pctechguide.com

  • Home
  • Guides
  • Tutorials
  • Articles
  • Reviews
  • Glossary
  • Contact

Hard Disks – What IS ATA and Ultra ATA?

In the second half of 1997 EIDE’s 16.6 MBps limit was doubled to 33 MBps by the new Ultra ATA (also referred to as ATA-33 or Ultra DMA mode 2 protocol). As well as increasing the data transfer rate, Ultra ATA also improved data integrity by using a data transfer error detection code called Cyclical Redundancy Check ( CRC).

The original ATA interface is based on transistor-transistor logic (TTL) bus interface technology, which is in turn based on the old industry standard architecture ( ISA) bus protocol. This protocol uses an asynchronous data transfer method. Both data and command signals are sent along a signal pulse called a strobe, but the data and command signals are not interconnected. Only one type of signal (data or command) can be sent at a time, meaning a data request must be completed before a command or other type of signal can be sent along the same strobe.

Ultra

Starting with ATA-2 the more efficient synchronous method of data transfer is used. In synchronous mode, the drive controls the strobe and synchronises the data and command signals with the rising edge of each pulse. Synchronous data transfers interpret the rising edge of the strobe as a signal separator. Each pulse of the strobe can carry a data or command signal, allowing data and commands to be interspersed along the strobe. To get improved performance in this environment, it is logical to increase the strobe rate. A faster strobe means faster data transfer, but as the strobe rate increases, the system becomes increasingly sensitive to electro-magnetic interference (EMI, also known as signal interference or noise) which can cause data corruption and transfer errors. ATA-2 includes PIO mode 4 or DMA Mode 2 which, with the advent of the Intel Triton chipset in 1994, allowed support for a higher data transfer rate of 16.6 MBps.

ATA-3 added the Self-Monitoring Analysis and Reporting Technology ( SMART) feature, which resulted in more reliable hard drives.

ATA-4 includes Ultra ATA which, in an effort to avoid EMI, makes the most of existing strobe rates by using both the rising and falling edges of the strobe as signal separators. Thus twice as much data is transferred at the same strobe rate in the same time period. While ATA-2 and ATA-3 transfer data at burst rates up to 16.6 Mbytes per second, Ultra ATA provides burst transfer rates up to 33.3 MBps. The ATA-4 specification adds Ultra DMA mode 2 (33.3 MBps) to the previous PIO modes 0-4 and traditional DMA modes 0-2. The Cyclical Redundancy Check (CRC) implemented by Ultra DMA was new to ATA. The CRC value is calculated on a per-burst basis by both the host and the HDD controller, and is stored in their respective CRC registers. At the end of each burst, the host sends the contents of its CRC register to the HDD controller, which compares the host’s value against its own. If the HDD controller reports an error to the host, the host retries the command that produced the CRC error.

ATA-4 also provided for the integration of the AT Attachment Program Interface (ATAPI) standard. Up until this time ATAPI – which provides a common interface for CD-ROM drives, tape backup drives and other removable storage drives – had been a separate standard.

ATA-5 includes Ultra ATA/66 which doubles the Ultra ATA burst transfer rate by reducing setup times and increasing the strobe rate. The faster strobe rate increases EMI, which cannot be eliminated by the standard 40-pin cable used by ATA and Ultra ATA. To eliminate this increase in EMI, a new 40-pin, 80-conductor cable was developed. This cable adds 40 additional grounds lines between each of the original 40 ground and signal lines. The additional 40 lines help shield the signal from EMI. The new connector remains plug-compatible with existing 40-pin headers and Ultra ATA/66 hard drives are backward-compatible with Ultra ATA/33 and DMA, and with existing EIDE/IDE hard drives, CD-ROM drives and host systems. The ATA-5 specification introduces new Cyclic Redundancy Check (CRC) error detection code and adds Ultra DMA modes 3 (44.4 MBps) and 4 (66.6 MBps) to the previous PIO modes 0-4, DMA modes 0-2, and Ultra DMA mode 2.

ATA-6 – also referred to as Ultra DMA mode 5 – soon followed. This increased higher burst data transfer rates to a maximum 100 MBps by reducing its signal voltage – and associated timing requirements – from 5V to 3.3V.

