* Posts by Simon Harris

2773 publicly visible posts • joined 1 Mar 2007

This whopping 16-bit computer processor is being built by hand, transistor by transistor

Simon Harris

Re: Totally brilliant, but not exactly "transistor by transistor"

All the logic that does computation is done transistor by transistor.

The only place that LSI has been used is on the 7-segment display boards - apparently it was too complex decoding hex (octal?) digits to a 7-segment display in transistors for something that is there 'for debugging purposes'. To quote Newman...

"I spent a bit of time trying to work out how to do the 7-segment display using discrete transistors but the answer is vast. Really, really big. It would have near doubled the size of the thing and the circuitry for the display would have obscured the circuitry for the processor which would have undermined what I was trying to do. As its only for debug and not proper function I went for chips. This is definitely NOT cheating, it is just for debug. It is irritating though."

Simon Harris

Re: Quite a challenge

Here is an interesting piece on how the 6502 decodes instructions:

http://www.pagetable.com/?p=39

It explains how the instruction decode causes undefined opcodes to do the strange things that they do.

Simon Harris

Re: Beat the clock

He found out that a state transition takes about 1uS to propagate through a gate, and to work right through an adder was about 40uS (change on the LSB through to carry out) - it's this that sets the maximum clock frequency.

Simon Harris

Re: I wish I could help out

"I wonder if you can step-by-step the clock for debugging?"

Apparently, yes.

http://megaprocessor.com/VitalStatistics.html

Simon Harris

You might want to read the creator's web pages, particularly this one...

http://megaprocessor.com/progress.html

where he explains the limitation.

Simon Harris

Re: That's cheating - he should do it in Minecraft.

Minecraft? It would be cheating to do it as a simulation.

Why not get back to reality and do it with Lego?

Simon Harris

Re: Kudos and beer

If you're still interested LittleDiode claim to have some of the HC variety in stock.

Simon Harris

Re: 3,500 LEDs

The memory appears to be an array of bistable flip-flops with a density of approximately 1 bit per square inch.

Simon Harris

If you look at his website, where the pictures are bigger, you'll see there are PCBs for the modules, mostly linked together via ribbon cable terminated with IDC connectors.

Simon Harris

I'm waiting for the FORTRAN compiler.

Simon Harris

Drum storage...

Will he be 'repurposing' the washing machine?

Simon Harris

"Would be better using discrete logic surely?"

Nothing wrong with doing it with discrete logic, or valves for that matter, if that's your own preference - the challenge of building it with discrete transistors is his.

Simon Harris

Re: For fuck's sake.

Maybe his oscillator is off by 2.4%

Simon Harris

... on an ASR33 at 110 baud.

Sharing Economy latest: Women's breast milk is the new 'liquid gold' of the internet

Simon Harris

Liquid gold of the internet.

I thought Bitcoin was supposed to be modelled on gold and gold mining, and was therefore the gold of the internet.

If breast milk is usurping it as the new gold of the internet, I vote we name it Titcoin.

Vauxhall VXR8: You know when you've been tangoed

Simon Harris

Re: James Bond would be proud...

Apparently the gps is programmed to avoid escape routes with low bridges.

INTERNET of BOOBS: Scorching French lass reveals networked bikini

Simon Harris

Re: "the e-kini will record the temperature"

"WTF does temperature have to do with UV exposure?"

And anyway, if the sensor is stuck in the bikini won't it be measuring body temperature?

I know skin temperature is generally a bit below core temperature, and varies from place to place, so I'll put myself forward for conducting temperature measuring experiments on areas of the body normally in contact with the bikini. Purely in the name of science and sensor calibration of course :)

Simon Harris

Re: The bikini isn't French

Looks like the Romans invented skateboards too...

https://en.wikipedia.org/wiki/Villa_Romana_del_Casale#/media/File:Villa_romana_skier.jpg

Simon Harris

Re: Temperature?

And what about those foolish enough to get their kit off at the top of a mountain? Plenty of sunlight but a bit parky apparently!

