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  • Is there a utility to visualise / isolate and watch application calls

    - by MyStream
    Note: I'm not sure what to search for so guidance on that may be just as valuable as an answer. I'm looking for a way to visually compare activity of two applications (in this case a webserver with php communicating with the system or mysql or network devices, etc) such that I can compare the performance at a glance. I know there are tools to generate data dumps from benchmarks for apache and some available for php for tracing that you can dump and analyse but what I'm looking for is something that can report performance metrics visually from data on calls (what called what, how long did it take, how much memory did it consume, how can that be represented visually in a call stack) and present it graphically as if it were a topology or layered visual with different elements of system calls occupying different layers. A typical visual may consist of (e.g. using swim diagrams as just one analogy): Network (details here relevant to network diagnostics) | ^ back out v | Linux (details here related to firewall/routing diagnostics) ^ back to network | | V ^ back to system Apache (details here related to web request) | | ^ response to V | apache PHP (etc) PHP---------->other accesses to php files/resources----- | ^ v | MySQL (total time) MySQL | ^ V | Each call listed + time + tables hit/record returned My aim would be to be able to 'inspect' a request/range of requests over a period of time to see what constituted the activity at that point in time and trace it from beginning to end as a diagnostic tool. Is there any such work in this direction? I realise it would be intensive on the server, but the intention is to benchmark and analyse processes against each other for both educational and professional reasons and a visual aid is a great eye-opener compared to raw statistics or dozens of discrete activity vs time graphs. It's hard to show the full cycle. Any pointers welcome. Thanks! FROM COMMENTS: > XHProf in conjunction with other programs such as Perconna toolkit > (percona.com/doc/percona-toolkit/2.0/pt-pmp.html) for mySQL run apache > with httpd -X & (Single threaded debug mode and background) then > attach with strace -> kcache grind

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  • SFTP access without hassle

    - by enobayram
    I'm trying to provide access to a local folder for someone over the internet. After googling around a bit, I've come to the conclusion that SFTP is the safest thing to expose through the firewall to the chaotic and evil world of the Internet. I'm planning to use the openssh-server to this end. Even though I trust that openssh will stop a random attacker, I'm not so sure about the security of my computer once someone is connected through ssh. In particular, even if I don't give that person's user account any privileges whatsoever, he might just be able to "su" to, say, "nobody". And since I was never worried about such things before, I might have given some moderate privileges to nobody at some point (not sudo rights surely!). I would of course value your comments about giving privileges to nobody in the first place, but that's not the point, really. My aim is to give SFTP access to someone in such a sandboxed state that I shouldn't need to worry about such things (at least not more so than I should have done before). Is this really possible? Am I speaking nonsense or worried in vain?

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  • Standing and sitting while using a computer at work

    - by Adam Batkin
    I would like to be able to comfortably switch between sitting and standing while at work (I'm a software developer, so I spend most of my day in front of a computer). For the past couple of months I have been using a large elevated stand that sits on my desk (designed expressly for this purpose) containing my keyboard and mouse, and my monitors have been raised as high as possible and aimed upwards. So I can stand all day and I'm pretty comfortable (my right wrist may be at too much of an angle when it's on my mouse, but that's a separate issue). The only problem is that sometimes I want to be able to sit. I can easily place my keyboard and mouse back down under the elevated stand, but I have to look up pretty steeply and that is uncomfortable and makes it difficult to see the screens since they are tilted upwards. My monitor mounts are difficult to adjust quickly/easily, so I can't just re-aim them. I would of course love one of those hydraulic standing/sitting desks (cost isn't the problem). But I'm in a row of "trader-style" desks where it's basically a very long surface with people sitting at 6-foot intervals. What type of equipment do you recommend? I suppose the best thing would be some sort of monitor stand (it must be able to hold 2-3 LCDs) that can easily be lowered and raised. But any other suggestions are also welcome.

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  • What is the bash syntax to create a new directory in the directory above?

    - by mozerella
    I aim to make a script for mogrify. The mogrify command will resize images in a directory and put the resized images into a directory on the same directory level, with the same name as the work directory, but with a suffix (_a). The new directory will be moved to another collection later on. Something like this, #!/bin/bash mkdir ../n_a for file in *{.JPG|.jpg}; do mogrify -path ../n_a -resize 1200x1200 -quality 96;done I'm guessing ../ denotes the parent dir when working in a child directory, but I need help here. Edit: "n" needs to be replaced with the syntax for the working directory name. Sorry there was a typo as well third script line, should have read n not x Edit2: This script does exactly what I need and it's silent. #!/bin/bash DEST="../${PWD##*/}_a" mkdir -p $DEST mogrify -path $DEST -resize 1200x1200 -quality 96 *.jpg *.JPG thanks to vgoff for the correct PWD syntax and cesareriva http://www.cesareriva.com/archives/722 for showing me the DEST function. Something else: ${PWD##*/}_a is not caring for spaces in the directory name and the script fails. An empty dir is created in the same dir as the images. Found it out now, it needs quotations on the $DEST too, presumably to help mkdir create the dir with a space in the name, and mogrify to write the files to the right place, like this #!/bin/bash DEST="../${PWD##*/}_a" mkdir -p "$DEST" mogrify -path "$DEST" -resize 1200x1200 -quality 96 *.jpg *.JPG

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  • Error getting PAM / Linux integrated with Active Directory

    - by topper
    I'm trying to add a Linux server to a network which is controlled by AD. The aim is that users of the server will be able to authenticate against the AD domain. I have Kerberos working, but NSS / PAM are more problematic. I'm trying to debug with a simple command such as the following, please see the error. Can anyone assist me to debug? root@antonyg04:~# ldapsearch -H ldap://raadc04.corp.MUNGED.com/ -x -D "cn=MUNGED,ou=Users,dc=corp,dc=MUNGED,dc=com" -W uid=MUNGED Enter LDAP Password: ldap_bind: Invalid credentials (49) additional info: 80090308: LdapErr: DSID-0C090334, comment: AcceptSecurityContext error, data 525, vece I have had to munge some details, but I can tell you that cn=MUNGED is my username for logging into the AD domain, and the password that I typed was the password for said domain. I don't know why it says "Invalid credentials", and the rest of the error is so cryptic, I have no idea. Is my approach somehow flawed? Is my DN obviously wrong? How can I confirm the correct DN? There was a tool online but I can't find it. NB I have no access to the AD Server for administration or configuration.

