What is the difference between Ultra ATA and SATA

P-ATA / Ultra-ATA / EIDE

EIDE or ATA are old interfaces for connecting hard disks and removable storage drives such as CD-ROM, DVD or streamer in a computer. EIDE has been replaced by SATA.

The EIDE interface (Enhandced Integrated Drive Electronics) is a further development of the IDE standard. The EIDE interface is also known as the ATA interface. ATA stands for Advanced Technology (AT) Attachment. The term EIDE is rarely used. With the advent of Serial ATA (S-ATA), the name P-ATA became more and more common. Where the P stands for parallel.

Note: With EIDE and ATA you have to distinguish something fundamental before you lump them together. EIDE defines the connection of the drives, such as pin assignment, connectors, cables and electrical signals. ATA defines the protocol with which the data is transported over the lines.

EIDE architecture

EIDE and ATA support up to 4 drives and enable not only the connection of hard disks, but also of removable storage drives (ATAPI) such as CD-ROM, CD burner, DVD and streamer.

Connection and cable

Two EIDE connectors on a motherboard

EIDE ribbon cable

EIDE / ATA modes

In the course of time, since EIDE / ATA existed, the hard disk manufacturers have agreed on different operating modes. This made it possible to operate older hard disks and drives in parallel with newer ones. However, this has the disadvantage that the faster devices have to adapt to the slower devices in terms of speed.

PIO mode and DMA mode

There are two protocols for data transfer. The PIO mode (Programmable Input Output) and the DMA mode (Direct Memory Access). In PIO mode, the main processor is responsible for every read and write process. He is busy until the process is completed. During this time, he cannot carry out any other processing. It was only with the introduction of the DMA mode that the data could be loaded directly into the main memory without any detours.

IDE (ATA-1) PIO 03.33 MB / s1989
IDE (ATA-1) PIO 15.22 Mbytes / s 
IDE (ATA-1) PIO 28.33 Mbytes / s 
IDE multiword DMA 04.16 Mbytes / s 
IDE multiword DMA 113.33 Mbytes / s 
IDE Multiword DMA 216.66 Mbytes / s 
E-IDE (Fast ATA-2) PIO 311.11 Mbytes / s1994
E-IDE (Fast ATA-2) PIO 416.66 Mbytes / s 

Ultra DMA mode (Ultra ATA)

The Ultra-DMA mode supports higher data transfer rates and has built-in security mechanisms. In addition, the load on the main processor during data transmission is reduced by a bus master driver. This driver must be activated. It must be deactivated for devices that cannot handle it.
Bus mastering is a data transfer method for the transmission of data and commands in which the host controller accesses the main memory directly without loading the processor. This allows the processor to take care of other tasks. This increased the transfer rate with a significantly lower processor load. The entire system runs noticeably faster.

Up to the UDMA-33 specification, 40-wire ribbon cables were used. From UDMA-66, an 80-core ribbon cable must be used, with a maximum cable length of 18 inches (approx. 45 cm). The 40 additional lines are ground lines, which prevent crosstalk between the signal-carrying lines. Since this ribbon cable takes up a lot of space in a computer case, the UDMA cable is also available as a round version. It takes up less space.
From UDMA-66, the position of master and slave on the cable is prescribed. Before that, the correct jumper assignment was sufficient. Since UDMA-66, the master drive has to be at the end and the slave drive in the middle of the cable. To make it easier to connect the drives, the plugs on the ribbon cable have been standardized in terms of color. Blue stands for the EIDE host that is located on the mainboard. The connector for the slave drive is gray and the connector for the master drive is black.
The Ultra-DMA-133 standard is backwards compatible. Older Ultra-ATA hard drives (66 and 100) can also be operated on the corresponding controllers.

Ultra-DMA 0 (ATA-16 / ATA-3)16.66 Mbytes / s1996
Ultra-DMA 1 (ATA-25)25.0 Mbytes / s 
Ultra-DMA 2 (ATA-33 / ATA-4)33.33 Mbytes / s1997
Ultra-DMA 3 (ATA-44)44.4 Mbytes / s 
Ultra-DMA 4 (Ultra-ATA-66 / ATA-5)66.66 Mbytes / s1999
Ultra-DMA 5 (Ultra-ATA-100 / ATA-6)99.99 (100) Mbytes / s2000
Ultra-DMA 6 (Ultra-ATA-133 / ATA-7)133 MB / s2001

Configuration of EIDE devices

A maximum of 2 devices can be connected to an (E) IDE line. The master device is plugged into the end of the cable. The jumper should be set on the master (M) at the back of the device. A second device goes to the second connector, in the middle of the cable. This is operated as a slave. The jumper (S) should be set accordingly.
When using Cable Select (CS), the jumpers must be inserted accordingly on both devices. The position or the operating mode is set via a (not) connected wire in the ribbon cable. This automatic function does not work in some device constellations. It is therefore advisable to make the manual setting in any case. If you only have two devices, that's no problem either.
The software configuration of hard disks and drives is done in the BIOS. There you set the EIDE connection to Auto-Detect. Only when this setting fails is it possible to manually enter the hard disks or drive parameters. As a rule, this is not necessary.

ATAPI - Advanced Technology Attachment with Packet Interface

ATAPI stands for Advanced Technology (AT) Attachment with Packet Interface and is an extension of the ATA instruction set for connecting a CD-ROM drive or another removable drive (e.g. ZIP drive) to the EIDE interface.
In the emerging multimedia age, computers were equipped with CD-ROM drives. A CD-ROM controller plug-in card was also built into the computer with the drive. Each CD-ROM manufacturer supplied its own controller card for its CD-ROM drives.
As an intermediate stage, sound cards were equipped with the 3 to 4 most important interfaces onboard. In the long run and with the onset of the CD-ROM boom, this became too expensive. In addition, the proprietary interfaces were not fast enough to do the work in a multimedia computer.
The solution was to connect CD-ROM drives to either the SCSI bus or the EIDE interface. The EIDE interface was chosen for the cheap consumer computers. But there was a problem with this: A fixed drive letter is assigned to each device connected to the EIDE interface. And so it is no longer a removable drive. Changing the CD-ROM would result in a restart of the computer.
For this reason, the ATAPI command set was developed to be able to control CD-ROMs via the EIDE interface. The BIOS is even able to boot the operating system from a CD-ROM or DVD.

Overview: Interfaces for hard disks and removable storage drives

Overview: hard drives and removable storage drives

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Everything you need to know about computer technology.

Computer technology primer

The computer technology primer is a book about the basics of computer technology, processor technology, semiconductor memory, interfaces, data storage devices, drives and important hardware components.

I want that!