This essay will show you some knowledge about internal and external hard drive power cable as well as HDD interfaces. Read more related information on MiniTool partition resizer official website.
What Is Hard Drive Power Cable?
hard drive power cables connect hard disk drives to power supply unit (PSU) on a computer motherboard power connecting. To make it simple, they are lines to connect hard disks and motherboards together.
Hard Drive Power Cable Types
The types of power cable for hard drives are determined by the hard disk drive interface.
Commonly, there are different interfaces on a hard drive for power supply and data transmission separately. Yet, there are still hard disks that have the same interface for both power and data connection. That is, you only need one connecting cable to connect the drive with the motherboard for both data and power transmission.
Hard Drive Early Interfaces
The earliest hard drive interfaces were bit-serial data interfaces that connect HDDs to controllers with two cables, one for data and the other for control. And, an extra cable is needed for power supply.
SMD
Storage Module Device is a kind of bit serial data interface introduced by the Control Data Corporation (CDC). SMD interface was the popular standard interface for minicomputers in the 1970s and 1980s.
ST-506/ST-412/ST-412RLL
They were bit-serial data interfaces introduced by Seagate Technology in early 1980. They were standard interfaces for most small HDDs in the 1980s and early 1990s. They used MFM (Modified Frequency Modulation) or latter RLL (Run Length Limited) for the data encoding method.
ESDI
Enhance Small Disk Interface is also a type of bit serial data interface first introduced by Maxtor in the late 1980s and sponsored by ANSI. ESDI is an industry-standard interface similar to ST412 that supporting higher data rate flow.
Word Serial Interfaces
Traditional word serial interfaces connect hard disks to bus adapters with one cable for both control and data.
CTL-I
Controller Interface is a word-serial interface and 8-bit disk interface introduced by IBM for its mainframe hard drives beginning with the 3333 in 1972.
SCSI
Small Computer System Interface is a kind of word serial interface sponsored by ANSI and introduced in the middle 1980s. it is the standard interface explicitly deployed to minimize system integration efforts for most enterprise, server, and workstation HDDs in the 20th century.
Server-class SCSI can make use of differential transmission, either low voltage differential (LVD) or high voltage differential (HVD).
SCSI was originally named SASI (Shugart Associates System Interface, introduced by Shugart Associates circa 1978) and was replaced by SAS.
PATA
Parallel AT Attachment is also a word serial interface that was introduced in the late 1980s by Conner Peripherals and later sponsored by ANSI. It replaced ST-412, ST-506, and ESDI, and was originally IDE and then was standardized under the name AT Attachment (ATA).
AT Attachment reflects the integration of the controller with the hard drive. Yet, the integration was not new with IDE since it has been done a few years earlier within SCSI disks. The integration of the controller and hard drive standardizes the host/controller interface, reduces the programming complexity, as well as reduces system cost and complexity.
PATA is a standard HDD interface on all except for enterprise HDDs until superseded by SATA.
Bit Serial Interfaces
Modern bit serial interfaces connect a hard disk drive to a host bus interface adapter, which is integrated into the southbridge on the motherboard in most computers, with a single control/data cable. Additionally, a power cable is required to directly connect the HDD with the PSU.
SDI
DECs Standard Disk Interface is an early example of a modern bit-serial interface type.
FC
Fibre Channel replaced parallel SCSI in enterprise hard drives. It is a serial protocol. Usually, the Fibre Channel Arbitrated Loop (FC-AL) connection topology is used in hard disks.
SATA
Serial AT Attachment data cable has one data pair for differential transmission of data to the drive, and one pair for differential receiving from the drive; that needs the data to be transmitted serially. A similar differential transmission system is used in USB, FireWire, differential SCSI, and so on.
SATA succeeded PATA. It is sponsored by ANSI and introduced in 2003. SATA is the most common interface for all HDDs except for enterprise ones just like PATA.
SAS
Serial Attached SCSI is the new generation of the serial communication protocols for devices that are designed for much higher data transmission speed. It is the successor to SCSI sponsored by ANSI and introduced in 2004. SAS is the most common interface for enterprise HDDs like SCSI.
SAS makes use of a mechanically identical power and data connector for standard 3.5” SATA1 and SATA2 hard drives. SAS is compatible with SATA, and many server-oriented SAS RAID controllers are also able to address SATA disks.
More About Hard Drive Power Cable
Sometimes, you can’t directly connect an HDD power cable with a hard disk. Then, you can make use of a SATA hard drive power cable adapter, a hard drive power extension cable, an SSD hard drive power cable splitter (Y shape), etc. for those kinds of drives like SSDs, internal hard drives, external hard drive, western digital (WD) hard drives, Toshiba hard drives, Seagate hard drives, desktop hard drives, laptop hard drives…
About The Author
Position: Columnist
Like many of you, Helen was once annoyed by computer problems such as “could not reconnect all network drives in Windows”, “CPU does not have POPCNT”, and “Is SSD good for long-term storage”. Later, such issues haven’t bothered her since she became a tech writer. Helen has even managed to help lots of readers solve their problems.