Modern PC Hard Drive Terms and Technology
Are you confused about hard drives and drive terminology? IDE, Enhanced IDE, EIDE, ULTRA ATA, FASTATA and ATA/ATAPI. Do these letter mean anything to you? Well, read on a learn!
First, hard drives and controllers can be boiled down into two camps: SCSI (Small Computer Serial Interface) which we won't discuss here because these are mostly found in large, expensive servers (the cheapest SCSI drive is around $300). We will, however, be looking closely at the second and most widely found type, which is the ATA format of hard drive.
All IDE, EIDE, UTRA IDE, ULTRA or FAST ATA drives and most CD drives are all ATA complaint devices.
The AT comes from the old IBM AT (which I believe stood for Advanced Technology). That final "A" in the initials comes from the word Attachment. So ATA describes an attachment to an IBM PC AT computer.
The original ATA standard (sometimes called ATA-1) provided a maximum data transfer rate of 3.5 megabytes (MB) per second using a multi-pin connector.
When the ATA-2 standard came out in 1987, a few companies started calling this IDE to be hip and separate themselves from the original offering.
So, Enhanced ATA or IDE (FASTATA or EIDE) was a label put on some devices using the next ATA-3 standard. All of these used similar PIO (Programmed In and Out) and DMA (Direct Memory Access -- which is how the old Atari ST used to work with hard dives by-passing the CPU and getting the data straight from the buss) parameters to control data transfer. This refers to a set of protocols that make your computer flip from read to write and pass data across the buss from the connection to the CPU (Central Processing Unit) which is all controlled by the BIOS (Basic In and Outs). BIOS is a time share regulator that routes the signals around your box. Some mother boards and BIOS can automatically sense and handle an ATA device, making the PIO and DMA choices for you. Sometimes you have to go in, defeat these settings and try a number value to see if it improves performance.
With ATA-3 came the first major change: ATAPI support was fully integrated into the ATA process. ATAPI standards were created by CD ROM and back up tape manufacturers whose systems used a process closer to the SCSI method of data transfer. When they added full ATAPI support in ATA-3 and ATA-4 a method of using PIO and DMA processes native to the original ATA specifications were added to convert the SCSI-like data transfers of CD ROM and small back up tape drives. This standard covers most of the 1990s.
With ATA-4 the data transfer rate was also upped to 33 and many drives and devices started referring to themselves as ATA33. This is because 33 sounds bigger than 4! ATA-4 sounds rather slow when you can name your drive as meeting the 33 MB per second standard called for in ATA-4. So lets call it ATA33 and sound bigger and faster! This marks the start of the term UDMA or ULTRA DMA.
By now we are at the end of 1998 and any machine made late in late 1997 or 1998 is now ATA33 complaint. Staring with the new millennium things changed radically with the introduction of the ATA-5 standard.
ATA-5 used an entirely new cord and connectors that is color coded blue, gray and black. It is missing pin 34 and every connector is given extra grounding which reduces cross-talk and noise (bleed of signal from one channel to another, something the audiophile may experience with headphones when listening to old records and cassette tapes where you hear bleed in the music before the actual sounds begin). By reducing noise they were able to greatly extend data transfer to 66 MB per second and all the hard drive makers started totting their ATA66 drives!
Starting at the end of 2001 and now into 2002 was quickly introduced the ATA-5 set of standards that are expected to keep the throughput on par with the new concepts in computing, such as digital video capture, broadband internet and network sharing of resources. These days you will see many hardrives calling themselves ATA100, which is nothing more than an improved ATA66 (in fact most tests only show a 1% speed increase between ATA100 and ATA66 drives) with the temporary or "should have" features now a formal part of the specifications that a manufacturer must follow in creating devices.
The primary changes are voltage regulation and cross-talk, which help to improve throughput and bandwidth past the 66 MB per second range, which becomes important as we develop 2 gigahertz (GH) CPU (Central Processing Unit) chips, ultra fast memory (or RAM) chips and hard drives that move at or over 10,000 RPM with super micro fine recording heads that pack extra signal onto new and improved magnetic disks. What ATA100 is supposed to do is allow Intel, Maxtor, Western Digital and Segate some room to improve their wares and still have computers that work faster than the devices installed into them!
Herein lies the problem, if you have a 1996 or even a 1997 computer it is probably ATA-3 complaint while a new hard drive you buy in the stores today is ATA-5 complaint. While you are backward compatible, you probably shouldn't use the new connector cord and must set the jumpers manually on the hard drive. You may even need to set the PIO and DMA settings in BIOS manually at startup to get the best performance, as your computer is probably not UDMA compatible. What this ultimately means is a fast 7200 RPM hard drive may only give you 40% of the horsepower it would give on a new machine.
If you bought your computer after 1998 or in 1999 it is ATA-4 complaint and can run both ATA66 and ATA100 drives with no significant problems (software from the hard drive company can make up for any BIOS incompatibilities) using the new color coded cord.
Any machine made with a motherboard manufactured in 2002 is probably ATA-5 complaint and will keep up with the Jones until ATA-6 and ATA-7 arrive (and both are in the works) in a year or two!
So, again. If you see a hard drive marked ATA100 (all of them are by now) it will run in any machine ever made, the only thing is that it will blaze in a new computer, while your old P-1 200 MHz computer using Windows 95 will only get a fraction of the speed that hard drive is capable of delivering.
IDE, EIDE, FASTATA are just a bunch of words describing a system that stopped being made in 1990! It's all ATA/ATAPI. The big factor is efficiency and automation, which may not be supported in machines made last century, so you'll have to do a little manual tweaking or live with slower results.