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  • ffmpeg - creating DNxHD MFX files with alphas

    - by Hugh
    I'm struggling with something in FFMpeg at the moment... I'm trying to make DNxHD 1080p/24, 36Mb/s MXF files from a sequence of PNG files. My current command-line is: ffmpeg -y -f image2 -i /tmp/temp.%04d.png -s 1920x1080 -r 24 -vcodec dnxhd -f mxf -pix_fmt rgb32 -b 36Mb /tmp/temp.mxf To which ffmpeg gives me the output: Input #0, image2, from '/tmp/temp.%04d.png': Duration: 00:00:01.60, start: 0.000000, bitrate: N/A Stream #0.0: Video: png, rgb32, 1920x1080, 25 tbr, 25 tbn, 25 tbc Output #0, mxf, to '/tmp/temp.mxf': Stream #0.0: Video: dnxhd, yuv422p, 1920x1080, q=2-31, 36000 kb/s, 90k tbn, 24 tbc Stream mapping: Stream #0.0 -> #0.0 [mxf @ 0x1005800]unsupported video frame rate Could not write header for output file #0 (incorrect codec parameters ?) There are a few things in here that concern me: The output stream is insisting on being yuv422p, which doesn't support alpha. 24fps is an unsupported video frame rate? I've tried 23.976 too, and get the same thing. I then tried the same thing, but writing to a quicktime (still DNxHD, though) with: ffmpeg -y -f image2 -i /tmp/temp.%04d.png -s 1920x1080 -r 24 -vcodec dnxhd -f mov -pix_fmt rgb32 -b 36Mb /tmp/temp.mov This gives me the output: Input #0, image2, from '/tmp/1274263259.28098.%04d.png': Duration: 00:00:01.60, start: 0.000000, bitrate: N/A Stream #0.0: Video: png, rgb32, 1920x1080, 25 tbr, 25 tbn, 25 tbc Output #0, mov, to '/tmp/1274263259.28098.mov': Stream #0.0: Video: dnxhd, yuv422p, 1920x1080, q=2-31, 36000 kb/s, 90k tbn, 24 tbc Stream mapping: Stream #0.0 -> #0.0 Press [q] to stop encoding frame= 39 fps= 9 q=1.0 Lsize= 7177kB time=1.62 bitrate=36180.8kbits/s video:7176kB audio:0kB global headers:0kB muxing overhead 0.013636% Which obviously works, to a certain extent, but still has the issue of being yuv422p, and therefore losing the alpha. If I'm going to QuickTime, then I can get what I need using Shake, but my main aim here is to be able to generate .mxf files. Any thoughts? Thanks

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  • Would a USB hub work in reverse?

    - by Tim
    Imagine for a moment with a 4 port USB hub. Normally how this would work is the hub has one plug that goes to the computer, then 4 ports that you can plug in other things to (thumb drive, keyboard, mouse etc). I am wondering if I can use it in reverse. So I would have 1 keyboard going in to the hub, and then plug in male to male usb cables from the 4 ports to 4 different PCs, my aim is that when a key is pressed on the keyboard all 4 PCs will receive it as if the keyboard were plugged in to them. Does anyone know if this would work? And if not does anyone have any ideas how I could get the same effect? EDIT: So I am looking for more of a KVM switch type device rather than a USB hub. However all of the KVM switches I've found use some sort of mechanism to select which computer you'll be using. (some are physical switches / buttons, others do it via software "automatically" some how) However I need to have 1 keyboard hooked up to 2 computers and when I press a key on the keyboard I want the keypress to be sent to both computers simultaneously, not to one or the other. Does anyone know if KVMs with this feature exist?

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  • What arguments do I send a function being called by a button in python?

