Ciro Santilli Born: 1965
Died: 2010+-ish
This is the lowest level of abstraction computer, at which the basic gates and power are described.
At this level, you are basically thinking about the 3D layered structure of a chip, and how to make machines that will allow you to create better, usually smaller, gates.
What a legendary place.
As mentioned at youtu.be/16BzIG0lrEs?t=397 from Video "Applied Materials by Asianometry (2021)", originally the companies fabs would make their own equipment. But eventually things got so complicated that it became worth it for separate companies to focus on equipment, which then then sell to the fabs.
As of 2020 leading makers of the most important fab photolithography equipment.
First there were dominant Elmer and Geophysics Corporation of America dominating the market.
Then a Japanese government project managed to make Nikon and Canon Inc. catch up, and in 1989, when Ciro Santilli was born, they had 70% of the market.
youtu.be/SB8qIO6Ti_M?t=240 In 1995, ASML had reached 25% market share. Then it managed the folloging faster than the others:
- TwinScan, reached 50% market share in 2002
- Immersion litography
- EUV. There was a big split between EUV vs particle beams, and ASML bet on EUV and EUV won.
- youtu.be/SB8qIO6Ti_M?t=459 they have an insane number of software engineers working on software for the machine, which is insanely complex. They are big on UML.
- youtu.be/SB8qIO6Ti_M?t=634 they use ZEISS optics, don't develop their own. More precisely, the majority owned subsidiary Carl Zeiss SMT.
- youtu.be/SB8qIO6Ti_M?t=703 IMEC collaborations worked well. Notably the ASML/Philips/ZEISS trinity
- www.youtube.com/watch?v=XLNsYecX_2Q ASML: Chip making goes vacuum with EUV (2009) Self promotional video, some good shots of their buildings.
Parent/predecessor of ASML.
This is the mantra of the semiconductor industry:
- power and area are the main limiting factors of chips, i.e., your budget:
- chip area is ultra expensive because there are sporadic errors in the fabrication process, and each error in any part of the chip can potentially break the entire chip. Although there areThe percentage of working chips is called the yield.In some cases however, e.g. if the error only affects single CPU of a multi-core CPU, then they actually deactivate the broken CPU after testing, and sell the worse CPU cheaper with a clear branding of that: this is called binning www.tomshardware.com/uk/reviews/glossary-binning-definition,5892.html
- power is a major semiconductor limit as of 2010's and onwards. If everything turns on at once, the chip would burn. Designs have to account for that.
- performance is the goal.Conceptually, this is basically a set of algorithms that you want your hardware to solve, each one with a respective weight of importance.Serial performance is fundamentally limited by the longest path that electrons have to travel in a given clock cycle.The way to work around it is to create pipelines, splitting up single operations into multiple smaller operations, and storing intermediate results in memories.
They put a lot of expensive equipment together, much of it made by other companies, and they make the entire chip for companies ordering them.
A list of fabs can be seen at: en.wikipedia.org/wiki/List_of_semiconductor_fabrication_plants and basically summarizes all the companies that have fabs.
Some nice insights at: Robert Noyce: The Man Behind the Microchip by Leslie Berlin (2006).
One of the companies that has fabs, which buys machines from companies such as ASML and puts them together in so called "silicon fabs" to make the chips
As the quintessential fabless fab, there is on thing TSMC can never ever do: sell their own design! It must forever remain a fab-only company, that will never compete with its customers. This is highlighted e.g. at youtu.be/TRZqE6H-dww?t=936 from Video "How Nvidia Won Graphics Cards by Asianometry (2021)".
- UCM failed because it focused too much on the internal market, and was shielded from external competition, so it didn't become world leading
- one of TSMC's great advances was the fabless business model approach.
- they managed to do large technology transfers from the West to kickstart things off
- one of their main victories was investing early in CMOS, before it became huge, and winning that market
Basically what register transfer level compiles to in order to achieve a real chip implementation.
After this is done, the final step is place and route.
They can be designed by third parties besides the semiconductor fabrication plants. E.g. Arm Ltd. markets its Artisan Standard Cell Libraries as mentioned e.g. at: web.archive.org/web/20211007050341/https://developer.arm.com/ip-products/physical-ip/logic This came from a 2004 acquisition: www.eetimes.com/arm-to-acquire-artisan-components-for-913-million/, obviously.
The standard cell library is typically composed of a bunch of versions of somewhat simple gates, e.g.:and so on.
- AND with 2 inputs
- AND with 3 inputs
- AND with 4 inputs
- OR with 2 inputs
- OR with 3 inputs
Simulations are then carried out, and the electric properties of those structures are characterized in a standard way as a bunch of tables of numbers that specify things like:Those are then used in power, performance and area estimates.
- how long it takes for electrons to pass through
- how much heat it produces
Open source ones:
- www.quora.com/Are-there-good-open-source-standard-cell-libraries-to-learn-IC-synthesis-with-EDA-tools/answer/Ciro-Santilli Are there good open source standard cell libraries to learn IC synthesis with EDA tools?
