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  • gnome-tweak-tool doesn't start due to "ImportError: No module named gi" error

    - by Khajak Vahanyan
    I am using Ubuntu 11.10 with Gnome Shell and have a problem with gnome-tweak-tool. When I click on it, it does nothing and when I try to open with terminal it gives this error: Traceback (most recent call last): File "/usr/bin/gnome-tweak-tool", line 22, in <module> import gi ImportError: No module named gi I googled a bit, found some solutions (reinstalled some python-gobject packages), but still didn't help./

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  • Upgrade to 11.10 caused rt2800usb module to be blacklisted

    - by Shevek
    I just upgraded from Kubuntu 11.04 to 11.10, and I noticed that after the upgrade my USB wireless card was no longer recognized. It turns out that the rt2800usb module had been added (automatically, I assume, unless previously the module had been loading despite being blacklisted) to /etc/modprobe.d/blacklist.conf. I re-enabled the wireless card by commenting out the blacklist line and adding rt2800usb to /etc/modules, but I was wondering if there was a reason for rt2800usb being added to the blacklist.

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  • Kernel module implementation estimate

    - by Ivan Teterevkov
    I have a very abstract question about a kernel module writing estimate. How much dev-hours/months may required to write or, especially, port an existant kernel driver for a new PCI HBA from one operating system to another (with different kernel API)? I am porting an already written kernel module for 82599 for Linux kernel to OS X's IOKit and try to get a working alpha. I can't imagine for how long this task may expand in time.

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  • Recording Available - Features and Functions Payments Module

    - by MHundal
    The Payments Module recording provides a high-level overview of Payments Processing in ETPM.  The recording discusses the Payments Data Model, including Payment Events, Tenders, Tender Control, Deposit and Deposit Control.  In addition, there is a product demonstration of payment processing in the system. Payments Module Overview:  https://oracletalk.webex.com/oracletalk/ldr.php?AT=pb&SP=MC&rID=67364002&rKey=9fe755e4f41a2d4d

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  • How to load kernel module at startup on FC9?

    - by dicroce
    I need to know how to automatically load a kernel module at startup on FC9. All the sites talk about adding an entry to /etc/modules.conf.... But that does not exist on FC9... Instead I have /etc/modprobe.d/ directory... Now, I suppose I need to put a file in this dir for my driver but I have no idea how to write this file... I just need "modprobe name" to be run...

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  • Any software for pattern-matching and -rewriting source code?

    - by Steven A. Lowe
    I have some old software (in a language that's not dead but is dead to me ;-)) that implements a basic pattern-matching and -rewriting system for source code. I am considering resurrecting this code, translating it into a modern language, and open-sourcing the project as a refactoring power-tool. Before I go much further, I want to know if anything like this exists already (my google-fu is fanning air on this tonight). Here's how it works: the pattern-matching part matches source-code patterns spanning multiple lines of code using a template with binding variables, the pattern-rewriting part uses a template to rewrite the matched code, inserting the contents of the bound variables from the matching template matching and rewriting templates are associated (1:1) by a simple (unconditional) rewrite rule the software operates on the abstract syntax tree (AST) of the input application, and outputs a modified AST which can then be regenerated into new source code for example, suppose we find a bunch of while-loops that really should be for-loops. The following template will match the while-loop pattern: Template oldLoopPtrn int @cnt@ = 0; while (@cnt@ < @max@) { … @body@ ++@cnt@; } End_Template while the following template will specify the output rewrite pattern: Template newLoopPtrn for(int @cnt@ = 0; @cnt@ < @max@; @cnt@++) { @body@ } End_Template and a simple rule to associate them Rule oldLoopPtrn --> newLoopPtrn so code that looks like this int i=0; while(i<arrlen) { printf("element %d: %f\n",i,arr[i]); ++i; } gets automatically rewritten to look like this for(int i = 0; i < arrlen; i++) { printf("element %d: %f\n",i,arr[i]); } The closest thing I've seen like this is some of the code-refactoring tools, but they seem to be geared towards interactive rewriting of selected snippets, not wholesale automated changes. I believe that this kind of tool could supercharge refactoring, and would work on multiple languages (even HTML/CSS). I also believe that converting and polishing the code base would be a huge project that I simply cannot do alone in any reasonable amount of time. So, anything like this out there already? If not, any obvious features (besides rewrite-rule conditions) to consider? EDIT: The one feature of this system that I like very much is that the template patterns are fairly obvious and easy to read because they're written in the same language as the target source code, not in some esoteric mutated regex/BNF format.

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  • Maven test dependency in multi module project

    - by user209947
    I use maven to build a multi module project. My module 2 depends on Module 1 src at compile scope and module 1 tests in test scope. Module 2 - <dependency> <groupId>blah</groupId> <artifactId>MODULE1</artifactId> <version>blah</version> <classifier>tests</classifier> <scope>test</scope> </dependency> This works fine. Say my module 3 depends on Module1 src and tests at compile time. Module 3 - <dependency> <groupId>blah</groupId> <artifactId>MODULE1</artifactId> <version>blah</version> <classifier>tests</classifier> <scope>complie</scope> </dependency> When I run mvn clean install, my build runs till module 3, fails at module 3 as it couldnt resolve the module 1 test dependency. Then I do a mvn install on module 3 alone, go back and run mvn install on my parent pom to make it build. How can i fix this?

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  • kernel module compiling error

