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216 views

DMA settings in Windows 10

My Acer Aspire One 2GB has suddenly started running as slow as molasses. It can sometime take up to a minute to open a program. Googling around I see that my HD may have switched from DMA to PIO after ...
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35 views

Is latency from hardware interrupts a hardware, driver or kernel issue?

Being a power user I have spent countless hours tuning systems, checking DPC latency blah blah All of this begs the question why are we still dealing with these issues? I personally can't tell if ...
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2answers
372 views

Are few UDMA_CRC_Error_Count errors in an SSD an issue?

Some SMART stats: Device Model: Samsung SSD 850 EVO 500GB Firmware Version: EMT01B6Q 9 Power_On_Hours 0x0032 099 099 000 Old_age Always - 252 12 ...
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76 views

How to calculate the rate by which CPU would be slowed down due to DMA transfer?

A DMA controller transfers 16 bit words to memory using cycle stealing .The words are assembled from a device that transmits characters at the rate of 2400 characters per second . The CPU is fetching ...
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25 views

An interrupt of a DMA(=Direct Memory Access) and a running kernel process

Can an interrupt of a DMA(=Direct Memory Access) stop a running kernel process?
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0answers
28 views

DMA/CPU/BIND/NFS and polling

Which of the following is not true? (a) CPU enables interrupts while the DMA is transmitting information. (b) BIND binds SOCKET to an IP address. (c) NFS executes the same request again even though ...
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2answers
890 views

How do I enable DMA on a SATA controller?

I don't see any section "IDE ATA/ATAPI controllers" in device manager: What does this mean? and Can I know on which devices DMA can be enabled?
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145 views

IOMMU cache coherency

In today's x86/x64 motherboards there can be found IOMMU's from Intel and AMD. They allow peripheral devices to perform DMA (direct memory access) operations into system RAM using virtual instead of ...
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0answers
63 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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2answers
280 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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0answers
382 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 ...
0
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1answer
124 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
122 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
297 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 ...
2
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1answer
884 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
80 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 ...
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1answer
45 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 ...
4
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2answers
1k 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 ...