Faster Data Transfer

 < Day Day Up > 



Much has been written about how processors and PC buses have kept boosting clock rates higher and higher. Far less attention, though, has been paid to the fact that disk drives, by and large, have matched this pace with ever faster data transfer rates. Just look at some of the advances in the last few years alone. For ATA (IDE) disks, for example, we had the release of the Ultra DMA (UDMA) standard in 1998 which offered transfer modes of up to 33 MBps. That was quickly followed in 1999 by further gains that meant that 66 MBps became the standard. By 2000, however, 66 MBps paled in comparison to the new 100-MBps standard. The end of 2001 again heralded even greater speeds with the announcement of the Ultra ATA/133 interface specification with a 133-MBps data rate.

Not to be outdone, the SCSI drive has also been making great strides. The SCSI Trade Association, in fact, has had a very busy year. Besides recently celebrating the SCSI's 13th anniversary, it released the seventh generation of the standard, Ultra320 SCSI. It is designed for servers, network storage, high-end workstations, and RAID storage applications. This new bus operates at 320 MBps — twice as fast as the sixth-generation spec. The group also reports that Ultra640 is firmly in the works. When that comes out, the data transfer rate on SCSI will double once again.

External hard drives also have advances worthy of note. The 400-Mbps FireWire connection standard (IEEE 1394), for example, is gaining popularity. Because of the improving data transfer rate, these devices are now becoming adequate for multimedia applications, such as digital video editing, as well as backing up internal hard drives.

According to Cahners In-Stat (Newton, Massachusetts), over 35 million PC-based and consumer electronics products supporting FireWire were shipped in 2002, with a predicted annual growth rate of 30 percent. Further, the Converging Markets and Technologies Group at Cahners In-Stat predicts that, because of their ease of use and high performance, we will see continued growth for IEEE 1394 devices. It is expected that by 2005 more than 200 million products will ship with the interface.

On the speed front, though, the actual rotation speed of disks has not improved quite so quickly, as 7500 rpm has been standard in PCs for quite some time, as has 10,000 rpm in many server systems. More recently, 15,000-rpm drives have begun to appear, although they have yet to be made available in the greater than 100-GB sizes of their 10,000-rpm counterparts. What does the extra 5000 rpm buy for the enterprise? For lengthy film or video edits, for example, where the head does not have to move much as it reads a huge block of data sequentially off a disk, a 50 percent improvement can be obtained with a 15,000-rpm drive. But, what about the more common scenario where you have loads of small I/Os with multiple users accessing a server or applications where data is read from all over the disk in quick succession? The good news is that the faster drives still provide a noticeable performance gain — perhaps as much as 40 percent.



 < Day Day Up > 



Server Disk Management in a Windows Enviornment
Server Disk Management in a Windows Enviornment
ISBN: N/A
EAN: N/A
Year: 2003
Pages: 197

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net