A set of software programs that compile high level register transfer level languages such as Verilog into something that a fab can actually produce. One is reminded of a compiler toolchain but on a lower level.
The most important steps of that include:
- logic synthesis: mapping the Verilog to a standard cell library
- place and route: mapping the synthesis output into the 2D surface of the chip
Step of electronic design automation that maps the register transfer level input (e.g. Verilog) to a standard cell library.
The output of this step is another Verilog file, but one that exclusively uses interlinked cell library components.
Given a bunch of interlinked standard cell library elements from the logic synthesis step, actually decide where exactly they are going to go on 2D (stacked 2D) integrated circuit surface.
Sample output format of place and route would be GDSII.
The main ones as of 2020 are:
- Mentor Graphics, which was bought by Siemens in 2017
- Cadence Design Systems
- Synopsys
They apparently even produced a real working small RISC-V chip with the flow, not bad.
Very good channel to learn some basics of semiconductor device fabrication!
Focuses mostly on the semiconductor industry.
youtu.be/aL_kzMlqgt4?t=661 from Video "SMIC, Explained by Asianometry (2021)" from mentions he is of Chinese ascent, ancestors from Ningbo. Earlier in the same video he mentions he worked on some startups. He doesn't appear to speak perfect Mandarin Chinese anymore though based on pronounciation of Chinese names.
asianometry.substack.com/ gives an abbreviated name "Jon Y".
It is quite amazing to read through books such as The Supermen: The Story of Seymour Cray by Charles J. Murray (1997), as it makes you notice that earlier CPUs (all before the 70's) were not made with integrated circuits, but rather smaller pieces glued up on PCBs! E.g. the arithmetic logic unit was actually a discrete component at one point.
The reason for this can also be understood quite clearly by reading books such as Robert Noyce: The Man Behind the Microchip by Leslie Berlin (2006). The first integrated circuits were just too small for this. It was initially unimaginable that a CPU would fit in a single chip! Even just having a very small number of components on a chip was already revolutionary and enough to kick-start the industry. Just imagine how much money any level of integration saved in those early days for production, e.g. as opposed to manually soldering point-to-point constructions. Also the reliability, size an weight gains were amazing. In particular for military and spacial applications originally.
Uploaded by the Computer History Museum. There is value in tutorials written by early pioneers of the field, this is pure gold.
Shows:
- photomasks
- silicon ingots and wafer processing
Register transfer level is the abstraction level at which computer chips are mostly designed.
The only two truly relevant RTL languages as of 2020 are: Verilog and VHDL. Everything else compiles to those, because that's all that EDA vendors support.
Compilers for RTL languages such as Verilog and VHDL abstract away the details of the specific semiconductor technology used for those exact same reasons.
The compilers essentially compile the RTL languages into a standard cell library.
Examples of companies that work at this level include:
- Intel. Intel also has semiconductor fabrication plants however.
- Arm which does not have fabs, and is therefore called a "fabless" company.
In the past, most computer designers would have their own fabs.
But once designs started getting very complicated, it started to make sense to separate concerns between designers and fabs.
What this means is that design companies would primarily write register transfer level, then use electronic design automation tools to get a final manufacturable chip, and then send that to the fab.
It is in this point of time that TSMC came along, and benefied and helped establish this trend.
The term "Fabless" could in theory refer to other areas of industry besides the semiconductor industry, but it is mostly used in that context.
One very good thing about this is that it makes it easy to create test cases directly in C++. You just supply inputs and clock the simulation directly in a C++ loop, then read outputs and assert them with
assert(). And you can inspect variables by printing them or with GDB. This is infinitely more convenient than doing these IO-type tasks in Verilog itself.Some simulation examples under verilog.
First install Verilator. On Ubuntu:
Tested on Verilator 4.038, Ubuntu 22.04.
sudo apt install verilatorRun all examples, which have assertions in them:
cd verilator
make runFile structure is for example:
- verilog/counter.v: Verilog file
- verilog/counter.cpp: C++ loop which clocks the design and runs tests with assertions on the outputs
- verilog/counter.params: gcc compilation flags for this example
- verilog/counter_tb.v: Verilog version of the C++ test. Not used by Verilator. Verilator can't actually run out
_tbfiles, because they do in Verilog IO things that we do better from C++ in Verilator, so Verilator didn't bother implementing them. This is a good thing.
Example list:
- verilog/negator.v, verilog/negator.cpp: the simplest non-identity combinatorial circuit!
- verilog/counter.v, verilog/counter.cpp: sequential hello world. Synchronous active high reset with active high enable signal. Adapted from: www.asic-world.com/verilog/first1.html
- verilog/subleq.v, verilog/subleq.cpp: subleq one instruction set computer with separated instruction and data RAMs
The example under verilog/interactive showcases how to create a simple interactive visual Verilog example using Verilator and SDL.
You could e.g. expand such an example to create a simple (or complex) video game for example if you were insane enough. But please don't waste your time doing that, Ciro Santilli begs you.
