But which set of books will they show you? :-)
bill
-- Bill Gunshannon | de-moc-ra-cy (di mok' ra see) n. Three wolves billg999@cs.scranton.edu | and a sheep voting on what's for dinner. University of Scranton | Scranton, Pennsylvania | #include
I was wondering why the old computes couldn't be used for that.
-- I think I am an Elephant, Behind another Elephant Behind /another/ Elephant who isn't really there.... A.A. Milne
Linux does not use that much ram, from the raspbian I installed 50 days ago (uptime is 48 days now)
There is 64 mb used by the graphics engine, as per my config, and the Linux kernel uses 26MB before freeing up space.
The X server uses 37 MB, the variuos LXDE processes about 45 MB, and then come the applications, which then have 448-26-45-37=340 MB, which is quite enough for a browser and an IDE. And, yes, that can be tight if you start with 256MB less.
ARM code is a bit tighter than x86, the code segments in /bin are generally 8-17% smaller. Not all that much, but it contributes.
The 256MB version should have around 85M between them, something which would run intense paging once you start more than a few shells.
The 900Mhz (overclocked) 512M runs a browser; chromium is the one that has the best "feel", but you can only have 5-6 windows open before it hits paging. It is also essential to have a _fast_ SD card when it comes to modern desktop applications. Otherwise it will die performance-wise once the applications starts doing I/O.
It can do around 25 mb/sec worth of I/O, restricted by the interrupt load.
Really not bad for a $50 piece of hardware.
And I wouldn't be ashamed to offer it to any developer of stock
*n*x code. They get to see another world from the wintel, if nothing else.-- mrr
I am designing a real-time monitoring platform for a hosting centre. I plan on using rpis to drive _all_ the monitors, around 12 in total; and use phidgets (again, around 12) to sample environmentals, and have trimslices as hubs; 4. All powered by a dual marine power supply at 12V backed by enough battery to last 48 hours, including switches and some emergency internet back door.
Actually, the screens themselves take around 70% of the power budget. We may dispense with 2/3rds of them if the power cut takes more than 4-5 hours.
-- mrr
"Policy" amongst other reasons,such as the school or local authority normally not owning them, and so they aren't allowed to give them away, they're owned by the IT supplier. If they do own them, then they're required to dispose of them in the most cost effective manner possible, which is normally by accepting the best tender from a selected disposal firm. There is a possibility that confidential data could be retrieved from the hard drive, even if it's only cached data. Any operating system or other software licences aren't allowed off the school network, so the HD would have to be either removed or securely wiped to a satisfactory standard.
There is also the paranoia which is rampant nowadays, what if it were to burst into flames and burn the child's home down? Could "we" be held to account? The people deciding such things aren't capable of making reasoned decisions in this field, and the ones who are, aren't allowed to, and wouldn't normally be consulted.
Mostly though, it's because by the time a computer is too old and slow to be used as the schools do, it's far too slow and short of memory to do anything useful with modern software.
If you want your child to learn (Mainline) computing properly, buy them a cheap old system from the guy in the market or back street, and load an operating system onto it. I recently bought an old computer box which had a Windows 2000 authentication sticker on it for £39, and although the HD had been wiped, it's not hard to find a working installation .iso and burn it to CD. Or, I could have just put Linux onto it for nothing. Add a cheap keyboard. mouse and display for another £40 quid, and Bob's your uncle. My box needed a new cooling fan as it kept cutting out, which cost me tenner or so, and, if I'd not known how to change one already, it would have been an educational experience learning how.
The Pi is a very good and cheap way to learn about the basics of computing at low level, and how the software interacts with hardware, which is somnething that can't be done cheaply with mainline computer gear.
-- Tciao for Now! John.
You're reading too much into that. This was already discussed, in the earl y days of this newsgroup.
Learning isn't just in school. There have always been kids who learn thing s by themselves, out of curiosity or because they are experience based lear ners. They'd be the ones pursuing hobby electronics or amateur radio or am ateur astronomy (including building their own telescope) or whatever.
I didn't get a computer until late, 1979. A KIM-1, it had all of 1K of RAM, a calculator style keyboard and readout, and could only save things via a cassette recorder, if I hooked one up. One couldn't do much anything pract ical with it, so it was a toy, a place to play/learn about computers. It h ad a great monitor in ROM, so I could single step instructions, see the reg isters after each step. I could just enter one op-code and see what happene d, since the monitor would take care of the rest, or run a few bits of code , getting it right and then putting it together with other things. I didn't read books in anticipation of playing with the computer, I'd use them in t andem, or even try things or think of something, then run to the book.
