Yes, you can jump to the ASCII-armor area, but you can't pass parameters, which would have to come after the zero byte. Which is why the area is slightly larger than 16MB.
Slightly off-topic, but does anybody know whether IA64 or x86-64 allow you to make the stack non-executable in the same way you can on SPARC?
and hpa replied to this:
x86-64 definitely does, and it's the default on Linux/x86-64.
Up to now, x86 chips have not been able to separate Read from Execute privileges for memory segments, which makes it hard to make stacks non-executable. This is excellent news for anyone looking forward to AMD's x86-64 chips...it keeps looking like they've done the Right Things.
OT: did any subscribers see the "Microsoft DVD standard" article that was posted in TMF? It caught my eye and I refreshed the main page and it was gone, replaced by this article. Do the editors revoke certain articles before they go live? Was there a major factual error or something?
Whether or not Unix sockets are networking depends on your definition of networking. Yes, they use the same interface as INET sockets. However, they're completely 100% limited to local-host communication. How can something be a networking component if it can't talk to another host?
As I see it, Unix sockets are a form of inter-process communication which happens to act like inter-host communication. Which makes it easy to write code which communicates with either another process or another host, and does so efficiently in both cases. AFAIK, Unix sockets are the fastest form of IPC. Do you know why the shared-memory extension for X is mostly unused? Because it turns out that it's not any faster than Unix sockets, once you add synchronization.
Unix sockets are NOT the same as for example accessing a local drive through an NFS mount on the local server. That does indeed go through networking to the 127.0.0.1 address (which is fast, but not NEARLY as fast as AF_UNIX sockets).
Yes, X uses a protocol over the local sockets. That's inter-process communication. The X server runs as its own process, and that's a Good Thing.
No, it does not ever touch the network stack. Really. I promise. You can run X locally on a kernel which doesn't even have networking compiled in. Unix sockets are like signals, shared memory, message queues, and other forms of inter-process communication. They simply use the same socket interface as TCP/IP sockets.
X WINDOWS DOES NOT USE NETWORKING FOR THE LOCAL SERVER
X WINDOWS DOES NOT USE NETWORKING FOR THE LOCAL SERVER
X WINDOWS DOES NOT USE NETWORKING FOR THE LOCAL SERVER
Look here for an explanation of what Unix domain sockets are. They have nothing to do with networking and are the most efficient form of IPC on Linux. As a bonus, you can write code which uses either AF_UNIX sockets or AF_INET (TCP/IP) sockets seamlessly--but AF_UNIX sockets still have nothing to do with networking. Got it?
WineX will be successful if game developers make the simple choice to write Windows code which will run on WineX. For example, as of last time I looked, out-of-process COM objects weren't supported in Wine. It's certainly possible to design almost any Windows app to use in-process COM objects. If software houses begin to look at Wine's capabilities and say "hey, if I design within those (reasonable) limitations, then my app will run pretty easily on Linux."
Linux is a custom kernel which provides a source-compatible copy of the Unix APIs. The same thing will happen to Windows. I predict that in five to ten years, some version of the Windows 98 API will become a practically open standard with at least one full implementation, and any operating system will be able to run any app which will run on Windows 98.
OK, we have a galaxy (far far away) with at least a few thousand planets. Each planet would presumably have on the order of 1-10 billion inhabitants. So what are the chances that:
1. a "remote" planet called Tatooine continually becomes vitally important to the fate of the galaxy, time and time again?
2. The same five to ten characters coincidentally reappear, time and time again? C-3PO was actually made by Anakin and just happened to be on the ship that was attacked near Tatooine and end up on Luke's farm? Now Chewbacca is going to show up, as a "coincidence?"
I suppose you could make arguments about the 'Force' making these coincidences happen. But you have to admit that's retro-explanations. Everything in Episodes 4-6 indicated that these characters were meeting for the first time, with no prior history. Now Lucas (and Star Wars fanboys) want to convince us that "no, really there's a whole previous story with these characters, which was never alluded to in the 'later' episodes."
It just goes to show what a crap storyteller Lucas is these days. How he got that way, I don't know. But Star Wars these days is about as well-written as the Daredevil movie.
I believe that K+R C allows this, at least unofficially. I seem to recall something like this from the UNIX 6th ed. sources (in the famous Lions book). They declare a struct type, then later take a scalar variable (not sure if it was even a pointer) and dereference it as that struct without so much as a cast.
struct { int width } foo; int rod; bar = rod.width;
I have an HDTV tv which has a standard VGA port, which the manual says will accept 1080i input: 1920x1080 60hz interlaced.
