The Humble Origins of ARM Processors

you know, PCs. But when it comes to more lightweight devices, you know, like mobile devices, there's another name, ARM a r M. Recently, news broke that the graphics card company in Vidio would be acquiring ARM for a staggering forty billion dollars a princely some so I thought it would be a good idea to kind of go on a full rundown on what ARM is, its history, and what this acquisition means for the industry and for people like

you and me. And this is gonna be a two parter because ARM has been around for a while and its story is actually really interesting. Plus it gives me opportunities to go off on crazy tangents and tell you guys, how various stuff works, which you know is kind of my jam. As the kids say, you know, fifteen years ago. We'll start with some history lessons. Now, typically when I cover the history of a company or a technology, I run into a few cases where dates maybe a little confusing.

Sometimes one source will have a specific date for an event that conflicts with a date that's found in another source, and so at that point I will usually say that I'm sorry, I apologize. I can't get too specific. And you would think that ARM wouldn't have this issue. The

company isn't that old. We can measure its age in a few decades, but we only go back to the nineteen eighties or so to to look at origins really the late nineteen seventies, And yet when it comes to particulars such as which events really got things started for ARM, there's actually a lot of disagreements. So I'm going to give you a a version of ARMS history. But you know, don't think of this as the definitive version, because some people say, no, you shouldn't trace its history to that point.

That silly go to this other point instead. Here in the United States, when we talk about the early days of personal computers, the names that typically pop up in those discussions are Apple, Texas Instruments, Commodore, maybe Tandy, and then IBM would follow not too long behind does. But across the pond in the UK there was another computer company that was trying to get an early part of the personal computer era, and this company was called Acorn

Computers Limited. The three co founders of the company where Chris Curry, Hermann Hauser and Andy Hopper, whom I suppose was just not dedicated enough to go all in with the illiterate names of the other two founders, way to go and y. Chris Curry was born in nineteen forty six in Cambridge, England. He studied math and physics in school and went on to work for various technology companies, including Pie Limited that's a p y e. Not you know the kind of pie that I love, The Royal

Radar Establishment and Sinclair Radionics. While his stints at Pie and Royal Radar were fairly short, he stuck around at Sinclair for several years. By the late nineteen seventies, Curry was interested in developing computers, but he was finding no real support at Sinclair. He had been working on some stuff he was trying to pitch the idea to Sinclair, but he wasn't finding them very receptive. So we're gonna leave off for now with with Curry and move on

and we'll regroup in a second. Swapping over to Hermann Hauser, who was born in Austria in nineteen forty eight. He came to Cambridge as a teenager to attend school and learn English, but he really enjoyed it. He went on to pursue advanced studies in places like Vienna University, but he came back to England attending King's College in Cambridge

and getting an advanced degree. They're smart, dude. His work in physics led him to become friends with Curry, and when Curry was ready to start a company to manufacture and market personal computers, Houser was on board. Andy Hopper was the youngest of the three co founders, having been born in nineteen fifty three in Warsaw, Poland. Hopper studied in London and later Swansea University before pursuing postgraduate studies at the University of Cambridge. He focused on computer science

and he was researching networking technologies. He co founded a company called Orbis Limited, which focused mostly on Networking Tech, and this entity would end up merging with Curry and

Houser's efforts to bring Acorn Computers Limited to life. Although the original name for the actual company was Cambridge Processing Unit Limited CPU cute right, but the co founders decided to use the name Acorn Computers as the trading name for the company, allegedly choosing the name Acorn so that their computers would appear ahead of rival Apple Computers whenever

it was in an alphabetical listing. One of the earliest jobs that the group had was to develop micro controllers for fruit machines, and folks, I consider myself an Anglo file but when I first read that, I have to admit I had no idea what the heck it meant. In my imagination, it was some sort of harvesting device that depended on micro controllers to do something like pick apples. But no, that, of course, is not what a fruit

machine is. And my guess is there's more than a few of you out there giggling at my ignorance right now. It's well warranted. So a fruit machine in this context is what Brits call a slot machine. I guess they do it because of the symbols of fruit that appear

on the various parts of the slot machine. So the first big job that this new company had was designing micro controllers for these gambling machines the slot machines to make the more difficult to tamper with, as there were some clever hackers who are finding ways to rig big payouts from the machines. And while the machines are designed to take money from you, uh, they don't like the design to go the opposite direction. The house is not

