ARM architecture family

Small chips help computers work.

These chips are part of a big family. They use very little power. This helps them stay cool. Because they are cool, they fit in small tools. You can find them in phones and tablets. They are even in some big supercomputers. Many billions of these chips have been made. They are used in many things you use every day.

Do you have a phone?

Arm is a large family of computer chips.

These chips use a set of rules called an instruction set architecture. This set tells the chip how to do its work. A company called Arm Holdings makes these rules. They let other companies use them to build devices.

Arm chips are very good at saving power. They also do not get very hot. This makes them perfect for small things like phones and tablets. They are even used in some of the fastest supercomputers. Over 230 billion of these chips have been made.

Long ago, a team at Acorn wanted a new chip. They wanted it to be very fast but cheap. They looked at a simple design from a university. They also wanted to make it easy for the chip to talk to other parts. This helped the chip handle tasks quickly. The first chip was called the ARM1. It worked well as a tool for the BBC Micro computer.

Later, they made the ARM2. It was much faster than other chips at that time. It used fewer parts to do its job. This helped it stay cool and use less power.

Arm is a huge family of computer designs used in many devices.

These designs use a set of rules called an instruction set architecture. This architecture tells the processor how to carry out tasks. A company called Arm Holdings creates these rules and licenses them. This means other companies pay to use the rules to build their own hardware. Because these chips use very little power and stay cool, they are perfect for portable tools. You can find them in smartphones, tablets, and laptops. They are even used in massive supercomputers like Fugaku. Over 230 billion Arm chips have been made so far.

How these chips work is based on a simple design called RISC. This stands for Reduced Instruction Set Computer. The original team at Acorn wanted a chip that was fast but simple. They used a trick to handle interrupts, which are signals that tell a chip to stop and do something else. By using a 26-bit address space, they could save the chip's state in just one step. This made the chip much faster at responding to new tasks. They also used special memory instructions called S-cycles. These allowed the chip to talk to memory twice as fast.

This was very helpful for making graphics look smooth.

The history of Arm began with a company called Acorn. In 1981, Acorn made the successful BBC Micro computer. They wanted to build a new machine that was ten times faster than the BBC Micro. They also wanted it to cost the same price. In late 1983, the team decided to design their own processor. They named it the Acorn RISC Machine. Sophie Wilson wrote the instructions for the chip using a language called BBC BASIC.

This work helped the team know they were on the right track.

The first real chip was the ARM1, which worked in April 1985. It ran at a speed of 6 MHz. Later, the team released the ARM2 design in late 1986. This new version ran at 8 MHz and was much more powerful. It used only 30,000 transistors to do its work. This was much fewer than the 68,000 transistors used by other chips. Because it had fewer parts, it stayed cool and used less electricity. The ARM2 was used in the Acorn Archimedes computers starting in June 1987.

Today, Arm technology has grown into many different versions. The ARMv8-A architecture was released in 2011 to support 64-bit math. This allows computers to handle much larger amounts of data. There are also special versions like "Thumb" to help save space in the code.

You can see this technology in small devices like a Raspberry Pi. It is also inside many modern chips used in science and industry.

From tiny sensors to giant supercomputers, Arm is everywhere in our digital world.

Arm is a massive family of instruction set architectures (ISAs) used in computer processors.

An ISA acts as a set of rules that tells a processor how to perform tasks. Arm Holdings develops these rules and licenses them to other companies. These companies then build the physical hardware that follows the Arm instructions. Because Arm chips use low power and generate little heat, they are ideal for portable devices. You can find them in smartphones, tablets, and laptops. They are also used in massive supercomputers, such as the Fugaku system.

With over 230 billion chips produced, Arm is the most widely used architecture family in the world.

The Arm design is based on Reduced Instruction Set Computer (RISC) principles. This approach focuses on using a small, efficient set of instructions to keep the hardware simple. The original designers at Acorn used specific methods to increase performance. For example, they used a 26-bit address space to handle interrupts quickly. An interrupt is a signal that tells the processor to stop its current task to handle something else. By limiting the address space, the entire state of the machine could be saved in a single operation. This halved the overhead required to manage interrupts.

Another key mechanism involves how the processor communicates with memory. The designers utilized a feature called page mode DRAM. Page mode allows the chip to access memory much faster if the data is in the same location. The Arm architecture includes special memory access instructions known as "S-cycles." These S-cycles allow the processor to fill or save multiple registers within a single memory page. This effectively doubled memory performance in certain tasks. This was especially useful for improving the speed of computer graphics.

The history of Arm began with a company called Acorn Computers. In 1981, Acorn released the BBC Micro, which was very successful. The team wanted to create a new machine with ten times the performance of the BBC Micro. They also wanted to keep the price the same to compete with the IBM Personal Computer. In late 1983, the team decided to design their own CPU. They named it the Acorn RISC Machine. Sophie Wilson developed the instruction set by writing a simulation in BBC BASIC.

The first working silicon samples were known as the ARM1. These chips were tested and worked correctly on April 26, 1985. The ARM1 ran at a speed of 6 MHz. It was first used as a second processor for the BBC Micro. Later, in late 1986, the team introduced the ARM2 design. This version ran at 8 MHz and was much more powerful. The ARM2 featured a 32-bit data bus and 27 32-bit registers. It also included a Booth multiplier to handle multiplication tasks more efficiently.

The ARM2 was remarkably efficient compared to other chips of its time. It used only 30,000 transistors to function. In comparison, the Motorola 68000 used about 68,000 transistors. Because it had fewer transistors and lacked microcode, the ARM2 used less power. This simplicity allowed it to stay cool without complex thermal packaging. The ARM2 was powerful enough to compete with expensive workstations. It was used in the Acorn Archimedes computers starting in June 1987.

Over the years, the Arm architecture has evolved through many different generations. The original designs were 32-bit, but they had limitations on how much memory they could use. The ARMv3 series removed these limits by providing a full 32-bit address space. In 2011, the ARMv8-A architecture was released. This major update added support for 64-bit arithmetic and a 64-bit address space.

This allows modern computers to process much larger amounts of data at once.

There are also specialized versions of the architecture for different roles. The "Thumb" extensions allow for both 32-bit and 16-bit instructions. This improves code density, which helps save memory space. Another extension called Jazelle was added to handle Java bytecode directly. Recent versions have also added simultaneous multithreading (SMT) to improve performance.

From tiny embedded systems to the world's fastest supercomputers, Arm technology connects many different fields of science and computing.