Teaching kids to code is self-defence, not a vocational skill

Simon Harris
Pint

Maybe there are a lot of big cracks that need painting over.

Does this come in megalitres too? ---------->

Simon Harris

"It's a bit like the difference between teaching somebody how to use a calculator, (useful but you only learn how to get the result), and teaching them how to use a slide-rule, (they also learn how the mathematics works in general and can apply it to other things)."

I never used a slide rule, but I was taught how to use 4-figure tables, so I guess the same principle applies. However, before I had a calculator or table book, I'd already been taught properly how to do arithmetic by hand. I believe there is a difference between teaching someone how to press the buttons on a calculator and teaching how to use the calculator properly with a mental check of whether its answer looks about right.

Simon Harris

Although muddling away manually on a problem a few times with different data may give the student the ability to recognise when something is more effectively solved by writing a program.

Facebook ditches HTML mobe future in favour of Zuck-style JavaScript

Simon Harris

iterate “really, really” quickly.

I hope not. My phone already grinds to a halt when app updates come in. I hate to think what it would be like if they keep coming around again really really quickly.

TERROR in ORBIT: Dodgy rocket burp biffs International Space Station off track

Simon Harris
Coat

Re: True "Big Red Button" story.... @ Anonymous Coward

From your story, I think you must have misread the headline as TERROR in OBIT!

Simon Harris

"Is there a big red "do not touch" button in NASA HQ that does this?"

However a sign did light up afterwards saying "Please do not press this button again".

Russia's to blame for pro-ISIS megahack on French TV network

Simon Harris

Re: That was believeable until the "grammatical mistakes"

Was just about to point out the same thing about the time zones.

And anyway, since when do computer programmers respect office hours?

Is that a graphics driver on your shop's register – or a RAM-slurping bank card thief?

Simon Harris

Re: Picture. @Tom 13.

My comment was referring to the front page picture El Reg used to illustrate the story (not carried over to the story itself, so when the story was dropped from headline status the picture disappeared with it - thanks El Reg!) which was a close-up of a PCB containing 1980s vintage AM9016s, if I remember correctly, which were drop-in replacements for the MK4116 chips typically used on CGA cards.

Simon Harris

Picture.

If the graphics system in my computer used 16K x 1 RAM chips, I'd be a bit suspicious if a display driver announced itself as anything more than a CGA controller!

The USB Lego, bluetooth coffee cups and connected cats of Computex 2015

Simon Harris

Gigabyte

Is that an inflatable sword in your pocket or...

Windows 8.1 market share grows, Windows 7 slips, Windows 10 lurks

Simon Harris

OS X

Could the discrepancy between Statcounter and Netmarketshare of OSX simply be because for Statcounter, OS X is listed as 'OS X', which could mean an aggregation of all versions, but for Netmarketshare it is specifically OS X 10.10?

Hubble spots Pluto's moons are a chaotic mess of tumbling rock

Simon Harris

Re: Rugby Balls

Doug Hamilton's ball identification skills are quite astute. American football balls have more pointy ends.

Couple sues estate agent who sold them her mum's snake-infested house

Simon Harris
IT Angle

How did they get in?

Through an open SSSSSSSSSSSSSH port.

Chinese bloke escapes execution for Forbidden City nude photo shoot

Simon Harris

Pasties.

I've looked everywhere in Cash'n'Carrion for those El Reg Pasties in which the model is attired, but can't find them anywhere.

Pray tell me, where can some be obtained?

Naked cyclists take a hard line on 'aroused' protest participant

Simon Harris

Re: The route @TRT

Pett Bottom? Cockering Road? ... you're just making up rude-sounding place names now aren't you?*

* actually I checked, and they're real places!

Simon Harris

The route

The organisers may have themselves to blame. Did the route take in lots of cobbled streets? - I believe Canterbury has quite a few!

