Here is a growing set of data and links regarding the PCI and various other computer and interconnect 'busses' we have used on a variety of projects.

Computer architecture notes

• Typical PC design
  • Useful intro to typical modern PC architecture, including processor, memory, bus, bridges, etc.
  • The Art of Assembly Language contains many excellent chapters on x86 and PC architecture in general, optimizations, data representation, etc. This is great material when doing high performance, low level work.
  • Paper on Pentium P6 micro and memory architecture

PCI Bus

• Forums, SIGS and specifications
  • The PCI-SIG provides a forum for its 900+ member companies who develop differentiated, interoperable products based on its specifications.
    Most of the technical material on this site is only available to members, including the key bus specification documents. However, there is enough useful information overall on the site to warrant some examination.
• PCI bus connector types
  • Types of PCI connectors and cards is a bit outdated (no PCI-Express) but still useful and quite clear
• PCI descriptions and programming basics
  • Programming PCI-Devices under Linux is a short tutorial about PCI programming under Linux. It describes the PCI basics and its implementation under Linux.
• PCI optimizations in hardware and software
  • Performance issues in PCI reading is a (Postscript) document from CERN with substantial info on things to consider when reading data via PCI bus. Particle physics instrumentation people really have to worry about these things at the kinds of data rates they think about when conducting certain collider experiments.
  • Techniques for Increasing PCI Performance is a useful Intel document (.pdf) related to noted topic. It is rather high level but introduces certain concepts mandatory to understanding real PCI performance issues.
  • Write Combining Memory Implementation Guidelines is another Intel (.pdf) document describing memory write optimizations related to Intel x86 and PCI architecture. Key stuff.
  • Intel Architecture Software Developer's Manual Volume 3 contains lots more info on MTRR, cache, and other performance considerations under x86 and PCI/memory use
  • 64bit/66Mhz Computing and PCI Bus performance is a nice (.pdf) summary of performance scaling as bus width and clock rate scale
  • Notes on PCI Latency timers
  • PDF document on PCI latency settings
  • PCI in realtime apps contains a detailed analysis and discussion of PCI considerations in real-time, high performance acquisition. Quite long, quite detailed
  • Notes on HyperTransport flow control compared to PCI
• PCI-X
  • This document (.pdf) from Acer Corp. presents an useful overview of PCI-X bus
• PCI Express
  • Article introducing PCI-Express
  • This article has some excellent material on PC architecture, PCI bus, and requirements and evolution that lead to PCI Express
  • PCI Technology paper from Digi International has excellent material on evolution of PCI from PCI 1, 2, 2.1-2.3, PCI-X and PCI Express. Lots of material on connectors, voltages, compatibility, etc. between various flavors of PCI. Most useful!

AGP Bus

It is fascinating to me how fast technology is pushed aside by marketeers. Many of the links below themselves link to AGP information on the Intel website. However, as of the time this page was developed (late 2004) Intel is in the throes of pushing everybody over to PCI-Express and so just about all AGP related content on the Intel site redirects to pages about PCI-Express. Thanks, marketing monkeys.

• General bus description and notes
  • Brief introduction to AGP; older but quite useful material, plus some nice links
  • More detailed look at AGP features and limits
  • AGP info, including specs
  • AGP Aperture description and comments
• Bus variants and compatibility notes
  • AGP Compatibiity notes is very handy, regarding connectors, interface voltages, and interoperability between AGP flavors
• Performance, benchmarks, and optimization
  • Simple notes and graphics describing rated performance of 4 generations of AGP interface
  • Linux and AGP contains much useful information including this excellent reference to benchmarking AGP under Linux
  • AGP in the context Direct Rendering Infrastructure (DRI) of XFree86 X11 implementation
  • Article on AGP describes evolution of AGP, as well as real vs. published performance gains in AGP 1x vs 2x vs 4x vs 8x
  • Some notes on AGP optimization and register/feature reading
  • Hardware implementation of AGP provides an excellent overview of AGP internals on the bus
  • Comparison between PCI and AGP is another excellent article
  • A closer look at AGP 8x has some excellent technical material covering timing and bandwidth across generations of AGP bus

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