Dorchester — Sep 14th 2021

Euan explained the technical wonders and evolution of Apple’s new M1 chip which is replacing Intel processors across the Mac range and is also used in the iPad Pro. He discussed some very technical details but the talk was aimed at a more general audience and he successfully held our interest and attention.

After visiting the development of integrated circuits from Jack Kilby’s first experimental design through Apple’s use of the Motorola 6800 in the original Macintosh, IBM’s Power PC, and the change to Intel’s designs, we were shown close-up views of the A14 and M1, annotated to show the different processing areas which Apple have incorporated within the M1 and which were supplementary chips on previous ‘Intel’ motherboards.

Apple was one of the founders of ARM with Acorn and as ownership changed Apple kept its access to ARM’s developments. Apple designs its own iPhone and iPad chips (the A series) and around ten years experience has enabled it to design the M1 chips that outclass the slow development of Intel X86 technology. This means that Apple’s closely integrated hardware, and system-software (System on a Chip) can at last develop as Apple intends.

ARM architecture (its Instruction Set or language grammar) is RISC. A Reduced Instruction Set Computer uses short, simple 4-Byte instructions which can be processed fast, unlike the X86 Intel CISC Complex Instruction Set which favours a set of long instructions of variable length. Other well-known computers using ARM have been the BBC Computer, Archimedes, and recently the Raspberry Pi.

Inefficient Sequential Instruction Processing draws more power (with heat issues). While this originally suited CISC architecture it became clear that Parallel Processing of instructions (also referred to as out-of-order processing, would be more efficient as dependent processes do not have to be completed before others can take place. This work is done by de-coders. De-coders can easily identify ARM RISC 4-Byte instructions but have to guess the start point of complex (variable length) instructions. Adding more than four decoders to x86 CISC architecture is very hard, but the M1 chips have eight, and three times the usual buffer size. The power draw / heat issue means that the base M1 MacBook Air needs no fan, but runs faster than the great majority of X86 laptops, with much better battery life.

Apple’s M1 is able to give the CPU and GPU equal access to all RAM (Unified Memory) which is mounted immediately next to the M1 which makes short work of the different CPU/GPU memory transfer requirements.

Euan also discussed the advantages and disadvantages of chiplets and briefly touched on Apple’s hybrid Interposer layer patents. The M1 is a ’monolithic’ chip and unlike, for example Intel’s Skylake, doesn’t use chiplets. Apple’s interposer layer links chip elements electronically to the chip substrate contacts, and can contain special sub-elements within itself.

Currently Intel’s foundry has difficulty producing less than 10 nanometre structures while Apple’s partner foundry Taiwan’s TSMC makes the M1 at 5nm and is developing 3nm process. TSMC is a major shareholder in Dutch ASML who supply their Extreme Ultraviolet (EUV) machines which use exotic ultra-short wavelength light capable of such precision lithography. Each M1 chip has 16 Billion transistors.

What became clear is that it is Apple’s continued control of both the hardware and software that has enabled them to leap forward of their competitors who have to supply chips to cover a wide range of applications as well as personal computers etc.
After the break we discussed David Chaplin’s printing problem: since replacing his 27” iMac with the new 24” M1 iMac, whilst both computer and iPhones print, the two family iPads won’t. The most cogent suggestion was to try to delete and reselect the printer, though no one was quite sure how you do that on an IOS device.
David M demonstrated how, using OS Maps he had selected a recommended route which he thought he had saved it when downloading the map. On arrival at the start point, where there was no ‘phone network, he discovered that the map had been saved, but the route hadn’t. This led to a general discussion about, and enthusiasm for, OS Maps. John Lemon explained why the change of ownership of ViewRanger made it a less attractive app while favouring the ever-improving OSMaps. John has now provided a link to a great introduction to OS Maps by Tim Newman, a project manager at OS which is well worth 23 minutes of your time to watch.


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