    - by wati
    sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is the location of the previous definition hello-1.c:6:0: warning: "_KERNEL_" redefined [enabled by default] <command-line>:0:0: note: this is the location of the previous definition In file included from /lib/modules/3.2.0-25-generic/build/include/linux/list.h:4:0, from /lib/modules/3.2.0-25-generic/build/include/linux/module.h:9, from hello-1.c:7: /lib/modules/3.2.0-25-generic/build/include/linux/types.h:13:2: warning: #warning "Attempt to use kernel headers from user space, see http://kernelnewbies.org/KernelHeaders" [-Wcpp] In file included from /lib/modules/3.2.0-25-generic/build/include/linux/module.h:9:0, from hello-1.c:7: /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘INIT_LIST_HEAD’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:26:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:27:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_add’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:41:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:42:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:43:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:44:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_add’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:62:28: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_add_tail’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:76:22: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_del’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:88:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:89:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_del_entry’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:101:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:101:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_del’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:106:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:106:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:107:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:108:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_replace’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:125:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:125:17: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:126:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:127:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:127:17: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:128:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_is_last’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:179:13: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_empty’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:188:13: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_empty_careful’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:206:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:207:40: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_rotate_left’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:219:15: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_is_singular’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:230:35: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:230:49: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_cut_position’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:236:37: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:237:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:237:19: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:238:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:239:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:240:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:241:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:242:11: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_cut_position’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:265:8: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__list_splice’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:277:32: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:278:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:280:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:281:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:283:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:284:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_splice’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:296:33: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_splice_tail’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:308:27: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_splice_init’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:322:33: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘list_splice_tail_init’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:339:27: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘INIT_HLIST_NODE’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:572:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:573:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_unhashed’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:578:11: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_empty’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:583:11: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘__hlist_del’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:588:29: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:589:31: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:592:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_del’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:598:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:599:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_add_head’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:612:30: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:613:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:615:8: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:615:20: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:616:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:617:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:617:15: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_add_before’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:624:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:624:17: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:625:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:626:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:626:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:627:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_add_after’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:633:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:633:16: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:634:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:635:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:635:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:637:9: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:638:7: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:638:29: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_add_fake’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:644:3: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:644:15: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h: In function ‘hlist_move_list’: /lib/modules/3.2.0-25-generic/build/include/linux/list.h:654:5: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:654:18: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:655:9: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:656:6: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:656:27: error: dereferencing pointer to incomplete type /lib/modules/3.2.0-25-generic/build/include/linux/list.h:657:5: error: dereferencing pointer to incomplete type In file included from /lib/modules/3.2.0-25-generic/build/include/linux/module.h:12:0, from hello-1.c:7: /lib/modules/3.2.0-25-generic/build/include/linux/cache.h: At top level: /lib/modules/3.2.0-25-generic/build/include/linux/cache.h:5:23: fatal error: asm/cache.h: No such file or directory compilation terminated. make: *** [hello-1.o] Error 1 i got this error after compiling an helloworld program my program is #define MODULE #define LINUX #define _KERNEL_ #include <linux/module.h> #include <linux/kernel.h> int init_module(void) { printk("<1>hello World 1.\n"); return 0; } void cleanup_module(void) { printk(KERN_ALERT "goodbye world 1.\n"); } MODULE_LICENSE("GPL"); my make file is: TARGET := hello-1 WARN := -W -Wall -Wstrict-prototypes -Wmissing-prototypes INCLUDE := -isystem /lib/modules/`uname -r`/build/include CFLAGS := -O2 -DMODULE -D_KERNEL_ ${WARN} ${INCLUDE} CC := gcc-4.6 ${TARGET}.o: ${TARGET}.c .PHONY: clean clean: rm -rf ${TARGET}.o iam usin kernel 3.2.0.25 as novice i can't able to figure out where the problem is I SEARCHED EVERY THING I CAN TO KNOW ABOUT THIS ERROR BUT I CANT UNDERSTAND &I GET IRRELEVANT DOCS anybody help me please

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  • Organizations &amp; Architecture UNISA Studies &ndash; Chap 7