Woman dumps ultra-rare $200,000 Apple 1 computer in the trash

Simon Harris

Re: The tricky bits

"http://gizmodo.com/ben-heck-shows-you-how-to-build-an-apple-1-replica-from-1656803971"

Saying it's a replica is a bit strong. These are fairly generic 6502 systems with RAM and EPROM not available at the time of release of the Apple 1, video systems alien to the Apple 1 (generated using much more modern microcontrollers) and just arranged to be compatible with the Apple 1 memory and peripheral map where possible, programmed with the Apple 1 monitor and all built on completely different PCBs or prototyping boards.

It may be functionally similar, but you're not going to get rich passing it off as the real thing!

Simon Harris

Interesting close-up

Showing my ignorance here, but I never realised before that the Apple 1 had been explicitly designed with a 6800 option in mind.

Docker death blow to PaaS? The fat lady isn’t singing just yet folks

Simon Harris

Oh... it's Platform as a Service.

From the illustration, I'd assumed it was Piggy as a Service!

Why voice and apps sometimes don't beat an old-fashioned knob

Simon Harris

Re: It certainly seems to have downsides

'I hope El Reg take notice and start using "Belgium Everywhere" instead of IoT across the board.'

Belgium Everywhere - definitely worth a trademark!

BRAIN STORM: Nine mislaid cerebra found near railway line in New York

Simon Harris

Re: Obviously the work of a trainee consultant

...or brain training

Simon Harris

University of Texas discovered it was missing 60 jars of brains

I suspect Dr. Alfred Necessiter.

WOODEN computer chips reveal humanity's cyber elf future

Simon Harris

Wood chip?

Will we now be seeing retro 1970s style IoT wallpaper?

Elon Musk's SpaceX: Now we help do SURVEILLANCE for the SPOOKS

Simon Harris

Re: Hmmm. . .

Dyson sphere?

I believe they already make a Dyson Ball.

Microsoft: Free Windows 10 for THIEVES and PIRATES? They can GET STUFFED

Simon Harris

It also happens if you leave it offline long enough.

One machine I have was bought to be used offline - after a while it declares itself illegal until I get around to re-registering it.

Windows 10 to MELT YOUR BRAIN and TAKE OVER YOUR LIFE

Simon Harris
Coat

"It depends whether Polly is convergent or divergent."

So, the alternative option was Microsoft bundling Flappy Bird.

Simon Harris

Re: Not just Eye Candy then

Maybe now that everyone's so used to mouse clicking and touch-screen swiping, Microsoft should bundle Colossal Cave and Zork to remind people how to use the keyboard.

Drone penetrates Virgin's shapely space arse

Simon Harris
Joke

Re: Buttocks...

So while Virgin will only be going sub-orbital for the moment...

3D Robotics is going all the way to Uranus.

It’s Adobe’s Creative Cloud TITSUP birthday. Ease the pain with its RGB-wrangling rivals

Simon Harris

Re: most changes you make will be irreversible/lack of non destructive editing,

"Not sure what is meant by this"

Non-destructive editing is different from what you're doing with The Gimp.

With NDE, the software keeps a list of all the edits made and the renderer takes the original image and applies the edits at rendering time to produce the display image, but does not alter the original.

With The Gimp, the edits are made to the original bitmap.

NDE can produce better images - imagine a situation where you have an image with 3 channels of 8-bit data (e.g. RGB) - you apply curves to it to enhance contrast. In The Gimp, this will change the values of the data itself, requantising it to new 8-bit values. In a NDE editing system, the values in the original are not changed - just how they are mapped to the next stage of editing. You decide your image looks better in black and white, so you apply another filter. In The Gimp, your image data is changed and requantised again, in the NDE editor, the B&W conversion is just another remapping. The repeated requantisation will reduce the quality of an image. The remapping won't - the editing pipeline may work at a higher bit-depth than the original image.

RAF radar station crew begs public for cash to buy gaming LAN kit

Simon Harris

But isn't there generally an isolation transformer between the ethernet controller and the cable?