It was the same way I'd learned electronics starting in 1971 at 11 when I s tarted buying the hobby electronic magazines. None of it made any sense, i t was a steep cliff up, but I kept at it and picked up through osmosis, som ething that interested me so I kept learning, consuming anything I could ge t my hands on. I got my ham license at 12, not even studying much for the test, I was likely the youngest ham in Canada that June, because the rules had just changed in April so I didn't have to wait till I was 15.
This is how little children learn. They can't read, they can't even unders tand words, but they experience the world and learn from it. This is map-m aking, this is hacking.
Seymour Papert understood this, he'd watched small children, and the hacker s at MIT, and came up with Logo. It's not a "simple programming language", it's an "environment for playing/learning". "What happens if I do this... " and you can try it and learn. Sadly, once out of the lab, it became a "s imple programming language" and the teacher stood at the front of the class and instructed the kids in the language.
Lots of people do well because of that kind of learning, if nothing else it 's the basis of more formal learning. It's an enthusiasm that often isn't there in school, because people decide to play with computers on their own, but in school the curriculum is decided by the teacher or school.
If nothing else, I learned about learning by playing with electronics and c omputers when I was younger.
The Pi is like that. Something so cheap that it's not an impediment. Scro unge a keyboard and hook it up t the family tv set, just like in the days of the Commodore 64 or Vic-20. Yes, in this day and age most homes have a computer, but they are being used for "serious things", doing the wrong th ing can damage it. When a friend got a used Mac Plus in 1994, her daughter well summed it up by saying "I want to try things, but I'm afraid". She k new that trying things was learning, she knew that if she made a mistake sh e might erase something important, and then her mother would be upset with her. She didn't want that, so she didn't try things.
Making mistakes is learning, trying things is learning, but if you're too a fraid, that doesn't happen. You stick to the path, you stick to the map. I f you have a computer that isn't being used for important things, you can d o whatever you wish. It gets better, since unless you are storing things on the Pi, any accidental erasing of the operating system just means restorin g it. It's close to the days of the Commodore 64 when the "operating system ", actually BASIC in ROM, couldn't be erased because it was in ROM, If som ething locks up, turn off the computer, and turn it back on.
30 years ago, you could either get something really low end like the SIncla ir ZX-81, or spend hundreds of dollars for the TI-99 or the C64. YOu can g et the Pi today for a lot less, and it's a way better computer. I remember trying to learn C in 1988, on a 2MHz computer with 64K of RAM and 2 floppy drives. Just "hello world" took a long time to compile, and if there were errors they scrolled by so fast, and it was complicated to edit. I was us ing a 1GHz computer with 512K of RAM until October, and compiling small C p rograms on that was instant. It was like running an interpreted program on a ROM based computer in the old days, you'd be back at the command line ri ght away. So the Pi may not be like "new computers" but it's a really dece nt system, far better than home computers in the old days. It bes to be p layed with, which is where the intent is. Let kids play at programming, tr ying things and learning.You don't need schools when you can get the Pi so cheap. That's the bane o f the self learner, resources often aren't there because the money isn't th ere. Do I spend money on books, or on hardware to actually try things? Th e Pi beats that.
Michael
....snipped oots of good stuff for brevity...
Well said.
And, if the 'big computer' in your house can run CVS or an equivalent version control system, its easy to install that on the RPi (CVS is part of the Rasbian distro) and proof the stuff you've created against loss if the SD card breaks or you have to re-flash it.
-- martin@ | Martin Gregorie gregorie. | Essex, UK org |
:-)
-- Ineptocracy (in-ep-toc?-ra-cy) ? a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.
On Thu, 20 Jun 2013 08:50:24 +0100, Mark declaimed the following:
A somewhat common joke (in the late 70s) for Grand Valley State Colleges* Thomas Jefferson College that one could get a degree in dandelion growing.
* Now GVS University -- it was "colleges", plural, as it was considered a cluster college, having on the one campus: College of Arts&Sciences -- being the "traditional" "liberal arts", William James College -- using a pass/fail grading and focused on "career" subjects, and Thomas Jefferson College -- being the real "liberal arts", College IV [renamed Kirkhoff College after a significant donation ] was the part-time continuing education unit; TJC offered a Bachelor of Philosophy, and students laid out a course of study via consultation with an academic advisor -- no fixed majors. TJC closed in 1980; in protest many of the TJC graduating class wore "Down with Amway" stickers on their gowns (Rich DeVos was on the Board of Control).
--
Wulfraed Dennis Lee Bieber AF6VN
wlfraed@ix.netcom.com HTTP://wlfraed.home.netcom.com/
I had been wondering about QEMU, though I'm amazed that any of these things are even slightly usable on fast PCs, never mind an Rpi.