a big fan of that. A few years later, the UK launched an initiative to put a computer in every classroom. Acorn Computers secured the contract to provide these computers to produce them, and it was called the BBC Micro. The Micro used a processor called the six five O two. This was an eight bit processor from Rockwell h Though engineers from Most Technology originally developed the six five O two processor, the six five O two was a low

cost processor that totally changed the processor market. It was much less expensive than Intel's d D processor at the time, and as such, the six five O two had found its way into numerous technologies in the including the Atrey video game console and the Apple two Computer Systems, among others. The micro contract gave Acorn Computers some momentum. In three the company wanted to free itself from dependence upon processors

from other companies. To computer scientists from Cambridge University, Sophie Wilson and Steve Ferber became the head designers for the new thirty two bit processor. Ferber focused on the actual physical design of the chips architecture, while Wilson was focusing

on the instruction set. The limited resources forced the pair to come up with a simplified approach to processors, and they chose to go with a specific approach to processor design in a category called reduced instruction set computing or risk r I s C. This is in contrast with complex instruction set computing or see I s C CISC. But what does that actually mean? Well, let's take a

step back to understand this. A processor's job is to perform arithmetic and logic operations on data, and this includes basic stuff like you know, adding and subtracting, kind of like your basic calculator, and it can also involve transferring numbers and comparing different numbers to one another. The data comes in as binary or let's be zeros and ones. The processor follows instructions given to it by a program.

So the processor gets its instructions like, you know, add the next two numbers together and then send it on, and then the processor executes that instruction on the supplied zeros and ones that come in. And that's basically what's going on with a processor at a very high level. In addition, we describe the number of operations a processor can complete in a second as its clock speed, which we talk about in hurts. A single pulse of the processor is a cycle. A one Hurts processor would only

be able to complete a single operation every second. It would be unfathomably slow to us. A decent processor speed today is somewhere between two point five and three point five giga hurts. That's decent. I'm not talking about top of the line, but that would mean two point five to three point five billion cycles per second. So the processors in modern computers are pulsing billions of times every second,

and each pulse can power and operation. Now, some instructions are pretty simple and they might only require one or two cycles to complete that instruction. Other instructions are more complicated and might have lots more steps involved, and this is where we get to the risk versus CISK approach. A risk based processor handles very simple instructions, so it handles each individual instruction very quickly, like within a cycle.

CISC systems can handle much more complicated instructions. The flip side of that is that while a risk based processor can execute individual instructions very very quickly, you might need a lot more instructions to complete your overall task. The CISK approach might take longer to execute a single instruction, but you need fewer instructions overall to complete your task. Now that is a little confusing, So I'll use an analogy.

If I told the typical person, I need you to go outside and check the weather, that's a deceptively complicated instruction because there's a lot of other stuff that's nested in that request. For example, if I were to try and tell this to a robot, I might have to include what direction the robot needs to go in, how fast it should move, where of the door is, whether that door opens inward or outward, the actual mechanism the robot would have to manipulate to open the door, and

so on. So what appears to be a simple task is actually when you break it down into its individual components, much more complicated. So a program running on a risk based processor has to break down instructions kind of in that way in a longer series of simple tasks that add up to whatever you're end goal is. But risk chips are highly optimized, so for certain applications a risk

based chip can be ideal. These days, we have a lot of risk chips and stuff like mobile devices, for example, because these devices are rarely running super complicated software and they need that low power, high efficiency output. One related thing I'd like to mention, though it doesn't tie directly into arms history or anything, is what is called a semantic gap. Now, remember when I said that processors taken

data in the form of zeros and ones. This binary code is a type of machine language, or the kind of information a machine can actually process. Machines are not able to process information in other forms directly. The information must ultimately convert into machine language, in this case zeros and ones, and information that we can express pretty succinctly with language and numerals. Beyond just the ones and zeros, that ends up taking up a lot of space. You have to use a lot of ones and zeros to

represent that kind of information. But computers are really good at processing machine code. It happens lightning fast. However, programming computers in machine code is really really hard. I mean, imagine having to type in a string of tens of thousands of zeros and ones while you're trying to program a machine, and you know that if you make just one mistake, you mess up the whole program because the

whole chain is screwed up after that. Heck, if you did make a mistake, it would be really hard for you to track down where you made the mistake in the programming. You would have to compare two different, very long sheets of zeros and ones, and you'd probably lose your mind. That's one of the big reasons computer scientists

have developed various programming languages. The idea is that the programming language is something that's easier for human beings to work with, but machines can't understand programming languages without the use of something called a compiler. The compiler's job is essentially that of a translator. It takes the program that's been written in whatever programming language and converts the instructions into machine code so that the computer can process it.