    - by MarkPearl
    Learning Outcomes Name different device categories Discuss the functions and structure of I/.O modules Describe the principles of Programmed I/O Describe the principles of Interrupt-driven I/O Describe the principles of DMA Discuss the evolution characteristic of I/O channels Describe different types of I/O interface Explain the principles of point-to-point and multipoint configurations Discuss the way in which a FireWire serial bus functions Discuss the principles of InfiniBand architecture External Devices An external device attaches to the computer by a link to an I/O module. The link is used to exchange control, status, and data between the I/O module and the external device. External devices can be classified into 3 categories… Human readable – e.g. video display Machine readable – e.g. magnetic disk Communications – e.g. wifi card I/O Modules An I/O module has two major functions… Interface to the processor and memory via the system bus or central switch Interface to one or more peripheral devices by tailored data links Module Functions The major functions or requirements for an I/O module fall into the following categories… Control and timing Processor communication Device communication Data buffering Error detection I/O function includes a control and timing requirement, to coordinate the flow of traffic between internal resources and external devices. Processor communication involves the following… Command decoding Data Status reporting Address recognition The I/O device must be able to perform device communication. This communication involves commands, status information, and data. An essential task of an I/O module is data buffering due to the relative slow speeds of most external devices. An I/O module is often responsible for error detection and for subsequently reporting errors to the processor. I/O Module Structure An I/O module functions to allow the processor to view a wide range of devices in a simple minded way. The I/O module may hide the details of timing, formats, and the electro mechanics of an external device so that the processor can function in terms of simple reads and write commands. An I/O channel/processor is an I/O module that takes on most of the detailed processing burden, presenting a high-level interface to the processor. There are 3 techniques are possible for I/O operations Programmed I/O Interrupt[t I/O DMA Access Programmed I/O When a processor is executing a program and encounters an instruction relating to I/O it executes that instruction by issuing a command to the appropriate I/O module. With programmed I/O, the I/O module will perform the requested action and then set the appropriate bits in the I/O status register. The I/O module takes no further actions to alert the processor. I/O Commands To execute an I/O related instruction, the processor issues an address, specifying the particular I/O module and external device, and an I/O command. There are four types of I/O commands that an I/O module may receive when it is addressed by a processor… Control – used to activate a peripheral and tell it what to do Test – Used to test various status conditions associated with an I/O module and its peripherals Read – Causes the I/O module to obtain an item of data from the peripheral and place it in an internal buffer Write – Causes the I/O module to take an item of data form the data bus and subsequently transmit that data item to the peripheral The main disadvantage of this technique is it is a time consuming process that keeps the processor busy needlessly I/O Instructions With programmed I/O there is a close correspondence between the I/O related instructions that the processor fetches from memory and the I/O commands that the processor issues to an I/O module to execute the instructions. Typically there will be many I/O devices connected through I/O modules to the system – each device is given a unique identifier or address – when the processor issues an I/O command, the command contains the address of the address of the desired device, thus each I/O module must interpret the address lines to determine if the command is for itself. When the processor, main memory and I/O share a common bus, two modes of addressing are possible… Memory mapped I/O Isolated I/O (for a detailed explanation read page 245 of book) The advantage of memory mapped I/O over isolated I/O is that it has a large repertoire of instructions that can be used, allowing more efficient programming. The disadvantage of memory mapped I/O over isolated I/O is that valuable memory address space is sued up. Interrupts driven I/O Interrupt driven I/O works as follows… The processor issues an I/O command to a module and then goes on to do some other useful work The I/O module will then interrupts the processor to request service when is is ready to exchange data with the processor The processor then executes the data transfer and then resumes its former processing Interrupt Processing The occurrence of an interrupt triggers a number of events, both in the processor hardware and in software. When an I/O device completes an I/O operations the following sequence of hardware events occurs… The device issues an interrupt signal to the processor The processor finishes execution of the current instruction before responding to the interrupt The processor tests for an interrupt – determines that there is one – and sends an acknowledgement signal to the device that issues the interrupt. The acknowledgement allows the device to remove its interrupt signal The processor now needs to prepare to transfer control to the interrupt routine. To begin, it needs to save information needed to resume the current program at the point of interrupt. The minimum information required is the status of the processor and the location of the next instruction to be executed. The processor now loads the program counter with the entry location of the interrupt-handling program that will respond to this interrupt. It also saves the values of the process registers because the Interrupt operation may modify these The interrupt handler processes the interrupt – this includes examination of status information relating to the I/O operation or other event that caused an interrupt When interrupt processing is complete, the saved register values are retrieved from the stack and restored to the registers Finally, the PSW and program counter values from the stack are restored. Design Issues Two design issues arise in implementing interrupt I/O Because there will be multiple I/O modules, how does the processor determine which device issued the interrupt? If multiple interrupts have occurred, how does the processor decide which one to process? Addressing device recognition, 4 general categories of techniques are in common use… Multiple interrupt lines Software poll Daisy chain Bus arbitration For a detailed explanation of these approaches read page 250 of the textbook. Interrupt driven I/O while more efficient than simple programmed I/O still requires the active intervention of the processor to transfer data between memory and an I/O module, and any data transfer must traverse a path through the processor. Thus is suffers from two inherent drawbacks… The I/O transfer rate is limited by the speed with which the processor can test and service a device The processor is tied up in managing an I/O transfer; a number of instructions must be executed for each I/O transfer Direct Memory Access When large volumes of data are to be moved, an efficient technique is direct memory access (DMA) DMA Function DMA involves an additional module on the system bus. The DMA module is capable of mimicking the processor and taking over control of the system from the processor. It needs to do this to transfer data to and from memory over the system bus. DMA must the bus only when the processor does not need it, or it must force the processor to suspend operation temporarily (most common – referred to as cycle stealing). When the processor wishes to read or write a block of data, it issues a command to the DMA module by sending to the DMA module the following information… Whether a read or write is requested using the read or write control line between the processor and the DMA module The address of the I/O device involved, communicated on the data lines The starting location in memory to read from or write to, communicated on the data lines and stored by the DMA module in its address register The number of words to be read or written, communicated via the data lines and stored in the data count register The processor then continues with other work, it delegates the I/O operation to the DMA module which transfers the entire block of data, one word at a time, directly to or from memory without going through the processor. When the transfer is complete, the DMA module sends an interrupt signal to the processor, this the processor is involved only at the beginning and end of the transfer. I/O Channels and Processors Characteristics of I/O Channels As one proceeds along the evolutionary path, more and more of the I/O function is performed without CPU involvement. The I/O channel represents an extension of the DMA concept. An I/O channel ahs the ability to execute I/O instructions, which gives it complete control over I/O operations. In a computer system with such devices, the CPU does not execute I/O instructions – such instructions are stored in main memory to be executed by a special purpose processor in the I/O channel itself. Two types of I/O channels are common A selector channel controls multiple high-speed devices. A multiplexor channel can handle I/O with multiple characters as fast as possible to multiple devices. The external interface: FireWire and InfiniBand Types of Interfaces One major characteristic of the interface is whether it is serial or parallel parallel interface – there are multiple lines connecting the I/O module and the peripheral, and multiple bits are transferred simultaneously serial interface – there is only one line used to transmit data, and bits must be transmitted one at a time With new generation serial interfaces, parallel interfaces are becoming less common. In either case, the I/O module must engage in a dialogue with the peripheral. In general terms the dialog may look as follows… The I/O module sends a control signal requesting permission to send data The peripheral acknowledges the request The I/O module transfers data The peripheral acknowledges receipt of data For a detailed explanation of FireWire and InfiniBand technology read page 264 – 270 of the textbook

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  • Ubuntu 12.04 OpenCL with Intel and Radeon?