    - by Jared
    I have a UI, in that UI is 4 text fields and 1 int field, then I have a function that calls to another function based on what's inside of the text fields, this function has (self, *args). My function that is being called to takes five arguments and I don't know what to put in it to make it actually work with my UI because python button's send an argument of their own. I have tried self and *args, but it doesn't work. Here is my code, didn't include most of the UI code since it is self explanatory: def crBC(self, IKJoint, FKJoint, bindJoint, xQuan, switch): ''' You should have a controller with an attribute 'ikFkBlend' - The name can be changed after the script executes. Controller should contain an enum - FK/DYN(0), IK(1). Specify the IK joint, then either the dynamic or FK joint, then the bind joint. Then a quantity of joints to pass through and connect. Tested currently on 600 joints (200 x 3), executed in less than a second. Returns nothing. Please open your script editor for details. ''' import itertools # gets children joints of the selected joint chHipIK = cmds.listRelatives(IKJoint, ad = True, type = 'joint') chHipFK = cmds.listRelatives(FKJoint, ad = True, type = 'joint') chHipBind = cmds.listRelatives(bindJoint, ad = True, type = 'joint') # list is built backwards, this reverses the list chHipIK.reverse() chHipFK.reverse() chHipBind.reverse() # appends the initial joint to the list chHipIK.append(IKJoint) chHipFK.append(FKJoint) chHipBind.append(bindJoint) # puts the last joint at the start of the list because the initial joint # was added to the end chHipIK.insert(0, chHipIK.pop()) chHipFK.insert(0, chHipFK.pop()) chHipBind.insert(0, chHipBind.pop()) # pops off the remaining joints in the list the user does not wish to be blended chHipBind[xQuan:] = [] chHipIK[xQuan:] = [] chHipFK[xQuan:] = [] # goes through the bind joints, makes a blend colors for each one, connects # the switch to the blender for a, b, c in itertools.izip(chHipBind, chHipIK, chHipFK): rotBC = cmds.shadingNode('blendColors', asUtility = True, n = a + 'rotate_BC') tranBC = cmds.shadingNode('blendColors', asUtility = True, n = a + 'tran_BC') scaleBC = cmds.shadingNode('blendColors', asUtility = True, n = a + 'scale_BC') cmds.connectAttr(switch + '.ikFkSwitch', rotBC + '.blender') cmds.connectAttr(switch + '.ikFkSwitch', tranBC + '.blender') cmds.connectAttr(switch + '.ikFkSwitch', scaleBC + '.blender') # goes through the ik joints, connects to the blend colors cmds.connectAttr(b + '.rotate', rotBC + '.color1', force = True) cmds.connectAttr(b + '.translate', tranBC + '.color1', force = True) cmds.connectAttr(b + '.scale', scaleBC + '.color1', force = True) # connects FK joints to the blend colors cmds.connectAttr(c + '.rotate', rotBC + '.color2') cmds.connectAttr(c + '.translate', tranBC + '.color2') cmds.connectAttr(c + '.scale', scaleBC + '.color2') # connects blend colors to bind joints cmds.connectAttr(rotBC + '.output', a + '.rotate') cmds.connectAttr(tranBC + '.output', a + '.translate') cmds.connectAttr(scaleBC + '.output', a + '.scale') ------------------- def execCrBC(self, *args): g.crBC(cmds.textField(self.ikJBC, q = True, tx = True), cmds.textField(self.fkJBC, q = True, tx = True), cmds.textField(self.bindJBC, q = True, tx = True), cmds.intField(self.bQBC, q = True, v = True), cmds.textField(self.sCBC, q = True, tx = True)) ------------------- self.bQBC = cmds.intField() cmds.text(l = '') self.sCBC = cmds.textField() cmds.text(l = '') cmds.button(l = 'Help Docs', c = self.crBC.__doc__) cmds.setParent('..') cmds.button(l = 'Create', c = self.execCrBC) Here is the code causing the problem as requested: import maya.cmds as cmds import jtRigUI.createDummyRig as dum import jtRigUI.createSkeleton as sk import jtRigUI.generalUtilities as gu import jtRigUI.createLegRig as lr import jtRigUI.createArmRig as ar class RUI(dum.Dict, dum.Dummy, sk.Skel, sk.FiSkel, lr.LeanLocs, lr.LegRig, ar.ArmRig, gu.Gutils): def __init__(self, charNameUI, gScaleUI, fingButtonGrp, thumbCheckBox, spineButtonGrp, neckButtonGrp, ikJBC, fkJBC, bindJBC, bQBC, sCBC): rigUI = 'rigUI' if cmds.window(rigUI, exists = True): cmds.deleteUI(rigUI) rigUI = cmds.window(rigUI, t = 'JT Rigging UI', sizeable = False, tb = True, mnb = False, mxb = False, menuBar = True, tlb = True, nm = 5) form = cmds.formLayout() tabs = cmds.tabLayout(innerMarginWidth = 1, innerMarginHeight = 1) rigUIMenu = cmds.menu('Help', hm = True) aboutMenu = cmds.menuItem('about') cmds.popupMenu('about', button = 1) deleteUIMenu = cmds.menu('Delete', hm = True) cmds.menuItem('dummySkeleton') cmds.formLayout(form, edit = True, attachForm = ((tabs, 'top', 0), (tabs, 'left', 0), (tabs, 'bottom', 0), (tabs, 'right', 0)), w = 30) tab1 = cmds.rowColumnLayout('Dummy') #cmds.columnLayout(rowSpacing = 10) #cmds.setParent('..') cmds.frameLayout(l = 'A: Dummy Skeleton Setup', w = 400) self.charNameUI = cmds.textFieldGrp (label="Optional Character Name:", ann="Insert a name for the character or leave empty.", tx = '', w = 1) fingJUI = cmds.frameLayout(l = 'B: Number of Fingers', w = 10) cmds.text('\n', h = 5) self.fingButtonGrp = cmds.radioButtonGrp('fingRadio', p = fingJUI, l = 'Fingers: ', sl = 4, w = 1, numberOfRadioButtons = 4, labelArray4 = ['One', 'Two', 'Three', 'Four'], ct2 = ('left', 'left'), cw5 = [60,60,60,60,60]) self.thumbCheckBox = cmds.checkBoxGrp(l = 'Thumb: ', v1 = True) cmds.text('\n', h = 5) spineJUI = cmds.frameLayout(l = 'C: Number of Spine Joints') cmds.text('\n', h = 5) self.spineButtonGrp = cmds.radioButtonGrp('spineRadio', p = spineJUI, l = 'Spine Joints: ', sl = 2, w = 1, numberOfRadioButtons = 3, labelArray3 = ['Three', 'Five', 'Ten'], ct2 = ('left', 'left'), cw4 = [95,95,95,95]) cmds.text('\n', h = 5) neckJUI = cmds.frameLayout(l = 'D: Number of Neck Joints') cmds.text('\n', h = 5) self.neckButtonGrp = cmds.radioButtonGrp('neckRadio', p = neckJUI, l = 'Neck Joints: ', sl = 0, w = 1, numberOfRadioButtons = 3, labelArray3 = ['Two', 'Three', 'Four'], ct2 = ('left', 'left'), cw4 = [95,95,95,95]) cmds.text('\n', h = 5) cmds.setParent('..') cmds.setParent('..') cmds.setParent('..') cmds.frameLayout('E: Creation') cmds.text('SAVE FIRST: CAN NOT UNDO', bgc = (0.2,0.2,0.2)) cmds.button(l = '\nCreate Dummy Skeleton\n', c = self.build) # also have it make char name field grey cmds.text('Elbows and Knees must have bend.', bgc = (0.2,0.2,0.2)) cmds.columnLayout() cmds.setParent('..') cmds.setParent('..') cmds.setParent('..') cmds.setParent('..') tab2 = cmds.rowColumnLayout('Skeleton') cmds.columnLayout(columnAttach = ('both', 5), rowSpacing = 10, columnWidth = 150) cmds.setParent('..') cmds.frameLayout(l = 'A: Skeleton Setup') cmds.text('SAVE FIRST: CAN NOT UNDO', bgc = (0.2,0.2,0.2)) cmds.button(l = '\nConvert to Skeleton - Orient - Set LRA\n', c = self.buildSkel) self.gScaleUI = cmds.textFieldGrp (label="Scale Multiplier:", ann="Scale multipler of Character: basis for all further base controllers", tx = '1.0', w = 1, ed = False, en = False, visible = True) cmds.frameLayout('B: Manual Orientation') cmds.text('You must manually check finger, thumb, leg, foot orientation specifically.\nConfirm rest of joints.\nSpine: X aim, Y point backwards from spine, Z to the side.\nFingers: X is aim, Y points upwards, Z to the side - Spread on Y, curl on Z.\nFoot: Pivots on Y, rolls on Z, leans on X.') cmds.columnLayout() cmds.setParent('..') cmds.frameLayout('C: Finalize Creation of Skeleton') cmds.button(l = '\nFinalize Skeleton\n', c = self.finishS) cmds.setParent('..') cmds.setParent('..') cmds.setParent('..') cmds.setParent('..') tab3 = cmds.rowColumnLayout('Legs') cmds.columnLayout(columnAttach = ('both', 5), rowSpacing = 10, columnWidth = 150) cmds.setParent('..') cmds.frameLayout(l = 'A: Leg Rig Setup') cmds.button(l = '\nGenerate Foot Lean Locators\n', c = self.makeLean) cmds.text('Place on either side of the foot.\nDo not rotate: Automatic orientation in place.') cmds.frameLayout(l = 'B: Rig Legs') cmds.button(l = '\nRig Legs\n', c = self.makeLegs) cmds.setParent('..') cmds.setParent('..') cmds.setParent('..') tab4 = cmds.rowColumnLayout('Arms') cmds.columnLayout(columnAttach = ('both', 5), rowSpacing = 10, columnWidth = 150) cmds.setParent('..') cmds.frameLayout(l = 'A: Arm Rig Setup') cmds.button(l = '\nA: Rig Arms\n', c = self.makeArms) cmds.setParent('..') cmds.setParent('..') tab5 = cmds.rowColumnLayout('Spine and Head') cmds.columnLayout(columnAttach = ('both', 5), rowSpacing = 10, columnWidth = 150) cmds.setParent('..') cmds.frameLayout(l = 'Spine Rig Setup') cmds.setParent('..') cmds.setParent('..') tab6 = cmds.rowColumnLayout('Stretchy IK') cmds.columnLayout(columnAttach = ('both', 5), rowSpacing = 10, columnWidth = 150) cmds.setParent('..') cmds.frameLayout(l = 'Stretchy Setup') cmds.setParent('..') cmds.setParent('..') tab6 = cmds.rowColumnLayout('Extras') cmds.scrollLayout(saw = 600, sah = 600, cr = True) cmds.columnLayout(columnAttach = ('both', 5), rowSpacing = 10, columnWidth = 150) cmds.setParent('..') cmds.frameLayout(l = 'General Utitlities') cmds.text('\nHere are all my general utilities for various things') cmds.frameLayout(l = 'Automatic Blend Colors Creation and Connection') cmds.rowColumnLayout(nc = 5, w = 10) cmds.text('IK Joint:') cmds.text(l = '') cmds.text('FK/Dyn Joint:') cmds.text(l = '') cmds.text('Bind Joint:') self.ikJBC = cmds.textField() cmds.text(l = '') self.fkJBC = cmds.textField() cmds.text(l = '') self.bindJBC = cmds.textField() cmds.text(' \nBlend Quantity:') cmds.text(l = '') cmds.text(' \nSwitch Control:') cmds.text(l = '') cmds.text(l = '') self.bQBC = cmds.intField() cmds.text(l = '') self.sCBC = cmds.textField() cmds.text(l = '') cmds.button(l = 'Help Docs', c = self.crBC.__doc__) cmds.setParent('..') cmds.button(l = 'Create', c = self.execCrBC) cmds.text(l = '') cmds.setParent('..') cmds.frameLayout(l = 'Make Spline IK Curve Stretch And Squash') cmds.rowColumnLayout(nc = 5, w = 10) cmds.text('Curve Name:') cmds.text(l = '') cmds.text('Setup Name:') cmds.text(l = '') cmds.text('Joint Quantity:') self.ikJBC = cmds.textField() cmds.text(l = '') self.fkJBC = cmds.textField() cmds.text(l = '') self.bindJBC = cmds.textField() cmds.text(' \nSwitch Control:') cmds.text(l = '') cmds.text(' \nGlobal Control:') cmds.text(l = '') cmds.text(l = '') self.bQBC = cmds.intField() cmds.text(l = '') self.sCBC = cmds.textField() cmds.text(l = '') cmds.button(l = 'Help Docs', c = self.crBC.__doc__) cmds.setParent('..') cmds.button(l = 'Create', c = self.execCrBC) cmds.setParent('..') cmds.showWindow(rigUI) r = RUI('charNameUI', 'gScaleUI', 'fingButtonGrp', 'thumbCheckBox', 'spineButtonGrp', 'neckButtonGrp', 'ikJBC', 'fkJBC', 'bindJBC', 'bQBC', 'sCBC') # last modified at 6.20 pm 29th June 2011

