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  • ntop to analyse bandwidth usage on multiple ASA 5505

    - by dunxd
    I have set up a netflow server at our data centre, which is connected via VPN to ~40 remote offices using Cisco ASA 5505. The aim is to analyse usage data and find out exactly how the remote connections are being used. I followed through http://techowto.files.wordpress.com/2008/09/ntop-guide.pdf to set up ntop and https://supportforums.cisco.com/docs/DOC-6114 to set up the ASAs. I can see from the Plugin Netflow Statistics page that netflow packets from my ASAs are being received - the counter is increasing. However, I am not seeing any breakdown on the Global Traffic Statistic page after switching to the Netflow interface. I'm just seeing a pie chart showing 100% traffic for eth0. The interfaces and documentation are a little hard to follow so I am not sure I have got things configured correctly. When setting up my NetFlow-device.2 I can specify Virtual NetFlow Interface Network Address - the web UI says This value is in the form of a network address and mask on the network where the actual NetFlow probe is located. is this a Network address (e.g. 192.168.0.0/24) or an actual host IP address (192.167.0.1/24)? If that should be a network address, is this the network in which one of my ASAs is or the network in which my ntop server is? If a host IP address, is this the IP address used by eth0 on my ntop server, the IP address of an ASA, or something else? Do I need a separate virtual interface for each ASA I am collecting netflow data from? Any guidance would be greatly welcome.

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  • Remote desktop type software that the client need not install anything...

    - by allentown
    I am primarily a Macintosh user, and can usually walk a client though any troubles they may have because I have a Macintosh in front of me. If they are on a different OS, things are close enough, or I cam remember, that I can get by. When trying to help clients on Windows, I get stuck. I do not have access to windows, and even if I did, there are far too many versions of Outlook, all with their various esoteric settings and checkboxes, that I could never see exactly what they are seeing. I mostly need to just help them with email setup. Something like copilot.com may do the trick. What is the simplest remote control software out there, ideally, it would accomplish these: No software needed on remote end, or, a single .exe that they can toss when done. I need Mac based software on my end. I do have ARD, which support VNC Free :) If possible, it would be really nice Needs a port forwarding proxy run by the company. There is no way I can get the user to alter their router, or to even plug directly into their WAN for a short time. On the Mac, I just have them open iChat, and this is all built in, proxying through AIM, looking for the same for Windows and Mac.

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  • Free tiered storage automation in linux?

    - by NginUS
    I have a couple virtualized fileservers running in QEMU/KVM on ProxmoxVE. The physical host has 4 storage tiers with significant performance variances. They're attached both locally and via NFS. These will be provided to the fileserver(s) as local disks, abstracted into pools, and handling multiple streams of data for the network. My aim is for this abstraction layer to intelligently pool the tiers. There's a similar post on the site here: Home-brew automatic tiered storage solutions with Linux? (Memory - SSD - HDD - remote storage) in which the accepted answer was a suggestion to abandon a linux solution for NexentaStor. I like the idea of running NexentaStor. It almost fits the bill. NexentaStor provides Hybrid Storage Pools, and I love the idea of checksumming. 16TB without incurring licensing fees is a huge plus as well. After the expense of the hardware, free is about all my budget can handle. I don't know if zfs pools are adaptive or dynamically allocated based on load, but it becomes irrelevant since NexentaStor doesn't support virtio network or block drivers, which is a must in my environment. Then I saw a commercial solution called SmartMove: http://www.enigmadata.com/smartmove.html And it looks like a step in the right direction, but I'm so broke I'd be wasting their time to even ask for a quote, so I'm looking for another option. I'm after a linux implementation that supports virtio drivers, and I'm at a loss as to which software is up to it.

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  • How to debug a kernel created using ubuntu-vm-builder?