Does anyone know of a video card which will support this resolution (and refresh rate)? Several support the resolution, but none seem to do 60hz interlaced.
Are you sure? I don't know much about NT's paging system directly, but rather by way of Linux and other 'modern OS' designs. As I understand it, an executable file's segments (code,data,bss) are simply mapped into the process's address space at load time, and only when the process accesses a page will it be faulted in.
The whole point of a paging system with unified disk-cache buffers / memory pages is to access memory completely virtually, and let page faulting and flushing read/write to disk as necessary. And in the vast majority of cases (of course there are always exceptions) that 'as necessary' clause is pretty accurate, and speeds up your system.
No modern operating system "copies" the entire executable into memory when it's run. It's paged in from disk as necessary. If it's already in the cache, then it basically is run from RAM anyway.
The concept of a paging VM system is so elegant that when it's done right, it makes most other optimizations (such as your EIP suggestion) unnecessary.
First, pagefiles (or swap partitions) are usually of fixed size. So their existance doesn't necessarily mean they're being used.
Second, RAM is used for disk cache as well as application memory space. 'Unused' RAM is really being used to cache your slow hard drive, which is a good thing.
Third, stuff is paged in and out when necessary to free up space for other stuff. It's swapped at the memory page level (4k) based on when data is used. So if you leave your system running for a while, the stuff that gets written to disk is stuff that hasn't been used.
The result is that the OS uses the physical RAM in a very efficient way. Your pagefile speeds up your system (assuming it's well written, and both NT and Linux do very well in this regard) and you really don't want to get rid of it.
Though I don't think it's a useful general-purpose concept to have a RAM-only FS, I'm hoping that fast RAM will catch up to magnetic disks in size. A standard FS/VM will end up caching everything if the RAM is available. I seem to recall that ext3 on Linux, if given the RAM for cache, is faster than many ramfs/tmpfs implementations. Plan9 completely removes the concept of a permanent filesystem versus temporary memory. Everything is mapped in memory, and everything is saved to disk (eventually). It's a neat concept, and it happens to go very well with 64-bit pointers and cheap RAM.
I'm hoping that hardware people will realize that we need huge amounts of fast memory...whether or not we think we need it. We're stuck in a "why would I need more RAM than the applications I run need?" kind of mindset. I think that the sudden freedom 64-bit pointers will provide to software developers will result in a paradigm shift in how memory (both permanent and temporary) is used. Though like all paradigm shifts, it's difficult to predict ahead of time exactly what the change will be like...
It's good that they're very precise, that it's not 5.001 or 4.999 users. Though why they need a gigabit connection for such a small group is beyond me.
Is it possible, with any of these solutions, to control them from a separate X session (or even from a command line) than where it runs? I would like to run a controlling session remotely from my laptop, and have the output sent from the server to the TV.
My TV supports a few good resolutions over a standard VGA connector (it's one of those HD-lite jobbies, which supports the format/resolution but not the wide aspect ratio). So I should just be able to run standard X from the video card.
You can do this, exactly as you say. I forget where the option is, but it lets you have a Konsole window attached to the bottom of a Konq window. When you change dirs in Konq, it cd's in the Konsole. That's about as far as they're linked, but it lets you do pretty much what you say.
if your ISP charges per computer connected, using a router/NAT device would be illegal if these became law.
If your ISP charges this way, then it's already a breach of contract to use NAT. If you want to use NAT, either pay up or find an ISP which doesn't charge additional per computer. What you'll find, of course, is that most likely the ISP which doesn't charge per computer will charge more overall. It's the same thing as when ISPs used to charge for dialup by the hour. People hated that, they wanted a flat rate per month. But the laws of economics state that the ISP's monthly charge will be equivalent to the hourly charges, averaged across all users.
Generally, if several companies in an industry start to charge extra for a service which was once included ('free'), then if people complain, they'll just roll it back in by including it in an increased base cost ('free'). So what you're left with is either 1. averaging the increased cost across all users, whether or not they use the feature which increases the cost, or 2. charging only the users which increase the company's cost. Obviously, then, people who would be charged want it included in the base cost ('free') and people who wouldn't be, want it as an extra. When it comes to NAT, I can guess where most Slashdotters will be...
