RTX2010 – Radiation-hardened stack machine microprocessor

http://en.wikipedia.org/wiki/RTX2010

by lelf • 12 years ago

156 60 12 years ago

en.wikipedia.org

lucaspiller• 12 years ago

Tech specs are available on the manufacturer's site:

http://www.intersil.com/en/products/space-and-harsh-environm...

lelf• 12 years ago

Philae is controlled by 2 RTX2010 CPUs (hot red), further 8 control the Experiments. 13 CPUs (10* RTX2010, 1* ADSP-21020, 2* 80C3x) in total. © https://twitter.com/philae2014/status/427842417920712704

userbinator2• 12 years ago

80C3x

An 8051-family microcontroller, the CPU architecture that's found almost everywhere - including space. I wonder if they're running Forth too, as this old discussion I found also mentions 80C32 and RTX2010 together with Forth:

https://groups.google.com/d/topic/comp.lang.forth/7PK44n68I_...

analog312• 12 years ago

The 8052AH-BASIC is better known because of a Byte Magazine article, but there was also a commercially available 8051 variant that was mask programmed with a built in Forth interpreter. I've never seen one.

keenerd• 12 years ago

For future archaeologists wondering why everyone is talking about Philae, the title of this thread used to be to the effect of "The rad-hard CPU used in Philae".

tinco• 12 years ago

I wonder how hard it is to create a radiation hardened CPU. Is the premise that radiation can flip bits in the on-die cache and registers? would simply making those redundant be a solution? Or could a single flash of radiation invalidate all memory on the device?

Sanddancer2• 12 years ago

There's all sorts of problems you have to deal with. Memory flipping is one of the most visible, but that radiation also will damage the lattice of the processor, making some transistors harder to flip on, and some much easier to flip on, leading to transient glitches, etc.

Redundancy's definitely one solution, which is one reason why spacecraft tend to have multiple processors and/or processors with redundant logic pipelines. They also tend to use different substrates that are harder for cosmic rays to effect, different, more expensive, casings that offer more shielding, and also larger, older, more vetted processes. For example, this chip is uses a 1 micron process, which is a lot bigger than the process used in current cpus, which means that there's a lot more mass in the transistors to soak the effects of radiation, making it harder to cause damage.

Osmium• 12 years ago

Or we can use alternative semiconductors that are more radiation-resistant. One of many reasons why materials discovery is still very important even if initial chips will never match the performance of silicon.

miga• 12 years ago

Like silicon on sapphire?

noselasd• 12 years ago

Yes, one of the premises is it flips bits, a phenomena called Single Event Upset(SEU) - e.g. the open source LEON FT (http://www.gaisler.com/index.php/products/processors/leon3ft) processor, is designed to be able to correct and detect such errors - in addition to being manufactured with materials that block radiation. In spacecrafts such radiation hardened processors are often used in addition to having redundancy.

One issue with only using redundancy to overcome errors from radiation is you'll have a hard time determining which processor has an error - especially when several processors are affected at the same time.

wtracy• 12 years ago

Would optical processors be immune to some of these problems?

Animats• 12 years ago

If it's rad-hard, it's export-controlled in the US. See the US Munitions List, category XV, section (d), "Radiation-hardened microelectronic circuits".

https://www.pmddtc.state.gov/regulations_laws/documents/offi...

So mass market products aren't made radiation-hard. Rad-hard CPUs more modern than that FORTH engine exist; Atmel makes a rad-hard SPARC. But they're produced in tiny quantities and are thus very expensive.

SixSigma2• 12 years ago

I'm pretty sure the marketing of "Our CPU is used on the probe" is enough to get a donation or two.

Igglyboo• 12 years ago

I wonder this as well, is it really not enough to simply encase it in lead or something similar?

jng• 12 years ago

I'm sure Mr. Moore feels vindicated that the fruits of his design work have powered humanity's first comet landing ever.

Still, it's telling of the industry's regard for Forth that the manufacturer itself manages to misspell the language as "Fourth" in the chip's official product page.

cbd1984• 12 years ago

To be fair, Moore originally wanted the language to be called "Fourth":

The file holding the interpreter was labeled FORTH, for 4th (next) generation software - but the operating system restricted file names to 5 characters.

http://www.colorforth.com/HOPL.html

It was the OS for the IBM 1130: http://en.wikipedia.org/wiki/IBM_1130

Because it was the cheapest computer IBM had at the time, it got used by a lot of young pioneers in their salad days.

lbruder• 12 years ago

Well, it was the original name Forth was going to have. Just that the OS it was built on allowed only five character file names...

jacquesm3• 12 years ago

Hah, an old friend. A company I worked with had a Novix in 1986/1987 for prototyping purposes (early days number plate recognition system). Before we got it we had to sign an unreasonable amount of paper. Rumor had it this is the chip powering the Tomahawk cruisemissile.

abecedarius2• 12 years ago

Brought a smile to my face too: I had a summer job in 1986 at FORTH, Inc., and spent some quality time with my officemate's cmForth manual. (cmForth was Chuck Moore's new Forth dialect for the Novix. IIRC the manual said the multiply-step instruction didn't quite work and gave a software workaround.)

