Slashdot Log In
FourHead: One PC, Four Users
Posted by
timothy
on Sat Jul 03, 2004 03:11 PM
from the four-times-the-fun dept.
from the four-times-the-fun dept.
LoganGD writes "A reseach group from UFPR university in Brazil, C3SL has managed to make one Linux box run four terminals at the same time. That means four mice, keyboards, displays and users with just one CPU. The way they managed to do that can be found at the FourHead project webpage. The fact that one computer science laboratory can suport up to 60 users whit only 15 PCs is really attractive for low-resource groups and countries."
This discussion has been archived.
No new comments can be posted.
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
Full
Abbreviated
Hidden
Loading... please wait.
The heat! The heat! (Score:3, Insightful)
I would be interested to see how they handle it!
Re:The heat! The heat! (Score:5, Insightful)
As for the noise, it'll still be quieter than 4 separate boxes.
Parent
Hate to burst your bubble... (Score:5, Insightful)
I don't think anyone could argue that these create massive amounts of heat. What heat they do create can easily be exhausted by a case fan.
This is definitely a setup for an environment where people are literally running on a shoestring budget. This is a really nice ability, and I'm glad someone has done it.
Parent
Re:Hate to burst your bubble... (Score:3, Interesting)
Heat has never been an issue. And this is a standard ATX case - no mods, no heavy cooling. Just one intake, one exhast, and the PSU.
They're TNT2, and hardware GLX is supported... (Score:5, Informative)
Backtracking to Utah-GLX's driver (project page here [sourceforge.net], this will allow many complex openGL-phile programs to run at the same time given its architecture. I, however, doubt that older XFree86 3.3.6 will scale to this feat; I simply don't know. Yet, the Utah-GLX driver system has been ported to XFree86-4.x; it is a openGL GLX driver package in the form of dynamically loaded X Server modules/extensions and can be manipulated into and without the X Server without having to restart the X Server. It's somwhat parallel to the DRI driver, to provide an alternative, but it is not being maintaned anymore; Utah-GLX is dead and someone needs to commandeer!
I am using three Athlon Thunderbid 700MHz computers with a total 9 nVidia TNT2 adaptors total (three per computer), S-Video composite output to NTSC televisions, and quad-bonded 100BaseTX ZNYX LAN adaptors for verry low-latency threaded shared openGL rendering; I use as Chromium 3D videowalls, by using XFree86 4.3 and Utah-GLX's nVidia openGLX driver.
And yes, Quake3 looks hot!
Parent
OOOOH..... linguistic pet peeve (Score:4, Funny)
Drives me nuts every time someone says 'literally' to modify a phrase that it is literally impossible to construe in any way but figuratively.
~Sub
-1 Troll
-1 Flamebait
+1 Linguistic Merit
+1 Crankiness
Parent
Re:The heat! Probably not a problem.... (Score:3, Informative)
My machine has been running for a few weeks and is not noticeably hot, however they are not the latest state of the art graphics cards, esp
In Brazil? (Score:3, Funny)
This is new? (Score:3, Insightful)
Re:This is new? (Score:3, Insightful)
However running multiple instances of X on a single computer is pretty new. Before you had seperate machines that acted as X terminals that had their own low-power proccessor and video card for driving the gui and their own keyboard and mouse. Then those plugged in thru the network and into the computer that way.
With this method you simply attatch the monitors and keyboards to a single machine and share the resources that way.
More direct and a bigger pain in the arse. PC's wer
Re:This is new? (Score:3, Insightful)
Is it? My computer is running 3 right now... I use them to allow me to keep my work as one user while graphically logging in as another, or allowing others to login to the computer without me having to disturb my desktop environments.
Re:This is new? (Score:3, Insightful)
No it isn't. The first server listens at port 6000, the second server listens on port 6001, and so on. You specify which server to use with the DISPLAY variable (or the -display parameter) x.x.x.x:y.z where y is the server number. Multiple displays has been supported by X for a long time. Multiple input devices have been at bit less supported, but I guess that some of the CAD engineers early in the '90 have used it.
Virtual display
Re:This is new? (Score:5, Informative)
Parent
This has been done a long time ago... (Score:4, Informative)
http://cambuca.ldhs.cetuc.puc-rio.br/mult
But if one uses XGGI, its easy to get eight or more users on a single PC.
- A.C.