    - by user265592
    Aim: Trying to perform a code walkthrough of what functions are getting called for sending and receiving packets over the network. I am building a kernel and using gdb for debugging/ tracing purposes. I have build a vm using the following command : time sudo ubuntu-vm-builder qemu precise --arch 'amd64' --mem '1024' --rootsize '4096' --swapsize '1024' --kernel-flavour 'generic' --hostname 'ubuntu' --components 'main' --name 'Bob' --user 'ubuntu' --pass 'ubuntu' --bridge 'br0' --libvirt 'qemu:///system' And I can run the VM successfully in qemu using the following command: qemu-system-x86_64 -smp 1 -drive file=tmpGgEOzK.qcow2 "$@" -net nic -net user -serial stdio -redir tcp:2222::22 Now, I want to debug the kernel using gdb. For this I need an executable with debug symbols(vmlinux), which apparently I don't have, as the vm-builder never asked for any such options and simply created a .qcow2 file. Question 1: Am I taking the correct approach to solve the problem and is there an easier way to do it? Question 2: Is there a way to debug this kernel using GDB? P.S: I don't have hardware support for KVM. Please correct me if I am wrong. Thanks.

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  • [tcpdump] Proxy delegate refusing connexion ?

    - by simtris
    Hi guys, I'm a little disapointed ! My aim was to build a VERY simple smtp proxy under debian to handle mail from a port (51234) and forward it to the standard 25 port. I compile and install a "delegate" witch can handle easily that. It's working very well like that : delegated SERVER="smtp://anotherSmtpServer:25" -P51234 The strange thing is, it's working on my virtual test machine and on the dedicated server in local but I can't manage to use it trought internet. I test it like that. telnet [mySrv] 51234 Of course, no firewal, no deny host, no ined/xined, the service delegated is listening on the right port ... 2 clues : The port is answering trought internet with nmap as "51234/tcp open tcpwrapped" have a look at the tcpdump following : 22:50:54.864398 IP [myIp].1699 [mySrv].51234: S 2486749330:2486749330(0) win 65535 22:50:54.864449 IP [mySrv].51234 [myIp].1699: S 2486963525:2486963525(0) ack 2486749331 win 5840 22:50:54.948169 IP [myIp].1699 [mySrv].51234: . ack 1 win 64240 22:50:54.965134 IP [mySrv].43554 [myIp].auth: S 2485396968:2485396968(0) win 5840 22:50:55.243128 IP [myIp] [mySrv]: ICMP [myIp] tcp port auth unreachable, length 68 22:50:55.249646 IP [mySrv].51234 [myIp].1699: F 1:1(0) ack 1 win 46 22:50:55.309853 IP [myIp].1699 [mySrv].51234: . ack 2 win 64240 22:50:55.310126 IP [myIp].1699 [mySrv].51234: F 1:1(0) ack 2 win 64240 22:50:55.310137 IP [mySrv].51234 [myIp].1699: . ack 2 win 46 The part "auth" seems suspect to me but didn't ring a bell. I could certaily do with some help. Thx a lot !

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  • Varnish, Nginx, Apache, APC, Meteor, Cpanel & Wordpress On A Single Server, Any Good?

    - by Aahan
    Yes, I have read many close questions, but I needed a specific answer and hence this question. First, these are my new server specifications: Linux Server (CentOS), Intel Xeon 3470 Quad Core (2.93GHz x 4) processor, 4 GB DDR3 Memory, 1TB Hard Disk Space, 10 TB Bandwidth and 9 Dedicated IPs. AIM: To speed up my wordpress blog + Increase server's capacity to handle heavy load PLAN: This is how I am planning to setup my server - - VARNISH (in the front, to cache server responses) NGINX (to effectively handle static content & overcome the C10k problem) APACHE (behind Nginx, to effectively deliver dynamic content) APC (PHP page, database & object caching) CPANEL (which requires Apache, and I require it) WORDPRESS W3 TOTAL CACHE (caching plugin for Wordpress). So , will the setup work? Have anyone tried it? Please shower your thoughts and knowledge. NOTE: I can't do without Apache because I am used to that .htaccess & Cpanel stuff. So, it's not any option. All others are options. Please try to help. I hope I am clear in what I wanted to ask.

