pio vs dma , What is the Difference ?

[ABNER]

Hello , Can you Tell What is the Actual difference between PIO and DMA? I have seen these two options available for my dvd Drive , Can You tell me what are these options mean and how to change or switch from one to another , please help me Thanks in advance

[Fabian]

DMA is much faster because it allows your device to access the memory of your PC without going through the processor. This mode is also essential to play a movie on DVD, because if the flow is insufficient then movies will lag

[RoninBlade]

DMA (Dynamic Memory Access) access a dynamic memory therefore faster (PIO) Programmed Input / Output , PIO (Programmable I/O) uses your processor to manage data transfers from the drive to memory.DMA (Direct Memory Access) uses the disk controller to transfer data directly from the drive to memory, resulting in better performance and freeing up the CPU to do other things. therefore PIO is slow, UDMA is fast

Pio = 15 MB/s
UDMA mode 2 = 33 MB/s
UDMA Mode 4 = 66 MB/s
UDMA mode 5 = 100 Mb/s
UDMA Mode 6 = 133 Mb/s

[Rawko]

Programmed Input / Output (PIO): This was the initial method used by hard drives and ATA standards. The first PIO modes 0,1 and 2 were greatly dependent on the processor. With the arrival of the 486 and Pentium, a new standard was adopted VLB (Vesa Local Bus) and a new PIO mode was introduced called "Block PIO allowing more data transfer.


Direct Memory Access (DMA): With the emergence Chipset Intel 430 TX, bus-mastering DMA has enabled the transfer of data between the chipset, hard disk and main memory (RAM) without needing the processor. The performance of the system have increased significantly since then the processor no longer has to wait for the hard disk. however, should be managed by the operating system, Win98 and Win95 OSR2 can manage but not Win95 OSR1 that needs a patch.