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  • Red Gate Coder interviews: Alex Davies

    - by Michael Williamson
    Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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  • 202 blog articles

    - by mprove
    All my blog articles under blogs.oracle.com since August 2005: 202 blog articles Apr 2012 blogs.oracle.com design patch Mar 2012 Interaction 12 - Critique Mar 2012 Typing. Clicking. Dancing. Feb 2012 Desktop Mobility in Hospitals with Oracle VDI /video Feb 2012 Interaction 12 in Dublin - Highlights of Day 3 Feb 2012 Interaction 12 in Dublin - Highlights of Day 2 Feb 2012 Interaction 12 in Dublin - Highlights of Day 1 Feb 2012 Shit Interaction Designers Say Feb 2012 Tips'n'Tricks for WebCenter #3: How to display custom page titles in Spaces Jan 2012 Tips'n'Tricks for WebCenter #2: How to create an Admin menu in Spaces and save a lot of time Jan 2012 Tips'n'Tricks for WebCenter #1: How to apply custom resources in Spaces Jan 2012 Merry XMas and a Happy 2012! Dec 2011 One Year Oracle SocialChat - The Movie Nov 2011 Frank Ludolph's Last Working Day Nov 2011 Hans Rosling at TED Oct 2011 200 Countries x 200 Years Oct 2011 Blog Aggregation for Desktop Virtualization Oct 2011 Oracle VDI at OOW 2011 Sep 2011 Design for Conversations & Conversations for Design Sep 2011 All Oracle UX Blogs Aug 2011 Farewell Loriot Aug 2011 Oracle VDI 3.3 Overview Aug 2011 Sutherland's Closing Remarks at HyperKult Aug 2011 Surface and Subface Aug 2011 Back to Childhood in UI Design Jul 2011 The Art of Engineering and The Engineering of Art Jul 2011 Oracle VDI Seminar - June-30 Jun 2011 SGD White Paper May 2011 TEDxHamburg Live Feed May 2011 Oracle VDI in 3 Minutes May 2011 Space Ship Earth 2011 May 2011 blog moving times Apr 2011 Frozen tag cloud Apr 2011 Oracle: Hardware Software Complete in 1953 Apr 2011 Interaction Design with Wireframes Apr 2011 A guide to closing down a project Feb 2011 Oracle VDI 3.2.2 Jan 2011 free VDI charts Jan 2011 Sun Founders Panel 2006 Dec 2010 Sutherland on Leadership Dec 2010 SocialChat: Efficiency of E20 Dec 2010 ALWAYS ON Desktop Virtualization Nov 2010 12,000 Desktops at JavaOne Nov 2010 SocialChat on Sharing Best Practices Oct 2010 Globe of Visitors Oct 2010 SocialChat about the Next Big Thing Oct 2010 Oracle VDI UX Story - Wireframes Oct 2010 What's a PC anyway? Oct 2010 SocialChat on Getting Things Done Oct 2010 SocialChat on Infoglut Oct 2010 IT Twenty Twenty Oct 2010 Desktop Virtualization Webcasts from OOW Oct 2010 Oracle VDI 3.2 Overview Sep 2010 Blog Usability Top 7 Sep 2010 100 and counting Aug 2010 Oracle'izing the VDI Blogs Aug 2010 SocialChat on Apple Aug 2010 SocialChat on Video Conferencing Aug 2010 Oracle VDI 3.2 - Features and Screenshots Aug 2010 SocialChat: Don't stop making waves Aug 2010 SocialChat: Giving Back to the Community Aug 2010 SocialChat on Learning in Meetings Aug 2010 iPAD's Natural User Interface Jul 2010 Last day for Sun Microsystems GmbH Jun 2010 SirValUse Celebration Snippets Jun 2010 10 years SirValUse - Happy Birthday! Jun 2010 Wim on Virtualization May 2010 New Home for Oracle VDI Apr 2010 Renaissance Slide Sorter Comments Apr 2010 Unboxing Sun Ray 3 Plus Apr 2010 Desktop Virtualisierung mit Sun VDI 3.1 Apr 2010 Blog Relaunch Mar 2010 Social Messaging Slides from CeBIT Mar 2010 Social Messaging Talk at CeBIT Feb 2010 Welcome Oracle Jan 2010 My last presentation at Sun Jan 2010 Ivan Sutherland on Leadership Jan 2010 Learning French with Sun VDI Jan 2010 Learning Danish with Sun Ray Jan 2010 VDI workshop in Nieuwegein Jan 2010 Happy New Year 2010 Jan 2010 On Creating Slides Dec 2009 Best VDI Ever Nov 2009 How to store the Big Bang Nov 2009 Social Enterprise Tools. Beipiel Sun. Nov 2009 Nov-19 Nov 2009 PDF and ODF links on your blog Nov 2009 Q&A on VDI and MySQL Cluster Nov 2009 Zürich next week: Swiss Intranet Summit 09 Nov 2009 Designing for a Sustainable World - World Usabiltiy Day, Nov-12 Nov 2009 How to export a desktop from VDI 3 Nov 2009 Virtualisation Roadshow in the UK Nov 2009 Project Wonderland at EDUCAUSE 09 Nov 2009 VDI Roadshow in Dublin, Nov-26, 2009 Nov 2009 Sun VDI at EDUCAUSE 09 Nov 2009 Sun VDI 3.1 Architecture and New Features Oct 2009 VDI 3.1 is Early-Access Sep 2009 Virtualization for MySQL on VMware Sep 2009 Silpion & 13. Stock Sommerparty Sep 2009 Sun Ray and VMware View 3.1.1 2009-08-31 New Set of Sun Ray Status Icons 2009-08-25 Virtualizing the VDI Core? 2009-08-23 World Usability Day Hamburg 2009 - CfP 2009-07-16 Rising Sun 2009-07-15 featuring twittermeme 2009-06-19 ISC09 Student Party on June-20 /Hamburg 2009-06-18 Before and behind the curtain of JavaOne 2009-06-09 20k desktops at JavaOne 2009-06-01 sweet microblogging 2009-05-25 VDI 3 - Why you need 3 VDI hosts and what you can do about that? 2009-05-21 IA Konferenz 2009 2009-05-20 Sun VDI 3 UX Story - Power of the Web 2009-05-06 Planet of Sun and Oracle User Experience Design 2009-04-22 Sun VDI 3 UX Story - User Research 2009-04-08 Sun VDI 3 UX Story - Concept Workshops 2009-04-06 Localized documentation for Sun Ray Connector for VMware View Manager 1.1 2009-04-03 Sun VDI 3 Press Release 2009-03-25 Sun VDI 3 launches today! 2009-03-25 Sun Ray Connector for VMware View Manager 1.1 Update 2009-03-11 desktop virtualization wiki relaunch 2009-03-06 VDI 3 at CeBIT hall 6, booth E36 2009-03-02 Keyboard layout problems with Sun Ray Connector for VMware VDM 2009-02-23 wikis.sun.com tips & tricks 2009-02-23 Sun VDI 3 is in Early Access 2009-02-09 VirtualCenter unable to decrypt passwords 2009-02-02 Sun & VMware Desktop Training 2009-01-30 VDI at next09? 2009-01-16 Sun VDI: How to use virtual machines with multiple network adapters 2009-01-07 Sun Ray and VMware View 2009-01-07 Hamburg World Usability Day 2008 - Webcasts 2009-01-06 Sun Ray Connector for VMware VDM slides 2008-12-15 mother of all demos 2008-12-08 Build your own Thumper 2008-12-03 Troubleshooting Sun Ray Connector for VMware VDM 2008-12-02 My Roller Tag Cloud 2008-11-28 Sun Ray Connector: SSL connection to VDM 2008-11-25 Setting up SSL and Sun Ray Connector for VMware VDM 2008-11-13 Inspiration for Today and Tomorrow 2008-10-23 Sun Ray Connector for VMware VDM released 2008-10-14 From Sketchpad to ILoveSketch 2008-10-09 Desktop Virtualization on Xing 2008-10-06 User Experience Forum on Xing 2008-10-06 Sun Ray Connector for VMware VDM certified 2008-09-17 Virtual Clouds over Las Vegas 2008-09-14 Bill Verplank sketches metaphors 2008-09-04 End of Early Access - Sun Ray Connector for VMware 2008-08-27 Early Access: Sun Ray Connector for VMware Virtual Desktop Manager 2008-08-12 Sun Virtual Desktop Connector - Insides on Recycling Part 2 2008-07-20 Sun Virtual Desktop Connector - Insides on Recycling Part 3 2008-07-20 Sun Virtual Desktop Connector - Insides on Recycling 2008-07-20 lost in wiki space 2008-07-07 Evolution of the Desktop 2008-06-17 Virtual Desktop Webcast 2008-06-16 Woodstock 2008-06-16 What's a Desktop PC anyway? 2008-06-09 Virtual-T-Box 2008-06-05 Virtualization Glossary 2008-05-06 Five User Experience Principles 2008-04-25 Virtualization News Feed 2008-04-21 Acetylcholinesterase - Second Season 2008-04-18 Acetylcholinesterase - End of Signal 2007-12-31 Produkt-Management ist... 2007-10-22 Usability Verbände, Verteiler und Netzwerke. 2007-10-02 The Meaning is the Message 2007-09-28 Visualization Methods 2007-09-10 Inhouse und Open Source Projekte – Usability verankern und Synergien nutzen 2007-09-03 Der Schwabe Darth Vader entdeckt das Virale Marketing 2007-08-29 Dick Hardt 3.0 on Identity 2.0 2007-08-27 quality of written text depends on the tool 2007-07-27 podcasts for reboot9 2007-06-04 It is the user's itch that need to be scratched 2007-05-25 A duel at reboot9 2007-05-14 Taxonomien und Folksonomien - Tagging als neues HCI-Element 2007-05-10 Dueling Interaction Models of Personal-Computing and Web-Computing 2007-03-01 22.März: Weizenbaum. Rebel at Work. /Filmpremiere Hamburg 2007-02-25 Bruce Sterling at UbiComp 2006 /webcast 2006-11-12 FSOSS 2006 /webcasts 2006-11-10 Highway 101 2006-11-09 User Experience Roundtable Hamburg: EuroGEL 2006 2006-11-08 Douglas Adams' Hyperland (BBC 1990) 2006-10-08 Taxonomien und Folksonomien – Tagging als neues HCI-Element 2006-09-13 Usability im Unternehmen 2006-09-13 Doug does HyperScope 2006-08-26 TED Talks and TechTalks 2006-08-21 Kai Krause über seine Freundschaft zu Douglas Adams 2006-07-20 Rebel At Work: Film Portrait on Weizenbaum 2006-07-04 Gabriele Fischer, mp3 2006-06-07 Dick Hardt at ETech 06 2006-06-05 Weinberger: From Control to Conversation 2006-04-16 Eye Tracking at User Experience Roundtable Hamburg 2006-04-14 dropping knowledge 2006-04-09 GEL 2005 2006-03-13 slide photos of reboot7 2006-03-04 Dick Hardt on Identity 2.0 2006-02-28 User Experience Newsletter #13: Versioning 2006-02-03 Ester Dyson on Choice and Happyness 2006-02-02 Requirements-Engineering im Spannungsfeld von Individual- und Produktsoftware 2006-01-15 User Experience Newsletter #12: Intuition Quiz 2005-11-30 User Experience und Requirements-Engineering für Software-Projekte 2005-10-31 Ivan Sutherland on "Research and Fun" 2005-10-18 Ars Electronica / Mensch und Computer 2005 2005-09-14 60 Jahre nach Memex: Über die Unvereinbarkeit von Desktop- und Web-Paradigma 2005-08-31 reboot 7 2005-06-30