    - by Steve
    I want to setup my Ubuntu 12.04 with OpenCL(Open Computing Language) support for i7 2600k and Radeon HD5870. My Monitor is connected to the integrated Graphics of the i7. Intel OpenCL SDK is installed and working. Iteration of avaliable OpenCL devices shows 2 entries for Intel. As recommended I installed AMD APP SDK 2.6 first and then the fglrx driver. I installed fglrx from Ubuntu repositories. This works fine till here. When I run aticonfig --inital -f and restart the system I get into trouble. Xorg starts only in low-graphics mode. cat /var/log/Xorg.0.log [ 21.201] X.Org X Server 1.12.2 Release Date: 2012-05-29 [ 21.201] X Protocol Version 11, Revision 0 [ 21.201] Build Operating System: Linux 2.6.24-29-xen x86_64 Ubuntu [ 21.201] Current Operating System: Linux chimera 3.2.0-24-generic #39-Ubuntu SMP Mon May 21 16:52:17 UTC 2012 x86_ [ 21.201] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.2.0-24-generic root=UUID=c137757b-486b-4514-9dfe-00c97662 [ 21.201] Build Date: 05 June 2012 08:35:55AM [ 21.201] xorg-server 2:1.12.2+git20120605+server-1.12-branch.aaf48906-0ubuntu0ricotz~precise (For technical suppor [ 21.201] Current version of pixman: 0.26.0 [ 21.201] Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. [ 21.201] Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. [ 21.201] (==) Log file: "/var/log/Xorg.0.log", Time: Fri Jun 8 14:22:36 2012 [ 21.247] (==) Using config file: "/etc/X11/xorg.conf" [ 21.247] (==) Using system config directory "/usr/share/X11/xorg.conf.d" [ 21.450] (==) ServerLayout "aticonfig Layout" [ 21.450] (**) |-->Screen "aticonfig-Screen[0]-0" (0) [ 21.450] (**) | |-->Monitor "aticonfig-Monitor[0]-0" [ 21.451] (**) | |-->Device "aticonfig-Device[0]-0" [ 21.451] (==) Automatically adding devices [ 21.451] (==) Automatically enabling devices [ 21.466] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist. [ 21.466] Entry deleted from font path. [ 21.466] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist. [ 21.466] Entry deleted from font path. [ 21.466] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist. [ 21.466] Entry deleted from font path. [ 21.473] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist. [ 21.473] Entry deleted from font path. [ 21.473] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist. [ 21.473] Entry deleted from font path. [ 21.473] (WW) The directory "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType" does not exist. [ 21.473] Entry deleted from font path. [ 21.473] (==) FontPath set to: /usr/share/fonts/X11/misc, /usr/share/fonts/X11/Type1, built-ins [ 21.473] (==) ModulePath set to "/usr/lib/x86_64-linux-gnu/xorg/extra-modules,/usr/lib/xorg/extra-modules,/usr/lib [ 21.473] (II) The server relies on udev to provide the list of input devices. If no devices become available, reconfigure udev or disable AutoAddDevices. [ 21.473] (II) Loader magic: 0x7f0ad3b9ab00 [ 21.473] (II) Module ABI versions: [ 21.473] X.Org ANSI C Emulation: 0.4 [ 21.473] X.Org Video Driver: 12.0 [ 21.473] X.Org XInput driver : 16.0 [ 21.473] X.Org Server Extension : 6.0 [ 21.473] (--) PCI:*(0:0:2:0) 8086:0122:1458:d000 rev 9, Mem @ 0xfb800000/4194304, 0xe0000000/268435456, I/O @ 0x00 [ 21.473] (--) PCI: (0:1:0:0) 1002:6898:1787:2289 rev 0, Mem @ 0xd0000000/268435456, 0xfbdc0000/131072, I/O @ 0x000 [ 21.473] (II) Open ACPI successful (/var/run/acpid.socket) [ 21.473] (II) "extmod" will be loaded by default. [ 21.473] (II) "dbe" will be loaded by default. [ 21.473] (II) "glx" will be loaded. This was enabled by default and also specified in the config file. [ 21.473] (II) "record" will be loaded by default. [ 21.473] (II) "dri" will be loaded by default. [ 21.473] (II) "dri2" will be loaded by default. [ 21.473] (II) LoadModule: "glx" [ 21.732] (II) Loading /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/extensions/libgl [ 21.934] (II) Module glx: vendor="Advanced Micro Devices, Inc." [ 21.934] compiled for 6.9.0, module version = 1.0.0 [ 21.934] (II) Loading extension GLX [ 21.934] (II) LoadModule: "extmod" [ 22.028] (II) Loading /usr/lib/xorg/modules/extensions/libextmod.so [ 22.041] (II) Module extmod: vendor="X.Org Foundation" [ 22.041] compiled for 1.12.2, module version = 1.0.0 [ 22.041] Module class: X.Org Server Extension [ 22.041] ABI class: X.Org Server Extension, version 6.0 [ 22.041] (II) Loading extension MIT-SCREEN-SAVER [ 22.041] (II) Loading extension XFree86-VidModeExtension [ 22.041] (II) Loading extension XFree86-DGA [ 22.041] (II) Loading extension DPMS [ 22.041] (II) Loading extension XVideo [ 22.041] (II) Loading extension XVideo-MotionCompensation [ 22.041] (II) Loading extension X-Resource [ 22.041] (II) LoadModule: "dbe" [ 22.041] (II) Loading /usr/lib/xorg/modules/extensions/libdbe.so [ 22.066] (II) Module dbe: vendor="X.Org Foundation" [ 22.066] compiled for 1.12.2, module version = 1.0.0 [ 22.066] Module class: X.Org Server Extension [ 22.066] ABI class: X.Org Server Extension, version 6.0 [ 22.066] (II) Loading extension DOUBLE-BUFFER [ 22.066] (II) LoadModule: "record" [ 22.066] (II) Loading /usr/lib/xorg/modules/extensions/librecord.so [ 22.077] (II) Module record: vendor="X.Org Foundation" [ 22.077] compiled for 1.12.2, module version = 1.13.0 [ 22.077] Module class: X.Org Server Extension [ 22.077] ABI class: X.Org Server Extension, version 6.0 [ 22.077] (II) Loading extension RECORD [ 22.077] (II) LoadModule: "dri" [ 22.077] (II) Loading /usr/lib/xorg/modules/extensions/libdri.so [ 22.082] (II) Module dri: vendor="X.Org Foundation" [ 22.082] compiled for 1.12.2, module version = 1.0.0 [ 22.082] ABI class: X.Org Server Extension, version 6.0 [ 22.082] (II) Loading extension XFree86-DRI [ 22.082] (II) LoadModule: "dri2" [ 22.082] (II) Loading /usr/lib/xorg/modules/extensions/libdri2.so [ 22.083] (II) Module dri2: vendor="X.Org