Recommended To Read:

What data recovery tools to buy if you want to start a data recovery business?

Free video data recovery training on how to recover lost data from different hard drives?

Where to buy head and platter replacement tools at good prices?

Data recover case studies step by step guide

I want to attend professional data recovery training courses

Data transfers between your computer and your hard disk can be done using two methods: PIO (Programmed I/O) or UDMA (Ultra Direct Memory Access). In the first method, the computer CPU is in charge of the transfers between the hard disk and the RAM memory. In the second method, the motherboard chipset is in charge of this transfer. This means that in UDMA mode the CPU is not used to move data from the hard disk to the memory, raising your PC performance, since the CPU will be available during these transfers.

ATA-33 and UDMA/33, ATA-66 and UDMA/66 etc mean the same thing.
The listed transfer rate (66 MB/s, 100 MB/s, 133 MB/s etc) is rarelly achieved.

Hard disks with transfer rates up to 16.6 MB/s use PIO mode, while hard disks beginning at 25 MB/s uses the UDMA mode.

All chipsets – i.e. all motherboards – can operate with PIO modes. But to operate with UDMA modes the following criteria must be matched:

* The chipset (south bridge) must be compatible with the hard disk’s UDMA mode. Otherwise the hard disk will be accessed with the chipset’s maximum transfer rate. For example, if you install an ATA-100 hard disk on an ATA-66 motherboard, the maximum transfer rate will be 66 MB/s due to the chipset limitation.
* The bus mastering drivers must be enable on the operating system. UDMA modes are software programmed – the operating system must program the chipset to perform the transfers thus releasing the CPU from this task. If the operating system is not correctly configured, the hard disk will be accessed only at 16 MB/s, even if you have a 133 MB/s hard drive installed on your PC.
* A 80-wire flat cable must be used with ATA-66, ATA-100 and ATA-133 hard disks. Otherwise the disk will be accessed up to 33 MB/s only.

Data recovery Salon welcomes your comments and share with us your ideas, suggestions and experience. Data recovery salon is dedicated in sharing the most useful data recovery information with our users and only if you are good at data recovery or related knowledge, please kindly drop us an email and we will publish your article here. We need to make data recovery Salon to be the most professional and free data recovery E-book online.