ARM Processor - Sowing the Seeds of Success - Computerphile 

The way he so stoicly and eloquently brushes aside the question of how it feels to be part of the revolution of arm, and subsequently gives most of the credit to the companies, uni's and designers earnes him all the respect he needs. There is a case for modesty. He's one of the posterboys for sure.

@ ~ 9:45 or so: "...effectively we were powering the chip [(the ARM processor)] from the signal inputs..." Holy cow!

When I did study 25 years ago, a lot of computer science people had "No risc no fun" stickers at their doors here in Germany.

he's modest, but he's had quite a remarkable career

Brings back memories. I joined Acorn from college in 1983 as a lowly technical writer, in spite of my BSc in comp. sci., because it was the only company I wanted work for and I would have mopped the floors if it got me in there. I didn't learn about the ARM until one of the guys working on ISO Pascal for the Beeb (which I was writing the user guide for) leaked it to me. After that I used to go and hang around Roger's desk and he'd show me ARM BASIC running on an emulator that was running on an NS16032 second processor. As Steve remembered, BASIC was running on the actual silicon days after they got the first chips back. I believe there was one minor rev. they had to do to get the chip ready for production, and maybe a move from a 3 micron process to 2 micron.

The ARM running without a power connection reminds me of when Frank Whittle was testing one of the first jet engines. It started to over speed so they cut fuel. But the engine kept going, faster, generating more thrust. Turned out fuel had collected in the burners. Something terribly British (pythonesque) about machines that mysteriously work but you don't know how.

9:20 Remarkable! In case what he said was missed, as he's quite a humble man about it, he was going to test how much current the first ARM chip drew when running. He connected a multi-meter to the power supply and turned it on and began running code on the ARM. Yet the meter read zero. He hadn't remembered to connect the power supply at all. No power was coming from the PSU into the ARM CPU; the ARM chip was so efficient, it was running from power leaking out of the board's capacitors as they slowly drained which is an absolutely minuscule amount of power. And yet the CPU had 2-4x the performance of the VAX 11/780 minicomputer. Can there be any wonder why ARM is the most popular, widely used CPU architecture in the world? An absolutely genius, brilliant design. Cheers to Dr. Furber and Ms. Wilson. Visionaries.

I've been privileged to have participated on two day session titled "ARM System Architecture" by Professor Furber himself! I even have a diploma signed by him :)

This series of videos has been one of the most interesting in the history of this channel. I could listen to Prof. Furber forever.

As an erstwhile owner of Model B's and A3000/A5000's I revere Prof Furber and Sophie Wilson. BBC Basic and particularly Basic V was/is the best structured, easiest to use and most elegant version of Basic I have ever seen. And the same goes for ARM Assembler, which I think is a direct reflection of the simplicity of the RISC concept. And imbedding an assembler in Basic was pure genius, it made it so easy to develop a program in Basic then just convert the intensively used bits to Assembler. Still the most pleasurable programming experience I've ever had.

The magnitude of Acorn's achievement coming up with the ARM is something that shouldn't be understated. It makes them one of the few microcomputer companies who actually rolled their own processors - and one of very few who did it without actually owning their own chip factories or having been active in electronics component manufacturing _before_ starting to make computers. Quite a feat. In fact I'm having trouble thinking of another example - Commodore had ownership of MOS, who were setup first and foremost as a microchip manufacturer in direct competition with Motorola and Intel. Texas Instruments were a long established IC manufacturer. DEC, who started out building minicomputers from piles of mini PCBs filled with discrete components and evolved to making a lot of their own ICs for their bigger systems, sort of flipped between making their own processors for their smaller machines (terminals, the Rainbow and VAX workstations) and just using Intel or Motorola (depending on machine) parts instead. Other big names just bought commodity parts on the whole and only contracted out production of specific accessory parts such as glue ASICs. EG IBM could actually have made their own parts if they wanted, given their decades in the computing field, but simply found it cheaper and easier to buy in bulk from Intel, and about the only custom device in the PC was the BIOS ROM, and the character ROMs on the video cards - something which can be considered a direct contributor to the clone industry, as it turned out to be an exceptionally easy machine to copy, only needing a bit of BIOS reverse engineering. Apple just used MOS processors, and the most complicated custom piece in their early 80s designs would have been something like the IWM that looked after video and disc access. Atari did similar, buying from MOS then Motorola, and contracting various, seemingly random generic IC fabricators to make parts like their video chips (8-bits, ST) and then Glue & MMU ASICs (ST). Sinclair was similar, using Zilog CPUs and commodity memory, only moving to having Ferranti make ULAs for them from the ZX81 onwards. So on and so forth. Possibly the only direct analogue is Sun, when they started producing the (also RISC, so possibly ARM-inspired) Alphas some years later on...