Foundation" [ 22.083] compiled for 1.12.2, module version = 1.2.0 [ 22.083] ABI class: X.Org Server Extension, version 6.0 [ 22.083] (II) Loading extension DRI2 [ 22.083] (II) LoadModule: "fglrx" [ 22.083] (II) Loading /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/drivers/fglrx_dr [ 22.399] (II) Module fglrx: vendor="FireGL - ATI Technologies Inc." [ 22.399] compiled for 1.4.99.906, module version = 8.96.4 [ 22.399] Module class: X.Org Video Driver [ 22.399] (II) Loading sub module "fglrxdrm" [ 22.399] (II) LoadModule: "fglrxdrm" [ 22.399] (II) Loading /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/linux/libfglrxdr [ 22.445] (II) Module fglrxdrm: vendor="FireGL - ATI Technologies Inc." [ 22.445] compiled for 1.4.99.906, module version = 8.96.4 [ 22.445] (II) ATI Proprietary Linux Driver Version Identifier:8.96.4 [ 22.445] (II) ATI Proprietary Linux Driver Release Identifier: 8.96.7 [ 22.445] (II) ATI Proprietary Linux Driver Build Date: Mar 12 2012 13:06:50 [ 22.445] (++) using VT number 7 [ 22.445] (WW) Falling back to old probe method for fglrx [ 23.043] (II) Loading PCS database from /etc/ati/amdpcsdb [ 23.082] (--) Chipset Supported AMD Graphics Processor (0x6898) found [ 23.107] (WW) fglrx: No matching Device section for instance (BusID PCI:0@1:0:1) found [ 23.107] (II) fglrx: intel VGA device detected, load intel driver. [ 23.107] (II) LoadModule: "intel" [ 23.211] (II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so [ 23.475] (II) Module intel: vendor="X.Org Foundation" [ 23.475] compiled for 1.12.2, module version = 2.19.0 [ 23.475] Module class: X.Org Video Driver [ 23.475] ABI class: X.Org Video Driver, version 12.0 [ 23.476] ukiDynamicMajor: found major device number 249 [ 23.476] ukiDynamicMajor: found major device number 249 [ 23.476] ukiOpenByBusid: Searching for BusID PCI:1:0:0 [ 23.476] ukiOpenDevice: node name is /dev/ati/card0 [ 23.476] ukiOpenDevice: open result is 8, (OK) [ 23.476] ukiOpenByBusid: ukiOpenMinor returns 8 [ 23.476] ukiOpenByBusid: ukiGetBusid reports PCI:1:0:0 [ 23.540] (WW) PowerXpress feature is not supported [ 23.540] (EE) No devices detected. [ 23.540] (==) Matched intel as autoconfigured driver 0 [ 23.540] (==) Matched vesa as autoconfigured driver 1 [ 23.540] (==) Matched fbdev as autoconfigured driver 2 [ 23.540] (==) Assigned the driver to the xf86ConfigLayout [ 23.540] (II) LoadModule: "intel" [ 23.540] (II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so [ 23.540] (II) Module intel: vendor="X.Org Foundation" [ 23.540] compiled for 1.12.2, module version = 2.19.0 [ 23.540] Module class: X.Org Video Driver [ 23.540] ABI class: X.Org Video Driver, version 12.0 [ 23.540] (II) UnloadModule: "intel" [ 23.540] (II) Unloading intel [ 23.540] (II) Failed to load module "intel" (already loaded, 32522) [ 23.540] (II) LoadModule: "vesa" [ 23.583] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so [ 23.620] (II) Module vesa: vendor="X.Org Foundation" [ 23.620] compiled for 1.12.2, module version = 2.3.1 [ 23.620] Module class: X.Org Video Driver [ 23.620] ABI class: X.Org Video Driver, version 12.0 [ 23.620] (II) LoadModule: "fbdev" [ 23.620] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so [ 23.661] (II) Module fbdev: vendor="X.Org Foundation" [ 23.661] compiled for 1.12.2, module version = 0.4.2 [ 23.661] Module class: X.Org Video Driver [ 23.661] ABI class: X.Org Video Driver, version 12.0 [ 23.661] (II) ATI Proprietary Linux Driver Version Identifier:8.96.4 [ 23.661] (II) ATI Proprietary Linux Driver Release Identifier: 8.96.7 [ 23.661] (II) ATI Proprietary Linux Driver Build Date: Mar 12 2012 13:06:50 [ 23.661] (II) intel: Driver for Intel Integrated Graphics Chipsets: i810, i810-dc100, i810e, i815, i830M, 845G, 854, 852GM/855GM, 865G, 915G, E7221 (i915), 915GM, 945G, 945GM, 945GME, Pineview GM, Pineview G, 965G, G35, 965Q, 946GZ, 965GM, 965GME/GLE, G33, Q35, Q33, GM45, 4 Series, G45/G43, Q45/Q43, G41, B43, B43, Clarkdale, Arrandale, Sandybridge Desktop (GT1), Sandybridge Desktop (GT2), Sandybridge Desktop (GT2+), Sandybridge Mobile (GT1), Sandybridge Mobile (GT2), Sandybridge Mobile (GT2+), Sandybridge Server, Ivybridge Mobile (GT1), Ivybridge Mobile (GT2), Ivybridge Desktop (GT1), Ivybridge Desktop (GT2), Ivybridge Server, Ivybridge Server (GT2) [ 23.661] (II) VESA: driver for VESA chipsets: vesa [ 23.661] (II) FBDEV: driver for framebuffer: fbdev [ 23.661] (++) using VT number 7 [ 23.661] (WW) xf86OpenConsole: setpgid failed: Operation not permitted [ 23.661] (WW) xf86OpenConsole: setsid failed: Operation not permitted [ 23.661] (WW) Falling back to old probe method for fglrx [ 23.661] (II) Loading PCS database from /etc/ati/amdpcsdb [ 23.661] (WW) Falling back to old probe method for vesa [ 23.661] (WW) Falling back to old probe method for fbdev [ 23.661] (EE) No devices detected. [ 23.661] Fatal server error: [ 23.661] no screens found [ 23.661] Please consult the The X.Org Foundation support at http://wiki.x.org for help. [ 23.661] Please also check the log file at "/var/log/Xorg.0.log" for additional information. [ 23.661] xorg.conf: cat /etc/X11/xorg.conf Section "ServerLayout" Identifier "aticonfig Layout" Screen 0 "aticonfig-Screen[0]-0" 0 0 EndSection Section "Module" Load "glx" EndSection Section "Monitor" Identifier "aticonfig-Monitor[0]-0" Option "VendorName" "ATI Proprietary Driver" Option "ModelName" "Generic Autodetecting Monitor" Option "DPMS" "true" EndSection Section "Device" Identifier "aticonfig-Device[0]-0" Driver "fglrx" BusID "PCI:1:0:0" EndSection Section "Screen" Identifier "aticonfig-Screen[0]-0" Device "aticonfig-Device[0]-0" Monitor "aticonfig-Monitor[0]-0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection Is there a way to get the Radeon to work in a hybrid configuration or to use the Radeon as an OpenCL only device?

