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DMA is the ability for the device to take control of the system's memory bus (become the 'bus master') and write directly to system memory locations without the need for software running on the system's host processor.
This is really a logical 'bus' concept dating from the time when everything was directly connected to the (single) processor's address and data bus pins. Normally the processor was 'bus master' - it emitted the necessary voltages to drive the address and data buses. For another device to write to or read from the system memory (or any other device connected to the memory buses), a Direct Memory Access [DMA], it had to ask the processor to put its bus drivers into high-impedance mode, so that it was not interfering, electrically, with the buses. When finished, the device then relinquishes its master status.
On a modern system there are many, many different buses which run at different speeds and have different electrical characteristics. To cross between these different buses, there are different bus controllers. On Intel processor-based systems, the key one for PCI Express operations is the Memory Controller Hub, which connects the processors' Front Side Bus to the memory buses (now normally two), the PCI Express channels, and the Inter-Hub Transport which connects to the I/O Controller Hub (on Intel chipsets). On AMD processor-based systems, the memory buses connect directly to the processor, while the PCI Express channels are connected to a PCI Express controller which connects to the processor(s) over a HyperTransport link.
Any operations that involve reading from or writing to a PCI Express device will need a PCI Express read or write sequence, whether driven by the processor or by the device itself. The PCI Express transaction is the read or write operation.
To get the results of a DMA write operation (i.e. the device writes to memory), you simply need to read from the physical memory addresses that the DMA operation wrote to. Conversely, to control a DMA read operation, you need to write the data to be transferred to a particular physical memory location (or locations), and program the device to perform the DMA from those locations. Actually, you can normally program the device to transfer the data from locations that already contain the correct data.
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:|Hi,
can any one give me a win32 api and also a control or library that can get the NEC MAC address from the Hardware itself not from the registry. it will be good if it can be used in C#.
May god give u good health and knowledge.
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i read the articles but the code in them gets them from the registry -and that has a possibility of bieng changed- not from the NIC Hardware, which is what i want.
but
Thanks for reply...;P
May god give u good health and knowledge.
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Reader Man San wrote: gets them from the registry
Little bit of hunting around GetAdaptersInfo, seems to be the api call. Still havnet found where it gets its info from.
http://www.codeproject.com/internet/IPHelper.asp[^]
I suppose the only way to know for sure would be to send a packet to local loop back and interrogate it for the MAC.
I'd love to help, but unfortunatley I have prior commitments monitoring the length of my grass. :Andrew Bleakley:
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Thanks,
i will need to check it by using programs that change the registry's saved MAC Address.
___________________________________________
May god give u good health and knowledge.
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Hmm, how about ShellExecuteEx() with an ipconfig /all command piped into t file that your code then opens and reads the MAC address from.
Either that or write an upperlayer driver that has an IOCTL interface which can be opened by your app and sends the query MAC address IOD to the adapter it binds to.
Truth is the subjection of reality to an individuals perception
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Thanks for the second idea, i thought about it but i am not good in hardware drivers, they are hard stuff for me.
___________________________________________
May god give u good health and knowledge.
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I can give you source code for such a 'protocol' driver if you like.
I takes an IOCTL from an app that opens a particular adapter, than, there is a generic OID handling IOCTL. YOu can set/request any OID with this.
It is a complete project, but you will need a DDK, preferably the 2003 server DDK. It has an inf file for installation too.
Truth is the subjection of reality to an individuals perception
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Recently, my PC at work has decided that every 5 minutes or so it will beep several dozen times. The beeps are not evenly spaced, and so I wondered if my PC is trying to send a morse code distress message! Strangely, a colleague's PC did exactly the same about a month ago, so he disconnected the speaker. We never found out what was causing it. I've no idea whether this is a hardware thing, or an OS thing (we're both on Win XP). I don't know where to start looking.
Does anyone have any idea what it could be? Has anyone had the same thing? Is anyone fluent in morse code, and translate the PC's distress call?
"The way of a fool seems right to him, but a wise man listens to advice" - Proverbs 12:15 (NIV)
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3 possibilities...
1) The fan and heatsink sitting on your CPU is so clogged that the processor is starting to overheat. Or some other hardware problem, for which you'll have to consult the manufacturer of the machine to find out.
2) You have a virus on your machine.
3) Someone has written and installed a little app on your machines and is in the corner laughing at you, seeing how long it will take before you figure it out.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Thanks for the ideas Dave. My thoughts on those:
1. That was my first thought (which is why I posted on the Hardware board), but as far as I can see the fan is OK, processor temp OK. I would kind of expected the occasional freeze if this was the case anyway. Still, jury's still out on other hardware problems. Bit of a coincidence that a colleagues PC did the same though.