The compiler is essentially a middleman between the program and the processor. We describe programming languages by calling them stuff like level or high level. This refers to how closely the language resembles the machine code. So a low level programming language is really only a couple of steps away from machine code itself. It's much easier for a compiler to handle that kind of language, but it's much harder

to program in. You have to frame your programming closer to machine code, but it's still easier than programming instructions than just ones and zeros. A high level programming language is modeled closer to how we would think in terms of a typical language. There are still rules you have to follow, and if you're not familiar with that particular language and you're looking at an example of it, it's not likely going to make a whole lot of sense to you. But it's much easier for humans to work

with these kind of languages. However, it's less efficient for compilers to handle that and compile that into machine language. We call this adding layers of abstraction. The programming lay. WHIGE provides an abstract platform that represents the various tasks that the processor will ultimately carry out, and the gap between what the programming language says and what the processor does is the semantic gap. CISK and risk designs deal

with this gap in different ways. A CISK design includes a lot of addressing modes and lots of different instructions. A RISK design has a much more simplified instruction set that can meet the requirements of user programs. It's really just two different methods to achieve a similar result. Depending upon the history you read, Acorn Computer slash Cambridge Processing Unit called their risk based design Acorn Risk Machines, or

they called it Advanced Risk Machines. Most histories say that originally it was Acorn Risk Machines and only later changed to Advanced Risk Machines. But either way, the initialism for this technolog g became a r M or ARM. When we come back, i'll talk about how this technology would ultimately transcend the company that spawned it, but first let's take a quick break. Steve Ferber, Sophie Wilson, and Robert Heaton program the initial instruction set for the ARM processor

in Basic. That's a programming language that originated back in nineteen sixty four. Basic stands for Beginners all Purpose Symbolic instruction Code. It's a high level programming language that, as the name implies, simplifies things for beginner programmers. The Acorn team weren't beginners, but they wanted to keep instructions as

simple as possible to optimize the processors. Their first effort yielded the ARM one processor That endeavor took two years of development, with the ARM one debuting in nine only debuting internally v l s I Technology, another company fabricating company, they actually produced the chip the working chips. The chip had fewer than twenty five thousand transistors on it and used a process with a resolution of three microns or micrometers.

That's one millionth of a meter for comparisons sake, Today's Intel processors have more than a billion transistors and they use a fabrication process with a resolution of just a few nanometers, and a nanometer is one billionth of a meter, so we've definitely come a long way since the early eighties.

The team learned a great deal through their experience of developing the ARM one, and rather than immediately go into production, the design team began to work on refining their product, creating the next generation of processors based on the architecture. They wanted to improve certain processes, and they added instructions

for stuff like multiply and multiply and accumulate. They built in capabilities that would allow the processor to perform real time digital signal processing, a necessity if they wanted the processor to be able to handle processes meant to you know, generate sounds for example, which the company considered an important part of a computer's capabilities. They increased the number of transistors on the microprocessor from twenty five thousand from ARM

one to thirty thousand for ARM two. The team also developed a coprocessor, which, as that name implies, is a processor that can work in concert with the primary processor. Coprocessors typically handle specific tasks. They're meant to kick in when something specific happens, and it offloads those tasks from

the responsibility of the primary process sessor. So this would be kind of like having two people dividing up work among them, and one person handles a subset of chores and the other person has to do all the rest of the chores. Now, in this case, the coprocessor was powering a floating point accelerator. Ah, but that leads us to ask what is a floating point? Well, I'm sad to be the one to have to tell you this. Please set yourself down and and prepare yourself. Computers have