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  • When module calling gets ugly

    - by Pete
    Has this ever happened to you? You've got a suite of well designed, single-responsibility modules, covered by unit tests. In any higher-level function you code, you are (95% of the code) simply taking output from one module and passing it as input to the next. Then, you notice this higher-level function has turned into a 100+ line script with multiple responsibilities. Here is the problem. It is difficult (impossible) to test that script. At least, it seems so. Do you agree? In my current project, all of the bugs came from this script. Further detail: each script represents a unique solution, or algorithm, formed by using different modules in different ways. Question: how can you remedy this situation? Knee-jerk answer: break the script up into single-responsibility modules. Comment on knee-jerk answer: it already is! Best answer I can come up with so far: create higher-level connector objects which "wire" modules together in particular ways (take output from one module, feed it as input to another module). Thus if our script was: FooInput fooIn = new FooInput(1, 2); FooOutput fooOutput = fooModule(fooIn); Double runtimevalue = getsomething(fooOutput.whatever); BarInput barIn = new BarInput( runtimevalue, fooOutput.someOtherValue); BarOutput barOut = barModule(BarIn); It would become with a connector: FooBarConnectionAlgo fooBarConnector = new fooBarConnector(fooModule, barModule); FooInput fooIn = new FooInput(1, 2); BarOutput barOut = fooBarConnector(fooIn); So the advantage is, besides hiding some code and making things clearer, we can test FooBarConnectionAlgo. I'm sure this situation comes up a lot. What do you do?

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  • Matrix Pattern Recognition Algorithm

    - by Andres
    I am designing a logic analyzer and I would like to implement some Matrix Algorithm. I have several channels each one represented by a row in the matrix and every element in the column would be the state, for example: Channel 1 1 0 0 1 0 1 1 0 1 Channel 2 1 1 0 1 1 0 0 1 1 Channel 3 0 1 0 1 1 0 1 0 0 Channel 4 0 0 1 0 0 1 0 0 1 I would like to detect a pattern inside my matrix for example, detect if exist and where the sub-matrix or pattern: 1 0 1 1 I think it can be accomplished testing element by element but I think there should be a better way of doing it. Is there any Java API or any way to do it ? If there is a API ARM optimized for NEON instructions would be great also but not mandatory. Thank you very much in advance.

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  • The UIManager Pattern

    - by Duncan Mills
    One of the most common mistakes that I see when reviewing ADF application code, is the sin of storing UI component references, most commonly things like table or tree components in Session or PageFlow scope. The reasons why this is bad are simple; firstly, these UI object references are not serializable so would not survive a session migration between servers and secondly there is no guarantee that the framework will re-use the same component tree from request to request, although in practice it generally does do so. So there danger here is, that at best you end up with an NPE after you session has migrated, and at worse, you end up pinning old generations of the component tree happily eating up your precious memory. So that's clear, we should never. ever, be storing references to components anywhere other than request scope (or maybe backing bean scope). So double check the scope of those binding attributes that map component references into a managed bean in your applications.  Why is it Such a Common Mistake?  At this point I want to examine why there is this urge to hold onto these references anyway? After all, JSF will obligingly populate your backing beans with the fresh and correct reference when needed.   In most cases, it seems that the rational is down to a lack of distinction within the application between what is data and what is presentation. I think perhaps, a cause of this is the logical separation between business data behind the ADF data binding (#{bindings}) façade and the UI components themselves. Developers tend to think, OK this is my data layer behind the bindings object and everything else is just UI.  Of course that's not the case.  The UI layer itself will have state which is intrinsically linked to the UI presentation rather than the business model, but at the same time should not be tighly bound to a specific instance of any single UI component. So here's the problem.  I think developers try and use the UI components as state-holders for this kind of data, rather than using them to represent that state. An example of this might be something like the selection state of a tabset (panelTabbed), you might be interested in knowing what the currently disclosed tab is. The temptation that leads to the component reference sin is to go and ask the tabset what the selection is.  That of course is fine in context - e.g. a handler within the same request scoped bean that's got the binding to the tabset. However, it leads to problems when you subsequently want the same information outside of the immediate scope.  The simple solution seems to be to chuck that component reference into session scope and then you can simply re-check in the same way, leading of course to this mistake. Turn it on its Head  So the correct solution to this is to turn the problem on its head. If you are going to be interested in the value or state of some component outside of the immediate request context then it becomes persistent state (persistent in the sense that it extends beyond the lifespan of a single request). So you need to externalize that state outside of the component and have the component reference and manipulate that state as needed rather than owning it. This is what I call the UIManager pattern.  Defining the Pattern The  UIManager pattern really is very simple. The premise is that every application should define a session scoped managed bean, appropriately named UIManger, which is specifically responsible for holding this persistent UI component related state.  The actual makeup of the UIManger class varies depending on a needs of the application and the amount of state that needs to be stored. Generally I'll start off with a Map in which individual flags can be created as required, although you could opt for a more formal set of typed member variables with getters and setters, or indeed a mix. This UIManager class is defined as a session scoped managed bean (#{uiManager}) in the faces-config.xml.  The pattern is to then inject this instance of the class into any other managed bean (usually request scope) that needs it using a managed property.  So typically you'll have something like this:   <managed-bean>     <managed-bean-name>uiManager</managed-bean-name>     <managed-bean-class>oracle.demo.view.state.UIManager</managed-bean-class>     <managed-bean-scope>session</managed-bean-scope>   </managed-bean>  When is then injected into any backing bean that needs it:    <managed-bean>     <managed-bean-name>mainPageBB</managed-bean-name>     <managed-bean-class>oracle.demo.view.MainBacking</managed-bean-class>     <managed-bean-scope>request</managed-bean-scope>     <managed-property>       <property-name>uiManager</property-name>       <property-class>oracle.demo.view.state.UIManager</property-class>       <value>#{uiManager}</value>     </managed-property>   </managed-bean> In this case the backing bean in question needs a member variable to hold and reference the UIManager: private UIManager _uiManager;  Which should be exposed via a getter and setter pair with names that match the managed property name (e.g. setUiManager(UIManager _uiManager), getUiManager()).  This will then give your code within the backing bean full access to the UI state. UI components in the page can, of course, directly reference the uiManager bean in their properties, for example, going back to the tab-set example you might have something like this: <af:paneltabbed>   <af:showDetailItem text="First"                disclosed="#{uiManager.settings['MAIN_TABSET_STATE'].['FIRST']}"> ...   </af:showDetailItem>   <af:showDetailItem text="Second"                      disclosed="#{uiManager.settings['MAIN_TABSET_STATE'].['SECOND']}">     ...   </af:showDetailItem>   ... </af:panelTabbed> Where in this case the settings member within the UI Manger is a Map which contains a Map of Booleans for each tab under the MAIN_TABSET_STATE key. (Just an example you could choose to store just an identifier for the selected tab or whatever, how you choose to store the state within UI Manger is up to you.) Get into the Habit So we can see that the UIManager pattern is not great strain to implement for an application and can even be retrofitted to an existing application with ease. The point is, however, that you should always take this approach rather than committing the sin of persistent component references which will bite you in the future or shotgun scattered UI flags on the session which are hard to maintain.  If you take the approach of always accessing all UI state via the uiManager, or perhaps a pageScope focused variant of it, you'll find your applications much easier to understand and maintain. Do it today!