-- Windmill, TiltNot@Nonetel.com Use t m i l l J.R.R. Tolkien:- @ O n e t e l . c o m All that is gold does not glister / Not all who wander are lost
You've convinced me. Thank you.
Look, I'm thick. Where computers are concerned I'm as thick as it's possible to be, so if I got a Raspberry Pi, would I be able to understand it? Is the documentation good?
-- I think I am an Elephant, Behind another Elephant Behind /another/ Elephant who isn't really there.... A.A. Milne
Its Linux/Unix so suffers from, the usual 'documentation is good, meta data is appalling' syndrome.
The sorts of conversations that used to go across the lab of 'I need to do X? Anyone? 'Type 'man Y'' where Y is some arbirtrary command you had never heard of, hasnt changed much. B=Nor on typing 'man Y' was it easy to find the one command line switch you needed that did what you wanted.
Except you shout across the internet these days, and google is a sort of metadata thing.
-- Ineptocracy (in-ep-toc?-ra-cy) ? a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.
That may be why it never made it as an STB. a typical DBV MUX spits out
50Mbps.
Indeed.
-- Ineptocracy (in-ep-toc?-ra-cy) ? a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.
For the default setup, you hook it up to power, mouse, keyboard (via USB) and add network (cat5 cable, or wifi) and add a HDMI display. Then you download the image to an SD card, and off you go. You have an instant very ubuntu-like Linux, with all the trappings. (except Wine, the windows non-emulator).
Yes, the window manager is a bit lightweight, and the browser a bit slow, but that is it. Software builds take around 10x as long as on a state-of-the-art ARM processor, but that is also close to instantaneous.
So, you have full linux, plus some hardware you can use for control and monitoring purposes. The documentation is simply overwhelming. The apt repository has 23000 applications for download.
-- mrr
That does surprise me - seeing as ARM is RISC and x86 isn't - I'd have thought the code density would be much better under x86, however a few quick & dirty checks shows it's not:
/bin/ls 112518 x86 94233 ARM
/bin/nano: 189176 x86 157991 ARM
Both systems running Wheezy (Raspbian on the Pi) and outputs from 'size'.
Gordon
The "apropos" command is supposed to cover that
Remember that this is not specific for Linux, it is specific for doing tasks that are a little more complicated than bare minimum every day activity.
In Windows it is no different. Everybody knows how to open a file in the explorer clickety-click or how to select files and move them somewhere else (always nice to predict if it will move or copy), but ask a Windows user to move all files from one folder and all subfolders that are owned by one specific user to another folder and you have him baffled and searching the help. It will be interesting to see if they find a solution.
But not every bit, which was the norm when memory was expensive.
It certainly does what I want. Some have said it's too slow for browsing, and that may be correct from where they stand. But with servers usually overloaded, an ftp transfer getting only 0.2 MB/s over a supposed 2 MB/s link, and a brain which is becoming hard-of-thinking (especially in the afternoons, unless I skip lunch), it's fine for me.
I have one such, bought as a lower power unit which could be left always on, but then there was the FitPC, and now the Pi which truly can be left on at little cost even when they raise energy prices.
-- Windmill, TiltNot@Nonetel.com Use t m i l l J.R.R. Tolkien:- @ O n e t e l . c o m All that is gold does not glister / Not all who wander are lost
I was thinking that if the kernel had (and Windows drivers used) some kind of basic USB primitives which I suppose must exist at some level, it ought to be possible, maybe with some added kernel hooks, to execute Windows drivers from inside Wine. But I know nothing about USB. Or Wine.
-- Windmill, TiltNot@Nonetel.com Use t m i l l J.R.R. Tolkien:- @ O n e t e l . c o m All that is gold does not glister / Not all who wander are lost
I used to think that developers should be forced to use 10 year old computers as an incentive towards bloat-reduction!
-- Windmill, TiltNot@Nonetel.com Use t m i l l J.R.R. Tolkien:- @ O n e t e l . c o m All that is gold does not glister / Not all who wander are lost
I tried QEMU on a mac G3. took 20 minutes to actually get to a dos prompt :-)
Id guess that you could do better on an ARM using some sort of tight assembler code to interpret X86 machine code in a very small core.
I mean an X86 is sort of a RISC machine with microde anyway? The real advantage is probably in having access to high speed local cache and pipelining..
(Hmm.. ARM looks pretty good as a processor. Just been reading the wiki. NIce instruction set. I can see why compiler writers would find way to make code smaller on ARM.)
Anyway I see no reason why you couldn't get CP/M at least running in a Z80 emulator, on a Pi :-)
Then you could run wordstar!
-- Ineptocracy (in-ep-toc?-ra-cy) ? a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.