2001
Patricia Hewitt 2001 to 2005
Alan Johnson 2005 to 2006
Alistair Darling 2006 to 2007
Pat McFadden 2007 to 2009
John Hutton 2007 to 2008
Peter Mandelson 2008 to 2009
Edward Davey 2010 to 2012
Norman Lamb 2012 to 2012
Jo Swinson 2012 to 2013
Jenny Willott 2013 to 2014
Jo Swinson 2014 to 2015
Anna Soubry 2015 to 2016
Margot James 2016 to 2018
Andrew Griffiths 2018 to 2018
Kelly Tolhurst 2018 to 2020
Paul Scully 2020 to 2022
Jane Hunt 2022 to 2022
Dean Russell 2022 to 2022
Kevin Hollinrake 2022
All have questions to answer.
That reminds me of the f***wits who don't understand "display sized to X" is not the same as "resize to X".
Last week I got an email with about three lines saying (paraphrased) "Thanks for the update. Bob." I wondered why it took ten seconds to open. I glanced at the inbox listing and wondered why it said (252M) at the end of the line. How TF is a three-line email 252M? Then I thought....uh oh.... There's a little image under the signiture line. Yep. Menu -> Display image. It was three times the width of my monitor, set to display in the email as 160 pixels wide.
Almost a decade ago I had a contract replacing post office counter hardware, and digging out my backups, the installation documentation is full of:
"stay on the phone until the Network Operations Centre remotely configures...."
"If the NOC cannot remotely resolve the issue, escalate to...."
It's not in the documentation I've dug out, but the final test was (along the lines of):
Test the system by doing a dummy transaction. Print a system balance. Enter a transaction using "VOID ITEM" as the product. When completed, void the transaction by doing X, Y, Z... Print a system balance to confirm it has reverted to the previous balance. Note in sign-off sheet.
it's not not knowing about Open Office or Libre Office, but not being *able* to obtain Open Office or Libre Office. I've worked on some installations where any connection to the outside would was severed and without WordPad being already on the machine it was impossible to read anything other than plain text. Hell, I've had to (attempt to) do system admin on installations where my only access was a *user* account.
"they can be difficult to find depending on how the developer chose to list the program."
And what the **** has where the developer chosen to put something got to do with anything. It's *YOUR* Start Menu, put it where *YOU* want it.
All my office tools go in Programs -> Office regardless of who wrote them, all my programming tools go in Programs -> Programming regardless of who wrote them, all my disk tools go in Programs -> Disk&File regardless of who wrote them, all my Internet apps go in Programs -> Internet regardless of who wrote them.
You you ever tried taking a 90 degree corner into a side street at 70mph? The Porche driver attempting that would be continuing along the A### at 65mph in a pile of scrap metal. Additionally, as stated in the above extract, you don't have 20mph zones immediately off 70mph roads, as that is not "a suitable area [...] where the roads already make it difficult to exceed 20mph"
but hey, the local scrotes will have unplugged it long before morning
There are even telly ads running at the moment which make a feature of somebody wandering up to an EV charger and unpluggng the person using it. Is this *really* the image they want to project? EV drivers are selfish sociopathic morons who cannot comprehend the existence of other people and their needs.
Maybe it's stealth advertising to turn people off EVs.
The only enforcement that works is highway engineering, not humans. Build the road infrastructure so that it is impossible to drive faster than 20mph.
A section from a paper I wrote last year:
When demarcating an area for a 20mph limit, Highways and Police want to see an area
which is clearly defined, and has a small number of entry/exit roads. This makes it
easier for clear "gateway" signage making it clear to motorists and pedestians that
they are in the restricted area. So, for instance, #### ######## has three access roads:
####### Road, ######## Avenue, and ######## Avenue. That would make it easy for
clear signage at the three access roads. Similarly, ###### #### has two access roads,
each end of ###### ####, and ###### with each end of ###### Road. ###### is even
better with a single access.