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  • OpenLDAP ACLs are not working

    - by Dr I
    First things first, I'm currently working with an OpenLDAP: slapd 2.4.36 on a Fedora release 19 (Schrödinger’s Cat). I've just install the openldap with yum and my configuration is the following one: ##### OpenLDAP Default configuration ##### # ##### OpenLDAP CORE CONFIGURATION ##### include /etc/openldap/schema/core.schema include /etc/openldap/schema/cosine.schema include /etc/openldap/schema/inetorgperson.schema include /etc/openldap/schema/nis.schema pidfile /var/lib/ldap/slapd.pid loglevel trace ##### Default Schema ##### database mdb directory /var/lib/ldap/ maxsize 1073741824 suffix "dc=domain,dc=tld" rootdn "cn=root,dc=domain,dc=tld" rootpw {SSHA}SECRETP@SSWORD ##### Default ACL ##### access to attrs=userpassword by self write by group.exact="cn=administrators,ou=builtin,ou=groups,dc=domain,dc=tld" write by anonymous auth by * none I launch my OpenLDAP service using: /usr/sbin/slapd -u ldap -h ldapi:/// ldap:/// -f /etc/openldap/slapd.conf As you can see it's a pretty simple ACL which aim to allow access to the userPassword attribute to a specific group read only, then to the owner read and write to anonymous requiring auth and refuse the access to everyone else. The problem is: Even using a valid user with correct password my ldapsearch ends with zero informations retrieved from the directory, plus I've got a strange response on the result line. # search result search: 2 result: 32 No such object # numResponses: 1 here is the ldapsearch request: ldapsearch -H ldap.domain.tld -W -b dc=domain,dc=tld -s sub -D cn=user,ou=service,ou=employees,ou=users,dc=domain,dc=tld I did not specify any filter as I want to check that ldapsearch is correctly printing only allowed attribute.

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  • What is the correct authentication mechanism when there are users inside and outside the domain?

    - by Gary Barrett
    We have a Windows 7 enterprise desktop data entry app for mobile (laptop) users with local SQL Express 2008 R2 Express db that syncs data with an SQL Server 2008 R2 Server db. Authentication is required before syncing the data. The existing group of users are part of the organisation's domain so normal scenario and they connect to the Sql Server directly. But there are plans for a second group of app users who belong to various partner organisations so they are outside our domain and have their own various separate domains/accounts. The aim is to deploy the desktop app to them and they will periodically sync data to our SQL Server. What I am uncertain of: Is it possible to authenticate users from another domain? Can permissions be managed via Active Directory etc? Which authentication protocol should be used in this scenario? Windows, Forms, SQL, etc? The IT people are requesting users of the system be managed via Active Directory. Is it possible to manage the external domain users access via Active Directory?

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  • Protect all XML-RPC calls with HTTP basic auth but one

    - by bodom_lx
    I set up a Django project for smartphone serving XML-RPC methods over HTTPS and using basic auth. All XML-RPC methods require username and password. I would like to implement a XML-RPC method to provide registration to the system. Obviously, this method should not require username and password. The following is the Apache conf section responsible for basic auth: <Location /RPC2> AuthType Basic AuthName "Login Required" Require valid-user AuthBasicProvider wsgi WSGIAuthUserScript /path/to/auth.wsgi </Location> This is my auth.wsgi: import os import sys sys.stdout = sys.stderr sys.path.append('/path/to/project') os.environ['DJANGO_SETTINGS_MODULE'] = 'project.settings' from django.contrib.auth.models import User from django import db def check_password(environ, user, password): """ Authenticates apache/mod_wsgi against Django's auth database. """ db.reset_queries() kwargs = {'username': user, 'is_active': True} try: # checks that the username is valid try: user = User.objects.get(**kwargs) except User.DoesNotExist: return None # verifies that the password is valid for the user if user.check_password(password): return True else: return False finally: db.connection.close() There are two dirty ways to achieve my aim with current situation: Have a dummy username/password to be used when trying to register to the system Have a separate Django/XML-RPC application on another URL (ie: /register) that is not protected by basic auth Both of them are very ugly, as I would also like to define a standard protocol to be used for services like mine (it's an open Dynamic Ridesharing Architecture) Is there a way to unprotect a single XML-RPC call (ie. a defined POST request) even if all XML-RPC calls over /RPC2 are protected?