There Ain't No Such Thing As A Free Lunch. Also known as the Second Law of Thermodynamics.
no, you don't understand...it's a firewall port issue, not a security one. I can use Mozilla over tls imap, but I can't get to that port through my company's outgoing firewall. I was wondering if I could use an apache virtual host and mod_proxy to connect from work.
I need the same thing. I stopped using Mozilla mail (and, well, Mozilla in general, in favor of Opera) because my work firewall is closed off to imap ports. I've been wondering if this should be possible with mod_proxy... couldn't I set it up so imap addresses of imap.server.com:80 got routed to my imapd?
The thing AMD needs to do is put 16 or 32 DIMM slots in the motherboard for their 64-bit processor. As many others have pointed out, RAM is dirt cheap for up to 1GB DIMMs. I could buy a 64-bit processor and motherboard plus 32GB of RAM for a reasonable sum.
That's 32 gigabytes. Just the disk caching speedups alone would be worthwhile. My firm belief is the only reason these huge RAM sizes aren't common is the 4GB physical / 3GB per process limits of current 32 bit OSs.
And why wouldn't the Skunk Works engineers have intended to make the F-117 as undetectable as possible?
They did, of course. But some people (possibly you?) seem to think that means a stealth aircraft is 100% invisible to radar and heat detection.
And what the hell does "heat-shielded" mean?
Heat shielded means that the exhaust ports are designed to avoid radiating obvious, detectable heat. Exactly what you said.
If a missile's radar has trouble tracking the target, so would any other radar. Judging by your lack of knowledge of this simple fact, I suggest you not inject your worthless, uninformed opinions.
Jesus, man, relax. I'm not an expert on this, but obviously neither are you. You claim I offered a worthless opinion, and then proceed to restate exactly what I said. The stealth fighter and bomber are designed to reduce radar reflection, heat emissions, electromagnetic radiation, and sonic signals. Reduce, not eliminate.
Slashdot Mirror
Yes, you can jump to the ASCII-armor area, but you can't pass parameters, which would have to come after the zero byte. Which is why the area is slightly larger than 16MB.
Someone on lkml asked:
Slightly off-topic, but does anybody know whether IA64 or x86-64 allow you to make the stack non-executable in the same way you can on SPARC?
and hpa replied to this:
x86-64 definitely does, and it's the default on Linux/x86-64.
Up to now, x86 chips have not been able to separate Read from Execute privileges for memory segments, which makes it hard to make stacks non-executable. This is excellent news for anyone looking forward to AMD's x86-64 chips...it keeps looking like they've done the Right Things.
OT: did any subscribers see the "Microsoft DVD standard" article that was posted in TMF? It caught my eye and I refreshed the main page and it was gone, replaced by this article. Do the editors revoke certain articles before they go live? Was there a major factual error or something?
OK, sorry, the FAQ wasn't the best link.
Whether or not Unix sockets are networking depends on your definition of networking. Yes, they use the same interface as INET sockets. However, they're completely 100% limited to local-host communication. How can something be a networking component if it can't talk to another host?
As I see it, Unix sockets are a form of inter-process communication which happens to act like inter-host communication. Which makes it easy to write code which communicates with either another process or another host, and does so efficiently in both cases. AFAIK, Unix sockets are the fastest form of IPC. Do you know why the shared-memory extension for X is mostly unused? Because it turns out that it's not any faster than Unix sockets, once you add synchronization.
Unix sockets are NOT the same as for example accessing a local drive through an NFS mount on the local server. That does indeed go through networking to the 127.0.0.1 address (which is fast, but not NEARLY as fast as AF_UNIX sockets).
Yes, X uses a protocol over the local sockets. That's inter-process communication. The X server runs as its own process, and that's a Good Thing.
No, it does not ever touch the network stack. Really. I promise. You can run X locally on a kernel which doesn't even have networking compiled in. Unix sockets are like signals, shared memory, message queues, and other forms of inter-process communication. They simply use the same socket interface as TCP/IP sockets.
To prevent uninformed comments about X:
X WINDOWS DOES NOT USE NETWORKING FOR THE LOCAL SERVER
X WINDOWS DOES NOT USE NETWORKING FOR THE LOCAL SERVER
X WINDOWS DOES NOT USE NETWORKING FOR THE LOCAL SERVER
Look here for an explanation of what Unix domain sockets are. They have nothing to do with networking and are the most efficient form of IPC on Linux. As a bonus, you can write code which uses either AF_UNIX sockets or AF_INET (TCP/IP) sockets seamlessly--but AF_UNIX sockets still have nothing to do with networking. Got it?
there are eight other posts in this thread trying to explain that X WINDOWS DOES NOT USE THE NETWORK FOR A LOCAL SERVER.