a limited capacity. Computing memory is not infinite, and so we have to start making some concessions when we're working with numbers. Now, as you may be aware, some numbers can be really really big or really really small, and they might have a super long, perhaps even infinite number of numbers behind a decimal point. Computers can't cope with that. They have limitation on what they can handle. So we have to make some concessions, and floating points are one

of the ways we make concessions. Now, at some point we have to cut off numbers, and when and where we cut off numbers depends upon what we're doing. So, for example, if we are making a tool like a rake, you know, just an old lawn rake, and you want the handle for this rake to be five ft long, you probably don't actually care if the handle comes out to be four ft eleven inches and some change, or five foot and a fraction of an inch that level

of precision isn't really important to you. It needs to be five ft ish, but if it's not exactly at five ft it's not a deal breaker. But let's say you're building a transistor for a processor. Well, in that case, you're working in a very very very small frame of reference, and so the difference of a fraction of a meter represents a gargantu one difference. On the flip side, you're not likely to ever have to worry about distances of

a centimeter. That would be way too big. So you just have to have a way to maintain accuracy relative to what you're doing. You have a different, you know, context for your work. This gets a bit more complicated when you need to work with both really big and really small numbers at the same time. For example, let's say you're a scientist and you're working with Newton's gravitational constant. That is a very small number that starts with a decimal. Then you have ten zeros before you get to the

first non zero number, which is a six. By the way, you might also be working with the speed of light. That's a very big number, but the computer memory can't really handle number sizes that include that wide a spectrum of numbers, and that's why floating points are used, and

they're sort of like using numbers and scientific notation. You've got a significant with contains the digit of the number or the digits of whatever number you're talking about, and you've got an exponent which tells you where the decimal point needs to be in relation to the first digit

in the significant. So if I have a significant of one point seven and I have an exponent of six, it would be the same as if I wrote that number in the scientific notation as one point seven times ten to the sixth power, which is the same thing as one million, seven hundred thousand. These are all just different ways to represent the same value. So one point seven significant with an exponent of six is one million,

seven hundred thousand. Likewise, if I had a significant of one point seven and an exponent of negative six, this would be the same as one point seven times ten to the negative sixth power or point zero zero zero zero zero one seven. By using floating points, we can simplify how we represent numbers without damaging the value of those numbers. And let's get around the limitations of computer memory and how many bits a processor can handle at

a single time. We call the operations that processors perform on these types of numbers floating point operations, and we measure it in flops, which stands for floating point operations per second. A giga flop would be a billion floating point operations per second. The Japanese super computer Fugaku can reach more than four hundred fifteen peda flops. A pedal flop is a thousand million million floating point operations per second, So a pedal flop would be a one followed by

fifteen zeros yauza. So the ARM to architecture included a coprocessor for floating point acceleration, not a full floating point process, but to accelerate floating point operation calculations, as well as the possibility of adding other coprocessors with the basic ARM architecture. It was kind of a sort of a modular design.

This generation was called, fittingly enough, ARMED two, and the first product to market that featured the ARM two wasn't a fully fledged computer, but rather the ARM development system, which included the ARM processor, four megabytes of RAM, three support chips, and some development tools. So essentially this was a product meant for programmers. It wasn't like it was meant for your average end consumer. Meanwhile, at the company

at large, things were not going so super well. Acorn Computers was in a bit of a financial crisis and an Italian company known for computer systems and office equipment in Europe called Olivetti ing s c. And I know I've butchered it, but Olivetti is what's best known as it swept in and it acquired the English computer company.

At the time, Olivetti was reportedly unaware that within Acorn Computers there were engineers who are working on new processors because the original Acorn computers we're using processors made from other companies, so the acquisition would slow things down a little bit. That's one of the reasons why there was a delay between the development of the original ARM one processor and an actual Acorn computer system running on an