1975 called (Score:4, Funny)
1975 called. They want their computer headlines back.
Best regards,
Chairboy
Re:1975 called (Score:5, Funny)
Parent
Re:1975 called (Score:3, Funny)
(ob Seinfeld reference)
Multi-headed Computer (Score:5, Interesting)
Also, you don't need 4 cards, You could do it with two. NVidia's twinview allows you to run two seperate X-servers off of one card (provided of course that it has two outputs).
Re:Multi-headed Computer (Score:5, Interesting)
When I got a dualhead card, I knew that I wanted two separate desktops, between which I can switch with a hotkey, not by scrolling the mouse to the other display (I wanted to use virtual desktops on both). I was astounded that I could find absolutely no way of doing this, and no references to it on the Net.
The best I could do was make the screens separate and stop the mouse from going from the edge of one display to another, but then I found no way of moving the pointer to the other screen.
After a few months I found a suitable function call in the X libraries and wrote a small program, switchscreen [www.iki.fi], to switch between the displays. Now I've got two totally separate desktops between which I can move with a simple alt-tab.
You can read the details for configuring your X system like this in the README file included in the package.
Parent
Re:Multi-headed Computer (Score:3, Informative)
On multihead and Xinerama (Score:3, Interesting)
I use a standard (non-Xinerama) dual-head config and a dual-head aware window manager (Openbox 2.x). This setup has but one serious flaw, and that is the inability to move windows between the screens. What it offers over xinerama is that it does not require xinerama-aware applications. Popup notifications never show up in between the monitors, for example. The
Re:Multi-headed Computer (Score:3, Informative)
Ah, young Jedi, but there is a way...
Ruby, or Backstreet Ruby [tldp.org].
Note that this was in the article, though the link for Backstreet Ruby here [times.lv] is down - probably Slashdotted.
Beauty of open source.
My favorite line (Score:5, Funny)
Been there, done that (Score:4, Funny)
Hehe, it was good for playing tricks on my parents when they were sitting at the desk with the PS2 mouse and I'm sitting a few feet behind them with the handy wireless USB mouse.
*evillaugh*
Been there, done that (Score:5, Funny)
Man, this is old news. We did this few years ago with five or more people on one machine. All we needed was a really small computer class, some free chairs, one PC, one keyboard, one mouse and one display.
Fastest (or strongest) got the best seats and the one with specs got the keyboard.
Talking about multi-tasking...
Wow, lots of dumb responses... (Score:5, Informative)
'xterminals are cheaper' -- anyone care to back that up?
to:
'Windows terminal services can do this' -- don't know where to start on that one, suffice it to say: it can't.
to:
'This is just serial terminals' -- it isn't. RTFA.
I'm sure I missed a few...
Re:Wow, lots of dumb responses... (Score:4, Informative)
Sure
I buy NCD explora 701's and 402's all day long at $10.00 each the local community college was donated about 10,000 of the things and has no idea what to do with them. I have been buying lot's of 10 at $10.00 each and selling them to clients on the side. I also see them as well as the newer ones on ebay for around that price and up to $20.00 each. add a 15 inch monitor which can also be had for dirt (and has the EXACT same cost as this 4 head setup btw...) oh and keyboard, mouse. (same
I can add a workstation to a P-4 class server for around $75.00 each. that includes a new 15 inch monitor, mouse and keyboard + the ncd 701 terminal. each P-4 (1.2ghz) can handle about 10 users comfortably. and if you get 701 explora's or use old Pentium 233MMX machines, you get accelerated video playback (and most ALL xterminals support sound.) and seperate sound for EACH terminal... something that is not available on this 4 head setup.
the best way to actually set up a school full of x terminals is to have 3 servers... 1 for boot/ network management, 1 for 1/2 the apps and 1 for user login + storage and the rest of the apps.
using this setup we were able to install about 100 xterminals for a christian school for around $10,000.00US not including the wiring of the CAT-5e... that labor was donated by someone else.
so if you can show me that you can do it that cheaply (and yes, I make a profit at $75.00 each station... $39.00 each for gateway monitors, $10.00 each for the NCD terminals, $10.00 for cheap mouse and keyboard. that's $20.00 profit per station fro me) even at less than 100 units... my savings starts when the first pc is purchased. today's computers are horribly over-powered.
