IDE/PATA 

In this video from ITFreeTraining I will look at IDE and PATA. These technologies were used for hard disks back in the first computers; however, nowadays it is an obsolete technology. You will only come across it if you are fixing a very old computer.
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To start from the beginning, AT Attachment or ATA started to be used in computers in 1986. It was designed to connect storage devices, so is used to connect devices such as hard disks, CD ROMs and large capacity removable drives like zip drives.
ATA used a cable to allow the computer to communicate with the storage device. Although it is the technical name for it, we will see why you may see it called by several different names.
If I consider two different IDE hard disks. The one on the left is the larger one often used in desktop computers. The one on the right is a smaller version that is often used in laptops. Both of these have a circuit board which provides the interface. Essentially the circuit board is a drive controller creating a standard interface between the computer and the data on the drive. Before this, the drive controller was part of the motherboard. With IDE, the drive controller made the transition from the motherboard to the hard disk. This means a hard disk manufacturer only needed to make their hard disks compatible with this standard and then they would work with any computer that supported that standard.
The hard disk circuit board would handle steps such as working out where the data was, where to move the hard disk head and controlling other operations of the hard disk. This effectively took the load off the computer as it no longer had to perform these calculations, it only had to send the request to the hard disk’s circuit board to be actioned. This reduced the overhead on the computer as some of the processing was now done by the hard disk.
This initial design was incrementally improved over time and technically only the first design was called IDE, however the name stuck. Since every hard disk after this used a circuit board to process instructions, they effectively have integrated device electronics, so technically this is also incorrect. The main point to take away is, that if you see a hard disk like these, they may be referred to as IDE. Let’s have a closer look at the interface used by these hard disks.
ATAPI stands for ATA Packet Interface. ATA was designed for hard disks and thus lacked some features required for other devices. ATAPI added additional features to support non-hard-disk devices. For example, it adds the ability to eject media which is required for some devices.
Shown here are the common standards used. Don’t worry about remembering them as you are unlikely to come across this technology and it is backwards compatible anyway. If you do come across this technology, you may see it referred to as ATAPI followed by the version number, or UDMA. UDMA stands for Ultra Direct Memory Access. This allows the hard disks to transfer data at high speeds; however, required a change to the cable which I will cover later in the video.
The name Ultra ATA was a name created to differentiate it from the earlier ATA standard. After Ultra ATA is the speed in Megabytes per second. Since this technology is so old, if you come across a device, it will most likely support Ultra ATA/133 since this is the latest version.
The most important point to take away from this video is, that if you come across the terminology PATA, ATA, ATAPI, UDMA, IDE or EIDE they are all referring to the same technology. EIDE or Extended IDE referred to a newer version of IDE. I have not covered PATA yet but will cover it next.
The reason that we can bring all these standards under the same name is that they are improvements of the previous standards but are backwards compatible. The most noticeable similarity is that they all use a 40 or 80-wire ribbon cable.
Both cables have 40 pins, the difference is that the 80-wire cable has an extra ground wire for each data wire making 80 wires in total. Having a ground wire for each wire in the cable allows the cable to send more data at a higher speed. The top cable shown has 40 wires and the bottom cable 80 wires. You can see that it is difficult to tell which is which.
Description too long for RU-vid. Please see the following link for the rest of the description. itfreetraining.com/ap/3b40
References
“The Official CompTIA A+ Core Study Guide (Exam 220-1001)” Chapter 6 Paragraph 151 - 163
“CompTIA A+ Certification exam guide. Tenth edition” Pages 312 - 314
“Parallel ATA” en.wikipedia.org/wiki/Paralle...
“Picture: ATA cable” commons.wikimedia.org/wiki/Fi...
Credits
Trainer: Austin Mason ITFreeTraining.com
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