ARMED two processor. However, the day did eventually come around, and that day arrived in n seven, and that is when Acorn Computers launched the Archimedes. It was a home computer running on an ARM two processor with a clock speed of eight mega hurts, meaning it would send out eight million pulses per second. I wish I could say that the Archimedes revolutionized computing right away, but that just

wouldn't be true. The delays meant that Acorn Computers was way behind the chief competitor, which in seven was IBM, or rather computers running on IBM's design a k a IBM compatibles. While Acorn Computers was working on developing its ARM processor technology and then afterward as it sorted itself out post acquisition from Olivetti, the computing world was consolidating behind the IBM compatible approach. Apple's market share was already

heading forward decline. At this point. The company had released the Macintosh computer. In four Steve Jobs had been ousted or had left in a huff. Reports differ on this. IBM had taken aim at dominating the office computer space

and then expanded beyond to home computing. But IBM had also made some decisions that allowed some other manufacturers to build machines with essentially the same components as IBM's personal computers and licensed essentially the same operating system, allowing any company the chance to build their version of an IBM PC but offer it for a much more competitive price. IBM had effectively set its own course to ultimately withdraw from the home PC market further down the line, though

that would take several more years. The point, however, is that the IBM design was firmly entrenched in the market. There were tons of options for machines, and more importantly, there was an enormous amount of software available that had been developed specifically for the IBM design of computers. The our Comedies, a computer with a totally different processor and a different operating system was just getting started in this market, and there was no enormous library of software to support that.

System sales as a result were slow. I mean, what good is a computer if there's no software to run on the computer. You could program your own software, but that sort of approach tends to appeal to, you know, a super narrow sliver of the overall computer market. So it would take a few years for programmers to develop software for the ARM architecture and for the Archimedes platform to a point where it could stand as a worthy

alternative to the IBM PC. And I want to be clear here, I'm not saying the Archimedes was a bad computer. It wasn't. It was just that it was starting at a point where it was at a huge disadvantage to

the IBM PC, which had an enormous head start. Meanwhile, the R and D team with an Acorn was hard at work at the next generation of ARM architecture, which would be the ARM three, and man, it is so much easier to follow this naming convention compared to some other technologies, but don't get used to it, because before long things are going to get confusing again. So the ARM three saw further improvements in design, with an on chip data and instruction CASH and a four kilobyte capacity

of that CASH Ohana a bide is eight bits. A kilo bite is one thousand bites, or really because the power of two properties, it's more properly one thousand, twenty four bites. Will get more into that later. Essentially, this meant that more instructions could load into the pipeline for the processors simultaneously, which sped things up considerably. In addition, the team was able to get a much faster clock speed. The previous generation ran at eight Mega hurts, but the

ARM three hit twenty five Mega hurts. The first Acorn computers running on ARM three technology would launch in nineteen nine.

The team also worked to build a version of ARMED two tech that had a lower power requirement than the standard armed to processors, and this became known as armed to a S Little A Big S. This design was aimed at filling a market need for companies that were building lower cost portable and handheld devices like communication hand sets or portable computers, and the team got as far as developing working prototypes of the chip, but never got

to bring it to market. One thing that was working really well, however, was the general dedication to risk based architecture. The chips required less power than CISC based systems, and with the right software they were incredibly powerful and efficient, and they cost much less than the more complicated CISC bay systems did. As a result, more companies were getting

interested in developing risk based technologies. The ARM family of processors was a clear candidate for that model, but not everyone was keen on the idea of relying on a technology that belonged to a specific computer manufacturer, that being Acorn. There was, however, a solution to this problem, and I'll explain what it was after we return from this quick break. Behind closed doors, a series of meetings had been pushing the idea of breaking the ARM technology division out of

Acorn and into its own entity, its own company. Acorn itself was part of these discussions, and the idea would be that the ARM branch would spin off into a new company, and that company would then develop new ARM technologies, acting as a business to business enterprise. It would actually fabricate the technologies as well. It would be an original equipment manufacturer or o e M. That's a type of company that makes products that are used as components in

products made by other companies under their own branding. The two other companies that were part of this discussion in addition to Acorn were v L s I Technology that was the company that had fabricated the original ARM one processor, and drumroll please, Apple Computers. Presumably, Apple was keen on making use of ARM based processors, but didn't want to put out computers that could be said to have Acorn

computing technology inside them, spending off armwood sidestep that awkward fact. However, there is another explanation that isn't quite so, you know, petty, and this is that Apple had taken a keen interest in the ARM three processors in an effort to develop computers that could go up against the IBM compatible four D six generation, but the ARM three lacked an integrated memory management unit or mm U, and as such, Apple felt that the ARM processor design wasn't quite where Apple