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  • HintPath vs ReferencePath in Visual Studio

    - by toasteroven
    What exactly is the difference between the HintPath in a .csproj file and the ReferencePath in a .csproj.user file? We're trying to commit to a convention where dependency DLLs are in a "releases" svn repo and all projects point to a particular release. Since different developers have different folder structures, relative references won't work, so we came up with a scheme to use an environment variable pointing to the particular developer's releases folder to create an absolute reference. So after a reference is added, we manually edit the project file to change the reference to an absolute path using the environment variable. I've noticed that this can be done with both the HintPath and the ReferencePath, but the only difference I could find between them is that HintPath is resolved at build-time and ReferencePath when the project is loaded into the IDE. I'm not really sure what the ramifications of that are though. I have noticed that VS sometimes rewrites the .csproj.user and I have to rewrite the ReferencePath, but I'm not sure what triggers that. I've heard that it's best not to check in the .csproj.user file since it's user-specific, so I'd like to aim for that, but I've also heard that the HintPath-specified DLL isn't "guaranteed" to be loaded if the same DLL is e.g. located in the project's output directory. Any thoughts on this?

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  • 301 Redirect adding incorrect extra segments to a url

    - by Pentland_web
    I need to 301 redirect one segment of a url to a new version of it. My aim is redirect www.domain.co.uk/farm/whatever/ to www.domain.co.uk/farm_cottages/whatever/ The rule I am using to do this is: RedirectMatch 301 ^/farm/ /farm_cottages/ However for some reason it partially works but appends ?/farm/ after farm_cottages/ in the final url ie. www.domain.co.uk/farm_cottages/?/farm/whatever/ Here is my entire rewrite rule set as I believe one of the rewrite rules could be interfering with the redirect rule. #redirect /farm/ to /farm_cottages/ RedirectMatch 301 ^/farm/ /farm_cottages/ <IfModule mod_rewrite.c> RewriteEngine on # no WWW to WWW RewriteCond %{HTTP_HOST} !^www.domain.co.uk$ [NC] RewriteRule ^(.*)$ http://www.domain.co.uk/$1 [R=301,L] # Force trailing slash on URLs RewriteBase / RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_URI} !(.*)/$ RewriteRule ^(.*)$ http://www.domain.co.uk/$1/ [L,R=301] #Remove index.php RewriteCond $1 !\.(gif|jpe?g|png)$ [NC] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.*)$ /index.php?/$1 [L] RewriteCond %{THE_REQUEST} ^[^/]*/index\.php [NC] RewriteRule ^index\.php(.+) $1 [R=301,L] </IfModule> The site is built in Expressionengine and so the segments of url do not represent actual folders - I don't think this should matter though. Any ideas would be much appreciated! Thanks

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  • Applying Test Driven Development to a tightly coupled architecture

    - by Chris D
    Hi all, I've recently been studying TDD, attended a conference and have dabbled in few tests and already I'm 100% sold, I absolutely love it TDD. As a result I've raised this with my seniors and they are prepared to give it a chance, so they have tasked me with coming up with a way to implement TDD in the development of our enterprise product. The problem is our system has evolved since the days of VB6 to .NET and implements alot of legacy technology and some far from best practice development techniques i.e. alot of business logic in the ASP.NET code behind and client script. The largest problem however is how our classes are tightly coupled with database access; properties, methods, constructors - usually has some database access in some form or another. We use an in-house data access code generator tool that creates sqlDataAdapters that gives us all the database access we could ever want, which helps us develop extremely quickly, however, classes in our business layer are very tightly coupled to this data layer - we aren't even close to implementing some form of repository design. This and the issues above have created me all sorts of problems. I have tried to develop some unit tests for some existing classes I've already written but the tests take ALOT longer to run since db access is required, not to mention since we use the MS Enterprise Caching framework I am forced to fake a httpcontext for my tests to run successfully which isn't practical. Also, I can't see how to use TDD to drive the design of any new classes I write since they have to be soo tightly coupled to the database ... help! Because of the architecture of the system it appears I can't implement TDD without some real hack which in my eyes just defeats the aim of TDD and the huge benefits that come with. Does anyone have any suggestions how I could implement TDD with the constraints I'm bound too? or do I need to push the repository design pattern down my seniors throats and tell them we either change our architecture/development methodology or forget about TDD altogether? :) Thanks

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  • Handling multiple column data with Java

    - by Ender
    I am writing an application that reads in a large number of basic user details in the following format; once read in it then allows the user to search for a user's details using their email: NAME ROLE EMAIL --------------------------------------------------- Joe Bloggs Manager [email protected] John Smith Consultant [email protected] Alan Wright Tester [email protected] ... The problem I am suffering is that I need to store a large number of details of all people that have worked at the company. The file containing these details will be written on a yearly basis simply for reporting purposes, but the program will need to be able to access these details quickly. The way I aim to access these files is to have a program that asks the user for the name of the unique email of the member of staff and for the program to then return the name and the role from that line of the file. I've played around with text files, but am struggling with how I would handle multiple columns of data when it comes to searching this large file. What is the best format to store such data in? A text file? XML? The size doesn't bother me, but I'd like to be able to search it as quickly as possible. The file will need to contain a lot of entries, probably over the 10K mark over time.

