The implementation of a first-generation CELL processor that supports multiple operating systems including Linux consists of a 64b power processor element (PPE) and its L2 cache, multiple synergistic processor elements (SPE) [1] that each has its own local memory (LS) [2], a high-bandwidth internal element interconnect bus (EIB), two configurable non-coherent I/O interfaces, a memory interface controller (MIC), and a pervasive unit that supports extensive test, monitoring, and debug functions. The high level chip diagram is shown in Fig. 10.2.1. The key attributes include hardware content protection, virtualization and realtime support combined with extensive single-precision floatingpoint capability. By extending the Power architecture with SPE having coherent DMA access to system storage and with multioperating-system resource-management, CELL supports concurrent real-time and conventional computing. With a dual-threaded PPE and 8 SPEs this implementation is capable of handling 10 simultaneous threads and over 128 outstanding memory requests. Figure 10.2.7 shows the die micrograph with roughly 234M transistors from 17 physical entities and 580k repeaters and 1.4M nets implemented in 90nm SOI technology with 8 levels of copper interconnects and one local interconnect layer. At the center of the chip is the EIB composed of four 128b data rings plus a 64b tag operated at half the processor clock rate. The wires are arranged in groups of four, interleaved with GND and VDD shields twisted at the center to reduce coupling noise on the two unshielded wires. To ensure signal integrity, over 50% of global nets are engineered with 32k repeaters. The SoC uses 2965 C4s with four regions of different row-column pitches attached to a low-cost organic package. This structure supports 15 separate power domains on the chip, many of which overlap physically on the die. The processor element design, power and clock grids, global routing, and chip assembly support a modular design in a building-block-like construction.The chip contains 3 distinct clock-distribution systems, each sourced by an independent PLL, to support processor, bus interface, and memory-interface requirements. The main high-frequency clock grid covers over 85% of the chip, delivering the clock signal to processors and miscellaneous circuits. Second and third clock grids, each operating at fractions of the main clock signal, are interleaved with the main clock-grid structure, creating multiple clock frequency islands within the chip. All clock grids are constructed on the lowest impedance final two layers of metal, and are supported by a matrix of over 850 individually tuned buffers. This enables control of the clock-arrival times and skews, especially on the main clock grid that supports regions of widely varying clock-load densities. High-frequency clock-signal distribution optimization and verification rely on wire simulation models that includes frequency-sensitive inductance and resistance phenomena. As shown in Fig. 10.2.2, final worst-case clock skew ac...

The supercooling and freezing of a restricted liquid has been studied by the probing of its molecular dynamics with picosecond optical techniques. A newly developed transparent porous host material makes it possible to study the liquid viscosity as a function of the confining pore radius and temperature. The observed behavior is remarkably different from that of an ordinary liquid, and can be interpreted in terms of a simple model. PACS numbers: 64.70.Dv, 61.25.Em, 62.10.+$, It is well known that the properties of liquids can be modified by their confinement in very small pores. Experiments on helium in Vycor glass^ and on other confined liquids^ have revealed a variety of phenomena whose interpretation has often been difficult and frequently controversial. One example concerns the observed freezing-point depression of liquids in porous media, where it is still not clear whether the depression is a result of a finite-size-related shifting of the phase diagram or, in fact, a consequence of genuine supercooling below the normal freezing point. More generally, although a certain amount of progress has been made in recent years, ^'"^ there is not universal agreement on many fundamental issues concerning the phase transitions of a restricted liquid. We report here on a series of time-resolved optical experiments to study the dynamics of liquid oxygen in small pores. The use of a novel porous host material allowed a systematic investigation of liquid confinement effects as a function of pore size, thereby shedding new light on the properties of supercooled restricted liquid and the way it freezes. A simple model is presented which offers a qualitative interpretation of the experimental results.Well-characterized porous sol-gel glasses^ of good optical quality and moderate mechanical strength were used to confine the liquid. The most important features of the glasses include their high porosity ( ~ 70%) and a well-defined pore size and aspect ratio as characterized by mercury porosimetry, vaporpressure isotherms, and stereo transmission-electronmicroscope images. The pore size can be controlled in the fabrication process to provide a pore radius ranging from '-^ 10 to 250 A. The glasses were mounted in a copper and brass optical cell, which was then placed inside a variable-temperature optical cryostat. A small amount of helium gas was added to ensure thermal equilibrium of the porous glass with the surrounding cell, yielding a temperature stability of ±0.005 K. Research-grade oxygen gas was added carefully in measured doses until the pores were completely filled with the physisorbed liquid.A subpicosecond optical technique was used to study the dynamical properties of the restricted liquid as it was cooled below the ordinary bulk freezing point. Optical pulses of 500-fs duration at a 76-MHz repetition rate were obtained from a dual-jet dye laser, synchronously pumped by a mode-locked argon-ion laser. The dye-laser wavelength was set at 584 nm, far enough from the oxygen bimolecular absorption line at 577 nm to avoid an...

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A newly developed integrated SQUID magnetic spectrometer yields direct high-resolution measurements of the optically induced magnetization in a 10-^m-diam sample of Cd0.sMn0.2Te. Both the magnitude and the picosecond dynamics of the magnetic response have been studied and are seen to be dramatically dependent on the energy and polarization of the optical excitation. The data show that the overall sample magnetization changes upon illumination, and that the perturbed spins equilibrate through spin-lattice relaxation.PACS numbers: 78.20.Ls, 75.30.Et, 76.30.Fc, 85.70.Sq Magnetic and diluted magnetic semiconductors (DMS) have enjoyed continued interest and examination, principally because free carriers introduced either by doping 1 or by optical excitation across the band gap 2 couple strongly with the spins in the lattice. In metals, changes in carrier densities ordinarily do not lead to a modification of the magnetic behavior. In magnetic semiconductors, however, carriers may have a profound effect on the magnetic behavior, in some cases reversing the sign of the effective exchange interaction between ion spins. 1,3 These interactions also affect the energetics of the carriers, leading to anomalously large spin splittings of the conduction and valence bands as well as magnetization-dependent exciton recombination and polarization effects. Recent time-resolved experiments 4 " 6 in Mn-based II-VI DMS have succeeded in probing some of the dynamical aspects of these phenomena. However, the fundamental spin mechanics in these systems are still not well understood. In order to obtain a detailed understanding of the static and dynamic magnetic properties of DMS, we have developed a method of observing photoinduced magnetization 7 in real time with picosecond resolution.In this Letter we describe the new static and picosecond time-resolved techniques used to obtain absolute measurements of the magnetic response of a material upon optical stimulation. These methods offer a high-resolution magnetic spectroscopy which is useful for any system in which optical excitations are capable of perturbing the magnetic state. The photon energy and polarization as well as the sample temperature may be changed in order to explore the energetics and the orientation of the induced magnetization and its thermal dependence. Moreover, the fast time resolution allows the dynamical aspects of the system to be studied in different regimes as the optical energy and intensity are varied, providing information on the microscopic aspects of the induced magnetism and its subsequent relaxation. Although the construction details of the spectrometer are provided elsewhere, 8 a brief description of the apparatus will be given here. A planar thin-film dc SQUID 9 operating at cryogenic temperatures serves as a detector measuring directly the absolute change in magnetization of a small 10-^m-diam sample. In the present SQUID design the magnetic flux is sensed by two square pickup coils 17.5 //m on the diagonal wound in opposite senses to eliminate stray ...