View Full Version : ata and dma

24-08-2004, 03:49 PM
Some magazine call it as ata and some call it Dma.Ata is a hardware device that increases the output of data transfer of a hardrive.
Ata/33/66/100mhz and I see that in other places they call it dma 33/66/100
Are they the same thing?

Graham L
24-08-2004, 05:06 PM
Which magazines? Women's weekly?

ATA refers to the interface standard.

DMA (Direct memory access) refers to a way of transferring data between peripherals (such as disks) and the computer's memory, without involving the CPU, apart from setting up the transfer and being notified after it is done. The other transfer mode PIO (Programmed I/O) involves the CPU intimately. The CPU often has better things to do. The hardware in a DMA interface can do it.

But speed isn't necessarily because of DMA. Floppy disks use DMA and transfer at 500 kB/sec. PIO for MFM drives ran at 5MB/sec.

The numbers, 33,66,100 , refer to the speed of the bus in the computer. This indiocates how fast the memory buffer can accept data. A DMA can't run faster than PIO on the same computer. It will cause the CPU less "busyness", so might increase the "efficiency" of the system.