Mntsnow
01-13-2003, 6:43 AM
The first ATA hard drives appeared on the scene in the late 1980's, and have evolved into the latest ATA100 and ATA133 standards. Also known as IDE (for integrated drive electronics), the ATA standard has gone through a number of iterations. Today's ATA hard drives max out at 133MB/sec (Maxtor) and 100MB/sec (everyone else). The original ATA standard specified a connection speed of 3.3MB/sec. Early ATA drives offered 10-40MB of storage -- a staggering amount at the time, but completely useless for most PC applications today. Capacities have evolved along with connection speeds, and we now have 320GB ATA drives available. However, today's hard drives still use an interconnect standard that's over fifteen years old, even as capacities and drive technologies have progressed.
The ATA standard is a 16-bit, parallel connection. Parallel ATA uses source-synchronous (non-interlocked) clocking, which means that the clock signal is actually sent with the data. This can create problems as data rates -- and hence, clock rates -- increase. Because of potential signal reflection and signal skew issues, the ATA100 standard reduced the voltage for ATA100 signaling to 3.3v. The high clock rates also require 80-conductor cables, with alternating ground and signal wires. The net result is a maximum cable length of 18 inches for reliable operation in a wide variety of environments.
Serial ATA Defined: Serial ATA is, as the name implies, a serial link. A single Serial ATA (S-ATA) cable consists of a minimum of four wires, with differential pairs for transmitting and receiving data. The standard also allows for additional ground wires as deemed necessary. Maximum cable length for the S-ATA 1.0 standard is 1 meter (roughly 3.1 feet). This makes external S-ATA drives possible.
Read the full article at ExtremeTech (http://www.extremetech.com/article2/0,3973,813269,00.asp)
The ATA standard is a 16-bit, parallel connection. Parallel ATA uses source-synchronous (non-interlocked) clocking, which means that the clock signal is actually sent with the data. This can create problems as data rates -- and hence, clock rates -- increase. Because of potential signal reflection and signal skew issues, the ATA100 standard reduced the voltage for ATA100 signaling to 3.3v. The high clock rates also require 80-conductor cables, with alternating ground and signal wires. The net result is a maximum cable length of 18 inches for reliable operation in a wide variety of environments.
Serial ATA Defined: Serial ATA is, as the name implies, a serial link. A single Serial ATA (S-ATA) cable consists of a minimum of four wires, with differential pairs for transmitting and receiving data. The standard also allows for additional ground wires as deemed necessary. Maximum cable length for the S-ATA 1.0 standard is 1 meter (roughly 3.1 feet). This makes external S-ATA drives possible.
Read the full article at ExtremeTech (http://www.extremetech.com/article2/0,3973,813269,00.asp)