I worked (not actually programming, sadly) for the company who ported Smalltalk-80 to the ARM, in the form of an Archimedes. We had an actual Archimedes on one desk and on another we had a 80386 machine with an "Archimedes on an Expansion Card" which shared the monitor somehow. We also had a 386 port of Smalltalk-80 for comparison. What delighted me, for various reasons, was that the ARM running at 8MHz kicked the living bits out of the 386 running a much faster clock (I don't recall the exact speed after all this time, but it was at least 20 MHz, possibly double that). Our colleague who did all the heavy lifting was loaned various prototypes as new ARM variants came out. He had one which ran so fast it broke the speed-limiters on Flight Simulator making it impossible to play ;-)

"...effectively we were powering the chip [(the ARM processor)] from the signal inputs..." This was a well-known problem when working with CMOS chips. As documented in that famous book, "The Art Of Electronics" by Horowitz and Hill, if your (CMOS) circuit suddenly stopped working, it *may* be that one of your chips isn't connected to the power rails and that it's being powered by its inputs. Consider what happens when all of the inputs go "low" at the same time...

I have been a huge fan of ARM since doing low level mobile development. From a developers persecitve RISC is really wonderful to work with. Keep making these series. I really enjoy them.

I saw in an interview with Wilson saying that they were very worried about overheating of the package with high current draws so spent a lot of effort to make sure it economical with the juice. Even she was a bit surprised when the current draw figures were measured as to how low they were.

Great video, Brady! I love these technology history lessons! I think it's important to remember how we got here, and recognize the people who made it possible.

They came out with 64bit multi-core ARM CPUs recently which are now powering supercomputers and servers that have to be extremely power efficient, low thermals, and the ability to be more tightly packed than any other design. As you can probably figure out they also are being used in smartphones (they are much more powerful than how they are being used in phones, although some of this power is apparent in that you can leave a large amount of applications running at the same time without impacting the performance).

I could listen to this guy all day.

This a great episode. Thank you Brady and thanks to everyone involved in making this.

I have my exams in few days on arm processors and I am watching this video. Forgive my ignorance, but I didn't know who is this gentleman is so I paused the video and started reading the description. I came to know that he is Prof Steve Furber who's book I have been refering to for my course!!!🙏

outstanding, one of my favorite channels on youtube

Phenomenal video. Appreciate y’all sharing a brief history of the ARM processor.

I have so much admiration for these guys. I could listen to this chap's stories all day.

"powering the chip through the inputs" Brought a smile to my face. I knew immediately what happened. Been there, done that. Just not on a processor.

Fascinating! I really enjoy these videos on the early days of computing.

the co of arm today, his masters thesis is on my shelf there - wow furber is a legend! did enjoy reading his books on arm programming when i was a kid :)

I was impressed by the design back then (read about it in Byte magazine, probably) and I am still impressed now. Great job.

Thanks for this Sean, the professor's videos on ARM are very interesting. You should do a computerphile extra video of the him with his guitar!

Thanks Dr. Furber!

Such a great interview!

Steve Furber is working on neural networking of computers in Manchester University. A legend of Acorn computing (and the lovely Sinclairs)

Interesting interview, I am a Acorn fan and owner since BBC model B. Also new to me ... tape out... I laid out several simple PCBs using black tape and letraset pads. We called it "taping out" onto clear film as the last step after proto board and schematic approval. This was then sent off to the PCB manufacturer.

This is one of my favorite channels. Thanks!

Who is here after Apple's M1 Macs? Haha, my first computer ever was the Acorn's BBC Micro Model B!

Great background information! Excellent! I had a colleague who had an Acorn, it was a great system but unfortunately an island platform. But it booted fast had a great UI!