Do you hear me?
X WINDOWS DOES NOT USE THE NETWORK FOR A LOCAL SERVER.
X WINDOWS DOES NOT USE THE NETWORK FOR A LOCAL SERVER.
this would be a good place to start educating yourself.
WineX will be successful if game developers make the simple choice to write Windows code which will run on WineX. For example, as of last time I looked, out-of-process COM objects weren't supported in Wine. It's certainly possible to design almost any Windows app to use in-process COM objects. If software houses begin to look at Wine's capabilities and say "hey, if I design within those (reasonable) limitations, then my app will run pretty easily on Linux."
Linux is a custom kernel which provides a source-compatible copy of the Unix APIs. The same thing will happen to Windows. I predict that in five to ten years, some version of the Windows 98 API will become a practically open standard with at least one full implementation, and any operating system will be able to run any app which will run on Windows 98.
They're porting FreeBSD to Java? Wow, that's impressive. What OS do they run the JVM on?
OK, we have a galaxy (far far away) with at least a few thousand planets. Each planet would presumably have on the order of 1-10 billion inhabitants. So what are the chances that:
1. a "remote" planet called Tatooine continually becomes vitally important to the fate of the galaxy, time and time again?
2. The same five to ten characters coincidentally reappear, time and time again? C-3PO was actually made by Anakin and just happened to be on the ship that was attacked near Tatooine and end up on Luke's farm? Now Chewbacca is going to show up, as a "coincidence?"
I suppose you could make arguments about the 'Force' making these coincidences happen. But you have to admit that's retro-explanations. Everything in Episodes 4-6 indicated that these characters were meeting for the first time, with no prior history. Now Lucas (and Star Wars fanboys) want to convince us that "no, really there's a whole previous story with these characters, which was never alluded to in the 'later' episodes."
It just goes to show what a crap storyteller Lucas is these days. How he got that way, I don't know. But Star Wars these days is about as well-written as the Daredevil movie.
I believe that K+R C allows this, at least unofficially. I seem to recall something like this from the UNIX 6th ed. sources (in the famous Lions book). They declare a struct type, then later take a scalar variable (not sure if it was even a pointer) and dereference it as that struct without so much as a cast.
struct { int width } foo;
int rod;
bar = rod.width;
I have an HDTV tv which has a standard VGA port, which the manual says will accept 1080i input: 1920x1080 60hz interlaced.
Does anyone know of a video card which will support this resolution (and refresh rate)? Several support the resolution, but none seem to do 60hz interlaced.
Are you sure? I don't know much about NT's paging system directly, but rather by way of Linux and other 'modern OS' designs. As I understand it, an executable file's segments (code,data,bss) are simply mapped into the process's address space at load time, and only when the process accesses a page will it be faulted in.
The whole point of a paging system with unified disk-cache buffers / memory pages is to access memory completely virtually, and let page faulting and flushing read/write to disk as necessary. And in the vast majority of cases (of course there are always exceptions) that 'as necessary' clause is pretty accurate, and speeds up your system.
No modern operating system "copies" the entire executable into memory when it's run. It's paged in from disk as necessary. If it's already in the cache, then it basically is run from RAM anyway.
The concept of a paging VM system is so elegant that when it's done right, it makes most other optimizations (such as your EIP suggestion) unnecessary.
First, pagefiles (or swap partitions) are usually of fixed size. So their existance doesn't necessarily mean they're being used.
Second, RAM is used for disk cache as well as application memory space. 'Unused' RAM is really being used to cache your slow hard drive, which is a good thing.
Third, stuff is paged in and out when necessary to free up space for other stuff. It's swapped at the memory page level (4k) based on when data is used. So if you leave your system running for a while, the stuff that gets written to disk is stuff that hasn't been used.
The result is that the OS uses the physical RAM in a very efficient way. Your pagefile speeds up your system (assuming it's well written, and both NT and Linux do very well in this regard) and you really don't want to get rid of it.