Parent
Re:Wow, lots of dumb responses... (Score:3, Informative)
Thinsoft sells BeTwin [thinsoftinc.com] which does exactly that. (The first versions were "PC Buddy" back in '99. On an ISA card, even!)
Of course it's more expensive (you need to buy software) than the Linux solution, but what Windows solution isn't?
Benefit? (Score:4, Insightful)
The only way I see this as a good idea for any low budget organization is if they get donated lots and lots of monitors, keyboards, mice and computers with graphics cards for this project.
Great gamer machine. No latency! (Score:5, Interesting)
Re:Use some REAL hardware and you COULD do this (Score:3, Informative)
PCI-X is 4.3 GB/s (maximum!), and AGP 8X is 2.1 GB/s. Four graphics cards talking on a PCI-X bus would probably saturate it, especially given that it's shared-bus, so the number of bus arbitrations would be huge.
PCI-Express is point-to-point, so provided you could find a motherboard with 4 x16 links (good luck!) or at least had 4 x16 slots (again, good luck) you could do it.
But a 4 processor motherboard with 4
Diversity is good (Score:5, Interesting)
What's curious... (Score:3, Informative)
And now Microsoft woke up.
After NEXT, GECOS and a couple others, PC has a GUI! Windows 1.0! Years after Amiga with real multitasking introduces Task Switching and later ('95) first Multitasking. Then the puny '98 "multi-user" (Amiga had that some 5 years earlier, UNIX machines way before that). And now, in 2004 we hear that after users of XP are tired of the pseudo-multisession of Switch User, SP2 is to include REAL MULTISESSIONING! Yeah, right! Two users can work on the same computer at the same time! Yay!
Noticed the catch? The keyword is "two". Yeah. Two sessions ought to be enough...
And the reason this can't be done with Windows... (Score:4, Insightful)
Or that it can't support 4 different users on them (as opposed to 1 user getting a big display)? Probably not, at the very least, it would be hackable.
Maybe it can't support multiple keyboards, or mice? Again, the most it would need is some hacking.
Or maybe, just maybe, if you posted a webpage, telling someone how to use a single windows license for 4 users, M$ legal would go apeshit on you, and stomp you into a tiny, tiny greasestain?
BINGO!!
60 users on 15 PC's - try 60 users on an 8MB VAX (Score:5, Interesting)
Has computing gone forwards or backwards when it takes thousands of times the compute power to support fewer users, doing dumber things. We used to run whole research departments developing mathematical modelling, computational physics programmes on a single DEC VAX 11/750 with 8 MB of main memory and like 80 MB of hard disk space. It was so underutilised that astrophysics would rent out time on the darn thing to geophysics and chemistry.
This was on 4.2 BSD, the mother of all open source operating systems. And we had access to supercomputers at Argonne, NCAR, LANL, LBL and Cornell over the ARPAnet. in the freaking early 1980's.
AND we produced beautifully typeset scholarly papers and theses, full of equations using TeX. Try doing that with Office. Hnf.
Personally, I used to use maple to do the algebraic manipulations, and export to either fortran (to run a numerical simulation to get the results that formed my thesis) or to TeX (in order to publish it). Sure as hell can't do that with the stupid Office (open or MS) programmes you need 15 64MB computers to support only 60 users on in this model. Even if you insist on running a pointy-clicky GUI, with X10 we used to run dozens of graphics terminals off of one VAX
This article just proves that the net progress of computing is actually backwards because the computers certainly are getting bigger/faster/better more slowly than the intelligence and creativity of the users -- now they all need a GUI just to edit text and compile programs. To the point that it's a miracle when you can have more than one person using a computer at a time now. Sheesh!
Re:60 users on 15 PC's - try 60 users on an 8MB VA (Score:3, Insightful)
This is a lot different than that - this is about taking an interface that has been designed assuming there is one user in front of it, and hacking it to support multiple users. M
My first home computer (Score:3, Informative)
It had a Z80 CPU to handle I/O housekeeping chores and an MC68000 main CPU running XENIX (a flavor of UNIX).
It supported four users at the same time - each at their own terminal - with no additional goodies needed at the 16B+.
Mine did have a full load of memory, a larger hard drive, and a few Hayes modems so the other users could be remote, but the modems hooked right into the existing multiple ports on the machine.
For several years it was a minor mail and news server on the web (named tijil).
In what major way it this "new" thing astonishingly different from what I had 20 years ago on my desktop at home?