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  • AWS .NET SDK v2: the message-pump pattern

    - by Elton Stoneman
    Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2013/10/11/aws-.net-sdk-v2--the-message-pump-pattern.aspxVersion 2 of the AWS SDK for .NET has had a few pre-release iterations on NuGet and is stable, if a bit lacking in step-by-step guides. There’s at least one big reason to try it out: the SQS queue client now supports asynchronous reads, so you don’t need a clumsy polling mechanism to retrieve messages. The new approach  is easy to use, and lets you work with AWS queues in a similar way to the message-pump pattern used in the latest Azure SDK for Service Bus queues and topics. I’ve posted a simple wrapper class for subscribing to an SQS hub on gist here: A wrapper for the SQS client in the AWS SDK for.NET v2, which uses the message-pump pattern. Here’s the core functionality in the subscribe method: private async void Subscribe() { if (_isListening) { var request = new ReceiveMessageRequest { MaxNumberOfMessages = 10 }; request.QueueUrl = QueueUrl; var result = await _sqsClient.ReceiveMessageAsync(request, _cancellationTokenSource.Token); if (result.Messages.Count > 0) { foreach (var message in result.Messages) { if (_receiveAction != null && message != null) { _receiveAction(message.Body); DeleteMessage(message.ReceiptHandle); } } } } if (_isListening) { Subscribe(); } } which you call with something like this: client.Subscribe(x=>Log.Debug(x.Body)); The async SDK call returns when there is something in the queue, and will run your receive action for every message it gets in the batch (defaults to the maximum size of 10 messages per call). The listener will sit there awaiting messages until you stop it with: client.Unsubscribe(); Internally it has a cancellation token which it sets when you call unsubscribe, which cancels any in-flight call to SQS and stops the pump. The wrapper will also create the queue if it doesn’t exist at runtime. The Ensure() method gets called in the constructor so when you first use the client for a queue (sending or subscribing), it will set itself up: if (!Exists()) { var request = new CreateQueueRequest(); request.QueueName = QueueName; var response = _sqsClient.CreateQueue(request); QueueUrl = response.QueueUrl; } The Exists() check has to do make a call to ListQueues on the SNS client, as it doesn’t provide its own method to check if a queue exists. That call also populates the Amazon Resource Name, the unique identifier for this queue, which will be useful later. To use the wrapper, just instantiate and go: var queueClient = new QueueClient(“ProcessWorkflow”); queueClient.Subscribe(x=>Log.Debug(x.Body)); var message = {}; //etc. queueClient.Send(message);

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  • Composite-like pattern and SRP violation

    - by jimmy_keen
    Recently I've noticed myself implementing pattern similar to the one described below. Starting with interface: public interface IUserProvider { User GetUser(UserData data); } GetUser method's pure job is to somehow return user (that would be an operation speaking in composite terms). There might be many implementations of IUserProvider, which all do the same thing - return user basing on input data. It doesn't really matter, as they are only leaves in composite terms and that's fairly simple. Now, my leaves are used by one own them all composite class, which at the moment follows this implementation: public interface IUserProviderComposite : IUserProvider { void RegisterProvider(Predicate<UserData> predicate, IUserProvider provider); } public class UserProviderComposite : IUserProviderComposite { public User GetUser(SomeUserData data) ... public void RegisterProvider(Predicate<UserData> predicate, IUserProvider provider) ... } Idea behind UserProviderComposite is simple. You register providers, and this class acts as a reusable entry-point. When calling GetUser, it will use whatever registered provider matches predicate for requested user data (if that helps, it stores key-value map of predicates and providers internally). Now, what confuses me is whether RegisterProvider method (brings to mind composite's add operation) should be a part of that class. It kind of expands its responsibilities from providing user to also managing providers collection. As far as my understanding goes, this violates Single Responsibility Principle... or am I wrong here? I thought about extracting register part into separate entity and inject it to the composite. As long as it looks decent on paper (in terms of SRP), it feels bit awkward because: I would be essentially injecting Dictionary (or other key-value map) ...or silly wrapper around it, doing nothing more than adding entires This won't be following composite anymore (as add won't be part of composite) What exactly is the presented pattern called? Composite felt natural to compare it with, but I realize it's not exactly the one however nothing else rings any bells. Which approach would you take - stick with SRP or stick with "composite"/pattern? Or is the design here flawed and given the problem this can be done in a better way?

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  • Yippy &ndash; the F# MVVM Pattern

