No one will need more than 637 kb of memory
Even on Mars
The Curiosity Rover will upgrade its operating system before getting down to serious science, NASA said today. The Rover's onboard computer has wimpy specs, boasting just: A BAE RAD 750 single-board computer with a 200Mhz Power PC CPU; Two gigabytes of flash memory; 256 megabytes of DRAM; 256 kilobytes of electrically …
Each module has its own memory and processor, the cameras can do their own JPEG compression, subsampling etc. before handing it over to be transmitted back.
e.g. "Each camera has an 8 gigabyte internal buffer that permits it to store over 5,500 raw frames"
http://mars.jpl.nasa.gov/msl/mission/instruments/cameras/mastcam/
As I understood it, the 5 Mbit / 40Mbit thing - that wasn't link speed, but total downloaded data in particular passes.
"40 megabits per second connection to Earth, when it can get it"
Damn; wish I could get that. My home broadband (which is on a business tariff) is currently getting 0.13 Mbps (and has been for the last 3 months) despite numerous calls to BT.
Perhaps I should try seeing if I could piggy back off the NASA connection? Or maybe it already is, and they just haven't told me?
Seriously thought, it's one hell of an achievement. I for one would love the chance to play with toys this cool.
NASA: Okay you got everything, you are ready to go?
Curiosity: Yeah lets do it!
NASA: You sure you have *everything* you need at the other end?
Curiosity: yeah yeah, come on lets go!
NASA: Packed enough fuel? What abou...
Curiosity: YES YES! come on launch me already!
...years pass....
NASA: Come in Curiosity...please send us your science report.
Curiosity: Hang on having some problems, I can't find the science software..
NASA: ...
Curiosity: Probably I just dropped it somewhere, I am looking for it right now
NASA: ... Did you pack the science software Curiosity?
Curiosity: Yep.
NASA: ... You sure?
Curiosity: Absolutely. 70% sure.
NASA: ...
Curiosity: Although now you mention it I think I left it on the table back home. Can you go round and mail it to me?
NASA: ...
"At a press conference today, NASA suggested the latter is about to get a workout, with panellists saying the Rover's flight computer needs an upgrade before it can start to perform sophisticated experiments."
Is it still a flight computer? Or is that the point of the upgrade, they're changing it from a flight computer to a drive/rover computer?
"Good day, gentlemen. This is a pre-recorded briefing made prior to your departure. In which for security reasons, of the highest importance has been known onboard during the mission only by your Power 750 computer. Now that you are on the surface of Mars and the entire crew is revived, it can be told to you. 18 months ago, the first evidence of intelligent life off the Earth was discovered. It was buried 40 feet below the lunar surface, near the crater Tycho. Except for a single very powerful radio emission aimed at Mars, the 4 million year old black monolith has remained completely inert. It's origin and purpose....still a complete mystery."
I don;t think the data rate information is correct.
Doesn;t agrree with this.
http://mars.jpl.nasa.gov/msl/mission/communicationwithearth/data/
I'm surprised that they have had to upgrade the OS especially after such a short trip. I wrote the s/w for the SSP experiment on Cassini Huygens and the last thing I would have wanted to do was significant s/w upgrades. I didn't use an OS as they are too resource hungary..
On that my data rate allocation was about 2 to 10 slots of 100 bytes per 12 second cycle. (From memory)
However having carried out such an audacious landing procedure an OS upgrade should be a walk in the park.
Yeah, El Reg has massively misquoted the data rates - I did think it was odd to achieve data rates to Mars in excess of a lot of UK broadband speeds! 32 kilobits per second is the top rate direct to Earth, and the fastest link rate is 2 Megabits per second to the Mars Reconnaisance Orbiter, but that's only in view for 8 minutes per orbit!
Try putting your i7 rig with 48 gig or RAM and AMD Radian 993848203 graphics next to an unshielded nuclear reactor and then tell me that the Curiosity computer is wimpy. Spacebound computers have to survive crap that would roast most typical desktops and laptops in seconds. And given how you couldn't get The Tech Guys to make a housecall to Mars, having it work under extreme abuse is far more important than ridiculous performance figures.
Nuke, because the wimpy computer can survive one.
And on the other side, either the icy coldness of interplanetary space or the burning heat of direct sunshine.
Given those temperature differences, even the freaking *box* that your average computer comes in wouldn't be able to survive, let alone the contents.
Underestimating their memory requirements
Updating software while in flight.
I'd note that one of the attractions of a military COTS design is that there should be a cheaper non-rad hard version for development (of course BAe cheap might not be your idea of the word).
The under sizing of memory has resulted in them developing procedures to make *absolutely* sure that what they sent the lander is what is sitting in it's memory and QA procedures to ensure that when control is transferred to it that it'll do what they expect..
What would be surprising would be if they were not working on this new up load since launch and be ready to start sending as soon as it landed. It would also be surprising that at least some of the rover experiments are not available right now. That suggests either *gross* under sizing of main memory, or the landing software grew a *lot* after launch and the experiment control software had to be dumped to make room, which I'd be pretty surprised about.
BTW quite a lot of the S/W on it's 2 previous rovers were built using open software tools and NASA has a strong interest in certain parts of AI, particularly scheduling in constrained resource environments and automated fault detection (from telemetry), diagnosis and mitigation (you can't really repair something that's several million Km's away from you).
Mines the one with "Computers in Spaceflight: The NASA Experience" loaded in the Kindle.
If you have an interest in this area you won't be disappointed. It covers all the major programmes from Gemini (8 IPS. This is not a typo) to Shuttle (Mercury did not have one).
For anyone who saw "Space Cowboys" and wondered "What is the Skylab computer system actually like?" this will answer that.
You'll also see which (probably) had the best managed hardware development process and what NASA uses to write the software to test and diagnose everything from the ground equipment to the payloads.
Can you point us at a decent ebook version? archive.org has either a dodgy half-gigabyte PDF scan or an even dodgier OCR of it. There's a decent HTML version here:
http://www.hq.nasa.gov/pao/History/computers/Compspace.html
...but goddamn it, I want a copy for my Kindle.
Oops, didn't spot you'd already seen the 500MB version.
It's odd that AFAIK this one was written electronically so a *direct* document -> PDF conversion should have been pretty easy.
But NASA has a *huge* back catalog of stuff and I think scanning one of those summer jobs they give interns, with varying levels of results. Some are searchable and some seem to be straight bitmap scans of the pages.
I'm not sure what the NASA policy on people going to see them and scanning it themselves is.
Grumble grumble stupid frickin' huge downloads grumble grumble.
Here's a single-page version, with cleaned up formatting, of the online HTML version of the book: https://docs.google.com/document/d/1XTVLIkwoAEf5mZnSwRFCHaW1_PZ4gG4d15NWd2arvtA/edit
There's still some work left to do --- tidying up the boxes and figures, indenting quoted text, etc --- but it's *vastly* easier to read like that. I haven't managed to make an ebook version yet, though, as calibre seems to choke on Google Docs' output.
Google Docs so does not like documents that big.