needed it to be. However, developing a new ARM processor with an integrated MMU was going to be expensive and Acorn Computers just didn't have the resources to do it itself, so it really necessitated a move to an independent spinoff

that had more support behind it. So Acorn Computers would supply the design and engineering behind the development of the ARM architecture, primarily in the form of a workforce of twelve engineers v l S. I would supply the fabrication facilities to make physical chick and Apple would supply the cold hard cash needed to fund the whole thing. That's oversimplifying things a little bit, but generally that's how the arrangement worked. The new company was Advanced Risk Machines Limited

a k a. ARM Limited. The main goal for the new company was to advance ARM microprocessors. This new company had its fancy schmancy headquarters in a barn in Cambridge, England. Typically with tech companies, I talk about starting out in a garage. But with ARM it was a barn. And so while our story started in the late nineteen seventies with Acorn Computers, some ARM histories really point to nineteen nine as the beginning of ARM. I think that ends

up skipping some important early work. However, that's just my own personal opinion. Hermann Hauser of Acorn Computers slash Cambridge Processing Unit reached out to Robin Saxby to serve as the CEO of this new company. Saxby had come from Motorola and it worked closely with Acorn Computers back when the PCs the company made we're running on Motorola based chips. The first processor this new company developed was called wait for it, ARMS six. Wait I'm sorry, wait, hang on,

that can't be right. Six? Hang up? Wasn't the last full processor the ARM three? What the heck happened to four? And five? Why did we jump to six? What is it with tech companies and the desire to leap over entire numbers when releasing new versions of products? You know, I I wish I had answers for these questions, but my research didn't pull up anything definitive. Now that's not to say there aren't answers out there. It's entirely possible

that there is, and I just missed it. But based on what I could find, there was never any announcement for ARMED four or ARM five as planned commercial products, nor any record of an ARMED four or ARE five processor being produced, either as a potential product or even as just an internal prototype. Based on the information I can find, the fourth generation ARM processor was in fact the ARMS six, and the new company skipped four and

five for reasons that are beyond my ken. As it were, one thing that definitely shaped the development of the ARM six was an intended use for the tech within an ambitious Apple product, the Apple Newton. Now a lot has been said of the Newton, much of it unkind and for arguably justifiable reasons. The Newton was meant to be a defining example of personal digital assistance or p d a s. In fact, the story goes that the Apple CEO of the time, John Scully, coined the phrase personal

digital assistant to refer specifically to the Newton. It was in many ways a incursor to the iPhone, which would debut twenty years after the company had first started working on the Newton. So you could say that the Newton came out twenty years too early, and I think I think a lot of people would agree with you. The Newton had a tablet style form factor and it used a touch screen input with a stylus. Apple was pushing really hard for a device that could actually interpret handwriting.

So theoretically you would be able to write on the tablet in normal handwriting and the Newton would interpret each letter and capture it in text on screen. And that was a super cool and innovative idea. And Apple really needed a processor that could power operations without requiring too much juice, because a handheld computing device isn't really that useful if it can only operate for an hour or so before it needs a recharge. Would that in mind?

The ARM six micro architecture began to take shape with lots of decisions in the development guided by the knee eads of the Newton. The name of the family of ARM six microprocessors, because there were a few chips that fell under this designation, was the ARMS six macro cell. And I'll give a few of the changes that happened between the ARM three generation and the ARM six. For

one thing, the process had become more precise. The ARM three micro architecture used a one point five micron process, whereas the ARM six shrank that down to point eight microns. So what does that mean, Well, it means that the individual components on the chip could be made much smaller, which also means you could fit more components onto a microprocessor without having to increase the size of the actual

processor chip. This falls in line with an observation that Gordon Moore had made decades earlier, where he observed that market influences incentivized companies to develop new ways to cram smaller and smaller components onto a square inch of silicon wafer. The effect of this is that the number of transistors you could find on microprocessors would effectively double every two

years or so. Now these days we tend to reinterpret this to say that a computer's processing power doubles every two years or so due to Moore's law, and it's really more of an observation, but that's a matter for another episode. The point I really want to make is that moving from a one point five micron process to a point eight micron process is pretty much in line with that observation, as the point eight micron components were just a little over half the size of the one