The Police regularly remind people that they rarely have the resources to enforce
signed 20mph signs, and they prefer speed restrictions to be implemented with
road engineering works. With this in mind, a suitable area would be where the roads
already make it difficult to exceed 20mph, either because of narrowness, bends, or
already existing road humps and/or chicanes. #### ######## is an area where the
topology already contributes to restricting speed, with a lot of corners and
junctions to navigate through. Similarly, it is difficult to get past a brisk
walking pace through ###### Park.
A lot of councils are putting up 20MPH signs before they've passed the required laws, so they're spray-painted to mask them. As soon as the legislation is passed, they just have to clean the paint off.
That makes no sense. The "legislation" is to make 20MPH the *UNSIGNED* default. The current unsigned default is 30MPH, so if you want a 20MPH zone you simply put up a 20MPH signage (after the neccessary orders). Spray-painting 20MPH signs would be what you would do *AFTER* the legislation comes in, as then they would be erroneously superfluous.
What you would do is erect obscured *30*MPH signs in the areas that are currently unsigned default 30, and would become unsigned default 20 after the legislation is passed, and then remove the paint afterwards to remove them from the new unsigned default 20 zone, and make them signed *30*.
"The Luddites stood for quality goods produced by skilled workers paid a fair wage."
But I want just-good-enough goods, and use the surplus to more for *my* benefit. How *DARE* Luddites force me to consume what they force me to at their price. My resources are my resources to use to consume what ****I**** want to, not what they would force me to. Hand-crafted artisan loaf produced by skilled workers at five quid? **** off. Machine produced load at £1 thank you very much, I'll use the remaining four quid on more of what *I* want.
As with in a gold rush you make money by selling mining equipment, you make money on the stock market by selling trading systems. I used to work for a data and trading equipment supplier for the HK Stock Exchange. They had so many data lines coming into the office that HK Telecom installed an exchange on the next floor for our exclusive use. ;)
Even without the Tube the BBC has multiprocessing. A rich interupt-driven background environment, almost everything a foreground application needs to do is "fire and forget". Send a byte to the serial driver, it gets plonked in a buffer and control goes straight back to the caller. An interupt will be along to deal with it. Want some serial input? Ask to look at the serial input buffer. The background deals with all the hardware. Send a network packet? Pass a pointer to the networking system, go back to work, interupts feed it to the wire while you're doing something else. Sound? Plonk it in a buffer. Printer? Plonk it in a buffer. Hand it over, get on with your work, gets done in the background.
Going from that environment to the PC in the late '80s was staggering. "How on earth is this pile of crap so much crappier than what I started on eight years ago? You mean *I* have to frob the serial hardware *MYSELF*, like people?"
"Then those were improved, usually completely ignoring all the lessons learned in the previous generation, until the new generation gets replaced in turn by something smaller, cheaper, and far more stupid."
Every few years I find another generation of programmers strugging with serial comms, to which the answer is always "FLOW CONTROL!!!!!". How in earth are we in a universe where simple, basic, fundamental parts of our engineering craft is so completely omitted from people's learning, again and again and again?
Take the Post Office Horizon thing. Validating two-way message communication has been a known problem since CAESAR! I picked up an understanding of it in the early '80s before I'd even written a byte of networking code. Yet, people were writing, AND BEING PAID for omitting a fundamental piece of architectural structure, just like omitting cement from concrete, and not even being aware of the concept of needing cement in the first place.
No, it will be like phONEday. "Ah, 2025 is when they will start telling us they will be starting to turn stuff off". I was repeatedly banging my head against a wall back then repeatedly telling people NO!!!!! Date X is when they will FINISH TURNING THE OLD STUFF OFF, not when they start turning the new stuff on.
I saw way too many documents saying things like "From (date) please use (new dialling code). We don't know when the old code will be turned off, we presume it will overlap for some time after that date." NO!!!!! You *DO* know when the old code will be turned off. ON (DATE)!!!! You should be using the new code *NOW* to ensure you are no longer using it in plenty of time *BEFORE* (date).
For some reason all too many people thought "old X will stop on (date)" meant "you *must* *not* use new Y until after (date)".