Create2• 12 years ago

Raytheon refurbish...

jesrui• 12 years ago

Another microprocessor able to execute Forth natively is the b16, from one of the original authors of Gforth.

http://bernd-paysan.de/b16.html

ryanmk• 12 years ago

There's also GreenArrays GA144, which has 144 forth machines on a single microprocessor.

http://www.greenarraychips.com/

programmer_dude• 12 years ago

Can someone point to resources comparing stack machines and register based machines? The RTX2010 technical documentation talks about all the advantages of a stack machine but doesn't say anything about its shortcomings.

wlievens6• 12 years ago

Optimal register allocation is an NP-complete problem. By doing away with it, you don't need to allocate registers.

How that compares on a practical level, I have no idea. But it's one of the reasons the JVM has a stack-based model and no registers: it makes writing compilers for JVM byte code a lot easier.

s800• 12 years ago

Interesting. I agree with your statement regarding it being an NP-complete problem, as intuitively it seems that way, but do you have a reference by chance? Thanks!

CHY8722• 12 years ago

This isn't quite right - we don't in general really care whether we're allocating optimally (for example, if we have 16 registers we don't care if we can potentially allocate to 10), and heuristic based approaches are practically very useful (and cheap).

In terms of compiler writing, if you wanted to write any optimisations you'd probably want to manipulate 3-address code internally, if only because the data flow based analyses would be made easier (and then you would emit stack code in the last step).

This might be a reason why the JVM designers decided to use a stack machine, but I doubt it's an important one - they'd easily be able to get ahold of a few decent compiler writers if they needed to.

userbinator2• 12 years ago

http://en.wikipedia.org/wiki/Stack_machine#Performance_disad...

The biggest disadvantage is their performance because it's hard to make them do operations in parallel.

sehugg2• 12 years ago

A lot of the usual criticisms don't apply. This code will never be JIT-compiled. Instructions take either 1 or 2 cycles depending on whether memory is accessed, so there's no pipelining or caching concerns.

Actually in this thing the top two elements of the stack are held in registers. So if you wanted to use the ANSI C compiler instead of FORTH, you might just think of it as a two-register machine (there are actually quite a few more) with a few special stack-manipulation instructions.

mud_dauber2• 12 years ago

How cool - I joined Harris after grad school expressly to work on RTX architecture issues. (Previously I was a Forth developer.)

Nice to see this neat-but-underappreciated architecture in the news.

naland2• 12 years ago

Nice to see this neat-but-underappreciated architecture in the news.

It's already appreciated. Let me recall here the 'scientist' character (A&B Srugatsky) who explains the World as a huge inertial mass to the good or evil in the same.

Tertium non datur it is a principle of our mind sometimes used in computers.

naland2• 12 years ago

edit: Strugatsky. hi ±HN.

jacquesm3• 12 years ago

What does Russian SF have to do with the Forth high level machine?

imrehg• 12 years ago

Listed but unfortunately not stocked: http://www.mouser.tw/Search/Refine.aspx?Keyword=RTX2010

kens• 12 years ago

I looked on Alibaba and Shenzhen suppliers have the HS9-RTX-2010-RH for sale at 10 cents a chip, able to supply up to 100,000 chips per month.

How do they do this? They're lying. Various Alibaba vendors list literally every part number they can find as something they are selling. If someone wants it, then they see if they can actually get it.

In any case, the real price for the RX2010 was between $1000 and $10,000 according to this thread I found from 1999: http://www.strangegizmo.com/forth/MISC/msg01281.html

mud_dauber2• 12 years ago

Of course they are. The last place I'd go for reputable semiconductor suppliers is Alibaba. The LAST.

nraynaud• 12 years ago

it's quite strange that there is not backlash against those manufacturers that don't make their parts or their datasheet available. They are just a pain in the butt and they drive our buying power down.

SixSigma2• 12 years ago

A very closely related processor, the RTX2000, is described in detail in Koopman's book "Stack Computers: the new wave"

http://users.ece.cmu.edu/~koopman/stack_computers/index.html

The RTX2010 has had its own wikipedia entry too since 2008 : http://en.wikipedia.org/wiki/RTX2010

samatman• 12 years ago

The yearly Forth Day meeting is happening right now, and Chuck Moore (inventor of Forth, designer of the RTX2010) is going to give his annual fireside chat in a matter of hours. I'm honored to be in attendance.

So if HN has any questions, this is a good time to ask them. The hangout is here:

https://plus.google.com/u/0/115269917987589859757/posts

tailrecursion• 12 years ago

Sam, Chuck designed the Novix but the Harris RTX 2000, which is very similar, was designed by others.

These are 16-bit chips (the Novix addressed 128 KB) that use dedicated stack memories, that's 3 ports to memory total. The RTX puts the stacks on chip.

The nice thing about these CPUs is they can do stack, alu, and return in parallel, interrupts are cheap, timings are predictable, and programming model is nice if you like Forth. One disadvantage of the design is that clock rate is limited. RAM fetch and instruction processing have to fit between pulses meaning RAM has to be approx twice as fast as clock.

RTX2010 – Radiation-hardened stack machine microprocessor

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