point five micron version found in ARMED three microprocessors. In addition, the ARMS six increased the address space from twenty six bits to thirty two bits. Address space means the amount of memory that's set aside for a particular computational component, like a file or a connected device. Essentially, a computers processor uses memory addresses in order to access information stored

within the computer's actual memory. It's how a processor can pull relevant information for whatever process it needs to perform. The term twenty six bit or thirty two bit tells us how much memory the system can address. Now, remember that a bit is a unit of binary information, either

a zero or a one. So each bit can have one of two states or two values zero one, two states, and you can have twenty six bits with the twenty six bit system with that older are in three address space, and that meant that you had a maximum of two to the twenty six power number of address spaces. So that meant you can have a maximum of two to the twenty six power number of address spaces. That translates

to more than sixty seven million values. However, a thirty two bit address space knocks this up to two to the thirties second power values, and that goes up to nearly four point three billion values. So you see how a relatively small increase in bit size can have a much bigger effect. It's not doubling or quadrupling, it's much bigger than that. This meant that the ARM six could map up to four Gibby bytes of memory. Gibby bytes.

I said that correctly. This is a peculiar measurement, right, because I'm sure you've heard of gigabytes, but this is gibby bytes. Gibby g I b I means too to the power of thirties, So a gimba byte means one billion, seventy three million, seven one eight hundred four bytes. You can see how saying one give byte is more efficient. Isn't that helpful? Anyway? The ARM six micro architecture can map up to four of those bad boys in memory. A gimme byte, in case you're curious, is equal to

about one point oh seven four gigabytes. The whole story behind the various binary prefixes, because there's also kidby, maybe and tabby and more. All that is really interesting, but I'll save that for some other episode. The ARM six was backwards compatible with the old ARM three architecture. It had a twenty six bit mode of operation that it

could switch to instead of its thirty two bit. This helped avoid making the older software that had been designed for ARM three systems from going totally obsolete with the release of the new micro architecture. It had the integrated memory management unit that Apple wanted. It also had some new processor instructions, but I'm not going to go too far into the details, as I feel like it would largely be lost and we've got a lot more to

say about ARM coming up anyway. The first Newton model launched in with an ARM six ten risk microprocessor, and unfortunately, it would ultimately be something of a clunker. The chief problem with the Newton was not the fall of the ARM processor. It was that the most anticipated feature, the

handwriting recognition capability, just wasn't very good. There were lots of reviews that criticized the implementation of this feature, documenting times when the system performed poorly and just got stuff wrong. Fans of the cartoon sitcom The Simpsons might remember an episode where they made fun of this. The school bully, Nelson had one of his cronies take down the note beat up Martin on his Newton, but the device interpreted it as eat up Martha. So Nelson then grabs the

Newton and throws it at Martin, thus fulfilling the prophecy. Anyway, the Newton had a troubled launch, which is putting it mildly, and it would transition into a troubled life cycle. The device failed to get a really good hold in the marketplace, even as new versions of the hardware were released, and upon his return to Apple, Steve Jobs would discontinue the Newton in n eight. Meanwhile, over at ARM, CEO Robin

Saxby had a brilliant idea. He saw that depending on being a single source of fabrication for the ARM microprocessors is way too limiting. ARM needed more customers and would also need to meet the production needs of those customers. But being a small operation, this was a tough problem to be in you couldn't easily scale up. The solution was an interesting one. Saxby led the company toward moving to a more intellectual property approach to micro architecture. So

rather than produce the chips themselves. ARM Limited would license the design and instruction sets of these chips out to other fabricators. They would become what is called a fabless chip designer. They didn't produce the hardware themselves. The other chip manufacturers could produce their own ARM microprocessors built on the license designs coming from ARM itself. This move would prove to be a game changer for the company. We're

gonna leave off there for this episode. In our next episode, I'll pick up from that point forward, and we'll talk about how ARM evolved over the years and cemented itself as a huge player in the microprocessor space, as well as talk about the acquisition by in video, at least the proposed acquisition at the time of this recording, and what that means. If you guys have suggestions for future topics that I should cover on tech Stuff, reach out

to me. You can do so on Twitter. The handle is text stuff H s W and I'll talk to you again really soon. Text Stuff is an I Heart Radio production. For more podcasts from my Heart Radio, visit the I Heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows. Zero