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  • Protect all XML-RPC calls with HTTP basic auth but one

    - by bodom_lx
    I set up a Django project for smartphone serving XML-RPC methods over HTTPS and using basic auth. All XML-RPC methods require username and password. I would like to implement a XML-RPC method to provide registration to the system. Obviously, this method should not require username and password. The following is the Apache conf section responsible for basic auth: <Location /RPC2> AuthType Basic AuthName "Login Required" Require valid-user AuthBasicProvider wsgi WSGIAuthUserScript /path/to/auth.wsgi </Location> This is my auth.wsgi: import os import sys sys.stdout = sys.stderr sys.path.append('/path/to/project') os.environ['DJANGO_SETTINGS_MODULE'] = 'project.settings' from django.contrib.auth.models import User from django import db def check_password(environ, user, password): """ Authenticates apache/mod_wsgi against Django's auth database. """ db.reset_queries() kwargs = {'username': user, 'is_active': True} try: # checks that the username is valid try: user = User.objects.get(**kwargs) except User.DoesNotExist: return None # verifies that the password is valid for the user if user.check_password(password): return True else: return False finally: db.connection.close() There are two dirty ways to achieve my aim with current situation: Have a dummy username/password to be used when trying to register to the system Have a separate Django/XML-RPC application on another URL (ie: /register) that is not protected by basic auth Both of them are very ugly, as I would also like to define a standard protocol to be used for services like mine (it's an open Dynamic Ridesharing Architecture) Is there a way to unprotect a single XML-RPC call (ie. a defined POST request) even if all XML-RPC calls over /RPC2 are protected?

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  • Looking for issue tracker software for residential property management

    - by Rob
    This question is about a computer software (as per SU guidelines) application for centrally tracking issues concerning the management of a residental block of flats (apartments as they say in the US and France). Issues are incidents - and their resultant unplanned maintenance to address them, also planned one-off maintenance and also regular planned routine maintenance. I live in a block of flats (apartments), and along with other residents, are looking to more closely watch over issues with the communal, shared areas of the premises (corridors, courtyards, stairs, lifts, lights, trash/bin shed, bike stands, parking areas etc) and their maintenance, currently done by a property management company. Our own homes are our own affair internally, its the outside communal areas that I have the interest. The aim being to control costs and possibly reduce them, by proactively managing the property using historical data to predict issues and also to scrutinise maintenance charges against such data to ensure that the costs are as expected. Trending could also be established whereby recurrences of things can be detected and pre-empted to reduce costs. As a software professional, I'm aware of Bugzilla, eventum being free tools for software - which could be customised to fit this application, but wondered if there was something more appropriate. It might be useful for such software to be on a web server, with secure access, so that residents can log in and view the issues.

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  • How to disable monitor "sleep" on Ubuntu without access to X?

    - by exhuma
    I just received a CuBox (basically a tiny ARM based PC). It comes pre-installed with Ubuntu, and I did not (yet) want to fiddle with the OS itself. My aim is to have it automaticall start a browser in fullscrren upon boot. Using chromium with the "--kiosk" flag works perfectly in that regard. But now I have the problem that the screen turns off after a certain time. I managed to turn off the screen saver using: gconftool-2 -s /apps/gnome-screensaver/idle_activation_enabled --type=bool false And tried to turn off the power management using: gconftool-2 -s /apps/gnome-power-manager/ac_sleep_display --type=int 0 and gconftool-2 -s /apps/gnome-power-manager/timeout/sleep_display_ac --type=int 0 Neither of the power-management commands worked. Theoretically I could hook up a mouse and keyboard and configure it manually. But I want to learn how to do it over the console. The box will eventually be only reachable via SSH. So I'd like to be able to trouble-shoot it later. I don't quite know where to look for. I searched the gconf tree using gconftool-2 -S for anything related to the terms power, idle and sleep but did not find anything promising. Maybe it's not even gconf related... Any ideas what else I could look for?

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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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  • 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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