Take care,
Tomas
Re:Mainframe? (Score:5, Funny)
Parent
Re:Mainframe? (Score:5, Informative)
This is a standard computer handling several video outputs, keyboards and mice by itself. Just the same as any one person system, but handling multiple persons instead.
Or something.
Parent
Re:Mainframe? (Score:5, Interesting)
and has way more overhead and cost than using old P-I233 computers or dirt cheap x terminals on a network.
I can support 10 users on one machine using Linux Terminal server for 1/4th the cost of their supporting 4 people on one machine.
and I have a overall lower processor load.
It's neat, but nothing more than that right now.
Until the supply of free Pentium I class laptops and desktops dry up or the sources for dirt cheap xterminals dry up, it's nothing more than a expensive wy of doing things.
Parent
it does workstation stuff very well (Score:4, Insightful)
for you. Every now and then, you sit idle while you
wait for the PC.
Now get a 4x faster PC, and share it 4 ways.
Very seldom will all 4 users need the CPU at once.
So, nearly all of the time, you'll get better
performance. When you need the CPU, most likely
the other 3 users are reading, thinking, chatting,
drinking, picking their nose, or whatever. The
fast hardware is all yours.
Parent
Re:it does workstation stuff very well (Score:3, Insightful)
Which is why we moved away from the mainframe in the first place.
The benefit of this technology, if there is one, is that four users with bare minimum needs can share one commodity computer. Control four web terminals at your coffee house from a si
Re:it does workstation stuff very well (Score:3, Insightful)
That simplifies the explanation though.
You might go to 2x or 1.5x instead. The end
result is still faster most of the time, because
the PC spends nearly every moment being idle.
My load average is 0.14 right now, and I'm not
even using a modern system. (old 450 MHz Mac)
Despite the low usage, there are times when I
must wait.
With the 4-user box, you also save on electrical
power, noise, air conditioning, and physical space.
Re:Mainframe? (Score:5, Informative)
Do a bit more research, and you find that those mainframe installations had processors that ran at clock rates somewhere between 1 and 20 MHz, with typically a few megabytes (equivalent) of RAM, and a few hundred megabytes of hard disk. (And a few tape drives, but the tapes were not really used that much, by comparison.)
As a convenient example, consider the Control Data 6600 supercomputer at UT Austin in 1970. The CPU clock was 10 MHz, and it had just 131,072 words of main core memory, at 60 bits/word (which works out to about 1 Megabyte). It had two disk subsystems, one of which stored 168 million characters, the other storing 241 million characters.
Compare this with a 486/33, with 4 megabytes of RAM, a 200 Mb and a 340 Mb hard drive. 4 times as much RAM, probably comparable CPU throughput (the 6600 CPU was a master of parallel execution: it could be running as many as 10 instructions simultaneously).
The 6600 was heavily time-shared.
Late in the 1970s, things started getting interesting. The magic point was called "3M", which stood for "1 MIP, 1 Megabyte, 1 million pixels", and the price on that was JUST BARELY within reach of an individual.
Now look today. Our LOW END personal computers come with HUNDREDS of megabytes of RAM, hundreds of MIPS, tens or hundreds of gigabytes of disk storage, and several million pixels. (The limit on pixels is what you can get onto a display and refresh at a reasonable rate.)
What limited these guys to "only" four users per PC wasn't processing power or video bandwidth. It was the number of PCI video cards they could physically stuff into a PC motherboard.
Parent
Re:Economy? (Score:3, Informative)
Re:Economy? (Score:4, Insightful)
Also, boxes need replacing more often than monitors, so you get even more cost savings later on.
Parent
Re:Privacy issue? (Score:5, Informative)
I suggest 4 CD-ROM drives and correct permissions set in fstab so everyone can use -their own- drive only
Parent
Re:Privacy issue? (Score:3, Funny)
Re:LTSP still a better option (Score:4, Insightful)
Not unlikely hardware is more expensive than in the US and the wages are a lot lower for sure. And students are working on these PCs, so downtime is almost free. I believe such a four head solution also provides better response than a LTSP installation. Video playback and similiar stuff should be possible on a four head installation.
Parent
Re:I've wanted to do this with windows... (Score:3, Interesting)
In fact, we installed 10 workstations using this system on 5 PCs for a client of ours recently--replacing 10 old iMacs--to lower the TCO for a small call center.
It's been working great, no problems whatsoever.