An Open Source CPU!?
Linus Tech Tips
·Linus Tech Tips
·2019-05-06
·
1,805 words · ~9 min read
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have you ever found yourself relaxing in the tub thinking hmm
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how could i design my own CPU
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okay maybe that's not quite as likely but let's say you work for a large
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company that is legitimately looking to do something like that where do you even
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start i mean i guess could you license intellectual property
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from Intel or ARM i mean maybe but that kind of thing is
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going to cost you an ARM and a leg
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so then what other options are out there well when we asked just that question to
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krista asanovich co-creator of risk five
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he was quick to bring over actually like
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a team of people and one of these
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computers based on risk 5's free
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and open architecture which surprisingly
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functions like a normal pc
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and i cannot wait to tell you guys about this thing
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so there's a good chance that right now you're thinking okay
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cool tech demo quake 2. but
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i'm not going to have one of these open processors in my computer anytime soon
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so why should i care well you should care because you
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actually can expect to find risk 5 processors in
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your gaming rig much sooner than you'd think just
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for the time being not as your primary
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central processing unit so NVIDIA and western digital along with around 100
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other companies will soon be shipping products with risc-5 microprocessors on
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board due to it having better efficiency better security and that sweet sweet
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royalty-free license to boot in order to appreciate how cool risk 5
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actually is though we do need a bit of a history lesson
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so back in the 1960s RAM was made using
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tiny magnetic cores and these were super
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duper slow compared to the vacuum tube processors of the time
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so to make sure that the processor wasn't just wasting cycles while the RAM
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was catching up every instruction from the memory ran a
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little program hardwired inside the
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processor called microcode with the 70s
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came the space race where scientists figured out how to put a lot of
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transistors on one chip which meant that now fast memory could be put on the same
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chip as the CPU so then microcode just got
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thrown in the garbage bin of history right no just kidding a lot of that same
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microcode from way back then actually still exists in modern computers for
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software backwards compatibility the legendary Intel 8086 CPU pioneered a
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new computer architecture x86
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but you could make the argument that it was
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just hastily thrown together by Intel engineers in just a few weeks and they
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they had no way of knowing that it was going to become the de facto home
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computer architecture for decades to come
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thanks to its use in the original ibm pc
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but with an average of one instruction being added every couple of weeks since
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its inception x86 has gone from poorly thought out to
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today ballooning to over
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1500 instructions i mean think of it like the english language how many words
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do you use on a daily basis versus how many are in the dictionary in a modern
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world this kind of bloat leads to inefficiency not to mention needless
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difficulty for anyone that wants to make a processor so
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why is everyone still on x86 well
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software support is a big part since porting Windows and all of its programs
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to a new architecture has proven
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we could use a word like inconvenient i mean look at Windows rt on ARM
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total flop on top of that creating a good
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architecture in the first place is freaking hard to be clear those guys
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that threw it together were pretty talented they were pretty talented team
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and it's been a lot easier over the last
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several decades to just make the transistor smaller and pack in more of
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them at least it was easier until moore's law
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kind of petered out and huge leaps forward in CPU speeds
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basically stopped in the last five or so years
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so clearly a more usable alternative to x86 or ARM was needed one that was
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created with modern processors in mind and using the power of hindsight
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that other architectures didn't get to benefit from which is where krista and
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his team come in creating the reduced instruction set computing five or
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risk 5. the core of which has less than
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50 instructions instead of 1500ish there
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will probably be more by the time this video is out now those 50 instructions
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are locked down and won't be changing in the future so ideally a program made
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60 years from now using risk five should work just fine on processors
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being made today i mean slowly though
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but what if those 50 instructions aren't enough
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well risk five is customizable meaning that if say
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NVIDIA wants to create a processor that is specialized for ai and graphics they
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could actually add extra instructions for their task allowing for greater
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hardware specialization and much greater efficiency
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but of course there have been open source instruction sets before and they
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have never taken off so
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back to that question why do we care about this one well the
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members list for the risk five foundation is kind of a who's who of the
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biggest tech companies including but not limited to google samsung NVIDIA tesla
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ibm and a hundred or so more including a startup founded by the creators of risk
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five sci five to help kick start risk five
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adoption and to avoid that chicken and egg problem with hardware and software
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by creating the world's first commercial risk 5 silicon
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so this right here is the fu540
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which stands for freedom unleashed 540
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definitely not what else fu could mean
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towards lock down standards so so this
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one thousand dollar processor is well
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not particularly fast with four cores that on this particular board can clock
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up to 1.6 gigahertz on a 28 nanometer process node
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but breaking speed records is not exactly the point when this processor
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was announced with support for Linux back in february you could run pretty
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much nothing on it but here we are just six months later
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and 80 of the debian software library has been compiled for risk five meaning
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that all you need to install almost any app is a quick app get command
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but of course the point of this board isn't for you to run games on it even if
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it does run quake 2 thanks to this configuration
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so we've got the processor here which sits under this
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tiny little heat sink and fan then we've got the RAM so that's eight gigs of ddr4
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with ecc we've got gigabit Ethernet right here we've got usb and uh let's
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see yeah we've got a micro sd card reader right here
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but what makes it unique
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is this chip connector right here
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this allows for you to connect the CPU to
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well anything you'd like so
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currently on the table in front of me here we've got another unit that's
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connected to an fpga that handles pci
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express lanes for what you could kind of consider a a larger scale motherboard
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here so now we've got a graphics card
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this is just a regular hd 6450 AMD
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graphics card we've got a samsung m.2 drive on the other side plus
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we've got a bunch more i o but you know what else you could connect
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here pretty much anything
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this allows companies to build whatever custom solution they would like onto the
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sci-5 processor board so the tldr is
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that it can interface with whatever fpga
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or custom silicon is needed while getting the advantages of the risc-5
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instruction set Linux support and also
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all of the intellectual property and legal work that sci-fi has already put
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in to make sure that things like the RAM work with the CPU
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so in the future sci-fi is looking to have sort of a domino's pizza approach
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to custom chips where a company can come in and add on bits for say image
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processing or autonomous car ai but now you're probably wondering
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why have it open source then if sci-5 is sinking all this time into making these
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custom chips work and into the risk 5 instruction set
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why not lock it down so they can keep all the money
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well say that a company has a driver issue normally they would have to go to
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Intel or whoever to get it fixed causing a lot of work on both sides and
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potentially making the company have to disclose what exactly they're working on
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whereas when the software and the hardware is open source the company can
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just fix the bug and then upload a fix for the community afterwards the open
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source nature is also appealing to companies because if they invest in
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developing for risk five and sci five goes under
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then all of those man hours don't get wasted
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what's going to cause the real stiction of risk five though is in education
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because it's royalty free the most popular computer architecture textbooks
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being published right now and courses being taught in undergrad and graduate
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programs around the world use risk 5 to show students how computer
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hardware works on a very low level
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previously some fantasy architecture would have to be
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used and then when a computer engineer would enter the field they'd finally get
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to work with a messy proprietary isa
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so since very few students will switch up what architecture they use once
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entering the field the idea here is that you can expect a lot more custom
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hardware being made using risk 5 in the future in your hard drives in your
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graphics cards in your cars and maybe
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maybe someday even as the primary architecture of your home computer
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and you'd be running games more complex than quake 2 by that time so thanks for
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watching guys if this video sucked
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um hi AMD and Intel
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and ARM i guess hi guys uh but if you
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liked it get subscribed hit the like button or check out the link to where we
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where to buy the stuff we featured yeah i guess leveling i guess you could buy one if you really want to in the video
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description also linked in the description is our merch store which has cool shirts like this one and our
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community forum which you should totally join