Yes, we've gone all the way back to the 1880s where you had to have half a dozen telephones if you wanted to be able to contact all your contacts as they were subscribers to a dozen different 'phone companies. I can write an email with Thunderbird and it is receivable by somebody using Outlook, Claws, K9, Pegasus, whatever. I can make a phone call from my Virgin phone and connect to somebody using EE, BT, KCC, NTT, AT&T, HKT, whatever. I should be able to send a message with LINE and the recipient should be able to receive it with WotsApp and forward it to somebody using Telegram.
The usefulness of Google Groups was it was possible to dip into when on Somebody Else's Computer - library, work, friends, etc. without needing a news client. A few months ago I tried a no-install run-only client on a USB drive in the library, and port 119 was blocked, so even that route is blocked off. And last time I tried to run a file from a USB drive on a work computer, it deleted it. Everything is becoming walled gardens surrounded by electric fences and guards with cattle prods.
It's often too late to convince women to enter STEM fields by the time they graduate.
I've had this rant before. It's too late to convince ANYBODY to enter STEM fields by the time they are APPLYING TO UNIVERSITY. For engineering subjects, if you haven't already been fiddling in it for at least half a decade BEFORE UNIVERSITY, it's too late. If you're going into electronic engineering, you need to have been building your own radios at 12 years old. If going into mechanical engineering, you need to have been stripping down motorbikes at 12 year old. If going into computer engineering, you need to have been constructing your own computer hardware and/or software at 12 years old. Entrance to university is too late to be picking up an engineering subject.
There are other subjects like this. Spend your teens mucking out stables on the way to going into vetinary care. Spend your teens growing plants on the way to going into horticulture. Spend your teens writing (probably very bad) fiction and poetry on the way to doing creative writing-y stuff. These are subjects where it is an expression of innate skill, interest, and aptitude, applying to university is too late to be thinking "I wonder what I'm interested in."
just what is meant by "computing"
Exactly. To the vast majority of people - particularly noisy people, morons, and policy makers (but I repeat myself), "computing" is "anything electronic". So, that's everything from the IT Labourer changing printer cartridges to the theoretical algorthmic researcher. It's the same as saying "working in schools" covering cleaning the toilets to financial director of a 3,500-pupil academy. "I've got you a schools job. Waddya mean, you don't want to clean toilets? IT'S A SCHOOLS JOB! YOU SAID YOU WANTED A SCHOOLS JOB."
Oooo, I loved our Riso when I worked doing leaflet printing. Got into a good regular rythmn passing the output onto the drying desk, and then into the folding machine. kerthunk kerthunk kerthunk kerthunk :)
And the people coming in "oo, can I just use the photocopier..." Ok, that's 5 quid please, that's a 5,000 master you've just used.
I remember in 6th form on an open day at York University they proudly showed us the washing-machine-sized hard drives in the computer department. "That's ***TEN*** megabytes there". I was gobsmacked. Back at school the server had 200 megabytes in a case the size of a shoe box.
People complain about AI being biased due to the biased information it gets trained on, yet here we are people actually *DEMANDING* that AI be biased by limiting what it is trained on. If AI is only trained on content that people have chosen to sell it, then it will be biased to content that people have chosen to sell it.
I was a school governor and there was a yearly site check that was done in late July, which was simple because you've got the school year that imposes its schedule on you and prevents you forgetting.
Similarly, I check all my smoke detectors when the gas appliances are checked annually. The plumbers know when their certificate runs out and pesters reminds me, so again a schedule that doesn't get forgotten.
When I do my tax return I have a bunch of stuff I do at the same time - and while I may put it off for months, there is a hard deadline each year so over the long term the yearly tasks get done.
I check my car tyres every time I get petrol. I check various other things at the annual MOT. External prompting ensures it gets done.
But if it is something that is independent of anything prodding you to do, it will get forgotten about because that's how the human brain works. If the DVLA didn't tell me my car tax was about to expire, or the insurance company tell me the insurance was about to expire, I'd never remember to pay it.
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