Thanks for this interview!

Fascinating to listen to thanks for sharing.

that low consumpotion energy story is SICK !!!!!!! awesome!!!!!

This must be the best example of serendipity

Appreciate the video. I would love a complementary video to this to discuss RISC-V.

Great chip, used the Acorn Archimedes series, first machine I learned assembly language on so I got quite in depth with the OS and chip, awesome for its time. Glad to see ARM still going strong and found their niche in this otherwise dominated marketplace.

I have just noticed an error on the screen captured from 11:20 : the ARM1 had 25 000 transistors, but not the ARM2 : it had around 30 000, because contrary to the ARM1, the ARM2 has the multiplication instructions implemented.

Great interview !

Acorn machines were brilliant. The first machine I build to run BASIC on was an Acorn Atom (6502 processor) which came as a self build kit and worked great first time despite my inept engineering skills.......

Great video, very interesting.

#1 hit the summer of 85 was Tears For Fears "Everybody Wants to Rule the World". Who knew they were talking about computing chips.

Fascinating story!

OMG!! They did it! ARM killed x86! Congratulations!

Brady, could you get him to talk about the work he's doing with SpiNNaker? While the ARM stuff is interesting, it's history. He's still doing stuff on the bleeding edge that has potential to change everyone's life *completely*.

Wow, what a modest man.

not connecting the power supplies is one of the most extreme cases of make a bug a feature I've heard in my life

When Professor Furber noticed that his ARM chip was running without a power supply connection can only mean that computers have been Sentient life forms from the very beginning, and that they have just been waiting for the proper time to become our Silicon Overlords. Humans are Doomed.

It's interesting that he refers to Sophie Wilson as "Roger". That must be confusing for all parties involved.

Nice mention to the 65c816! That's the chip the SNES used.

I had 30 years of arm once (right) and only 29 years of the other arm (the left one). This was the result of me spinning very rapidly with my right arm at the axis point and my left arm traveling at very close to the speed of light (and thus aging more slowly), thus matching the cliche of the left being younger than the right.

I love computers! See, you helped make that happen in a way.

A well-engineered piece of hardware will work. A brilliantly-engineered piece of hardware will work even if it shouldn't. :)

Great video! But what is with the random zoom at 4:54?

Designed a microprocessor, couldn't properly connect it to a power supply and multimeter LOL

As an avid Commodore enthusiast... 3:00 Wouldn't that Phoenix, AZ company have been Bill Mensch's Western Design Center? :D

"only" 12 billion ARM cpu's at the time of making this video 7 yrs ago. Today in 2022 it is 230 billion ARM cpu's produced..

great video :)

Looking listening Learning so much news - so much new My first touch with ARM was in 1989 an Acorn StrongARM with dual CPU one intel - one arm the teacher showing this machine was running hot with it - i was and still am.. Amazed . . never heared much about it found one StrongARM in use at a local backery.. i said.. well.. its a very very good system unfortunatly.. i think the PC/XT (and up) is going to run over the market.. And so it came to be but - was it really ? since i found a fan-page, much later, about the StrongArm - listed all the models and versions of that time period and thought.. i was wrong.. and right.. but what if i knew - but i didn't do then. Will ARM be the next HOST on your PC Adventure - i dare to say YES with the move to online services and less local apps.. it will do well. ok, the static devices in decline the mobile devices as the new default so, ARM has already arrived a long time ago.

Where can I find the page shown on (11:18) that lists all those historical processors and their specifications?

As an ARM engineer, this is particularly neat to hear :)

The whole running on no power thing would make a great plot device in an Apollo 13 type movie.

The audio in this video was ridiculously low. You should look into that.

Who came here after seeing the Apple ARM news?

can someone please elaborate on the plastic vs ceramic packaging part? I've never heard of this before.

@Computerphile could you enable automatic subtitles for the video? thanks so much!

THe ARM design is so Handy

is there a chance to get other Manchester professors to give a small talk?

So who was the CEo of ARM who's Masters Thesis was on Steve's shelf?

What an amazingly humble and down-to-earth guy. If I invented ARM, I'd be struting around like Flavor Flav with a gold medallion the size of a hubcap hanging from my neck.

yay, computer scientist john lithgow is back!

great talk. plus i now know what tape out means. reliefed to hear although still called tape out, no tape is harmed in the process. symphatically dry.

