Disk Interface

What is Disk Interface?

A disk interface refers to the specific type of circuit board. This allows a hard drive or a floppy drive to communicate with the host computer.

Ideally, these interfaces can be defined as the physical as well as the logical means to connect the hard disk to the computer system.

Understanding Disk Interface

Understanding Disk Interface

The disk interfaces are the channels to transfer data from the hard disks cache to and from the memory of the computer system.

There are quite a few different varieties of interfaces that can be divided under the broad categories of IDE and SCSI based on their rate of data transmission and technical specifications.

In addition to that, there are also a few early hard disk interfaces such as:

Historically, there were the serial interfaces. These specific types of earliest interfaces connected the drives to the bus adapter by using only one cable to perform the combined function of data transfer and control.

The older interfaces supported the older hard drives that typically had two ribbon cables to serve two different purposes such as:

The modern drives, however, come with only one single ribbon cable to serve both the purposes.

Apart from that, the hard disk drive interfaces in the early days were referred to as bit serial data interfaces.

These interfaces usually had two cables to connect the drive to the controller. One of these cables was used for data transfer and the other for control.

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However, the contemporary bit serial interfaces use only one cable for data and control to connect the hard disk drives to the bus interface adapter of the host computers.

The data transfer rate and maximum storage capacity supported by some of the disk interfaces are mentioned here.

In the list, you will even find those of the older ones as well. This will help you to make a much better comparison.

Types of Hard Disk Interface

Typically, there are six major types of hard disk interfaces available such as Parallel ATA or IDE, Serial ATA, SCSI, M.2, SAS, and Fiber Channel.

All these different types of hard disk interfaces have different use cases such as:

Here is a brief description of each of the major types of hard disk interfaces.


Integrated Drive Electronics or IDE hard disk interface integrates the hard disk body and the controller. This particular feature offers significant benefits such as:

Also known as the first IDE-type hard disk ATA-1, this compatible and cost-effective interface uses three specific transmission modes such as:


Small Computer System Interface or SCSI is entirely different from IDE in the sense that it is designed as a high-speed data transmission technology commonly used in minicomputers more than in the hard disks.

Available in three different versions, namely SCSI 1, SCSI 2, and SCSI 3, this specific interface offers the following benefits:

However, it is expensive and offers little BIOS support, lacks a common SCSI software interface, and needs to be set for each individual computer system. All these features make it a favored option to use in high-end workstations and servers.

Fiber Channel:

It is pretty much the same as SCSI and is usually designed for the network systems, though modern hard disk systems also use it. The benefits offered by this interface include the following:

The better and improved features of the Fiber Channel make it suitable for use in:

The Fiber Channel supports different protocols with a diverse range of services offered such as:


Serial Advanced Technology Attachment or SATA interface connects the ATA hard drives to the motherboard of a computer via the serial connection mode and by using an embedded clock signal.

It offers better error correction not just for data but also for the transmission instructions, making it more reliable for data transfer. The features of it include:

SATA is usually available in three versions such as:


This new interface specification is designed to replace the mSATA interface and to be used for hard drives in Ultrabooks. These interfaces are usually divided into two specific types such as:


Serial Attached SCSI or SAS is similar to SATA technology using serial technology. It offers benefits such as:

SAS is made up of three specific types of protocols that help in transferring data between different types of devices. These are:

The SAS backplane can be linked to two ports, one for the high-performance SAS drives and the other for the high-capacity SATA drives. This means, SAS allows both SAS drives and SATA drives to coexist in a storage system at the same time.

Is SAS a Disk Interface?

Serial Attached Small Computer System Interface (SAS) is actually a point-to-point protocol that accesses the peripheral devices of a computer and allows digital transfer one bit at a time through thin cables.

It typically uses the regular SCSI command set and provides voluntary compatibility with different versions of Serial ATA such as version 2 and later.

In other words, SAS allows connecting most of the SATA drives to most of its controllers or backplanes. However, it is not possible to connect SAS drives to SATA backplanes.

Technically, the SAS standard can be defined by its different layers. In the order of highest to lowest, these layers are as follows:

Apart from that, it also follows three specific transport protocols as follows:

So, you can say that the SAS technology is a specific protocol that also acts as an interface for the modern hard drives.

Which Hard Drive Interface is Fastest?

If you compare Parallel Advanced Technology Attachment (PATA) and Serial Advanced Technology Attachment (SATA) hard drives, the latter is much faster than the former.

It can write with a throughput of about 600 MB/s to the disk with an interface rate of about 6 GB/s.

However, the SAS interface is even faster in data transmission, clocking between 375 MB/s and 750 MB/s.


The hard disk interface connects the host computer system to the hard disk.

The primary function of it is to act as a conduit for transmitting data between the memory of the host computer system and the cache of the hard disk.

Ideally, the speed of data transfer is determined by the type of the hard disk interface.