HP Professional AP500 Compaq Professional Workstation AP500 Key Technologies W - Page 7

WHITE PAPER (cont'd) Compaq Workstations - Key Technologies ULTRA ATA Ultra ATA is a definition for an ATA data transfer protocol. The Ultra ATA protocol is included in the ATA-4 specification, an industry-wide specification designed to provide firm guidelines to hardware developers and manufacturers. The development of the transfer protocol "Ultra ATA" hard drives (also known as UDMA, UATA, Ultra DMA, Ultra DMA-33) has increased the burst data transfer rate to 33.3 MB/s compared to Fast ATA, effectively doubling the transfer rate vs. Fast ATA. Due to faster transfer rates, Ultra ATA technology processes data twice as fast. This causes a reduction of 250 ms to 125 ms in time to empty the buffer. These savings in time allow the time to empty the buffer (400 ms) to equal the buffer fill time, thus eliminating the bottlenecks experienced with Fast ATA. CUSTOMER BENEFITS • Extends the data transfer rate. Provides improvement over Fast ATA speed of 16.6 MB per second to 33.3 MB per second. • Provides improved signal integrity through CRC (Cyclical Redundancy Check). Checks to verify the integrity of the data transferred by validating all data transferred across the cable. • Fully backward compatible. Uses the same electrical connection as Fast ATA and can run in standard EIDE mode with old ATA chipsets. Ultra ATA devices can also operate on an ATA bus with non-Ultra ATA devices. Q. Why does the Compaq Professional Workstation AP500 use Ultra ATA drives as well as Wide Ultra SCSI drives? A. The Compaq Professional Workstation AP500 will attract different users. Some may need the higher speed 40-MB per second data transfer rate of Wide-Ultra SCSI drives for extra performance. For those who find the 33.3-MB per second data transfer rate satisfactory, Ultra ATA drives provide excellent price/performance with almost no difference when using business productivity applications. WIDE-ULTRA SCSI HARD DRIVES Standard SCSI hard drive configurations for the Compaq Professional Workstation AP500 include a one-inch 4.3-GB 7200 rpm or 10,000 rpm hard drive, depending on the model. The standard hard drive occupies a bay in the removable drive cage. The AP500 is expandable for customers with additional storage requirements. It supports up to five one-inch hard drives or up to four 1.6-inch hard drives. For those customers who require even more storage, the integrated Wide-Ultra SCSI controller (with an external Wide-Ultra SCSI connector) supports external SCSI devices. The following table describes the available SCSI hard drive configurations. 7