Any device is not completely off when switched off, rather it has 1 watt of power flowing through the board or device, life!

4:10 *Sophie

Does this support the idea that an electronic device can be unplugged, yet the sensors such as microphone, camera, still recording / transmitting

Can ARM beat Intel x86 or AMD x64 design? If the main obsatcle is memory bandwidth, why not just increase the amount of cache memory or use DDR6 RAM?

my boy Furber is wicked smaht

A different response to the bandwidth problem can be seen in the design of both the BBC Micro itself, as well as the Atari ST and the original Amiga; sharing the memory bandwidth between the processor and the equally as hungry video system on an interleaved basis. The memory had about twice the speed as what the processor could use in both cases, so the video could be given an equal half, reading screenbuffer data out of a particular chunk of the same memory bank as the actual code and data. The available data rate of that sidechannel then determining the screen resolution and colour depth the computer could provide without slowing down the processor (and the amount of processor time it can borrow from determining the actual max and how slow the computer runs when using it). IE, turning the drawback into an advantage, in terms of cost saving and simplification of the architecture, instead of coming up with a whole new processor type and spending money on upping the general performance to take advantage of it. You don't get the sort of raw power (and better graphics) that the Archie offered, but you do get a reasonably performant computer for the lowest possible price. In the Beeb, that being 320x200/256 in mono or 160x200/256 in 4 colours (or the Teletext mode, which uses character mode to give the appearance of 320x200 in 8 colours) with no performance hit, or the max of 640x200/256 in mono and 320x200/256 in 4 colours. The 16-bits had about 4x the memory bandwidth (twice the clock, twice the bus width), so instead manage 640x200/256 in 4 colours and 320x200/256 in 16 colours with no slowdown, and the Amiga could pull up to 640x200/256 in 16 colours with a similar chronic amount of slowdown as experienced by the Beeb, or 320x200/256 in 64 colours with half as much... The PC's graphics cards don't show the same kind of coupling between general machine performance and resolution/colour depth as they run a completely separate bus to the rest of the machine, so gave e.g. BBC-like quality (from CGA) without slowing down the CPU despite using the same general memory technology and bus width. Which was rather important given how underpowered and bandwidth-inefficient the rest of the computer already was (struggling to reach the performance of a Beeb in the lower screen modes even so); with shared video, as seen in the PC Jr, it would have damn near come to a halt.

I have an Actron CP9550 that has an Arm Cortex M3 core in it. Got an iPod nano 2g that i picked out of the trash that has some sort of samsung soc that uses Arm. I have never attempted to open it but the Garmin GPS box that I trash picked probably has an Arm core or two in it. Dumpster divin' FTW

What's the water brand of the bottle to the left on his table?

2:45 "The turning point [in the design of the ARM] was a visit to [The Western Design Center, Inc.]".

As I understand .exe file contains OS commands and it does some work. And because it contains OS commands it can run on all CPU-s that run Windows OS?

358 likes and 0 dislikes holy shit

But how did they design the chips in the computers on which you design the chips?

*Two Intel reps visited the channel folks! :v*

What on earth does Brady say at 12:21? I've listened twenty times now.

I wish I still had my Archimedes.

could a stackable processor be any good for doubling performance by stacking more cpus ontop of the previous chip? imagine that for easy upgrades lol

This just shows that even ARM's principal designer also made silly mistake like all of us by powering up MCU through GPIOs.

Does ARM already have processors that operate at near-threshold voltage? Because that's what I'd be more ready to call magic.

Enable subtitles

Accidentally powering a micro only via IO pins, yeah been there done that, caused a bit of head scratching.

fairly young voice for a guy that age. (:

Wait I get the idea that less switching activity gives less power ~ higher resolution clock. But is he alluding to the idea that the chip didn't need a Vcc when he says he 'failed to connect the power supply' and 'effectively they were powering the chip from the signal inputs'? Aren't there some operations that require non-input voltage?

Watching this on my Macbook Pro with ARM instruction Set M1

"In inserting the ammeter into the power supply, I had failed to connect the power supply, so no current was flowing into the ammeter... But the chip was still running!" WTF.