This post features computer bus interfaces. There has been different through the history of computer science.
List of Computer Bus Interfaces
Classification of computer interfaces by function:
- System buses
- Expansion buses
- Storage interfaces
- External interfaces
System Buses
System buses featured on this post:
- FSB
- DMI
- HyperTransport
FSB
The front side bus (FSB) connects the CPU to the main memory.
DMI
Direct Media Interface (DMI) is used in Intel systems to connect the CPU to the chipset (replaces the FSB).
HyperTransport
HyperTransport is used in AMD systems to connect the CPU to the chipset.
Expansion Buses
A expansion bus is used to connect a card within a computer.
Expansion buses featured on this post:
- MCA
- EISA
- PCI
- AGP
- ePCI
MCA
MCA is an expansion bus developed by IBM.
EISA
EISA is an expansion bus that tried to compete with MCA. It was released in 1989.
PCI
A Peripheral Component Interconnect (PCI) is a standard to connects a computer to its expansion parts, such as a graphics card or a sound card, through the motherboard.
As of 2025, it is obsolete and has been replaced by PCIe.
AGP
AGP (Accelerated Graphics Port) is used for graphics cards in older systems. It has been replaced by PCIe.
PCIe
PCIe (PCI Express) is the modern, high-speed standard for expansion cards.
Storage Interfaces
A storage interface connects a storage device to the motherboard.
Internal Computer bus interfaces featured on this post:
- ATA
- PATA
- SATA
- Paralell SCSI
- SAS
- NVMe
ATA
Advanced Tecnology Attachment (ATA) is a technology to connect devices.
PATA
Parallel ATA (PATA), originally known as Advanced Tecnology Attachment (ATA), is a technology to connect devices desinged in 1986. It is also known as Integrated Drive Electronics (IDE), as it was the name of its first version.
As of 2025, it is obsolete.
https://en.wikipedia.org/wiki/Parallel_ATA
SATA
Serial ATA (SATA) was created in 2000, and replaced PATA.
It is used extensively on consumer devices.
https://en.wikipedia.org/wiki/Serial_ATA
Paralell SCSI
Small Computer System Interface (SCSI) is a set of standards for physically connecting and transferring data between computers and peripheral devices.
It is more used in enterprise devices and high performance computers.
SAS
Serial Attached SCSI (SAS) has replaced SCSI.
NMVe
Non-Volatile Memory Express (NMVe) is protocol for ultra-fast SSDs, typically using PCIe.
External Interfaces
External interfaces:
- USB
- ThunderBolt
- eSATA
USB
Universal Series Bus (USB)
USB versions:
- 1.0 (1996)
- 1.1 (1998)
- USB 2.0 (2000)
- USB 3.0 (2008)
- USB 3.1 (2013)
- USB 3.2 (2017)
- USB4 (2019)
- USB4 2.0 (2022)
Thunderbolt
Thunderbolt
eSATA
eSATA
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External References
- “Hard Drive Interfaces“; ifixit.com