ATA to Ultra ATA :: essays research papers

ATA to Ultra ATA/66 Advanced ATA Storage Interface Introduction Interface History Understanding the Need for a Faster Disc Interface Technology Overview Performance Increase Cost Stabilization Backward Compatibility System Requirements Data Integrity and Reliability Conclusions More Information Introduction The PC industry is constantly searching for advanced technology. This equates to more disc space, faster performance, more memory, better displays – virtually every component is under relentless pressure to improve. Continual improvement for the disc drive industry means lower costs, improved reliability, higher capacity, and better performance. As PC performance increases, the performance of the hard drive, which is the central input/output (I/O) device of the PC, becomes increasingly important. Improvement in disc drive performance is a complex area and is measured using several components: seek time, rotational latency, internal transfer rate, cache, and interface speed. Interface History The hard drive interface is the path through which data travels between the PC and the hard drive. The original ISA-dependent ATA (IDE) interface was limited to about 4 Mbytes/sec in the beginning, but reached as high as 8 Mbytes/sec. Interface protocols, such as programmed input/output (PIO) and direct memory access (DMA) modes, were designed to take advantage of the new local bus architectures that replaced ISA. ATA interface modes have progressed from PIO to DMA and now Ultra DMA, giving data transfer rates from 8.3, 11.1, and 13.3 Mbytes/sec up to 16.6, 33.3, and now 66.6 Mbytes/sec. Specification ATA ATA 2 ATA 3 ATA/ATAPI 4 ATA/ATAPI 5 Max Transfer Modes PIO 1 PIO 4 DMA 2 PIO 4 DMA 2 PIO 4 DMA 2 UDMA 2 PIO 4 DMA 2 UDMA 4 Max Transfer Rate 4 Mbytes/sec 16 Mbytes/sec 16 Mbytes/sec 33 Mbytes/sec 66 Mbyte/sec Max Connections 2 2 2 2 per cable 2 per cable Cable Required 40-pin 40-pin 40-pin 40-pin 40-pin, 80-conductor Additional Features - Base - Speed - Synchronous Transfers - S.M.A.R.T. - Secure Mode - Queuing - Overlap - ATAPI - Speed - Data Reliability Year Introduced 1981 1994 1996 1997 1999 The trends in the above chart show that several components have improved with the evolution of the ATA interface. Speed and functionality have made major strides over the years. Performance remains the most commonly considered attribute with interface developments, and Ultra ATA/66 makes burst data transfer rates of up to 66.6 Mbytes/sec possible. Understanding the Need for a Faster Disc Interface Ultra ATA/66 provides a low-cost, high-reliability, backwards-compatible solution to data transfer bottlenecks that slow overall system performance. As the data storage density (areal density) of disc drives and rotational speeds have increased, bottlenecks also increased, thus requiring the ATA interface to improve performance to attain compatible data transfer speeds.