2007-01-08 17:04:10 · 7 answers · asked by vimal 1 in Computers & Internet ➔ Hardware ➔ Other - Hardware
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DMA is Direct Memory Access.
DMA is a system that allows memory to be controlled without passing through the CPU.
Under most situations, the CPU handles the movement of memory for security and stability reasons. However, DMA can be enabled for certain operations, such as reading from a CD-ROM, so that the data read from the CD is not passed through the CPU but is instead pulled off of the CD and put directly into a memory location for use.
Although DMA is not always used, it has its uses. When it is enabled, the process of DMA overrides the CPU for handling the memory. This helps to solve some errors that occur for items when they are transferred through the CPU. Such errors include audio and video that is being read off of a CD-ROM. Occasionally, errors occur which can cause audio to be scratchy or video to be distorted. Under situations such as these, DMA can be a useful system since it works around these errors by bypassing the CPU.
2007-01-08 17:25:53 · answer #1 · answered by mallimalar_2000 7 · 3⤊ 0⤋
DMA stands for Direct Memory Access and it allows peripherals to access memory (Read or Write) without having to go through the CPU.
It works using a dedicated channel to access the memory callled DMA channel.
The main purpose of the DMA is to make the transfer of large ammounts of data much more quickly by transfering data by blocks instead of bit by bit.
2007-01-08 17:22:58 · answer #2 · answered by gdavid222 1 · 0⤊ 0⤋
DMA is Direct Memory Access, which allows different parts of the computer, eg harddrive, video cards, sound card, network card... to access the computer's memory without using (a lot of) cpu's power. The CPU will intiates the talks between the parts and the memory, but it won't do the work. It's the devices and the memory that will talk to each other, therefore making the CPU available for other tasks.
2007-01-08 17:14:10 · answer #3 · answered by loc_tho 2 · 0⤊ 0⤋
DMA is Direct Memory Access. It was made popular in the mid 90s to replace the older PIO Mode. It used to be that device cards not integrated on the mobo suffered a crowded bus and had to wait for CPU and memory time.
WIth DMA in theory, the CPU is not really used to request access to RAM. DMA gives the device, such as a hard dive, the ability to interface directly with memory. It doesn't have to wait for the right moment.
2007-01-08 17:09:32 · answer #4 · answered by SirCharles 6 · 1⤊ 0⤋
It is a way of accessing to memory with out CPU direct interaction. DMA Initiate a counter from start of memory supposed to be written with device and will communicate with device till end of transmission
2007-01-08 17:26:02 · answer #5 · answered by khodadad_omid 2 · 1⤊ 0⤋
dma is direct memory acess
its used when the cpu needs to transfer bulk of data
say cd
the processing is just transferred to a co processor that controlls the dma transfer and cpu is free for other things
2007-01-08 20:19:52 · answer #6 · answered by sweetboy 3 · 0⤊ 0⤋
DMA is Direct Memory Access,
why don't you check this
http://www.computing.dcu.ie/~ray/NewCA104/DMABig.pdf
2007-01-09 23:21:02 · answer #7 · answered by Baseer A 2 · 0⤊ 0⤋