    - by MarkPearl
    I did a recent post on implementing WPF with F#. Today I would like to expand on this posting to give a simple implementation of the MVVM pattern in F#. A good read about this topic can also be found on Dean Chalk’s blog although my example of the pattern is possibly simpler. With the MVVM pattern one typically has 3 segments, the view, viewmodel and model. With the beauty of WPF binding one is able to link the state based viewmodel to the view. In my implementation I have kept the same principles. I have a view (MainView.xaml), and and a ViewModel (MainViewModel.fs).     What I would really like to illustrate in this posting is the binding between the View and the ViewModel so I am going to jump to that… In Program.fs I have the following code… module Program open System open System.Windows open System.Windows.Controls open System.Windows.Markup open myViewModels // Create the View and bind it to the View Model let myView = Application.LoadComponent(new System.Uri("/FSharpWPF;component/MainView.xaml", System.UriKind.Relative)) :?> Window myView.DataContext <- new MainViewModel() :> obj // Application Entry point [<STAThread>] [<EntryPoint>] let main(_) = (new Application()).Run(myView) You can see that I have simply created the view (myView) and then created an instance of my viewmodel (MainViewModel) and then bound it to the data context with the code… myView.DataContext <- new MainViewModel() :> obj If I have a look at my viewmodel (MainViewModel) it looks like this… module myViewModels open System open System.Windows open System.Windows.Input open System.ComponentModel open ViewModelBase type MainViewModel() = // private variables let mutable _title = "Bound Data to Textbox" // public properties member x.Title with get() = _title and set(v) = _title <- v // public commands member x.MyCommand = new FuncCommand ( (fun d -> true), (fun e -> x.ShowMessage) ) // public methods member public x.ShowMessage = let msg = MessageBox.Show(x.Title) () I have exposed a few things, namely a property called Title that is mutable, a command and a method called ShowMessage that simply pops up a message box when called. If I then look at my view which I have created in xaml (MainView.xaml) it looks as follows… <Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="F# WPF MVVM" Height="350" Width="525"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <TextBox Text="{Binding Path=Title, Mode=TwoWay}" Grid.Row="0"/> <Button Command="{Binding MyCommand}" Grid.Row="1"> <TextBlock Text="Click Me"/> </Button> </Grid> </Window>   It is also very simple. It has a button that’s command is bound to the MyCommand and a textbox that has its text bound to the Title property. One other module that I have created is my ViewModelBase. Right now it is used to store my commanding function but I would look to expand on it at a later stage to implement other commonly used functions… module ViewModelBase open System open System.Windows open System.Windows.Input open System.ComponentModel type FuncCommand (canExec:(obj -> bool),doExec:(obj -> unit)) = let cecEvent = new DelegateEvent<EventHandler>() interface ICommand with [<CLIEvent>] member x.CanExecuteChanged = cecEvent.Publish member x.CanExecute arg = canExec(arg) member x.Execute arg = doExec(arg) Put this all together and you have a basic project that implements the MVVM pattern in F#. For me this is quite exciting as it turned out to be a lot simpler to do than I originally thought possible. Also because I have my view in XAML I can use the XAML designer to design forms in F# which I believe is a much cleaner way to go rather than implementing it all in code. Finally if I look at my viewmodel code, it is actually quite clean and compact…

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  • Identifying the best pattern

    - by Daniel Grillo
    I'm developing a software to program a device. I have some commands like Reset, Read_Version, Read_memory, Write_memory, Erase_memory. Reset and Read_Version are fixed. They don't need parameters. Read_memory and Erase_memory need the same parameters that are Length and Address. Write_memory needs Lenght, Address and Data. For each command, I have the same steps in sequence, that are something like this sendCommand, waitForResponse, treatResponse. I'm having difficulty to identify which pattern should I use. Factory, Template Method, Strategy or other pattern.

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  • Pattern for performing game actions

    - by Arkiliknam
    Is there a generally accepted pattern for performing various actions within a game? A way a player can perform actions and also that an AI might perform actions, such as move, attack, self-destruct, etc. I currently have an abstract BaseAction which uses .NET generics to specify the different objects that get returned by the various actions. This is all implemented in a pattern similar to the Command, where each action is responsible for itself and does all that it needs. My reasoning for being abstract is so that I may have a single ActionHandler, and AI can just queue up different action implementing the baseAction. And the reason it is generic is so that the different actions can return result information relevant to the action (as different actions can have totally different outcomes in the game), along with some common beforeAction and afterAction implementations. So... is there a more accepted way of doing this, or does this sound alright?

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  • Making Class Diagram for MVC Pattern Project

    - by iMohammad
    I have a question about making a class diagram for an MVC based college senior project. If we have 2 actors of users in my system, lets say Undergrad and Graduate students are the children of abstract class called User. (Generalisation) Each actor has his own features. My question, in such case, do we need to have these two actors in separate classes which inherits from the abstract class User? even though, I'm going to implement them as roles using one Model called User Model ? I think you can see my confusion here. I code using MVC pattern, but I've never made a class diagram for this pattern. Thank you in advance!

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  • how to generate number pattern in triangular form

    - by Vignesh Vicky
    I want to print this pattern like right angled triangle 0 909 89098 7890987 678909876 56789098765 4567890987654 345678909876543 23456789098765432 1234567890987654321 I wrote following code # include<stdio.h> # include<conio.h> void main() { clrscr(); int i,j,x,z,k,f=1; for ( i=10;i>=1;i--,f++) { for(j=1;j<=f;j++,k--) { k=i; if(k!=10) { printf("%d",k); } if(k==10) { printf("0"); } } for(x=1;x<f;x++,z--) { z=9; printf("%d",z); } printf("%d/n"); } getch(); } what is wrong with this code? when i check manually it seems correct but when compiled gives different pattern

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  • Clarification on the Strategy Pattern

    - by Holly
    I've just been reading through some basic design patterns, Could someone tell me if the term "strategy pattern" only applies if your implementing a completely abstract interface? What about when your children (concretes?) inherit from a parent class (the strategy?) with some implemented methods and some virtual and/or abstract functions? Otherwise the rest of the implementation, the idea that you can switch between different children at run time, is identical. This is something i'm quite familiar with, i was wondering if you would still call it the Strategy Pattern or if that term only applies to using an interface. Apologies if this question is not appropriate! Or if this is just nitpicking :) I'm still learning and i'm not really sure if design patterns are quite heavily defined within the industry or just a concept to be implemented as you like.

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  • Tester/Doer pattern: Assume the caller conforms to the pattern or be defensive and repeat the check?

    - by Daniel Hilgarth
    Assume a simple class that implements the Tester/Doer pattern: public class FooCommandHandler : ICommandHandler { public bool CanHandle(object command) { return command is FooCommand; } public void Handle(object command) { var fooCommand = (FooCommand)command; // Do something with fooCommand } } Now, if someone doesn't conform to the pattern and calls Handle without verifying the command via CanHandle, the code in Handle throws an exception. However, depending on the actual implementation of Handle this can be a whole range of different exceptions. The following implementation would check CanHandle again in Handle and throw a descriptive exception: public void Handle(object command) { if(!CanHandle(command)) throw new TesterDoerPatternUsageViolationException("Please call CanHandle first"); // actual implementation of handling the command. } This has the advantage that the exception is very descriptive. It has the disadvantage that CanHandle is called twice for "good" clients. Is there a consensus on which variation should be used?

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