Introduction

• Data-intensive applications;
  • transaction processing,
  • information retrieval,
  • data mining and analysis,
  • multimedia services,
  • computational physics/chemistry/biology and nanotechnology.
• High performance may come from
  • fast dense circuitry,
  • parallelism.
• Parallel processors are computer systems consisting of
  • multiple processing units
  • connected via some interconnection network
  • plus the software needed to make the processing units work together.

• Uniprocessor - Single processor supercomputers have achieved great speeds and have been pushing hardware technology to the physical limit of chip manufacturing.
  • Physical and architectural bounds (Lithography, $\mu$m size, destructive quantum effects.
  • Proposed solutions are maskless lithography process and nanoimprint lithography for the semiconductor).
  • Uniprocessor systems can achieve to a limited computational power and not capable of delivering solutions to some problems in reasonable time.
• Multiprocessor - Multiple processors cooperate to jointly execute a single computational task in order to speed up its execution.

  Figure 2.1: Abstraction Layers

  

Figure 2.2: View of the Field

• New issues arise;
  • Multiple threads of control vs. single thread of control
  • Partitioning for concurrent execution
  • Task Scheduling
  • Synchronization
  • Performance

• Past Trends in Parallel Architecture (inside the box)
  • Completely custom designed components; processors, memory, interconnects, I/O.
  • The first three are the major components for the aspects of the parallel computation.
    • Longer R&D time (2-3 years).
    • Expensive systems.
    • Quickly becoming outdated.
  • In the form of internally linked processors was the main form of parallelism.
  • Advances in computer networks $\Rightarrow$ in the form of networked autonomous computers.
• New Trends in Parallel Architecture (outside the box)
  • Instead of putting everything in a single box and tightly couple processors to memory, the Internet achieved a kind of parallelism by loosely connecting everything outside of the box.
  • Network of PCs and workstations connected via LAN or WAN forms a Parallel System.
  • Compete favourably (cost/performance).
  • Utilize unused cycles of systems sitting idle.