The example is also described at: stackoverflow.com/questions/38108243/is-it-possible-to-do-interactive-user-input-and-output-simulation-in-vhdl-or-ver/38174654#38174654
Usage: install dependencies:
then run as either:
Tested on Verilator 4.038, Ubuntu 22.04.
sudo apt install libsdl2-dev verilatormake run RUN=and2
make run RUN=moveIn those examples, the more interesting application specific logic is delegated to Verilog (e.g.: move game character on map), while boring timing and display matters can be handled by SDL and C++.
Examples under vhdl.
Run all examples, which have assertions in them:
cd vhdl
./runFiles:
- Examples
- Basic
- vhdl/hello_world_tb.vhdl: hello world
- vhdl/min_tb.vhdl: min
- vhdl/assert_tb.vhdl: assert
- Lexer
- vhdl/comments_tb.vhdl: comments
- vhdl/case_insensitive_tb.vhdl: case insensitive
- vhdl/whitespace_tb.vhdl: whitespace
- vhdl/literals_tb.vhdl: literals
- Flow control
- vhdl/procedure_tb.vhdl: procedure
- vhdl/function_tb.vhdl: function
- vhdl/operators_tb.vhdl: operators
- Types
- vhdl/integer_types_tb.vhdl: integer types
- vhdl/array_tb.vhdl: array
- vhdl/record_tb.vhdl.bak: record. TODO fails with "GHDL Bug occurred" on GHDL 1.0.0
- vhdl/generic_tb.vhdl: generic
- vhdl/package_test_tb.vhdl: Packages
- vhdl/standard_package_tb.vhdl: standard package
- textio
- vhdl/write_tb.vhdl: write
- vhdl/read_tb.vhdl: read
- vhdl/std_logic_tb.vhdl: std_logic
- vhdl/stop_delta_tb.vhdl:
--stop-delta
- Basic
- Applications
- Combinatoric
- vhdl/adder.vhdl: adder
- vhdl/sqrt8_tb.vhdl: sqrt8
- Sequential
- vhdl/clock_tb.vhdl: clock
- vhdl/counter.vhdl: counter
- Combinatoric
- Helpers
- vhdl/template_tb.vhdl: template
As of 2020's, it is basically a cheap/slow/simple CPU used in embedded system applications.
It is interpreted. It actually implements a Python (-like ?) interpreter that can run on a microcontroller. See e.g.: Compile MicroPython code for Micro Bit locally.
As a result, it is both very convenient, as it does not require a C toolchain to build for, but also very slow and produces larger images.
The first thing you must understand is the Classic RISC pipeline with a concrete example.
The good:
- slick UI! But very hard to read characters, they're way too small.
- attempts to show state diffs with a flash. But it goes by too fast, would be better if it were more permanent
- Reverse debugging
The good:
- Reverse debugging
- circuit diagram
The bad:
- Clunky UI
- circuit diagram doesn't show any state??
Basically a synonym for central processing unit nowadays: electronics.stackexchange.com/questions/44740/whats-the-difference-between-a-microprocessor-and-a-cpu
It basically replaces a bunch of discrete digital components with a single chip. So you don't have to wire things manually.
Particularly fundamental if you would be putting those chips up a thousand cell towers for signal processing, and ever felt the need to reprogram them! Resoldering would be fun, would it? So you just do a over the wire update of everything.
Vs a microcontroller: same reason why you would want to use discrete components: speed. Especially when you want to do a bunch of things in parallel fast.
One limitation is that it only handles digital electronics: electronics.stackexchange.com/questions/25525/are-there-any-analog-fpgas There are some analog analogs, but they are much more restricted due to signal loss, which is exactly what digital electronics is very good at mitigating.
- 2020: Traininum in 2020, e.g. techcrunch.com/2020/12/01/aws-launches-trainium-its-new-custom-ml-training-chip/
- 2018: AWS Inferentia, mentioned at en.wikipedia.org/wiki/Annapurna_Labs
Our definition of fog computing: a system that uses the computational resources of individuals who volunteer their own devices, in which you give each of the volunteers part of a computational problem that you want to solve.
Folding@home and SETI@home are perfect example of that definition.
Advantages of fog: there is only one, reusing hardware that would be otherwise idle.
Disadvantages:
- in cloud, you can put your datacenter on the location with the cheapest possible power. On fog you can't.
- on fog there is some waste due to network communication.
- you will likely optimize code less well because you might be targeting a wide array of different types of hardware, so more power (and time) wastage. Furthermore, some of the hardware used will not not be optimal for the task, e.g. CPU instead of GPU.
All of this makes Ciro Santilli doubtful if it wouldn't be more efficient for volunteers simply to donate money rather than inefficient power usage.
Bibliography:
- greenfoldingathome.com/2018/05/28/is-foldinghome-a-waste-of-electricity/: useless article, does not compare to centralize, asks if folding the proteins is worth the power usage...
Basically means "company with huge server farms, and which usually rents them out like Amazon AWS or Google Cloud Platform