2. Mmm, thought of that too. In some ways more likely, as that would explain why my PC was not the only one, but our AV is generally good - though I know nothing's 100% effective - so we would usually consider ourselves to be (nominally) "virus-free"
3. No-one laughs at me and gets away with it. Do you hear me? NO-ONE! 
"The way of a fool seems right to him, but a wise man listens to advice" - Proverbs 12:15 (NIV)
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Yeah, I've got some machines aorund here that run fine, right up until the processor melts internally. The heatsink fins get so caked with dirt, in places that you can't see under the fan, that you have to take a can of air to them. Vaccuming them out doesn't do any good.
As for the prank, come on! You can't tell me that you haven't thought of doing this yourself! I did it with a small remote control "fart noise" maker. Taped it to the back of this girls machine and, err, "let 'em rip!" Not very often, but just enough to drive her nuts for about 3 weeks!
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Found it: my PS2 mouse is bust. I've switched it for a USB mouse, and I no longer have the beeps. I arrived at that because it started making my mouse pointer jump, and doing a scroll and a right-click, every time a system beep happened.
Dave Kreskowiak wrote: You can't tell me that you haven't thought of doing this yourself!
Yes, I have, but nobody's that much fun around here! In a previous company we used to do that kind of thing all the time. Ah, those were the days...
"The way of a fool seems right to him, but a wise man listens to advice" - Proverbs 12:15 (NIV)
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Paul S. Vickery wrote: Recently, my PC at work has decided that every 5 minutes or so it will beep several dozen times.
While not entirely similar, the only time I have had the little speaker go beeping like that was when I was doing a full recompile or something else processor intensive. Turns out the thermal paste was bad. Cleaned the old stuff off and replaced no noise since then. Strange don’t know if checking that will help or not but certainly worth a shot (I was seeing elevated temps on the CPU).
I'd love to help, but unfortunatley I have prior commitments monitoring the length of my grass. :Andrew Bleakley:
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I'm in the last year in computer scince faculty and i'm asking Can I Make an MP3 Palyer Support RM (real Media) . using a specific programming language or it is related to the hard ware itself
Thanks.
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First you'll need to find out what the hardware environment of hte player is and how to reprogram it. Try searching for guides on how to hack mp3 players to find ones that someone else has already figured out how to reprogram. THis will likley consist of loading a minimalist linux distro of some sort, hopefully with a audiuplayer that works with the platform.
Then you need to port/write a RM codec compatable with it. Search for real alternative, IIRC open source.
You'll need to repeat this for each mp3 player family you want to get RM working on.
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Thank you very much
honored
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Hi all,
I got the new SuperMicro X7DA3 server board with 3 PCI-X slots and 1 PCI slot. Two of the three PCI-X slots are connected to PXH-V chipset which is inturn connected to ESB2 chipset and the another one is directly connected to ESB2. When I install a PCI-X 133MHz board on one of the two PCI-X slots on PXH-V chipset, it runs at its full speed (794MBps) which is good, but when I install a 32bit 33MHz card on the second slot, the earlier card's speeds drop down significantly to 284MBps. Coming to the PCI 33MHz slot, when I install a 32bit 33MHz slot, I am getting around 60MBps when I am supposed to get around 90MBps.
Can someone help me out how I can configure these slots for their max bus transfers. I dont card about the 32bit card thats been installed on one of the PXH-V chipset, but I need the other card to run at its full speed. Anyone know about configuring the Latency timer for PCI slots? For now they are in default option, but I can change this value in bios.
thanks,
-Pavan
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i'm using both of windows Me and Windows XP SP2
Windows Me connect automaticlly to network and Internet after
installing LAN Card(calld Ethernet) with its software
but XP SP2 (Original) doesn't connect automaticlly nor manualy ever
I need Help Plz
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if its wireless connection , you have to disable WZC(wireless zero configuration) in winXp,bcoz in winXp its itbuilt facility of OS,so to avoide clash between yr wireless card and WZC it will be better to disable WZC.
rst
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for wired connection ---go to device manager--select properties of yr LAN card and at te bottom of this page check wether its enable or disable....
enable it...
if it works than its fine otherwise uninstall the drivers and reinstall it thru related web site....best of luk
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When I print I Have The printer Dialog box
I selecting the opsion "PRINT TO FILE"
I save this file into c:\
how can I print this file Now?????
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The print to file command just does a raw dump of the data that would have been sent to the printer. Open up the printer's print queue and drag the file into it.
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 I never knew you could drag the file! I would always do type filename > lpt1. 
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