Though I don't think it's a useful general-purpose concept to have a RAM-only FS, I'm hoping that fast RAM will catch up to magnetic disks in size. A standard FS/VM will end up caching everything if the RAM is available. I seem to recall that ext3 on Linux, if given the RAM for cache, is faster than many ramfs/tmpfs implementations. Plan9 completely removes the concept of a permanent filesystem versus temporary memory. Everything is mapped in memory, and everything is saved to disk (eventually). It's a neat concept, and it happens to go very well with 64-bit pointers and cheap RAM.
I'm hoping that hardware people will realize that we need huge amounts of fast memory...whether or not we think we need it. We're stuck in a "why would I need more RAM than the applications I run need?" kind of mindset. I think that the sudden freedom 64-bit pointers will provide to software developers will result in a paradigm shift in how memory (both permanent and temporary) is used. Though like all paradigm shifts, it's difficult to predict ahead of time exactly what the change will be like...
It's good that they're very precise, that it's not 5.001 or 4.999 users. Though why they need a gigabit connection for such a small group is beyond me.
Is it possible, with any of these solutions, to control them from a separate X session (or even from a command line) than where it runs? I would like to run a controlling session remotely from my laptop, and have the output sent from the server to the TV.
My TV supports a few good resolutions over a standard VGA connector (it's one of those HD-lite jobbies, which supports the format/resolution but not the wide aspect ratio). So I should just be able to run standard X from the video card.
Hey, don't say that...I just bought AMD stock.
You can do this, exactly as you say. I forget where the option is, but it lets you have a Konsole window attached to the bottom of a Konq window. When you change dirs in Konq, it cd's in the Konsole. That's about as far as they're linked, but it lets you do pretty much what you say.
if your ISP charges per computer connected, using a router/NAT device would be illegal if these became law.
If your ISP charges this way, then it's already a breach of contract to use NAT. If you want to use NAT, either pay up or find an ISP which doesn't charge additional per computer. What you'll find, of course, is that most likely the ISP which doesn't charge per computer will charge more overall. It's the same thing as when ISPs used to charge for dialup by the hour. People hated that, they wanted a flat rate per month. But the laws of economics state that the ISP's monthly charge will be equivalent to the hourly charges, averaged across all users.
Generally, if several companies in an industry start to charge extra for a service which was once included ('free'), then if people complain, they'll just roll it back in by including it in an increased base cost ('free'). So what you're left with is either 1. averaging the increased cost across all users, whether or not they use the feature which increases the cost, or 2. charging only the users which increase the company's cost. Obviously, then, people who would be charged want it included in the base cost ('free') and people who wouldn't be, want it as an extra. When it comes to NAT, I can guess where most Slashdotters will be...
There Ain't No Such Thing As A Free Lunch. Also known as the Second Law of Thermodynamics.
no, you don't understand...it's a firewall port issue, not a security one. I can use Mozilla over tls imap, but I can't get to that port through my company's outgoing firewall. I was wondering if I could use an apache virtual host and mod_proxy to connect from work.
I need the same thing. I stopped using Mozilla mail (and, well, Mozilla in general, in favor of Opera) because my work firewall is closed off to imap ports. I've been wondering if this should be possible with mod_proxy... couldn't I set it up so imap addresses of imap.server.com:80 got routed to my imapd?
The thing AMD needs to do is put 16 or 32 DIMM slots in the motherboard for their 64-bit processor. As many others have pointed out, RAM is dirt cheap for up to 1GB DIMMs. I could buy a 64-bit processor and motherboard plus 32GB of RAM for a reasonable sum.
That's 32 gigabytes. Just the disk caching speedups alone would be worthwhile. My firm belief is the only reason these huge RAM sizes aren't common is the 4GB physical / 3GB per process limits of current 32 bit OSs.
And why wouldn't the Skunk Works engineers have intended to make the F-117 as undetectable as possible?
They did, of course. But some people (possibly you?) seem to think that means a stealth aircraft is 100% invisible to radar and heat detection.
And what the hell does "heat-shielded" mean?
Heat shielded means that the exhaust ports are designed to avoid radiating obvious, detectable heat. Exactly what you said.
If a missile's radar has trouble tracking the target, so would any other radar. Judging by your lack of knowledge of this simple fact, I suggest you not inject your worthless, uninformed opinions.
Jesus, man, relax. I'm not an expert on this, but obviously neither are you. You claim I offered a worthless opinion, and then proceed to restate exactly what I said. The stealth fighter and bomber are designed to reduce radar reflection, heat emissions, electromagnetic radiation, and sonic signals. Reduce, not eliminate.