secure programming for linux and unix howto

... Group owns the Unix trademark, and it defines Unix as ``the Secure Programming for Linux and Unix HOWTO Trang 12worldwide Single UNIX Specification''.Linux is not derived from Unix source code, ... how to acquire random numbers (Chapter 11) Figure 1−1 Abstract View of a Program Secure Programming for Linux and Unix HOWTO Trang 10I issued an order and a search was made, and it was found ... user and group ids (uids and gids) for each process and afilesystem with read, write, and execute permissions (for user, group, and other) See Thompson [1974] andBach [1986] for general information

Ngày tải lên: 07/04/2017, 16:35

... the left) ofβ and selects the output link for forwarding the message according to the following rule: • for β k= 0, the message is forwarded over the upper link of the switch and • for β k= 1, ... turns (top), allowed turns for X Y routing (middle), and allowed turns for west-first routing (bottom) possible turns in a 2D mesh turns allowed for XY−Routing turn allowed for West−First−Routing ... cycles Examples are the west-first routing for two-dimensional meshes and the P-cube routing for n-dimensional hypercubes. The west-first routing algorithm for a two-dimensional mesh prohibits only

Ngày tải lên: 03/07/2014, 16:20

... buffer and to select the output channel to be used by inspecting the header informa-tion of the packet Thus, for a path of length l, the entire time for packet transmission with store-and-forward ... path have different bandwidths as this is typically the case in wide area networks (WANs) In this case, store-and-forward routing allows the utilization of the full bandwidth for every link on the ... time for packet transmission depends lin-early on the packet size and the length l of the path Packet transmission with store-and-forward routing is illustrated in Fig 2.30(b) The time for the

Ngày tải lên: 03/07/2014, 16:20

... Gbyte and 16 Gbytes Typical access times are one or a few processor cycles for the L1 cache, between 15 and 25 cycles for the L2 cache, between 100 and 1000 cycles for the main memory, and between ... and 128 Kbytes for the L1 cache and between Trang 6Fig 2.34 Illustration of atwo-level cache hierarchy processor instruction cache L1 data cache L2 cache main memory 256 Kbytes and 8 Mbytes for ... a direct mapped cache. Forv = 1 and k = m, a fully associative cache results Typical cases are v = m/4 and k = 4, leading to a 4-way set associative cache, and v = m/8 and k = 8, leading to an

Ngày tải lên: 03/07/2014, 16:20

... an easy and intuitive model. But the model has a performance disadvantage, since all memory accesses must be atomic and since memory accesses must be performed one after another. There- fore, processors ... (4). Thus, both P 1 and P 2 may print the old value for x 1 and x 2 , respectively. Partial store ordering (PSO) models relax both the W → W and the W → R ordering required for sequential consistency. ... different models, and there is no standardization as yet. 2.8 Exercises for Chap. 2 Exercise 2.1 Consider a two-dimensional mesh network with n rows and m columns. What is the bisection bandwidth of

Ngày tải lên: 03/07/2014, 16:20

... hard-ware and softhard-ware installation is taken into account But in contrast to sequential programming there are many more details and diversities in parallel programming and a machine-dependent programming ... [82], PC++ [22], DINO [151], and High-Performance Fortran (HPF) [54, 57] An example for an array assignment in Fortran 90 is a(1:n) = b(0:n-1) + c(1:n) The computations performed by this assignment ... details of single systems and provide an abstract view for the design and analysis of parallel programs 3.1 Models for Parallel Systems In the following, the types of models used for parallel processing

Ngày tải lên: 03/07/2014, 16:20

... be used for distributed address space The fork–join concept is, for example, used in OpenMP for the creation of threads executing a parallel loop, see Sect 6.3 for more details The spawn and exit ... array assignment is started not before the previous array assignment has been completed Aforall loop is provided in Fortran 95, but not in Fortran 90, see [122] for details 3.3.3.2 dopar Loop The ... variables to store those array operands of the right-hand side that might cause Trang 4conflicts and using these temporary variables on the right-hand side On the left-hand side, the original array

Ngày tải lên: 03/07/2014, 16:20

... for Pthreads and Sect 6.2.3 for Java threads Trang 33.4 Data Distributions for ArraysMany algorithms, especially from numerical analysis and scientific computing, are based on vectors and matrices ... the processors perform computations only on their part of the data Data distributions can be used for parallel programs for distributed as well as for shared memory machines For distributed memory ... Data Distribution for One-Dimensional Arrays For one-dimensional arrays the blockwise and the cyclic distribution of array ele-ments are typical data distributions For the formulation of the

Ngày tải lên: 03/07/2014, 16:20

... common memory, and can be performed in a blocked way. The computation and communication time for the matrix–vector product is ana- lyzed in Sect. 4.4.2. 3.7 Processes and Threads Parallel programming ... parent node and forwards those data blocks that are meant for a node in a subtree to its corresponding child node being the root of that subtree. Thus, the number of data blocks forwarded over ... A ∈ R n×m is an n × m matrix and b ∈ R m is a vector of size m. (In this section, we use bold-faced type for the notation of matrices or vectors and normal type for scalar values.) The sequential

Ngày tải lên: 03/07/2014, 16:20

... the case for the Pthreads library, see Sect 6.1.10 for more details The scheduler of the operating system on the other hand is tuned for an efficient use of the hardware resources, and there ... tries to set lock s2and then s1; after having locked s2successfully, T2waits for the release of s1 In this situation, s1 is locked by T1 and s2 by T2 Both threads T1 and T2 wait for the release of ... unlocked state and has no owner To avoid race conditions for the execution of a program part, a lock variablelis assigned to this program part and each thread executeslock(l) before entering the

