多机UNIX核心中的指令流控制结构—thread

Ｔｈｒｅａｄｓ－指令流结构成为多处理机ＵＮＩＸ操作系统中的一个基本结构。随着ＵＮＩＸ在多机环境下的不断开发，细颗粒开发，或者说指令级并发对提高系统的总处理能力显得越来越重要，并已从传统ＵＮＩＸ中的进程概念，发展为多处理机ＵＮＩＸ中的指令流／进程的概念。本文介绍了ｔｈｒｅａｄ的基本概念，ｔｈｒｅａｄ的构造，ｔｈｒｅａｄ的各种操作和多机ＵＮＩＸ中的一些实现算法。     

多处理机环境下UNIX文件系统的设计和实现

本文论述了在多处理机环境下UNIX 文件系统的设计和实现,以保证文件系统运行的正确性和极大限度地开发信息处理的并发性。文中提出多处理机UNIX 文件系统的模型、结构及特点。着重论述多处理机UNIX 文件系统主要数据结构低层缓冲区和内部其他数据结构的组织和管理。最后论述了多处理机环境中出现的数据一致性问题。     

UNIX操作系统从单机到多机的移植与改造技术

本文根据曙光一号并处理机上移植ＵＮＩＳ操作系统（ＳＮＩＸ）的经验，对Ｕ－ＮＩＸ操作系统从单机到多机的移植与改造技术进行了描述。包括多机硬体系结构的支持，ＵＮＩＸ源码选择，移植环境的建立，源码的改造等多方面所进行的工作。     

单机UNIX核心的并行化技术

本文主要阐述UNIX源程序从单处理机到共享存储器多处理机系统的移植技术.主要从三个方面介绍:基本移植技术,提高效率技术以及增加新概念.我们在国外研究成果和经验的基础上提出我们对该问题的看法.     

Simulation of multiple digital signal processor systems

The high speed needed in solving digital signal processing problems in real time has often given rise to multiple processor hardware designs. Devices such as the TMS32020 digital signal processor possess features designed to support concurrent processing. Progress in this area is currently hampered by the lack of suitable multiprocessor development tools. It is suggested that an incremental approach to multiprocessor development, using several methods of simulating the signal processor, may be used. Two simulation environments specifically for the development and testing of multiple digital signal processor designs are described. Firstly a single processor simulation system where the algorithms which will be performed by other concurrent processors may be executed in a high level language but without any need to simulate the instructions of the other processors. Secondly a multiple TMS32020 digital signal processor system where processors are simulated as several communicating tasks on a host computer using the IBM AIX (UNIX derived) multitasking operating system.     

Distributed Matrix-Free Solution of Large Sparse Linear Systems over Finite Fields

We describe a coarse-grain parallel approach for the homogeneous solution of linear systems. Our solutions are symbolic, i.e., exact rather than numerical approximations. We have performed an outer loop parallelization that works well in conjunction with a black box abstraction for the coefficient matrix. Our implementation can be run on a network cluster of UNIX workstations as well as on an SP-2 multiprocessor. Task distribution and management are effected through MPI and other packages. Fault tolerance, checkpointing, and recovery are incorporated. Detailed timings are presented for experiments with systems that arise in RSA challenge integer factoring efforts. For example, we can solve a 252,222 × 252,222 system with about 11.04 million nonzero entries over the Galois field with two elements using four processors of an SP-2 multiprocessor, in about 26.5 hours CPU time. Received June 1, 1997; revised March 10, 1998.     

Simulating the DYNIX operating system parallel programming interface on a UNIX system

This paper presents the implementation of multitasking functions of DYNIX Sequent computers on the UNIX operating system. The Sequent computers are shared memory multiprocessor computers running the DYNIX operating system. These functions support data and function partitioning. They let the user implement subprograms by the processors of a Sequent computer in parallel. The functions can synchronize, lock, and unlock data and program segments. As a result, the simulator allows the users to develop their multitasking programs on a uniprocessor computer such as a SUN workstation, and later port them to a Sequent computer. Further, the simulator adds a level of abstraction on top of UNIX for concurrent programming. The functions of the simulator allow the user to handle the communication and synchronization of the processes in a program at a higher level of abstraction, while concentrating on the design of multitasking algorithms. The simulator is applied to a parallel selection algorithm. © 1998 John Wiley & Sons, Ltd.     

UNIX系统行为安全特性及其防护研究

基于UNIX操作系统的工作原理,根据UNIX操作系统的行为,该文探讨了系统的安全问题。文章分析了UNIX系统的保护对象,以及影响这些对象安全的因素。研究了系统中根权限的重要性,以及它可能造成系统安全问题的方式。并结合操作系统内核构造,阐述了用户与系统的各种交互方式,而且着重分析了系统在网络中可能暴露的不安全因素。提出了基于UNIX工作原理的一些减小系统安全风险的方法。     

Portable parallel FFT for MIMD multiprocessors

A portable parallelization of the Cooley–Tukey FFT algorithm for MIMD multiprocessors is presented. The implementation uses the virtual machine for multiprocessors (VMMP) and PVM portable software packages. Since VMMP provides the same set of services on all target machines, a single version of the parallel FFT code was used for shared memory (25-processor Sequent Symmetry), shared bus (MOS-running distributed UNIX) and distributed memory multiprocessor (transputer network and 64-processor IBM SP2). It is accompanied with detailed performance analysis of the implementations. The algorithm achieved high efficiencies on all target machines. The analysis indicates that most overheads are caused by the target architecture and not by VMMP or PVM inefficiencies. The portability analysis of the FFT provides several important insights. On the message passing architecture, the parallel FFT algorithm can obtain linearly increasing speedup with respect to the number of processors with only a moderate increase in the problem size. The parallel FFT can be executed by any number of processors, but generally the number of processors is much less than the length of the input data. The results indicate that the parallel FFT is portable: it achieves very good speedups on either a shared memory multiprocessor with high memory bandwidth or on a message passing multiprocessor without any change in the programs. © 1998 John Wiley & Sons, Ltd.     

Experience with an efficient parallel kernel memory allocator

There has been great progress from the traditional allocation algorithms designed for small memories to more modern algorithms exemplified by McKusick's and Karels' allocator (McKusick MK, Karels MJ. Design of a general purpose memory allocator for the 4.3BSD UNIX kernel. In USENIX Conference Proceedings, Berkeley, CA, June 1988). Nonetheless, none of these algorithms have been designed to meet the needs of UNIX kernels supporting commercial data‐processing applications in a shared‐memory multiprocessor environment. On a shared‐memory multiprocessor, memory is a global resource. Therefore, allocator performance depends on synchronization primitives and manipulation of shared data as well as on raw CPU speed. Synchronization primitives and access to shared data depend on system bus interactions. The speed of system buses has not kept pace with that of CPUs, as witnessed by the ever‐larger caches found on recent systems. Thus, the performance of synchronization primitives and of memory allocators that use them have not received the full benefit of increased CPU performance. An earlier paper (McKenney PE, Slingwine J. Efficient kernel memory allocation on shared‐memory multiprocessors. In USENIX Conference Proceedings, Berkeley, CA, February 1993), describes an allocator designed to meet this situation. This article reviews the motivation for and design of the allocator and presents the experience gained during the seven years that the allocator has been in production use. Copyright © 2001 John Wiley & Sons, Ltd.