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If I am not mistaken these names all referrer to the same technology. Are there any differences between them? If not, why does this technology go by so many different names?

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    The computer industry has way too many acronyms (it seems worse than the military when you consider IBM had an acronym for "fan" -- A.M.D. for Air Movement Device). Good question (+1)! – Randolf Richardson Sep 30 '11 at 0:12
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IDE (Integrated Drive Electronics) was the original name, then they standardized on ATA (Advanced Technology Attachment) as being a broader standard that included additions like CD-ROMs and such. When SATA ( Serial ATA ) came out, people started using PATA (Parallel ATA) to refer to the older parallel connected bus (those using ribbon cable), to be more specific than the term ATA, which can refer to either. Both are part of the ATA standard, and use the same logical command sets, but SATA obviously has a different electrical interface. Both types of drives (SATA and PATA) are IDE devices.

Source: PC mag

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I found an interesting article here that explains the difference. It appears that it was actually called ATA, but IDE and PATA were just different names used by different branding.

It just goes to show how much competition (and money) there is amongst computer related companies to have their particular brand of the current technology accepted as the world standard. However, they all dipped out as plain old 'ATA' became the accepted term.

Once SATA was developed, it was named PATA.

All in all, the ATA standard has moved through seven recognised phases, (ATA-1, 2, 3, etc) and in 2001 stage 7 ATA hard drives came on the market (commonly called Ultra ATA-133). These could make data transfer rates of up to133 MB/sec (megabytes per second). ATA-7 is thought to be the last stage of development before Serial ATA took over. At this stage to make clear the distinction between ATA and the newer SATA standard, the older ATA standard was redefined and named Parallel ATA (or PATA).

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Integrated Drive Electronics was the original marketing name to differentiate from when the electronics were on a separate board (ST-506 and ESDI). But for example, SCSI drives also have their controllers integrated. So the standard was named "AT Attachment" for the IBM PC/AT (which in turn meant Advanced Technology, but ATA is not Advanced Technology Attachment). But IDE and ATA are synonymous. ATA is a better term.

ATA became PATA (Parallel) to differentiate from SATA (serial)

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Every SATA drive have an on-board chip-set that compress and decompress the data transfer, where as the PATA controller, on-board the motherboard, communicated directly with the drive's hardware before.

SATA to motherboard the data is compressed, the motherboard then has it's own chip-set which turns the data from the SATA device back into decompressed binary for the rest of the computer, the same has to be done for data being passed from the motherboard to the hard-drive.

Any transfer to/from the drives has to go through this process or neither components will understand the other.

  • No, the data is not compressed. It is serialized. Same number of bits ( actually SATA adds a few bits over the wire that get stripped back off ), they are just sent one at a time instead of 32 in parallel. – psusi May 11 '18 at 20:26
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ATA is also called Parallel AT Attachment,physically they have close relation but PATA seems the newer technology system.So,try looking at some older model of interface system that have port like small pin pierced out from device like HDD,CD-Drive....those pins which are parallel to each other and have about 15 to 20 or something pins are example of Parallel ATA. IDE also have same relation to ATA and PATA but those cabling system made up of flat wide surface that have 20 to 30 pins are IDE.There's newer system like EIDE which have higher bandwidth.

  • Can you be more detailed? Photos of the various connectors or some source material would be helpful. – kazoni Jul 7 '16 at 4:58
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I will try to give complete answer.

At the time of PC-AT (286) there was only one bus in the system. This bus was called system bus or host bus (nowadays it is known as ISA).

All devices (inlcuding CPU itself) were connected to this bus: memory controller, floppy disk controller, keyboard controller, timer etc.

First HDDs consisted of 2 parts: disk controller (connected to ISA) and dumb disk. Controller (like any ISA-based device) was accessed by programmer using IO and memory regions. It presented disk as blocks using head-cylinder-sector geometry and handeled low-level things (like moving drive heads) by itself.

ISA-->Controller-->Cable-->Dumb_disk

Compaq produced laptops at that time. They installed simple device to ISA bridge. This device is called "Host bus adapter" (HBA). Then, they moved controller to the disk drive and connected it to HBA with ribbon cable. Please note, that HBA is not controller: it is just an adapter. Controller was installed in disk! So, you can say that disk controller was connected to ISA with small aid of adapter.

ISA_BUS[HBA]---ribbon-cable-->CONTROLLER_AND_DISK

That was the first time controller was integrated to disk, so they called it IDE: Integrated Disk Electronics.

Later on, manufactures created standard called AT-Attachement (ATA) that desribed both physical connection (ribbon cable) and programming interface of controller (registers and their semantics). It is called AT Attachment because it was about attach disks to AT bus (ISA).

Every ATA device is IDE. But pre-ATA devices are not IDE, although every IDE device produced after early 90th is ATA.

In the middle of 90th arhitecture changed: instead of one bus they connected CPU to chip called "north bridge" with bus called front-side-bus. Northbridge was then connected to chip called "south bridge". They integrated ATA HBA and ISA and keyboard controller and other low-speed devices into south bridge. ATA stopped been "AT attachment" at that time, but name remained.

ATA had one problem: it was parallel. Each data line resided on separate wire (there were 40 wires in original ATA). Big number of lines limit speed because of crosstalk. First, they solved it by adding additional lines connected to ground, so ATA-4+ used 80 lines!

But ultimate solution was to move to serial bus. It increased controller complexity, but gave engineers ability to increase speed. So, they created serial version of ATA called "SATA". From then moment, old version was named parallel ATA or PATA.

PATA is ATA. And SATA is ATA. But when people talk about ATA they almost always talk about old, parallel version of ATA: PATA.

SATA can be ATA compatible, but they developed new version of HBA called AHCI (Advanced host controller interface). See: AHCI is controller, not an adapter from now. From that moment, we can say that SATA is regual bus (just like USB). That has 2 controllers: One controller resides on PCI (somewhere near "communication hub" (this is how they call "south birdge" now). Another one resides inside of disk, but this is complete different story.

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