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21 views

When doing IDE DMA on x86, can other CPUs access the memory?

I am unfamiliar with hardware. I am studying the IDE disk I/O and DMA on x86. I want to know that when doing a IDE disk I/O with DMA, can other CPUs access the memory (or exactly, the same memory ...
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1answer
81 views

Virtual Memory and MMU: when are they used and when not?

I'm wondering about how a Virtual Memory system could be managed alongside with a MMU when there's the need to mantain some "fixed" addresses in the address space. For example, when a machine boots ...
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138 views

PCI Express BAR memory mapping basic understanding

I am trying to understand how PCI Express works so i can write a windows driver that can read and write to a custom PCI Express device with no on-board memory. I understand that the Base Address ...
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0answers
170 views

PIO mode to DMA mode in Windows 7 in command line or script

My DVD drive falls to PIO mode from DMA mode. I would like to have a script or command line command to reset back to DMA mode in Windows 7 systems. I know the way to do this in windows XP. Even a VB ...
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1answer
89 views

How to stress the Windows XP kernel?

We have intermittant problems with writing DVDs where the writing process fails. We suspect that the problem is happening when the DVD driver switches from DMA mode to PIO mode and then in this mode ...
2
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1answer
64 views

Debian loses harddisk on bootup 4 times and then boots. Why?

Dmesg Dump: http://paste.debian.net/44975 at time 32.832045 That error is delaying my boot process significantly. Does anyone know what this is about? Devices: Maxtor IDE drive with new cable on ...
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1answer
129 views

Debian Wheezy, old computer, DMA read error, scales modes down until PIO

I got an old computer that I wanted to install debian wheezy on. Well that works but,at every bootup I get those errors: ata1.00: failed command: READ DMA when it happens the kernel softresets the ...
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1answer
300 views

Kernel bypass possible with non-specialised NIC?

Is it possible to perform kernel bypass and have a NIC send data to the user space (where I will write my network stack) with no copying, without having to purchase a specialised Solarflare etc NIC?
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2answers
64 views

DMA issue, keyboard about to die?

I have this message when I boot up debian and it takes a bit before booting when it reaches this error message: https://dl.dropboxusercontent.com/u/762638/Files/Images/dma_issue.jpg If I mount the ...
1
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1answer
37 views

IDE DMA sector numbering

I'm just playing around with the QEMU system emulator, and taking a look at the IDE disk emulation, specifically at the DMA disk accesses. I'm a little confused as to how DMA requests are actually ...
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48 views

Memory managemnt Linux 3.0+

using Ubuntu 12.04 with 2 Gb DDR3 ram with 3.2.0-39-generic free -k total used free shared buffers cached Mem: 2012040 1875968 136072 0 ...
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2answers
478 views

When a disk read or disk write occurs, where does the data go?

I understand that there is such a thing as a disk controller which contains a buffer, but was wondering if the CPU reads directly from this buffer, or whether the data must first go to a specific ...