Ngày tải lên: 03/07/2014, 16:21

... that parallel programming with processes or threads is difficult and is a big step for programmers used to sequential programming [114] It is often mentioned that, for example, thread programming ... consistency models for accessing shared variables, synchronization operations, and parallel loops A detailed description is given in [47] UPC compil-ers are available for several platforms For Linux systems, ... languages include Fortress, X10, and Chapel Fortress has been developed by Sun Microsystems Fortress is a new object-oriented language based on Fortran which facilitates program development for par-allel

Ngày tải lên: 03/07/2014, 16:21

... Examples for synthetic benchmarks are Whetstone [36, 39], which has originally been formulated in For- tran to measure floating-point performance, and Dhrystone [174] to measure inte- ger performance ... Per- formance Evaluation Cooperation), see www.spec.org for detailed information. The cooperation was founded in 1988 with the goal to define a standardized per- formance evaluation method for ... programs (9 written in C, 3 in C++) and 17 floating-point programs (6 written in Fortran, 3 in C, 4 in C++, and 4 in mixed C and Fortran). The integer programs include, for example, a compression program

Ngày tải lên: 03/07/2014, 16:21

... smaller input sets. This informa- tion can then be used for the modeling of the execution time for larger input sets, e.g., using extrapolation. • For different execution platforms, arithmetical operations ... interconnection network with these properties and parameters t S and t B , the time for a communication is mainly determined by the message size m and the path length p. For an implementation of global communication ... communication times are given as func- tions in closed form depending on the number of processors p and the message size m for store-and-forward as well as cut-through switching. Here we use the

Ngày tải lên: 03/07/2014, 16:21

... that d k−1  − d ≥ d For k = 1, 2, R11 = E1and R21 = E2 for all d and t∈ E k−1holds For d = 3 and d = 4, the estimation can be shown individually; Fig 4.6 shows the case d = 3 and Fig 4.7 shows ... hypercubes is performed to distribute the mes-sages received in phase 2 The phases 1 and 2 can be performed simultaneously and take time 2d Phase 3 has to be performed after phase 2 and takes time≤ ... that – For any two edges (x , y) ∈ A i and (x, y) ∈ A i, the bit position in which the nodes x and y differ is not the same bit position in which the nodes xand y differ The reason for this

Ngày tải lên: 03/07/2014, 16:21

... operations and r multiplication operations are performed. The time for a single-accumulation operation depends on the specific intercon- nection network and we consider the linear array and the hypercube ... expressed in closed form. This is a typical situa- tion for the analysis of functions for the parallel execution time, and approximations are used. In this specific case, the function for the linear ... real values. For T  (p) = 0, we get p ∗ = ±  4nα α+β . The second derivative is T  (p) = 4nα p 3 and T  (p ∗ ) > 0, meaning that T (p) has a minimum at p ∗ . From the formula for p ∗ ,

Ngày tải lên: 03/07/2014, 16:21

... and semantics of library routines for standard communication patterns as they have been considered in Sect 3.5.2 Language bindings for C, C++, Fortran-77, and Fortran-95 are sup-ported In the ... is best for P1?(d) Which of the three compilers is best for P2? Exercise 4.2 Consider the MIPS (Million Instructions Per Second) rate for esti-mating the performance of computer systems for a ... add and subtract 3.5 7 Floating-point multiply and divide 4.6 17 Compute the resulting MIPS rate for program X Exercise 4.3 There is a SPEC benchmark suite MPI2007 for evaluating the MPI performance

Ngày tải lên: 03/07/2014, 16:21

... processes 0 and 1 execute anMPI Recv()operation before anMPI Send() operation This leads to a deadlock because of mutual waiting: For process 0, the MPI Send() operation can be started not before the ... send and receive operations The MPI runtime system guarantees deadlock freedom, also for the case that no internal system buffers are used The parameterssendbuf andrecvbuf, specifying the send and ... both send and receive buffer For this function,countis the number of elements to be sent and to be received; these elements now should have identical typetype Trang 7208 5 Message-Passing Programming5.1.3

Ngày tải lên: 03/07/2014, 16:21

... Isend()andMPI Irecv(), respectively After control returns from these operations, send offset andrecv offsetare re-computed and MPI Wait()is used to wait for the completion of the send and receive ... mode, the local execution and termination of a send operation is not influenced by non-local events as is the case for the synchronous mode and can be the case for standard mode if no or too small ... is the case for point-to-point operations The main reason for this is to avoid a large number of additional MPI functions For the same rea-son, only the standard modus is supported for collective

Ngày tải lên: 03/07/2014, 16:21

... user and group ids (uids and gids) for each process and a filesystem with read, write, and execute permissions (for user, group, and other). See Thompson [1974] and Bach [1986] for general information ... like Unix. Therefore, Unix lessons learned generally apply to both, including information on security. Most of the information in this book applies to any Unix- like system. Linux- specific information ... to random input). 2.1.5. Comparing Linux and Unix This book uses the term Unix- like” to describe systems intentionally like Unix. In particular, the term Unix- like” includes all major Unix...

Ngày tải lên: 24/03/2014, 04:20

... systems, namely Microsoft Windows and Linux. It has also provided a small amount of infor- mation on the history of RS−232 as well as a design for a simple cross-platform serial port interface API. This ... program and the accuracy of the data. 3.3.1 Windows Reading and writing to a serial port in Windows is very simple and similar to reading and writing to a file. In fact, the functions used to read and ... specific appli- cation. 3.1.2 Linux Opening the serial port in Linux is performed in much the same way as it is in Windows, using the open() command. One caveat to Linux is that the user ID that...

Ngày tải lên: 05/11/2013, 20:15