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  • Session State with MVP and Application Controller patterns

    - by Graham Bunce
    Hi, I've created an MVP (passive view) framework for development and decided to go for an Application Controller pattern to manage the navigation between views. This is targeted at WinForms, ASP.NET and WPF interfaces. Although I'm not 100% convinced that these view technologies really swappable, that's my aim at the moment so my MVP framework is quite lightweight. What I'm struggling to fit in is the concept of a "Business Conversation" that needs state information to be either (a) maintained for the lifetime of the View or, more likely, (b) maintained across several views for the lifetime of a use case (business conversation). I want state management to be part of the framework as I don't want developers to worry about it. All they need to do is to "start" a conversation, "Register" objects and the framework does the rest until the "end" a conversation. Has anybody got any thoughts (patterns) to how to fit this into MVP? I was thinking it may be part of the Application Controller responsibility (delegating to a Conversation Manager object) as it knows about current state in order to send the user to the next view.... but then I thought it may be up to the Presenter to start and end the conversation so then it comes down the presenters to manage conversations and the objects registered for the that conversation. Unfortunately that means presenters can't be used in different conversations... so that idea doesn't seem right. As you can see, I don't think there is an easy answer (and I've looked for a while). So anybody else got any thoughts?

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  • SVM Classification - minimum number of input sets for each class

    - by Amol Joshi
    Im trying to build an app to detect images which are advertisements from the webpages. Once I detect those Ill not be allowing those to be displayed on the client side. From the help that I got here in stackoverflow, I thought SVM is the best approach to my aim. So, I have coded SVM and an SMO myself. The dataset which I have got from UCI data repository has 3280 instances ( Link to Dataset- http://archive.ics.uci.edu/ml/datasets/Internet+Advertisements )where around 400 of them are from class representing Advertisement images and rest of them representing non-advertisement images. Right now Im taking the first 2800 input sets and training the SVM. But after looking at the accuracy rate I realised that most of those 2800 input sets are from non-advertisement image class. So Im getting very good accuracy for that class. So what can I do here? About how many input set shall I give to SVM to train and how many of them for each class? Thanks. Cheers. ( Basically made a new question because the context was different from my previous question. http://stackoverflow.com/questions/1991113/optimization-of-neural-network-input-data )

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  • trouble accessing non-static functions from static functions in AS3

    - by Dogmatixed
    I have a class containing, among other things, a drop down menu. With the aim of saving space, and since the contents of the menu will never change, I've made a static DataProvider for the whole class that populates each instances menu. I was hoping to populate the list with actual functions like so: tmpArr.push({label:"Details...", funct:openDetailsMenu, args:""}); and then assign tmpArr to the DataProvider. Because the DataProvider is static the function that contains that code also needs to be static, but the functions in the array are non-static. At first it didn't seem like a problem, because when the user clicks on a menu item the drop down menu can call a non-static "executeFunction(funct, args)" on its parent. However, when I try to compile, the static function setting up the DataProvider it can't find the non-static functions being passed. If the compiler would just trust me the code would work fine! The simple solution is to just pass strings and use a switch statement to call functions based on that, but that's big, ugly, inelegant, and difficult to maintain, especially if something inherits from this class. The simpler solution is to just make the DataProvider non-static, but I'm wondering if anyone else has a good way of dealing with this? Making the static function able to see its non-static brethren? Thanks.

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  • Sentiment analysis for twitter in python

    - by Ran
    I'm looking for an open source implementation, preferably in python, of Textual Sentiment Analysis (http://en.wikipedia.org/wiki/Sentiment_analysis). Is anyone familiar with such open source implementation I can use? I'm writing an application that searches twitter for some search term, say "youtube", and counts "happy" tweets vs. "sad" tweets. I'm using Google's appengine, so it's in python. I'd like to be able to classify the returned search results from twitter and I'd like to do that in python. I haven't been able to find such sentiment analyzer so far, specifically not in python. Are you familiar with such open source implementation I can use? Preferably this is already in python, but if not, hopefully I can translate it to python. Note, the texts I'm analyzing are VERY short, they are tweets. So ideally, this classifier is optimized for such short texts. BTW, twitter does support the ":)" and ":(" operators in search, which aim to do just this, but unfortunately, the classification provided by them isn't that great, so I figured I might give this a try myself. Thanks! BTW, an early demo is here and the code I have so far is here and I'd love to opensource it with any interested developer.

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  • Computer science final year project ideas

    - by roul
    I'm a Computer Science undergraduate student in UK and should be deciding the subject of my final year project soon. The school is pretty flexible with the subject... "The topic can be any area of the subject which is of mutual interest to both the student and supervisor. Topics can range from purely theoretical studies to practical work building a system for some third party, although most projects aim to provide a balance between the theoretical and practical aspects of the subject." ...so I'm a bit lost since I want to do something in software engineering but have no idea what (subject) or with what (languages)! :) a) Languages: I've had experience with Java, C# and ASP.NET mostly but I would definitely be interested in learning new languages/frameworks. I'm kind of drawn by the idea of dynamic languages at the moment so IronPython seems likely. b) Subject: Anything that will keep me interested through the year and will give me the opportunity to learn a lot of stuff. Maybe something that has to do with music, or a fancy website, or a website about music :P anything really. Open to any thoughts/ideas, geeky or cool! Edit: Professors do usually supervise projects in their research areas but I currently have the choice to approach any of them according to my interest - whatever that is.

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  • QuickFix Component in Eclipse

    - by Daro Royoss
    My aim is to extend the eclipse QuickFix component and automate the process of solving syntax errors. Basically, the QuickFix component provides a list of solutions and my task is to select the best possible fix and apply it to the buggy code. But, for now I've been requested to print the resolutions for a marker in the console. I've tried to work out a tutorial and I'm kind of stuck right now. The tutorial I've tried to workout is: http://www.informit.com/articles/article.aspx?p=370625&seqNum=21 I've first added the extension in my plugin.xml file <extension point="org.eclipse.ui.ide.markerResolution"> <markerResolutionGenerator markerType="org.eclipse.core.resources.problemmarker" class="org.eclipse.escript.quickfix.QuickFixer"/> </extension> Then i have created the two classes QuickFixer and QuickFix. package quickfixer; import org.eclipse.core.resources.IMarker; import org.eclipse.core.runtime.CoreException; import org.eclipse.ui.IMarkerResolution; import org.eclipse.ui.IMarkerResolutionGenerator; class QuickFixer implements IMarkerResolutionGenerator { public IMarkerResolution[] getResolutions(IMarker arg0) { try { Object problem = arg0.getAttribute("Whatsup"); return new IMarkerResolution[] { new QuickFix("Fix #1 for "+problem), new QuickFix("Fix #2 for "+problem), }; } catch(CoreException e) { return new IMarkerResolution[0]; } } } then the class QuickFix: package quickfixer; import org.eclipse.core.resources.IMarker; import org.eclipse.jface.dialogs.MessageDialog; import org.eclipse.ui.IMarkerResolution; public class QuickFix implements IMarkerResolution { String label; QuickFix(String label) { this.label = label; } public String getLabel() { return label; } public void run(IMarker arg0) { MessageDialog.openInformation(null, "QuickFix Demo", "This quick-fix is not yet implemented"); System.out.println("Label: " + label); } } I've managed to correct all the errors i encountered and then i have run the plugin. I have not been able to get the label printed out in the console.Any suggestions???...

