pctechguide.com

  • Home
  • Guides
  • Tutorials
  • Articles
  • Reviews
  • Glossary
  • Contact

Local Bus Interfaces

Intel 80286 motherboards were capable of running expansion slots and the processor at different speeds over the same bus. However, dating from the introduction of the 386 chip in 1987, motherboards provided two bus systems. In addition to the official bus – whether ISA, EISA or MCA – there was also a 32-bit system bus connecting the processor itself to the main memory. It was the rise in popularity of the Graphical User Interface (GUI) – such as Microsoft Windows – and the consequent need for faster graphics that originally drove the concept of local bus peripherals. The bus by which they were connected was commonly referred to as the local bus because its high speed and the delicate nature of the processor means that it can only function over short distances.

Initial efforts to boost speed were proprietary: manufacturers integrated the graphics and hard disk controller into the system bus. This achieved significant performance improvements but limited the upgrade potential of the system. As a result, in the early 1990s, a group of graphics chipset and adapter manufacturers, the Video Electronics Standards Association (VESA), established a non-proprietary high-performance bus standard. Essentially, this extended the electronics of the 486 system bus to include two or three expansion slots: the VESA Local Bus (VL-Bus). The VL-Bus worked well and many cards became available, predominately graphics and IDE controllers.

The main problem with VL-Bus was its close coupling with the main processor. Connecting too many devices risked interfering with the processor itself, particularly if the signals went through a slot. VESA recommended that only two slots be used at clock frequencies up to 33MHz, or three if they are electrically buffered from the bus. At higher frequencies no more than two devices should be connected, and at 50MHz or above they should both be built into the motherboard.

The fact that the VL-Bus ran at the same clock frequency as the host CPU became a problem as processor speeds increased. The faster the peripherals are required to run, the more expensive they are, due to the difficulties associated with manufacturing high-speed components. Consequently, the difficulties in implementing the VL-Bus on newer chips such as the 40MHz and 50MHz 486s and the new 60/66MHz Pentium created the perfect conditions for Intel’s PCI (Peripheral Component Interconnect).

  • What Is The System Bus?
  • ISA Bus – Industry Standard Architecture
  • Local Bus Interfaces
  • PCI Bus Interfaces
  • What is AGP and AGP Pro?
  • Internal Interfaces Summary
  • PCI-X Interfaces
  • PCI Express Interfaces
  • IDE Interfaces
  • EIDE Interfaces
  • Hard Disks – What IS ATA and Ultra ATA?
  • Serial ATA (SATA) interface guide
  • SCSI Explained – With Pictures
  • SCSI Interface Evolution
  • Fibre Channel Interfaces
  • Hard Disks – What is Serial Storage Architecture?
  • I/O Interface Standards
  • How It Works: The Idea and Technology Behind USB
  • IEEE 1394 Interfaces
  • USB 2.0 Intefaces
  • FireWire 800 Interfaces

Filed Under: Interfaces

Latest Articles

DRAM – Dynamic Random Access Memory

DRAM chips are large, rectangular arrays of memory cells with support logic that is used for reading and writing data in the arrays, and refresh circuitry to maintain the integrity of stored data. Memory arrays are arranged in rows and columns of memory cells called wordlines and … [Read More...]

What is the Find Fast Indexer?

The Find Fast Indexer is a utility that builds indexes to speed finding Microsoft Office-suite documents when you've forgotten their filenames, but know certain text strings they contain. It is installed on your computer when you install Microsoft Office 97, a shortcut called Microsoft Find … [Read More...]

USB Sound Cards

Swiss semiconductor company Micronas has developed a technology which could render the sound card obsolete on future multimedia PC systems. Its USB audio controller integrates a DSP, DAC, operation amplifier, and a USB controller into … [Read More...]

Gaming Laptop Security Guide: Protecting Your High-End Hardware Investment in 2025

Since Jacob took over PC Tech Guide, we’ve looked at how tech intersects with personal well-being and digital safety. Gaming laptops are now … [Read More...]

20 Cool Creative Commons Photographs About the Future of AI

AI technology is starting to have a huge impact on our lives. The market value for AI is estimated to have been worth $279.22 billion in 2024 and it … [Read More...]

13 Impressive Stats on the Future of AI

AI technology is starting to become much more important in our everyday lives. Many businesses are using it as well. While he has created a lot of … [Read More...]

Graphic Designers on Reddit Share their Views of AI

There are clearly a lot of positive things about AI. However, it is not a good thing for everyone. One of the things that many people are worried … [Read More...]

Redditors Talk About the Impact of AI on Freelance Writers

AI technology has had a huge impact on our lives. A 2023 survey by Pew Research found that 56% of people use AI at least once a day or once a week. … [Read More...]

11 Most Popular Books on Perl Programming

Perl is not the most popular programming language. It has only one million users, compared to 12 million that use Python. However, it has a lot of … [Read More...]

Guides

  • Computer Communications
  • Mobile Computing
  • PC Components
  • PC Data Storage
  • PC Input-Output
  • PC Multimedia
  • Processors (CPUs)

Recent Posts

Celeron Mendocino

Starting with the 300A, all Celerons have come equipped with 128KB of on-die Level 2 cache running at full CPU speed and … [Read More...]

JavaScript Code that Shares Astrology Predictions on Website

Astrology may not be a topic that you expected to be covered on a PC technology website. However, we wanted to create a JavaScript program for people … [Read More...]

Scan Modes

PCs represent pictures in a variety of ways - the most common methods being are line art, halftone, greyscale, and … [Read More...]

[footer_backtotop]

Copyright © 2025 About | Privacy | Contact Information | Wrtie For Us | Disclaimer | Copyright License | Authors