The table below shows that several components have improved with the evolution of the ATA interface, realising progressive speed and functionality gains since the first ATA specification was introduced in 1981:

ATA ATA-2 ATA-3 ATA-4 ATA-5 ATA-6
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

PIO 4

DMA 2

UDMA 5

Max Transfer Rate 4 MBps 16 MBps 16 MBps 33 MBps 66 MBps 100 MBps
Max Connections 2 2 2 2 per cable 2 per cable 2 per cable
Cable Required 40-pin 40-pin 40-pin 40-pin 40-pin,

80-conductor

40-pin,

80-conductor

CRC No No No Yes Yes Yes
Introduced 1981 1994 1996 1997 1999 2000

Ultra ATA/100 had been expected to be the final generation of Parallel ATA interface before the industry completed its transition to Serial ATA. However, in the event, ATA/133 – also known as UltraDMA 133 – was announced in mid-2001, increasing throughput yet again, this time to 133 MBps.

  • What Is The System Bus?
  • ISA Bus – Industry Standard Architecture
  • Local Bus Interfaces
  • PCI Bus Interfaces
  • What is AGP and AGP Pro?
  • Internal Interfaces Summary
  • PCI-X Interfaces
  • PCI Express Interfaces
  • IDE Interfaces
  • EIDE Interfaces
  • Hard Disks – What IS ATA and Ultra ATA?
  • Serial ATA (SATA) interface guide
  • SCSI Explained – With Pictures
  • SCSI Interface Evolution
  • Fibre Channel Interfaces
  • Hard Disks – What is Serial Storage Architecture?
  • I/O Interface Standards
  • How It Works: The Idea and Technology Behind USB
  • IEEE 1394 Interfaces
  • USB 2.0 Intefaces
  • FireWire 800 Interfaces

Filed Under: Interfaces Tagged With: What IS ATA, What IS Ultra ATA

Latest Articles

Remove Annoying Malware in 5 Steps

Malware and viruses are a part of the computer landscape these days. Their presence shows no signs of slowing down. There are tools available to find and clean them, but malware still seems to find its way past these barriers at times. Furthermore, these tools have features to shield the computer … [Read More...]

Stellar Excel Recovery Review

Stellar Excel Recovery Stellar Excel Recovery is a great product that we highly recommend using if you are having problems with lost or corrupted data. This review will show you how the product works and why we like it so much. Check it out. » Download Stellar Excel Recovery … [Read More...]

Differences with Reverse Image Search on Desktop and Mobile Devices

Searches with images are a Google functionality with which users can find similar images, source of photographs or until the date in which an image was uploaded to the Internet. This functionality of Google Images is part of the advanced search options and allows users to use images to use the … [Read More...]

Gaming Laptop Security Guide: Protecting Your High-End Hardware Investment in 2025

Since Jacob took over PC Tech Guide, we’ve looked at how tech intersects with personal well-being and digital safety. Gaming laptops are now … [Read More...]

20 Cool Creative Commons Photographs About the Future of AI

AI technology is starting to have a huge impact on our lives. The market value for AI is estimated to have been worth $279.22 billion in 2024 and it … [Read More...]

13 Impressive Stats on the Future of AI

AI technology is starting to become much more important in our everyday lives. Many businesses are using it as well. While he has created a lot of … [Read More...]

Graphic Designers on Reddit Share their Views of AI

There are clearly a lot of positive things about AI. However, it is not a good thing for everyone. One of the things that many people are worried … [Read More...]

Redditors Talk About the Impact of AI on Freelance Writers

AI technology has had a huge impact on our lives. A 2023 survey by Pew Research found that 56% of people use AI at least once a day or once a week. … [Read More...]

11 Most Popular Books on Perl Programming

Perl is not the most popular programming language. It has only one million users, compared to 12 million that use Python. However, it has a lot of … [Read More...]

Guides

  • Computer Communications
  • Mobile Computing
  • PC Components
  • PC Data Storage
  • PC Input-Output
  • PC Multimedia
  • Processors (CPUs)

Recent Posts

12 Best Online Platforms for Self-Education

Self-education has become popular over the past few decades. Students now rely on alternatives to escape the financial burdens imposed by colleges. At … [Read More...]

UTRAN

UTRAN Definition: UMTS Terrestrial Radio Access Network: the name of the WCDMA radio network in UMTS. … [Read More...]

CD-ROM Photo CD

Photo CD has been specified by Kodak and Philips based on the CD-i Bridge specification. It comprises the … [Read More...]

[footer_backtotop]

Copyright © 2025 About | Privacy | Contact Information | Wrtie For Us | Disclaimer | Copyright License | Authors