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RTX2010 – Radiation-hardened stack machine microprocessor

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Re: RTX2010 – Radiation-hardened stack machine microprocessor

#11

Post by cbd1984 »

jng wrote: post #5

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.

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.

Re: RTX2010 – Radiation-hardened stack machine microprocessor

#12

Post by lbruder »

jng wrote: post #5

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.

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...

Re: RTX2010 – Radiation-hardened stack machine microprocessor

#14

Post by wlievens »

programmer_dude wrote: post #13

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.

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.

Re: RTX2010 – Radiation-hardened stack machine microprocessor

#15

Post by wlievens »

Osmium wrote: post #8
Sanddancer wrote: post #6

Earlier quoted context omitted.

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…

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.

Wouldn't work for all applications, tough, if I'm not mistaken, as you specifically need Silicon for imaging chips (CCD/CMOS). Or is that nonsense?

Re: RTX2010 – Radiation-hardened stack machine microprocessor

#16

Post by Someone »

wlievens wrote: post #15
Osmium wrote: post #8

Earlier quoted context omitted.

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.

Wouldn't work for all applications, tough, if I'm not mistaken, as you specifically need Silicon for imaging chips (CCD/CMOS). Or is that nonsense?

Why would you need silicon for that? Even if it were the only process we use now (which it isn't. As a simple example, Germanium-based photo diodes do exist), materials research could conceivably produce other materials that work, too.

There are even more exotic examples to think of. Eyes turn light into electricity without (AFAIK) Silicon. Maybe part of that physics/chemistry can be practically used elsewhere?

Re: RTX2010 – Radiation-hardened stack machine microprocessor

#17

Post by userbinator »

lelf wrote: post #3

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

> 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_...

Re: RTX2010 – Radiation-hardened stack machine microprocessor

#18

Post by userbinator »

programmer_dude wrote: post #13

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.

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.

Re: RTX2010 – Radiation-hardened stack machine microprocessor

#19

Post by sehugg »

programmer_dude wrote: post #13

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.

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.

Re: RTX2010 – Radiation-hardened stack machine microprocessor

#20

Post by gus_massa »

wlievens wrote: post #15
Osmium wrote: post #8

Earlier quoted context omitted.

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.

Wouldn't work for all applications, tough, if I'm not mistaken, as you specifically need Silicon for imaging chips (CCD/CMOS). Or is that nonsense?

Theoretically you can make integrated circuit with any semiconductor, but I don't know if anyone has been brave enough to try it.

The smallest integrated circuit is a diode, it has 1/2 transistors :). OK, a diode is not actually an integrated circuit, but if you can use a material to make a diode, you probably can use the same material to make an integrated circuit with enough money, time and ingenuity.

Some of the diodes are made of germanium. It has a very low band gap, that is useful for "crystal radios" ( http://en.wikipedia.org/wiki/Crystal_radio#Crystal_detector ). Perhaps this can be useful to make very low voltage CI, to reduce the power and heat. But perhaps there is a technical problem that I don't know.

The diodes in the LED have many semiconductors. The band gap of the material is related to the color ( http://en.wikipedia.org/wiki/Light-emitting_diode#Colors_and... ). With this you could make high voltage CI (like 10V?). Perhaps it may reduce the noise ratio??? But perhaps there is a technical problem that I don't know.

[kens: If you are reading this, I'd love to see a technical post about this subject.]

--

Edit: According to Wikipedia, one of the first CI was made of Germanium: http://en.wikipedia.org/wiki/Integrated_circuit#Invention

> Half a year after Kilby, Robert Noyce at Fairchild Semiconductor developed his own idea of an integrated circuit that solved many practical problems Kilby's had not. Noyce's design was made of silicon, whereas Kilby's chip was made of germanium. Noyce credited Kurt Lehovec of Sprague Electric for the principle of p–n junction isolation caused by the action of a biased p–n junction (the diode) as a key concept behind the IC.

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