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  • Accessing a com object's vtable in c#

    - by Martin Booth
    I'm attempting to access a com object's vtable in memory and getting nowhere. From what I have read, the first 4 bytes in memory of a com object should be a pointer to the vtableptr, which in turn is a pointer to the vtable. Although I'm not sure I expect to find my test method at slot 7 in this com object I have tried them all and nothing looks like the address of my function. If anyone can make the necessary changes to this sample to get it to work (the aim is just to try and invoke the Test method on the Tester class by accessing the com object's vtable and locating the method in whichever row it turns up) I would be very grateful. I know it is rare that anyone would need to do this, but please accept I do need to do something quite similar and have considered the alternatives Thanks in advance [ComVisible(true)] public class Tester { public void Test() { MessageBox.Show("Here"); } } public delegate void TestDelegate(); private void main() { Tester t = new Tester(); GCHandle objectHandle = GCHandle.Alloc(t); IntPtr objectPtr = GCHandle.ToIntPtr(objectHandle); IntPtr vTable = (IntPtr)Marshal.ReadInt32(objectPtr); IntPtr vTablePtr = (IntPtr)Marshal.ReadInt32(vTable); IntPtr functionPtr = (IntPtr)Marshal.ReadInt32(vTablePtr, 7 * 4); // 7 may be incorrect but i have tried many different values TestDelegate func = (TestDelegate)Marshal.GetDelegateForFunctionPointer(functionPtr, typeof(TestDelegate)); func(); objectHandle.Free(); }

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  • including tk.h and tcl.h in c program

    - by user362075
    hi, i am working on an ubuntu system. My aim is to basically make an IDE in C language using GUI tools from TCL/TK. I installed tcl 8.4, tk8.4, tcl8.4-dev, tk8.4-dev and have the tk.h and tcl.h headers file in my system. But, when I am running a basic hello world program it's showing a hell lot of errors. include "tk.h" include "stdio.h" void hello() { puts("Hello C++/Tk!"); } int main(int, char *argv[]) { init(argv[0]); button(".b") -text("Say Hello") -command(hello); pack(".b") -padx(20) -pady(6); } Some of the errors are tkDecls.h:644: error: expected declaration specifiers before ‘EXTERN’ /usr/include/libio.h:488: error: expected ‘)’ before ‘*’ token In file included from tk.h:1559, from new1.c:1: tkDecls.h:1196: error: storage class specified for parameter ‘TkStubs’ tkDecls.h:1201: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘attribute’ before ‘*’ token /usr/include/stdio.h:145: error: storage class specified for parameter ‘stdin’ tk.h:1273: error: declaration for parameter ‘Tk_PhotoHandle’ but no such parameter Can anyone please tell me how can I rectify these errors? Please help...

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  • including tk.h and tcl.h in c program

    - by user362075
    hi, i am working on an ubuntu system. My aim is to basically make an IDE in C language using GUI tools from TCL/TK. I installed tcl 8.4, tk8.4, tcl8.4-dev, tk8.4-dev and have the tk.h and tcl.h headers file in my system. But, when I am running a basic hello world program it's showing a hell lot of errors. include "tk.h" include "stdio.h" void hello() { puts("Hello C++/Tk!"); } int main(int, char *argv[]) { init(argv[0]); button(".b") -text("Say Hello") -command(hello); pack(".b") -padx(20) -pady(6); } Some of the errors are tkDecls.h:644: error: expected declaration specifiers before ‘EXTERN’ /usr/include/libio.h:488: error: expected ‘)’ before ‘*’ token In file included from tk.h:1559, from new1.c:1: tkDecls.h:1196: error: storage class specified for parameter ‘TkStubs’ tkDecls.h:1201: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘attribute’ before ‘*’ token /usr/include/stdio.h:145: error: storage class specified for parameter ‘stdin’ tk.h:1273: error: declaration for parameter ‘Tk_PhotoHandle’ but no such parameter Can anyone please tell me how can I rectify these errors? Please help...

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  • Flex - Drag and drop - Drop a subset of multiple items

    - by flanagann
    I'm developing two DataGrid with drag and drop support. Multiple items can be selected from the source data grid, and dropped into the target data grid. I'm using an drag and drop event listener which completes the operation only in certain cases. I'm using event.preventDefault() but it doesn't work, since it stops the drag and drop from all the items. My aim is, for example, finally dropping 2 elements from the total 4 elements that I previously selected. public function onDropPermission(event:DragEvent):void { var sourceGrid:mx.controls.DataGrid = new mx.controls.DataGrid(); sourceGrid = event.dragInitiator as mx.controls.DataGrid; var targetGrid:mx.controls.DataGrid = new mx.controls.DataGrid(); targetGrid = event.target as mx.controls.DataGrid; var i:int; for (i = 0; i < sourceGrid.selectedIndices.length; i++) { var j:int; for (j = 0; j < dataGroupPermissions.length; j++) { var permission:Permission = new Permission; permission = dataGroupPermissions[j] as Permission; if (permission.id == sourceGrid.selectedItems[i].id) { event.preventDefault(); } } } }

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  • Locking semaphores in C problem sys/sem

    - by Vojtech R.
    Hi, I have problem with my functions. Sometimes two processes enter into critical section. I can't find problem in this after I spent 10 hours by debugging. On what I should aim? // lock semaphore static int P(int sem_id) { struct sembuf sem_b; sem_b.sem_num = 0; sem_b.sem_op = -1; /* P() */ sem_b.sem_flg = 0; if (semop(sem_id, &sem_b, 1) == -1) { print_error("semop in P", errno); return(0); } return(1); } // unlock semaphore static int V(int sem_id) { struct sembuf sem_b[1]; sem_b.sem_num = 0; sem_b.sem_op = 1; /* V() */ sem_b.sem_flg = 0; if (semop(sem_id, &sem_b, 1) == -1) { print_error("semop in V", errno); return(0); } return(1); } The action loop: int mutex; if ((mutex=semget(key, 1, 0666))>=0) { // semaphore exists } while(1) { P(mutex); assert(get_val(mutex)==0); (*action)++; V(mutex); } Many thanks

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