What does DMA stand for?

[toph99]

and what drives does it work on? what does it do? thanx

 

[BT7990]

http://www.computerhope.com/jargon/jd.htm#direct_memory_access

 

[andrey]

DMA - Direct Memory Access

Ultra DMA/33, also known as UDMA or UATA, is the latest ATA/IDE hard disk drive interface. Ultra DMA/33?s predecessor, Fast-ATA, had a maximum burst transfer rate of 16.6 MB/sec. Ultra DMA/33 doubles Fast-ATA?s burst rate to 33 MB/sec.

The Ultra DMA/33 protocol removes bottlenecks associated with data transfers especially during sequential operations.

In addition to speed improvements, the protocol brings new data integrity capabilities to the ATA/IDE interface. Improved timing margins and the use of Cyclical Redundancy Check (CRC), a data protection verification not implemented in legacy ATA modes, help ensure the integrity of transferred data.

For even greater integrity, the protocol can be used at speeds slower than 33MB/sec. In this case, both signal and data integrity will surpass that of Fast-ATA.

Backward Compatibility

The Ultra DMA/33 protocol allows drives and systems to retain backward compatibility with the existing ATA standard. Because of this feature, installed PCs without the Ultra DMA/33 capability can use new disk drives in legacy ATA modes at transfer rates up to 16.6 MB/second. To take advantage of the high-speed 33 MB/second protocol, PC users in the installed base can purchase an Ultra DMA/33 PCI adapter card.

I hope this helps,

 

[toph99]

thanx, those helped alot =) i have a maxtor UDMA66 10gb hard drive, should i enable DMA on it? could this have any side effects?

 

[Mikewarrior2]

yes, enable it. It will not only improve performance(sometimes very dramatically), but it will also lower cpu usage during heavy hd access.



Mike

 

[toph99]

ok, thanx for the info =)

 

[dennilfloss]

Before you do this, make sure that you other components can handle this (for example, most recent CD-ROM drives, 12x and above support DMA transfers). CD-ROM drives that support Multiword DMA Mode 2, Ultra DMA or faster can use DMA transfers.

It is strongly recommended that you back up your drives and your Windows Registry before you enable DMA support or before you install and enable the driver to allow DMA support. If your system hangs up after you enable this feature, you'll need to replace the Registry after enabling DMA with the pre-DMA copy. Otherwise you'll be faced with editing Registry keys by hand to start your system again.

Because DMA transfers bypass the CPU to achieve greater speed, DMA problems could result in data loss. Make backup first rather than wishing you had later.